Aortic Dissection Diagnosis: A Comprehensive Guide for Clinicians

Introduction

Aortic dissection represents a critical and often fatal vascular emergency, characterized by a tear in the aortic intima, the innermost layer of the aortic wall. This tear allows blood to surge into the media layer, creating a false lumen and separating the aortic wall layers. This process can severely compromise blood flow to vital organs and lead to life-threatening complications. Prompt and accurate Diagnosis Of Aortic Dissection is paramount due to the condition’s high mortality rate, especially in its acute phase. Many individuals succumb to this condition before even reaching medical care. For those who survive to reach the hospital, rapid diagnosis and intervention are critical. Chronic aortic dissection, defined as present for more than two weeks, offers a slightly improved prognosis, but still requires careful management.

The classic presentation of acute aortic dissection is the sudden onset of excruciating, “tearing” chest pain. However, the clinical reality is often more nuanced, with subtle presentations frequently leading to delayed or missed diagnoses. Alarmingly, studies reveal that a significant proportion of aortic dissections are initially missed in the emergency department, with accurate diagnosis rates on first presentation ranging from a mere 15% to 43%. Without timely treatment, mortality escalates rapidly, approaching 50% within the first 48 hours of symptom onset. Despite its relative rarity compared to conditions like myocardial infarction, acute aortic dissection necessitates immediate diagnostic attention and a coordinated multidisciplinary healthcare approach. Outcomes are demonstrably better in specialized, high-volume centers equipped with experienced teams, established “aorta code” protocols, and dedicated aortic centers. Implementing a multidisciplinary strategy, integrating expertise from vascular surgery and cardiology, is crucial for enhancing patient outcomes in these critical situations. Aortic dissections are systematically classified using two primary anatomical systems: the Stanford and DeBakey classifications.

The Stanford classification system simplifies dissection categorization into two types based on the involvement of the ascending aorta (refer to Image. Stanford Classification of Aortic Dissection).

• Stanford Type A: This type involves the ascending aorta, irrespective of the location of the primary intimal tear. It is defined as any dissection proximal to the brachiocephalic artery (refer to Image. Type A Aortic Dissection).
• Stanford Type B: This type originates distal to the left subclavian artery and is confined to the descending aorta. Specifically, the Society for Vascular Surgery and the Society of Thoracic Surgeons define Stanford type B dissections as those where the entry tear is located beyond the origin of the innominate artery.

The DeBakey classification system further refines the categorization into three types, based on both the origin and the extent of the dissection:

• DeBakey Type 1: Originates in the ascending aorta and extends to involve the aortic arch and descending aorta.
• DeBakey Type 2: Originates in and remains localized to the ascending aorta.
• DeBakey Type 3: Begins in the descending aorta and extends distally, classified further into type 3a (above the diaphragm) and type 3b (below the diaphragm).

Ascending aortic dissections (Stanford type A or DeBakey types 1 and 2) are nearly twice as prevalent as descending dissections (Stanford type B or DeBakey type 3). This higher incidence underscores the urgency and specialized care required to mitigate the risk of fatal sequelae such as aortic rupture, stroke, or myocardial infarction (refer to Image. Aortic Dissection, Type A).

Figure: Stanford Classification of Aortic Dissection. This illustration visually differentiates between Stanford Type A and Type B aortic dissections, based on whether the ascending aorta is involved. Understanding these classifications is crucial for accurate diagnosis of aortic dissection. Image courtesy of Npatchett, Public Domain, via Wikimedia Commons.

Figure: Type A Aortic Dissection. This image illustrates a Type A aortic dissection, originating a few centimeters above the aortic valve and affecting the ascending aorta. This type of dissection necessitates urgent diagnosis of aortic dissection and surgical intervention. Contributed by F Farci, MD.

Figure: Aortic Dissection, Type A. Another visualization of a Type A aortic dissection, highlighting the tear above the aortic valve in the ascending aorta. Accurate diagnosis of aortic dissection type is critical for determining the appropriate treatment strategy. Contributed by F Farci, MD.

Etiology

Several predisposing factors elevate the risk of nontraumatic aortic dissection. Recognizing these risk factors is vital in the diagnosis of aortic dissection, especially in at-risk populations. These include:

• Hypertension: Chronic hypertension is a major risk factor, observed in approximately 70% of patients with distal Stanford type B dissections.
• Abrupt Blood Pressure Surge: Sudden, transient, and severe increases in blood pressure, such as those experienced during strenuous weight lifting or the use of sympathomimetic agents (e.g., cocaine, ecstasy, or energy drinks), can trigger aortic dissection.
• Genetic Conditions: Inherited connective tissue disorders significantly weaken the aortic wall, predisposing individuals to dissection.
  • Marfan Syndrome: A review by the International Registry of Acute Aortic Dissection (IRAD) revealed Marfan syndrome in 50% of patients younger than 40 years old, compared to only 2% in older patients. Cystic medial necrosis, a characteristic degeneration of the aortic media, is prevalent in Marfan syndrome.
  • Ehlers-Danlos Syndrome: This group of disorders affects collagen production, leading to weakened blood vessels.
  • Turner Syndrome: This chromosomal disorder in females is associated with various cardiovascular anomalies, including aortic abnormalities.
  • Bicuspid Aortic Valve: This congenital heart defect, where the aortic valve has two leaflets instead of three, is linked to aortic dilation and dissection.
  • Coarctation of the Aorta: A narrowing of the aorta can increase stress on the aortic wall, increasing dissection risk.
• Preexisting Aortic Aneurysm: An aneurysm weakens the aortic wall, making it more susceptible to tearing and dissection.
• Atherosclerosis: While less directly causative than hypertension, atherosclerosis contributes to aortic wall stiffness and vulnerability.
• Pregnancy and Delivery: The hemodynamic changes and hormonal influences of pregnancy and delivery, particularly in women with connective tissue disorders like Marfan syndrome, elevate dissection risk.
• Family History: A family history of aortic dissection or related aortic diseases increases individual risk.
• Aortic Instrumentation or Surgery: Prior procedures involving the aorta, such as coronary artery bypass grafting, valve replacement, or percutaneous interventions, can weaken the aortic wall or create entry points for dissection.
• Inflammatory or Infectious Diseases: Conditions causing vasculitis, such as syphilis and certain infections, as well as cocaine use, can inflame and weaken the aortic wall.

Epidemiology

Acute aortic dissection is a relatively rare but profoundly life-threatening condition. Its incidence ranges from 5 to 30 cases per 1 million people annually. To put this in perspective, acute myocardial infarction occurs at a rate of approximately 4400 cases per 1 million people each year, highlighting the comparative rarity of aortic dissection. Nevertheless, aortic dissection accounts for a significant proportion of emergency department visits for acute chest, back, or abdominal pain, representing about 3 out of every 1000 such presentations. The condition predominantly affects individuals between 40 and 70 years of age, with the highest incidence in the 50 to 65 age group. Approximately 75% of all aortic dissections occur within this age range, emphasizing age as a crucial risk factor in the diagnosis of aortic dissection.

While aortic dissection is three times more common in men than women, women often present later in the disease course and experience worse outcomes. The risk factor profile also differs between age groups. Older patients are more likely to have pre-existing hypertension, atherosclerosis, prior aortic aneurysm, or iatrogenic dissection. Younger patients, especially those under 40, are more frequently associated with connective tissue disorders like Marfan syndrome. Type A dissections, involving the ascending aorta, are twice as common as type B dissections and are considerably more fatal without urgent intervention, emphasizing the need for rapid diagnosis of aortic dissection in these cases. Hypertension is the most prevalent modifiable risk factor, present in approximately 75% of patients. Other significant risk factors include atherosclerosis, connective tissue disorders, and a history of cardiac surgery.

Pathophysiology

Aortic dissection initiates with a tear in the intimal layer of the aortic wall. This tear allows high-pressure arterial blood to penetrate into the aortic media, the middle layer, creating a false lumen. The aortic wall is composed of three layers: the intima, media, and adventitia. Chronic exposure to elevated pulsatile pressure and shear stress, especially in individuals with predisposing conditions, weakens these layers, culminating in the initial intimal tear. This tear most commonly occurs in the ascending aorta, particularly on the right lateral wall, where shear forces are maximal. Once the tear occurs, blood under arterial pressure enters between the intima and media, dissecting along the aortic wall and propagating the false lumen.

In most cases, the dissection extends either anterograde (distally) or retrograde (proximally). The direction of propagation dictates the types of complications that may arise. Distal propagation can obstruct blood flow to major aortic branches, leading to ischemia in territories supplied by the coronary, cerebral, spinal, or visceral arteries. Proximal propagation, characteristic of type A dissections, frequently leads to catastrophic, life-threatening complications such as acute aortic regurgitation, cardiac tamponade, or even aortic rupture. As the false lumen develops and expands, it typically becomes larger than the true lumen, further compromising true lumen flow and increasing the risk of aneurysm formation and eventual rupture if left untreated. The three most frequent sites for acute aortic dissection include:

• The ascending aorta approximately 2 to 2.5 cm above the aortic root (the most common site).
• The descending aorta just distal to the origin of the left subclavian artery.
• The aortic arch.

These dissections are highly lethal if not promptly recognized and treated, often resulting in death from aortic rupture or cardiac tamponade. Therefore, understanding the pathophysiology is crucial for effective diagnosis of aortic dissection and timely intervention.

Histopathology

Aortic dissection is an acute, life-threatening condition characterized by a tear in the aortic intima, allowing blood to flow between the layers of the aortic wall and create a false lumen. This false lumen forms between the intima-media and media-adventitia layers (refer to Image. Aortic Dissection Seen in Histology). This process can precipitate a sudden drop in systemic blood pressure and lead to catastrophic complications like hemopericardium and cardiac tamponade, potentially causing sudden death. Dissection commonly occurs in the outer one-third of the aortic media, a structurally vulnerable area due to chronic injury and repair processes often triggered by hemodynamic forces such as hypertension (refer to Image. Histologic Image of Aortic Dissection). The dissection can propagate in both anterograde and retrograde directions, potentially obstructing aortic branches and causing ischemia in organs like the brain, heart, or kidneys. Histopathological examination is essential for confirming the diagnosis of aortic dissection and understanding the underlying aortic wall pathology.

The media layer of the aorta, composed of smooth muscle cells, elastic fibers, collagen fibers, and extracellular matrix components like hyaluronic acid, undergoes pathological changes in the setting of chronic hypertension or genetic predisposition. These changes are collectively termed cystic medial degeneration and include:

• Mucoid Accumulation: An abnormal deposition of mucopolysaccharides within the aortic media, weakening its structural integrity.
• Alteration of Elastic Fibers: Elastic fibers are critical for maintaining the aorta’s elasticity and resistance to pulsatile pressure. In cystic medial degeneration, these fibers exhibit significant alterations:
  • Fragmentation: Elastic fibers break down into smaller segments, increasing the spaces between lamellar layers (translamellar spaces). This fragmentation weakens the aorta’s mechanical strength and elasticity, making it more prone to dissection.
  • Thinning: Elastic fibers become thinner, further weakening the vessel wall and widening the spaces between fibers. This thinning reduces the aorta’s overall resilience and increases susceptibility to dilation, aneurysm formation, and dissection.
  • Disorganization: The normally parallel arrangement of elastic fibers is disrupted. Disorganized fibers are haphazardly arranged and cannot effectively withstand pressure, leading to a loss of structural cohesion and increasing the risk of tears within the aortic wall.
• Altered Smooth Muscle Cells: Smooth muscle cells in the media undergo nuclear loss and disorganization.
  • Nuclear Cell Loss (Smooth Muscle Cell Necrosis): Smooth muscle cell necrosis can appear in bands or as wide areas where only ghost cell contours are visible.
  • Disarray of Smooth Muscle Cells: Smooth muscle cell disarray can be focal or nodular, disrupting the media’s structural organization.
• Laminar Medial Collapse: The collapse of elastic fibers, termed “laminar medial necrosis,” is coupled with a significant loss of interposed smooth muscle cells, indicating severe medial degeneration.
• Collagen Fibrosis: While less common in degenerative aortic disease, collagen fibers can become fibrotic, contributing to aortic stiffness and reduced elasticity.

These histopathological findings are often combined and must be carefully assessed to grade the severity of medial degeneration as mild, moderate, or severe. This grading, determined by evaluating the extent and distribution of degenerative lesions within the aortic wall, is crucial for understanding the underlying pathology and predicting potential outcomes. More severe degeneration is associated with a higher risk of complications such as aortic dissection or rupture. Histopathological evaluation using stains like Verhoeff-Van Gieson, Alcian blue, and Masson trichrome can effectively reveal the extent of these alterations, aiding in the accurate diagnosis of aortic dissection and risk stratification.

The vasa vasorum, a network of small vessels supplying the outer layers of the aortic wall, plays a critical role in maintaining the integrity of the media. Dysfunction of the vasa vasorum, such as obstruction or thickening, can lead to medial necrosis and contribute to the development of aortic dissection. Hypertension is the most significant risk factor for medial degeneration and aortic dissection, causing intimal thickening, aortic stiffness, and damage to elastic fibers. Aging further exacerbates these degenerative processes, with elastin loss, increased collagen deposition, and microcalcifications in the media, increasing dissection risk in older populations. This age-related degeneration is a primary physiological reason for the strong epidemiological correlation between age and aortic diseases like aneurysms and dissection. Genetic factors also significantly contribute to aortic dissection risk. Conditions such as Marfan syndrome, Ehlers-Danlos syndrome, and Loeys-Dietz syndrome result in altered elastic fiber meshwork, predisposing individuals to aneurysms and dissections. Congenital cardiovascular diseases, including bicuspid aortic valve, coarctation of the aorta, and tetralogy of Fallot, are also associated with structural abnormalities of the aortic wall, further increasing dissection risk.

Figure: Histologic Image of Aortic Dissection. This hematoxylin-eosin stained image, magnified 4x, shows an aortic dissection occurring in the outer one-third of the aortic media. Histological analysis is crucial in understanding the mechanisms of aortic dissection and refining the diagnosis of aortic dissection in complex cases. Contributed by F Farci, MD.

Figure: Aortic Dissection Seen in Histology. This histological image reveals an aortic dissection within the lamina media, with thrombotic residues in the false lumen indicating blood flow. Histopathology confirms the diagnosis of aortic dissection and helps differentiate it from other aortic pathologies. Image contributed by F Farci, MD.

History and Physical

Acute aortic dissection presents with a diverse array of symptoms that reflect the dissection’s extent and the specific cardiovascular structures involved. A detailed patient history is crucial in the diagnosis of aortic dissection, emphasizing three key elements: the quality, radiation, and intensity of pain at onset. Research has identified pain intensity at onset as one of the most reliable historical indicators for diagnosing acute aortic dissection. The classic presentation is a sudden, severe, tearing pain, reaching maximum intensity within minutes. The location of the pain can vary; anterior chest pain is more typical of dissections involving the ascending aorta, while back pain is more common in descending aortic dissections. Pain may also migrate as the dissection extends distally. Notably, in about 10% of cases, especially in individuals with Marfan syndrome, pain may be absent, complicating clinical recognition and the diagnosis of aortic dissection.

While severe chest or back pain is the hallmark symptom, aortic dissection can also manifest with neurological symptoms or limb ischemia, depending on the vessels involved. Clinical suspicion for acute aortic dissection should be heightened by the presence of chest pain combined with neurological deficits (such as stroke-like symptoms, limb weakness, or paresthesia), chest and abdominal pain, or chest pain accompanied by syncope. Neurological deficits are observed in approximately 20% of patients, and syncope is relatively common, potentially due to hypovolemia, arrhythmias, or myocardial infarction. If the dissection extends into peripheral vessels, symptoms such as loss of pulses, pain, and paresthesias in the extremities may occur. Physical examination findings are varied and can provide critical diagnostic clues. However, classical signs like blood pressure discrepancies between upper extremities, pulse deficits, or a diastolic murmur are present in less than 50% of confirmed acute aortic dissection cases. These signs, when present, should raise clinical suspicion, especially in combination with typical pain and neurological symptoms. Blood pressure discrepancies greater than 20 mm Hg between arms, a pulse deficit, or wide pulse pressure are significant red flags during physical examination, prompting further investigation for diagnosis of aortic dissection.

Hypertension is common in acute aortic dissection, but hypotension is a grave sign, often indicating aortic rupture or cardiac tamponade. Patients with hypotension may present with muffled heart sounds, syncope, and shock. A new diastolic murmur suggests aortic insufficiency, frequently associated with proximal dissections. If the dissection involves the carotid or subclavian arteries, signs of Horner syndrome (ptosis, miosis, and anhidrosis) or hoarseness due to recurrent laryngeal nerve involvement may appear. Dyspnea and hemoptysis may result from dissection rupture into the mediastinum. It is important to note that abdominal pain may also be present in aortic dissection, but clinicians should also consider non-dissection-related causes such as renal or biliary colic, or bowel obstruction/perforation. Similarly, pulse deficits can be indicative of non-dissection-related embolic phenomena or arterial occlusion. In summary, the clinical presentation of acute aortic dissection is highly variable. While classic signs and symptoms are invaluable for diagnosis, their absence does not rule out the condition. A comprehensive approach, integrating a detailed pain history, neurological findings, and physical examination features such as blood pressure discrepancies, pulse deficits, or murmurs, is essential to alert clinicians to the possibility of dissection and prompt immediate diagnostic evaluation for accurate diagnosis of aortic dissection.

Evaluation

The evaluation and workup for acute aortic dissection are centered on rapid identification and confirmation of the condition, given its high mortality if left untreated. The diagnostic approach is guided by clinical suspicion, the patient’s hemodynamic stability, and the availability of imaging modalities. An integrated approach combining clinical evaluation, laboratory tests, and advanced imaging modalities is essential to confirm the diagnosis of aortic dissection and determine the appropriate management strategy.

Clinical Evaluation

As previously discussed, the initial assessment begins with a focused history and physical examination, emphasizing pain characteristics and associated symptoms. Once a patient with suspected aortic dissection is identified based on these initial findings, further diagnostic workup is initiated to confirm the diagnosis of aortic dissection.

Electrocardiogram (ECG)

Although an electrocardiogram (ECG) is routinely performed in patients presenting with chest pain, its findings are often nonspecific in acute aortic dissection. ST-segment changes may suggest myocardial ischemia, particularly if the dissection extends to involve the coronary arteries. ECG findings consistent with acute myocardial infarction are present in approximately 8% of acute aortic dissection cases. However, a normal ECG does not exclude aortic dissection. A high index of clinical suspicion must be maintained based on presenting symptoms and history, even with a normal ECG, to ensure timely diagnosis of aortic dissection.

Chest Radiography

A chest x-ray may reveal suggestive findings such as a widened mediastinum (>8 cm), abnormal aortic contour, pleural effusion, or loss of the aortic knob. These findings can support the suspicion of aortic dissection. However, up to 20% of patients with aortic dissection may have a normal chest x-ray. Therefore, a normal chest x-ray does not rule out the diagnosis. Additional suggestive findings on chest radiography include:

• Left apical cap (pleural thickening at the apex of the lung)
• Pleural effusion (fluid accumulation in the pleural space)
• Deviation of the esophagus or trachea
• Depression of the left mainstem bronchus
• Loss of the paratracheal stripe (the radiolucent line along the trachea)

While chest radiography can provide initial clues, it is not sufficiently sensitive or specific for definitive diagnosis of aortic dissection.

Laboratory Evaluation

Laboratory tests serve as useful adjuncts in the evaluation of aortic dissection, helping to assess clinical status and organ function, but they are not diagnostic for acute aortic dissection. Important laboratory tests include:

• D-dimer: Elevated D-dimer levels (>500 ng/mL) demonstrate high sensitivity for acute aortic dissection. This elevation is due to increased fibrinolytic activity associated with the formation of a false lumen and subsequent thrombosis. However, D-dimer lacks specificity, as it can be elevated in various other conditions, including pulmonary embolism, deep vein thrombosis, and infection. D-dimer should not be used as a standalone diagnostic test for aortic dissection. However, a negative D-dimer result in low-risk patients may help rule out acute aortic dissection.
• Cardiac Biomarkers (Troponin): Mildly elevated troponin levels may be observed, especially if there is coronary artery involvement or myocardial infarction secondary to the dissection. However, markedly elevated troponin levels are more suggestive of primary myocardial infarction.
• Complete Blood Count (CBC): Leukocytosis (elevated white blood cell count) is a common but nonspecific finding, reflecting a general stress response. A drop in hematocrit may suggest intraluminal blood loss, though this is not always present early in dissection.
• Renal Function Tests (Creatinine, BUN): Elevated creatinine levels can indicate renal ischemia resulting from dissection involving the renal arteries. Baseline and serial renal function tests are important for monitoring organ perfusion.
• Serum Lactate Levels: Elevated lactate levels may indicate poor perfusion or tissue ischemia due to branch vessel involvement and compromised blood flow to vital organs.
• Smooth Muscle Myosin Heavy Chain Assay (SM-MHC): An elevated SM-MHC assay exhibits specificity for acute aortic dissection. This rapid 30-minute test detects circulating SM-MHC protein released from the aortic media during dissection. However, SM-MHC assay can only detect dissection after it has occurred and is not useful for predicting or monitoring chronic aortic dissections. While promising, SM-MHC assay is not yet widely available in all clinical settings.

While laboratory tests can provide supportive information and help assess the patient’s overall condition, they are not sufficient for definitive diagnosis of aortic dissection. Advanced imaging is essential for confirmation.

Imaging Modalities

Definitive diagnosis of aortic dissection relies on advanced imaging to directly visualize the intimal tear, delineate the extent of the dissection, and assess for complications. The choice of imaging modality is guided by the patient’s hemodynamic stability, clinical scenario, and institutional availability:

• Computed Tomography Angiography (CTA): CTA is often the first-line imaging modality for suspected aortic dissection due to its rapid acquisition time, widespread availability, and high accuracy. CTA provides excellent anatomical detail of the aorta and its branches, allowing for precise identification of the intimal flap, true and false lumens, and any associated complications such as branch vessel obstruction, pericardial effusion, or aortic rupture. ECG-gated CTA can further improve image quality, especially in the ascending aorta, by reducing motion artifact from cardiac pulsations.
• Transesophageal Echocardiography (TEE): TEE is a highly accurate and rapid imaging modality, particularly useful in hemodynamically unstable patients where transport to a CT or MRI scanner is not feasible. TEE provides real-time, high-resolution images of the ascending aorta and aortic arch, allowing for immediate diagnosis of aortic dissection at the bedside. TEE is especially sensitive for detecting proximal dissections (Stanford type A) and associated aortic regurgitation. However, visualization of the distal descending aorta and abdominal aorta can be limited by bowel gas and body habitus.
• Magnetic Resonance Imaging (MRI): MRI is highly accurate for diagnosis of aortic dissection and offers excellent soft tissue contrast without ionizing radiation. MRI provides detailed anatomical information, including visualization of the intimal flap, true and false lumens, branch vessel involvement, and aortic wall hematoma. MRI is particularly valuable for follow-up imaging in chronic dissections and in patients with contraindications to iodinated contrast agents used in CTA. However, MRI is less commonly used in acute settings due to longer acquisition times, limited availability in some emergency departments, and potential challenges in monitoring unstable patients within the MRI scanner.
• Transthoracic Echocardiography (TTE): TTE is readily available and noninvasive, making it a useful initial screening tool in patients with suspected aortic dissection. TTE can visualize the proximal ascending aorta and aortic root and can detect pericardial effusion and aortic regurgitation. However, TTE has limited sensitivity for diagnosis of aortic dissection compared to CTA, TEE, and MRI, particularly for dissections in the distal ascending aorta, aortic arch, and descending aorta, due to acoustic windows and image resolution limitations. TTE is most useful for rapid initial assessment and risk stratification, but further imaging with CTA, TEE, or MRI is typically required for definitive diagnosis.
• Aortography: Aortography, once considered the gold standard for evaluating aortic dissections, is now rarely used for initial diagnosis of aortic dissection. Aortography is invasive, requiring arterial puncture and contrast injection, and provides less anatomical detail compared to modern cross-sectional imaging modalities like CTA and MRI. However, aortography may still be employed in specific scenarios, such as when planning endovascular stent placement, to delineate aortic anatomy and guide intervention.

In summary, advanced imaging is paramount for definitive diagnosis of aortic dissection. CTA is frequently the initial modality of choice due to its speed and availability. TEE is invaluable for unstable patients, while MRI offers excellent detail and is preferred for follow-up. TTE can serve as an initial screening tool, but is not definitive. Aortography is now rarely used for primary diagnosis.

Risk Stratification Tools

Clinical decision-making tools, such as the Aortic Dissection Detection Risk Score (ADD-RS), can aid in identifying patients at high risk for acute aortic dissection (AAD). The ADD-RS incorporates clinical factors from patient history, physical examination, and initial imaging (chest x-ray) to stratify risk and guide the need for further diagnostic testing. A high-risk ADD-RS score, combined with elevated D-dimer levels, significantly increases the likelihood of AAD and may justify immediate advanced imaging, such as CTA or TEE, to confirm the diagnosis of aortic dissection. Prompt recognition and accurate diagnosis of AAD are crucial for preventing catastrophic complications, including aortic rupture, cardiac tamponade, and ischemic injury to vital organs. Timely imaging, particularly CTA, remains central to confirming the diagnosis and guiding subsequent management decisions.

Figure: Stanford Classification of Aortic Dissection. This illustration distinguishes between Stanford Type A and B dissections, based on ascending aorta involvement, essential for diagnosis of aortic dissection and treatment planning. Image courtesy of Npatchett, Public Domain, via Wikimedia Commons.

Treatment / Management

Management of aortic dissection necessitates immediate stabilization and prompt consultation with a cardiothoracic or vascular surgeon, regardless of the dissection location. Due to the high mortality associated with untreated acute aortic dissection (AAD), the management approach involves a combination of urgent surgical intervention and medical therapy aimed at reducing hemodynamic stress on the aorta. The initial steps in management are critical for improving patient outcomes and are directly linked to the speed and accuracy of diagnosis of aortic dissection.

Initial Stabilization and Medical Management

Once the diagnosis of aortic dissection is confirmed or strongly suspected, a multidisciplinary team should be activated immediately. Initial management priorities include:

• Monitoring and Access:

  • Continuous hemodynamic monitoring with an arterial line for real-time blood pressure measurements is essential for close surveillance and immediate intervention.
  • Placement of a central venous catheter facilitates hemodynamic monitoring and allows for the administration of medications and fluids.
  • Foley catheter insertion is crucial for monitoring urine output, as oliguria or anuria may indicate renal hypoperfusion secondary to dissection.

• Medical Therapy:

  • Analgesia: Pain control is paramount. Morphine is the preferred analgesic as it effectively manages pain and also decreases sympathetic tone, which helps reduce blood pressure and heart rate, both critical in limiting dissection propagation.
  • Heart Rate and Blood Pressure Control: Aggressive heart rate and blood pressure control are cornerstones of medical management.
    • Short-acting intravenous beta-blockers (e.g., esmolol or labetalol) are the first-line agents. The therapeutic goal is to maintain a heart rate of approximately 60 beats per minute to reduce the force of left ventricular ejection against the aortic wall (dp/dt).
      • Beta-blockers should be used with caution in the setting of acute aortic regurgitation, where compensatory tachycardia may be beneficial in maintaining cardiac output. In such cases, alternative agents or careful titration may be necessary.
    • If beta-blockers are contraindicated (e.g., in patients with severe asthma or bronchospastic disease), non-dihydropyridine calcium channel blockers, such as diltiazem or verapamil, can be used as alternatives to achieve heart rate control.
  • Blood Pressure Target: Systolic blood pressure should be rapidly lowered to between 100 and 120 mm Hg, provided that end-organ perfusion is not compromised. Close monitoring of neurological status, renal function, and peripheral perfusion is essential during blood pressure reduction. If additional blood pressure control is needed beyond beta-blockade, nitroprusside, a potent vasodilator, can be added to the regimen. Other vasodilators, such as nicardipine (a dihydropyridine calcium channel blocker), may also be used, often in combination with beta-blockers, to achieve target blood pressure.
  • Management of Hypotension: Hypotension in the setting of aortic dissection is a critical and ominous sign, often indicating aortic rupture or cardiac tamponade.
    • In hypotensive patients, initial management involves intravenous fluid resuscitation to restore intravascular volume and improve hemodynamic stability. However, excessive fluid administration should be avoided, as it can exacerbate aortic wall stress and potentially worsen the dissection. Careful titration of fluids with close hemodynamic monitoring is crucial. If hypotension persists despite fluid resuscitation, vasopressors are indicated.
    • Vasopressors (e.g., norepinephrine) can be administered to maintain adequate perfusion pressure and support systemic blood pressure. However, these agents should be used judiciously and carefully, as they can increase the force of ventricular contraction (inotropy) and potentially worsen the dissection propagation by increasing shear stress on the aortic wall. Inotropic agents like dobutamine should generally be avoided unless there is evidence of concomitant myocardial dysfunction.

Definitive Treatment Based on AAD Classification

The type and location of the dissection, as classified by the Stanford or DeBakey systems, are the primary determinants of whether surgical or medical intervention is required as definitive treatment. Accurate diagnosis of aortic dissection type is therefore paramount in guiding treatment strategy.

• Stanford Type A Dissections (Involving the Ascending Aorta):
  • Urgent Surgical Intervention: Stanford type A dissections are considered surgical emergencies due to the exceptionally high risk of catastrophic complications, including cardiac tamponade, severe aortic regurgitation, myocardial infarction, stroke, and aortic rupture. Without prompt surgical intervention, mortality rates are exceedingly high. Surgical mortality for type A dissections, even with optimal care, ranges from 5% to 20%, underscoring the severity of this condition. Surgical intervention aims to prevent or manage these life-threatening complications and involves:
    • Excision of the Intimal Tear: Surgical repair involves identifying and removing the primary intimal tear site, which is the entry point for blood into the false lumen. Obliterating entry points into the false lumen is crucial to prevent further dissection propagation.
    • Aortic Replacement: The diseased segment of the aorta, typically the ascending aorta, is replaced with a synthetic graft, usually made of Dacron or a similar biocompatible material, to reconstitute the aortic architecture and restore normal blood flow.
    • Aortic Valve Assessment and Repair/Replacement: If the dissection extends into the aortic root or involves the aortic valve, resulting in aortic regurgitation, valve repair or replacement with a prosthetic valve may be necessary. The decision to perform a Bentall procedure (combined aortic root and valve replacement) is based on the extent of aortic root involvement and valve dysfunction.
  • Management of Aortic Arch Involvement: AADs that extend into the aortic arch present significant surgical challenges and are among the most complex to manage. Surgical repair of arch dissections requires specialized techniques and expertise due to the need for cerebral protection during circulatory arrest and the higher risk of neurologic complications, including stroke and paraplegia. Strategies for cerebral protection during arch surgery include hypothermic circulatory arrest, selective antegrade cerebral perfusion, and retrograde cerebral perfusion.

Differential Diagnosis

The diagnosis of aortic dissection requires careful consideration of several other conditions that can mimic its presentation, particularly in patients presenting with acute chest pain. The differential diagnoses of aortic dissection include:

• Myocardial Infarction (Heart Attack): Myocardial infarction is a common cause of chest pain and shares some overlapping symptoms with aortic dissection, such as sudden onset chest pain and ECG changes. However, aortic dissection pain is typically described as tearing or ripping, while myocardial infarction pain is often described as crushing or pressure-like. Furthermore, aortic dissection may present with pulse deficits or blood pressure differentials, which are less common in myocardial infarction unless cardiogenic shock is present. Cardiac biomarkers (troponin) are typically markedly elevated in myocardial infarction, whereas they may be only mildly elevated or normal in aortic dissection, particularly if there is no coronary artery involvement.
• Aortic Aneurysm (Ruptured): Ruptured aortic aneurysm, especially abdominal aortic aneurysm, can present with sudden, severe abdominal or back pain, mimicking descending aortic dissection. However, ruptured aneurysm typically presents with profound hypotension and hemodynamic instability more rapidly than aortic dissection. Imaging is essential to differentiate between these conditions.
• Cardiac Tamponade (from another cause): Cardiac tamponade, regardless of the underlying cause (e.g., pericarditis, trauma, malignancy), can present with chest pain, shortness of breath, and hypotension, similar to aortic dissection with pericardial involvement. Echocardiography is crucial to diagnose cardiac tamponade by visualizing pericardial effusion and right ventricular diastolic collapse. While tamponade can be a complication of aortic dissection, it can also occur independently.
• Esophageal Rupture (Boerhaave Syndrome): Esophageal rupture, often associated with forceful vomiting, can cause sudden, severe chest pain, sometimes radiating to the back, mimicking aortic dissection. Esophageal rupture may also present with subcutaneous emphysema (air under the skin) and mediastinitis, which are not typical of aortic dissection unless complicated by rupture into the mediastinum. Contrast esophagography or CT scan of the chest can help diagnose esophageal rupture.
• Spontaneous Pneumothorax: Spontaneous pneumothorax, particularly tension pneumothorax, can cause sudden onset chest pain and shortness of breath, potentially resembling aortic dissection. Pneumothorax typically presents with unilateral chest pain, hyperresonance to percussion, and decreased breath sounds on the affected side. Chest x-ray is diagnostic for pneumothorax.
• Pulmonary Embolism (PE): Pulmonary embolism can cause sudden onset chest pain, shortness of breath, and hemodynamic instability, overlapping with symptoms of aortic dissection. PE pain is often pleuritic (worsened by breathing). Risk factors for PE, such as recent surgery, prolonged immobilization, or malignancy, may be present. CTA of the chest can diagnose both aortic dissection and pulmonary embolism, making it a useful initial imaging modality in undifferentiated patients with acute chest pain.
• Stroke or Transient Ischemic Attack (TIA): Neurological deficits are common in aortic dissection, particularly type A, due to involvement of the carotid or vertebral arteries. Therefore, stroke or TIA should be considered in the differential diagnosis of aortic dissection, especially when neurological symptoms are prominent. However, stroke/TIA typically lacks the severe, tearing chest pain characteristic of aortic dissection, although atypical presentations are possible. Imaging, such as CTA or MRI, can help differentiate between aortic dissection with neurological sequelae and primary cerebrovascular events.

A thorough clinical evaluation, combined with appropriate imaging, is essential to accurately differentiate aortic dissection from these other conditions and ensure timely and appropriate management. Rapid and accurate diagnosis of aortic dissection is critical given its high mortality.

Prognosis

The prognosis of aortic dissection is highly variable and depends on numerous factors, including the type and location of the dissection, the timeliness of diagnosis and intervention, and the presence of complications. Acute aortic dissection is associated with significant morbidity and mortality, particularly when diagnosis and management are delayed. Prompt and accurate diagnosis of aortic dissection, followed by appropriate treatment, markedly improves survival outcomes.

Prognosis Based on Dissection Type

• Stanford Type A Dissections:

  • Mortality without Treatment: Type A dissections are surgical emergencies due to the high risk of rapid and fatal complications, including cardiac tamponade, aortic rupture, myocardial infarction, and stroke. Without surgical intervention, the mortality rate for type A dissections is exceedingly high, increasing by 1% to 2% per hour within the first 24 to 48 hours of symptom onset, reaching nearly 50% by the end of the first week. Historically, untreated type A aortic dissection was almost uniformly fatal.
  • Surgical Mortality: With prompt surgical repair, the in-hospital mortality rate for type A dissections has improved significantly but remains substantial, ranging from approximately 15% to 30%. Surgical mortality is influenced by factors such as patient age, pre-existing comorbidities, hemodynamic status at presentation, and intraoperative complications. Despite successful surgical intervention in the acute phase, long-term mortality remains elevated due to the risks of recurrence, progressive aortic disease, and associated cardiovascular complications.
  • Long-Term Outcomes: Long-term survival after surgical repair of type A aortic dissection has improved over time with advances in surgical techniques and postoperative care. The 5-year survival rate after surgical repair is approximately 70% to 80%, while the 10-year survival rate decreases to around 50% to 60%. Late mortality is often attributed to complications such as aortic aneurysms (formation in the residual dissected aorta), redissection (recurrence of dissection), and subsequent cardiovascular events (e.g., myocardial infarction, stroke, heart failure). Ongoing surveillance and management of risk factors are crucial for improving long-term outcomes.

• Stanford Type B Dissections:

  • Prognosis with Medical Management: Uncomplicated type B dissections, defined as those without evidence of malperfusion, rupture, or rapid expansion, are typically initially managed conservatively with medical therapy focused on blood pressure control and heart rate reduction. The in-hospital mortality rate for medically managed uncomplicated type B dissections is lower than for type A, ranging around 10% to 15%. Patients who remain hemodynamically stable and without complications during the acute phase have a relatively favorable short-term prognosis with medical management alone.
  • Prognosis with Complications: Complicated type B dissections, which include those associated with malperfusion syndromes (ischemia of organs or limbs due to branch vessel obstruction), aortic rupture, rapid aortic expansion, or refractory pain or hypertension, carry a significantly higher risk of adverse outcomes. In these cases, in-hospital mortality can exceed 30% to 40% if not promptly treated with endovascular or surgical intervention. Complicated type B dissections often require more aggressive management strategies, including thoracic endovascular aortic repair (TEVAR) or open surgical repair.
  • Long-Term Outcomes: The long-term prognosis for type B dissections is also influenced by the presence of complications and the chosen treatment strategy. The 5-year survival rate for type B dissections, including both medically and interventionally managed patients, is approximately 75% to 85%. However, patients with type B dissection remain at increased risk of aortic aneurysm formation, redissection, and rupture over time. Regular imaging surveillance (typically with CT or MRI) and meticulous blood pressure control are critical for improving long-term prognosis and detecting and managing late complications.

Prognostic Factors

Several clinical and anatomical factors significantly influence the prognosis of patients with aortic dissection. These factors are important to consider in risk stratification and management decisions following diagnosis of aortic dissection.

• Time to Diagnosis and Treatment: The time elapsed between symptom onset, diagnosis of aortic dissection, and initiation of treatment is paramount, particularly for type A dissections. Delays in diagnosis and intervention significantly increase the risk of fatal outcomes due to the rapid progression of the disease and the potential for life-threatening complications. Every hour of delay in surgical repair for type A dissection increases mortality risk.
• Extent and Location of Dissection: The anatomical extent and location of the dissection significantly impact prognosis. Dissections involving the aortic arch or extending into the abdominal aorta are associated with a higher risk of complications, including organ malperfusion, neurologic deficits (stroke, spinal cord ischemia), and increased surgical complexity. Proximal dissections (type A) generally carry a worse prognosis than distal dissections (type B) due to the higher risk of cardiac complications.
• Presence of Complications at Presentation: The presence of complications at initial presentation is strongly associated with poor outcomes and increased mortality. Complications such as pericardial tamponade, acute aortic regurgitation, myocardial infarction, stroke, or malperfusion syndromes (e.g., mesenteric ischemia, limb ischemia) indicate more severe disease and are associated with significantly higher mortality rates.
• Patient Demographics and Comorbidities: Patient demographics and pre-existing comorbidities influence prognosis. Advanced age, history of hypertension, pre-existing aortic aneurysm, connective tissue disorders (e.g., Marfan syndrome, Ehlers-Danlos syndrome), and chronic kidney disease are associated with a worse prognosis. In particular, patients with genetic conditions like Marfan syndrome have an elevated risk of redissection and aneurysm formation, necessitating closer monitoring and more aggressive management.
• Hemodynamic Status at Presentation: Hemodynamic status at the time of diagnosis of aortic dissection is a critical prognostic factor. Hypotension or shock at presentation indicates severe complications, such as aortic rupture or cardiac tamponade, and is linked to a markedly increased risk of mortality. Patients presenting in extremis have a significantly worse prognosis.
• Surgical and Postoperative Complications: Surgical and postoperative complications can negatively impact prognosis. Complications such as neurologic deficits (stroke, spinal cord ischemia), renal failure, respiratory failure requiring prolonged intubation, infection, and bleeding are associated with elevated perioperative mortality and adverse long-term outcomes. The expertise of the surgical team and the center volume are important factors in minimizing surgical complications.

Even after successful initial treatment, patients with aortic dissection remain at risk for long-term complications and recurrence. Recurrent dissection or aneurysmal dilation at the site of the initial dissection or in other segments of the aorta is a significant long-term concern, particularly in patients with residual dissection in the descending aorta or those with underlying connective tissue disorders. Chronic aortic enlargement due to a persistent false lumen can lead to progressive dilation, rupture, or the need for reintervention years after the initial dissection. Furthermore, these patients are at increased risk for subsequent cardiovascular events, such as myocardial infarction and congestive heart failure, particularly if the dissection involved the coronary arteries or aortic valve. Up to 20% to 30% of patients may require reintervention within 5 years due to recurrent dissection, aneurysm repair, or complications arising from the initial surgical or endovascular procedure. Therefore, regular long-term follow-up with imaging and diligent management of modifiable risk factors, such as hypertension, is crucial to mitigating these risks and improving long-term outcomes after diagnosis of aortic dissection and treatment.

Long-Term Complications and Recurrence Risk

Despite successful initial treatment of aortic dissection, patients remain at risk for long-term complications and recurrence. These long-term risks necessitate ongoing surveillance and management to optimize patient outcomes and quality of life after the initial diagnosis of aortic dissection.

One of the primary long-term concerns is the possibility of redissection or aneurysm formation, either at the site of the initial dissection or in other segments of the aorta. This risk is particularly elevated in patients with underlying connective tissue disorders, such as Marfan syndrome, or those with residual dissection in the descending aorta. The persistent false lumen in type B dissections, even after medical management, can predispose to subsequent aortic pathology, including aneurysmal degeneration and rupture. Chronic aortic enlargement is another significant long-term issue, especially in patients with a persistent false lumen. Over time, the false lumen can lead to progressive aortic enlargement, ultimately resulting in aneurysmal dilation and, in severe cases, rupture or the need for additional surgical or endovascular interventions. Close monitoring with serial imaging, typically CT or MRI, is essential to detect these changes early and plan for timely intervention if needed. Imaging follow-up is typically recommended at 3, 6, and 12 months post-discharge, and annually thereafter, or more frequently as clinically indicated.

Patients who have experienced aortic dissection are also at increased risk for subsequent cardiovascular events, such as myocardial infarction and congestive heart failure. This increased cardiovascular risk is especially prominent if the initial dissection involved the coronary arteries or the aortic valve, which can compromise cardiac function over time. Aggressive management of cardiovascular risk factors, including hypertension, hyperlipidemia, and smoking cessation, is crucial in this patient population. Regular follow-up with a cardiologist is recommended to monitor for and manage these cardiovascular risks.

Reintervention rates are relatively high in patients who have survived aortic dissection, with up to 20% to 30% requiring additional procedures within 5 years of the initial event. Reinterventions may be necessary due to recurrent dissection, aneurysm repair, or complications stemming from the initial surgical or endovascular approach, such as endoleaks after TEVAR or graft-related issues after open surgical repair. Long-term care and diligent follow-up, including regular imaging and clinical assessments, are essential components of managing these patients to improve outcomes and reduce the risk of severe complications and reinterventions.

Prognosis and Quality of Life

Outcomes for patients with aortic dissection are significantly improved when managed by a dedicated interprofessional team of healthcare professionals. This team typically includes cardiologists, cardiothoracic surgeons, intensivists, pulmonologists, nephrologists, interventional radiologists, anesthesiologists, advanced practice clinicians, nurses, pharmacists, and other allied health professionals, such as social workers and physical therapists. Each member of this team plays a critical role in addressing the complex, multisystem nature of aortic dissection and optimizing patient care. Pharmacists are integral in patient education, particularly regarding the importance of blood pressure control and medication adherence, which are crucial for long-term prognosis and preventing complications and disease progression. Notably, clinical outcomes are generally better in high-volume centers, which manage a greater number of aortic dissection cases per year (typically defined as more than 5 aortic dissection cases per year), compared to lower-volume centers. This volume-outcome relationship highlights the importance of expertise and experience in the management of this complex condition. Patients benefit from care provided in centers with established protocols, dedicated aortic teams, and experienced surgeons and interventionalists.

Despite advances in surgical and endovascular techniques that have improved survival rates, the quality of life and functional status of survivors of aortic dissection can be compromised. Persistent pain, reduced exercise capacity, and psychological effects such as anxiety and depression are common among patients who have experienced an aortic dissection. Long-term management includes lifestyle modifications, stringent blood pressure control, and regular follow-up with imaging to detect complications early and prevent disease progression. Rehabilitation programs, including cardiac rehabilitation, may be beneficial in improving exercise capacity and overall quality of life. Psychosocial support, including counseling or support groups, can help patients cope with the emotional burden of aortic dissection and its aftermath. Overall, the prognosis of aortic dissection is largely influenced by early recognition, timely diagnosis of aortic dissection, prompt intervention, and diligent long-term monitoring and management. Comprehensive multidisciplinary care and patient adherence to treatment plans are essential to improving survival and reducing morbidity in this high-risk population, and to optimizing long-term quality of life.

Complications

Aortic dissection is associated with a wide range of potentially severe and life-threatening complications. These complications can arise acutely during the dissection event or develop as long-term sequelae, even after successful initial treatment. Recognition and management of these complications are crucial for improving patient outcomes following diagnosis of aortic dissection.

Common acute complications of aortic dissection include:

• Multiorgan Failure: Malperfusion resulting from branch vessel obstruction can lead to ischemia and failure of multiple organs, including the kidneys, liver, bowel, and extremities. Renal failure is a particularly common and serious complication.
• Stroke: Dissection involving the carotid or vertebral arteries can cause cerebral ischemia and stroke, leading to permanent neurological deficits.
• Myocardial Infarction: Dissection extending into the coronary arteries can compromise coronary blood flow and cause myocardial infarction (heart attack).
• Paraplegia: Dissection involving the spinal arteries can lead to spinal cord ischemia and paraplegia (loss of lower limb function).
• Renal Failure: Renal artery involvement can cause acute renal ischemia and renal failure, which may require dialysis.
• Amputation of Extremities: Limb ischemia due to obstruction of arteries supplying the extremities can lead to tissue necrosis and may necessitate amputation.
• Bowel Ischemia: Mesenteric artery involvement can cause bowel ischemia, potentially leading to bowel infarction and requiring surgical resection.
• Tamponade (Cardiac Tamponade): Rupture of the dissection into the pericardial space can cause hemopericardium and cardiac tamponade, a life-threatening condition where blood accumulation compresses the heart, impairing cardiac filling and output.
• Acute Aortic Regurgitation: Proximal dissections involving the aortic root can disrupt the aortic valve leaflets, causing acute aortic regurgitation, which can lead to heart failure and hemodynamic instability.
• Compression of Superior Vena Cava (SVC): In rare cases, dissection can compress the superior vena cava, leading to SVC syndrome with facial and upper extremity swelling and venous congestion.
• Death: Despite advances in management, aortic dissection remains a highly lethal condition, particularly in its acute phase and when complicated by rupture or malperfusion. Death can result from aortic rupture, cardiac tamponade, multiorgan failure, or other catastrophic complications.

Endoleak After Graft Placement

Endoleak is a significant and relatively common complication following endovascular aortic aneurysm repair (EVAR) or thoracic endovascular aortic repair (TEVAR) for aortic dissection, occurring in approximately 25% of patients. An endoleak is defined as the leakage of blood into the excluded aneurysmal sac or false lumen around the graft. This complication can lead to aneurysm sac pressurization and expansion over time, potentially increasing the risk of aneurysm rupture or redissection in the long term. Therefore, regular imaging follow-up with CTA is essential for all patients after EVAR or TEVAR to monitor for endoleaks, as they may develop at any point post-procedure.

Endoleaks are classified into 5 types based on the source of the blood flow, which has critical implications for subsequent patient management and the need for intervention (refer to Image. Endoleak Types). The type and location of the endoleak determine the appropriate management plan, which may range from continued surveillance to endovascular or surgical reintervention to seal the leak. The endoleak classification is as follows:

• Type I Endoleak: Leakage at the attachment sites of the graft due to an inadequate seal between the graft and the native aortic wall.
  • Type IA: Proximal attachment leak at the proximal graft landing zone in the aorta.
  • Type IB: Distal attachment leak at the distal graft landing zone in the iliac arteries.
  • Type IC: Occurs specifically with aorto-mono-iliac grafts and femoro-femoral bypass, where leakage originates from the contralateral nongrafted iliac artery.
• Type II Endoleak: Leakage into the aneurysm sac or false lumen from collateral vessels branching off the aorta, such as lumbar arteries, inferior mesenteric artery (IMA), or internal iliac arteries (hypogastric arteries). Type II endoleaks are often low-flow and may spontaneously resolve over time.
• Type III Endoleak: Leakage resulting from defects in the graft itself, including graft fractures, tears, or component separations (mechanical failure of the graft fabric or connections).
• Type IV Endoleak: Leakage through the graft material itself due to graft porosity. Type IV endoleaks are less common with modern graft materials.
• Type V Endoleak: Aneurysm expansion without any visible leakage on imaging (endotension). The mechanism of type V endoleak is not fully understood but may involve transmission of systemic pressure through the graft wall into the aneurysm sac or false lumen.

Figure: Endoleak Types. This illustration visually differentiates between the five types of aortic endoleaks following endovascular aortic repair, crucial for post-operative diagnosis of aortic dissection complications and management. Contributed by TW Kassem, MD.

Postoperative and Rehabilitation Care

Postoperative and Long-Term Management

After surgical or endovascular repair of aortic dissection, patients require ongoing postoperative and long-term management to prevent recurrence, monitor for late complications, and optimize their quality of life. Long-term care is a critical component of successful management following diagnosis of aortic dissection and initial treatment.

• Blood Pressure Control: Lifelong antihypertensive therapy is indicated for all patients post-aortic dissection repair to maintain optimal blood pressure control and reduce aortic wall stress. The target systolic blood pressure is generally less than 120 mm Hg. Beta-blockers remain the first-line agents for long-term blood pressure management in aortic dissection patients, as they reduce heart rate and aortic dp/dt, in addition to lowering blood pressure. Other antihypertensive medications, such as angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), calcium channel blockers, or diuretics, may be added based on individual patient needs, tolerance, comorbidities, and blood pressure response to beta-blockers. Regular blood pressure monitoring at home and during clinic visits is essential.
• Imaging Surveillance: Regular imaging follow-up is critical to monitor for aneurysm formation in the residual dissected aorta, residual dissection progression, graft complications (e.g., endoleaks, graft migration, graft limb occlusion), and other late complications. Imaging modality and frequency are individualized based on dissection type, treatment modality, and patient risk factors. CT angiography (CTA), magnetic resonance angiography (MRA), or echocardiography (TTE or TEE) may be used for surveillance. Initial follow-up imaging is typically performed at 3, 6, and 12 months after hospital discharge, with annual or biannual imaging thereafter, and more frequently if clinically indicated or if concerning findings are detected on surveillance imaging.
• Lifestyle Modifications: Patients should be advised to adopt and maintain healthy lifestyle modifications to minimize aortic stress and reduce cardiovascular risk factors. Recommendations include:
  • Avoidance of Strenuous Physical Activity and Heavy Lifting: Activities that cause significant increases in blood pressure or Valsalva maneuvers should be avoided to prevent increased aortic wall stress. Specific activity restrictions are individualized based on dissection type and aortic stability.
  • Smoking Cessation: Smoking is a major cardiovascular risk factor and accelerates atherosclerosis. Smoking cessation is strongly recommended for all patients.
  • Weight Management: Maintaining a healthy weight reduces overall cardiovascular strain.
  • Adherence to Antihypertensive Therapy: Strict adherence to prescribed antihypertensive medications is crucial for long-term management.
• Management of Complications: Late complications, such as aneurysm development, recurrent dissection, graft complications (endoleaks, graft infection, graft degeneration), or branch vessel obstruction, may necessitate reintervention. Decisions regarding reintervention should be guided by imaging findings, clinical symptoms, and patient risk factors, and made by a multidisciplinary aortic team. Reintervention may involve endovascular procedures (e.g., TEVAR extension, endoleak embolization) or open surgical repair.

Deterrence and Patient Education

Risk Factor Modification

Patient education plays a crucial role in the deterrence and long-term management of aortic dissection. Patients should be comprehensively educated about the various modifiable and non-modifiable risk factors contributing to the development of AAD. Effective risk factor modification and patient awareness are integral to reducing the incidence and improving the prognosis of aortic dissection, starting from the point of diagnosis of aortic dissection and extending throughout long-term management.

• Hypertension Management: Hypertension is the most significant modifiable risk factor for AAD. Strict, lifelong blood pressure control is crucial, typically with a target systolic blood pressure below 120 mm Hg. Patient education should emphasize the importance of:

  • Adhering to Antihypertensive Medications: Understanding the rationale behind each prescribed medication, potential side effects, and the importance of consistent medication intake.
  • Dietary Modifications: Adopting a heart-healthy diet, such as the DASH diet or Mediterranean diet, with reduced sodium intake, and increased fruits, vegetables, and whole grains.
  • Regular Exercise: Engaging in regular moderate-intensity aerobic exercise, after appropriate medical clearance, to help control blood pressure and improve cardiovascular health.
  • Avoiding Excessive Alcohol Consumption: Limiting alcohol intake to recommended guidelines.

• Avoidance of Stimulants: Cocaine and other stimulant drugs significantly increase blood pressure and the risk of aortic dissection. Patient education should strongly emphasize:

  • Avoiding Illicit Stimulants: Complete avoidance of cocaine, amphetamines, and other illicit stimulant drugs.
  • Caution with Over-the-Counter Stimulants: Awareness of potential risks associated with over-the-counter stimulants, such as decongestants containing pseudoephedrine or phenylephrine, and energy drinks with high caffeine content, especially in individuals with hypertension or underlying aortic conditions.
  • Seeking Help for Substance Use Disorders: Providing resources and support for patients struggling with substance use disorders.

• Atherosclerosis Management: While not as direct a risk factor as hypertension, atherosclerosis contributes to aortic stiffness and vascular disease. Patient counseling should focus on:

  • Cholesterol Management: Understanding the importance of lipid monitoring and adherence to cholesterol-lowering medications (statins) if indicated.
  • Smoking Cessation: Strongly emphasizing smoking cessation and providing resources and support for quitting.
  • Maintaining a Healthy Weight: Achieving and maintaining a healthy body weight through diet and exercise.

• Screening for Connective Tissue Disorders: Individuals with a family history of connective tissue disorders (e.g., Marfan syndrome, Ehlers-Danlos syndrome, Loeys-Dietz syndrome) or other genetic predispositions to aortic disease should undergo regular cardiovascular screening. Early identification of these conditions allows for:

  • Tailored Monitoring: More frequent aortic imaging surveillance to detect progressive aortic dilation or dissection early.
  • Preventive Strategies: Consideration of prophylactic beta-blocker therapy to reduce aortic wall stress and slow aortic dilation.
  • Early Elective Surgical Intervention: In cases of progressive aortic dilation meeting surgical thresholds, elective aortic repair may be recommended to prevent dissection or rupture.

Patient Awareness of Symptoms

Early recognition of AAD symptoms is critical for timely intervention and reducing mortality. Patient education should empower individuals to recognize and respond promptly to potential symptoms of aortic dissection, promoting early diagnosis of aortic dissection and improving outcomes. Key symptoms to emphasize include:

• Sudden, Severe Chest or Back Pain: Patients should understand that sudden, severe chest or back pain—often described as tearing, ripping, or shearing—is a hallmark symptom of AAD and warrants immediate medical attention. The pain is typically maximal at onset and may migrate as the dissection extends.
• Neurological Symptoms: Patients should be aware that symptoms such as sudden loss of consciousness (syncope), stroke-like symptoms (sudden weakness, paralysis, speech difficulty), or limb weakness or paresthesia may indicate an aortic dissection involving branch vessels supplying the brain or spinal cord, necessitating urgent evaluation.
• Other Symptoms: Awareness of less specific but potentially relevant symptoms, such as sudden onset shortness of breath, new onset of heart murmur (aortic regurgitation), or signs of limb ischemia (cold, pale, painful extremity), can be vital for early detection and prompting medical evaluation.

Crucially, patients should be educated to seek emergency medical care immediately if they experience these symptoms, rather than waiting or attempting self-treatment. Calling emergency services (911 in the US or local emergency number) is the most appropriate first step.

Medical Therapy Adherence and Long-term Monitoring

For patients with known aortic aneurysms or those at risk for AAD (e.g., individuals with connective tissue disorders, bicuspid aortic valve, family history), long-term management and monitoring are key to preventing progression and complications. Patient education is essential to ensure adherence to medical therapy and long-term surveillance recommendations.

• Medication Adherence: Beta-blockers are frequently prescribed to patients at risk for AAD to reduce heart rate and aortic wall stress, even in the absence of hypertension. Patients should be thoroughly counseled on:

  • Importance of Beta-Blocker Therapy: Understanding the rationale for beta-blocker use in preventing aortic events, even if blood pressure is well-controlled.
  • Medication Regimen and Side Effects: Understanding the prescribed medication regimen, potential side effects, and how to manage them.
  • Consistent Medication Intake: Emphasizing the importance of taking medications as prescribed and not discontinuing them without medical advice.

• Lifestyle Adjustments: Patients should receive clear guidance on lifestyle adjustments to minimize aortic stress.

  • Activity Restrictions: Physical activities that significantly increase blood pressure or cause Valsalva maneuvers (e.g., heavy lifting, straining, competitive sports, isometric exercises) should be avoided, especially in patients with a known aortic aneurysm or prior dissection. Moderate exercise, such as walking, swimming, or cycling, may be encouraged after consulting with a healthcare provider and with appropriate blood pressure control.
  • Hydration: Maintaining adequate hydration, especially during exercise or hot weather, to prevent dehydration and hypotension.

• Regular Follow-up and Imaging: Patients with connective tissue disorders, aortic aneurysms, or a history of aortic dissection should have routine follow-up appointments with a cardiologist or vascular specialist and undergo periodic aortic imaging (e.g., echocardiograms, CT, or MRI) to monitor aortic size and integrity. Education should include:

  • Frequency and Importance of Follow-up: Understanding the recommended frequency of follow-up visits and imaging studies, even in the absence of symptoms.
  • Purpose of Imaging: Explaining the purpose of surveillance imaging in detecting aortic dilation, dissection progression, or other complications early, allowing for timely intervention.
  • Communicating New Symptoms: Promptly reporting any new or worsening symptoms to their healthcare provider between scheduled follow-up visits.

Genetic Counseling and Screening

For individuals with a family history of AAD or related connective tissue disorders, genetic counseling and screening are crucial components of risk assessment and management.

• Family Screening: First-degree relatives (parents, siblings, children) of patients with a history of AAD, especially those with a known genetic predisposition or connective tissue disorder, should be screened for aortic abnormalities. Screening typically involves aortic imaging, such as echocardiography or CT angiography.
• Genetic Testing: Genetic testing may be recommended for patients with a strong family history of aortic dissection or features suggestive of a connective tissue disorder. Positive genetic test results in at-risk family members warrant routine aortic surveillance and implementation of preventive measures, such as beta-blocker therapy and lifestyle modifications.
• Preconception Counseling: Women with a history of connective tissue disorders or aortic pathology who are planning pregnancy should receive preconception counseling from a cardiologist or high-risk obstetrician. Counseling should assess the risk of aortic complications during pregnancy, which is elevated in women with aortic disease, particularly Marfan syndrome. Management strategies, such as elective aortic repair prior to conception or specialized high-risk obstetric care during pregnancy and delivery, should be discussed and planned.

Psychosocial Support and Patient Education

The emotional and psychological burden of living with a risk for AAD or managing its aftermath can be significant. Providing patients and their families with access to educational resources about AAD, support groups, and mental health services can improve coping mechanisms, reduce anxiety and depression, and enhance adherence to long-term management strategies. Patient education should also address common psychosocial concerns and provide resources for support.

Emergency Plans

Patients at high risk for AAD, especially those with known aortic aneurysms or connective tissue disorders, should have a clear emergency action plan in place, readily accessible to themselves and their family members. This plan should include:

• Knowing the Location of the Nearest Hospital with Advanced Imaging Capabilities: Identifying hospitals in their vicinity that have 24/7 availability of CTA or TEE and experienced aortic teams.
• Understanding When and How to Call Emergency Services: Clear instructions on when and how to call emergency medical services (911 or local emergency number), specifically for sudden severe chest pain, back pain, neurological symptoms, or other concerning symptoms suggestive of aortic dissection.
• Having a Summary of Medical History Readily Available: Keeping a readily accessible summary of their medical history, including prior aortic imaging results, list of current medications, allergies, and emergency contact information, to provide to healthcare providers in case of an emergency. This information can be kept electronically or in paper form.

Pearls and Other Issues

Despite optimal diagnostic algorithms and clinical vigilance, accurately diagnosing every case of acute aortic dissection (AAD) in the emergency department remains a significant clinical challenge. Several factors contribute to the persistent difficulty in achieving universally accurate diagnosis of aortic dissection in the acute setting.

One major contributing factor is the inherent variability in symptom severity and presentation in aortic dissection. Some patients, particularly in the early stages of dissection or those with atypical dissection patterns, may present with relatively mild or non-specific symptoms that do not immediately raise clinical suspicion for AAD. The classic “tearing” chest pain, while highly suggestive, is not universally present, and some patients may describe their pain differently or report pain in locations other than the chest or back. Atypical presentations, such as isolated abdominal pain, syncope without pain, or stroke-like symptoms without chest pain, can further obscure the diagnosis of aortic dissection.

The clinical presentation and laboratory findings in aortic dissection can also mimic other more common conditions, such as acute coronary syndrome (myocardial infarction), pulmonary embolism, musculoskeletal chest pain, or gastrointestinal emergencies. This clinical overlap can lead to misdiagnosis or delayed diagnosis of aortic dissection, especially in the absence of classic symptoms or in lower-risk patients. For example, ECG changes suggestive of ischemia may be present in aortic dissection involving the coronary arteries, potentially leading to an initial misdiagnosis of myocardial infarction. Elevated D-dimer levels, while sensitive for aortic dissection, are also non-specific and can be elevated in numerous other conditions, further complicating interpretation in the acute setting.

Another factor complicating diagnosis of aortic dissection is the occasional absence of expected physical examination findings. While physical exam signs such as pulse deficits, blood pressure differentials between arms, or a diastolic murmur suggestive of aortic regurgitation are important diagnostic clues when present, these classic signs are not consistently found in all patients with confirmed aortic dissection. Studies have shown that these classic physical exam findings are present in less than 50% of acute aortic dissection cases. The absence of these expected physical exam findings may falsely reassure clinicians and lower the index of suspicion for aortic dissection, potentially leading to missed or delayed diagnosis. Similarly, chest x-ray findings suggestive of widened mediastinum, while supportive, are also not uniformly present and lack sufficient sensitivity and specificity for definitive diagnosis of aortic dissection. Up to 20% of patients with aortic dissection may have a normal chest x-ray.

To mitigate the risk of missed or delayed diagnosis of aortic dissection, it is crucial to maintain a high index of suspicion for AAD in all patients presenting with chest pain or other suggestive symptoms, regardless of the presence or absence of classic findings. Every patient presenting with chest pain, back pain, syncope, or unexplained neurological deficits should be approached with the consideration that they could potentially have an aortic dissection, until proven otherwise. Establishing a detailed risk factor profile, including history of hypertension, connective tissue disorders, family history of aortic disease, and other predisposing conditions, is essential in risk stratification. Clinicians should be vigilant about atypical or subtle presentations of aortic dissection and consider advanced imaging, such as CTA or TEE, in patients with even moderate clinical suspicion, particularly in the presence of risk factors or suggestive, albeit non-specific, symptoms. Utilizing clinical decision support tools, such as the ADD-RS, in conjunction with D-dimer testing and appropriate imaging strategies, can help improve early diagnosis of aortic dissection and optimize patient outcomes. Continuous medical education and awareness campaigns for healthcare providers are also important in reinforcing the need for vigilance in considering and excluding aortic dissection in appropriate clinical scenarios.

Enhancing Healthcare Team Outcomes

Effective management of aortic dissection necessitates a coordinated, patient-centered approach involving a multidisciplinary team of healthcare professionals. This interprofessional team typically includes physicians (cardiologists, cardiothoracic surgeons, emergency medicine physicians, intensivists, radiologists), advanced practice clinicians (physician assistants, nurse practitioners), nurses, pharmacists, and other allied healthcare professionals (e.g., social workers, physical therapists, rehabilitation specialists). Each team member contributes unique expertise and skills that enhance patient outcomes and ensure patient safety throughout the continuum of care, from initial diagnosis of aortic dissection to long-term follow-up and rehabilitation.

Physicians, particularly cardiologists and cardiothoracic surgeons, lead the diagnostic and therapeutic decision-making process. Emergency medicine physicians are crucial in the initial recognition, resuscitation, and stabilization of patients presenting with suspected aortic dissection in the acute setting. Radiologists play a vital role in performing and interpreting advanced imaging studies (CTA, TEE, MRI) that are essential for definitive diagnosis of aortic dissection and for guiding treatment planning and follow-up. Intensivists manage critically ill patients in the intensive care unit (ICU) post-operatively or for medical management of complicated dissections.

Advanced practice clinicians and nurses provide continuous bedside monitoring, administer medications, manage hemodynamic support, and provide essential patient education and emotional support. Nurses are often the first to recognize subtle changes in patient condition and initiate rapid responses to potential complications. Pharmacists contribute by optimizing pharmacologic therapies, ensuring medication safety, and counseling patients on medication adherence, especially regarding antihypertensive medications and beta-blockers, which are critical for long-term prognosis and secondary prevention. Pharmacists also play a key role in medication reconciliation and preventing drug interactions.

Open and effective communication between all team members is vital to improving outcomes and ensuring patient safety in the complex management of aortic dissection. Regular interprofessional team meetings, structured communication protocols (e.g., SBAR – Situation, Background, Assessment, Recommendation), and a shared, collaboratively developed care plan help align treatment goals and strategies, minimize the risk of medical errors, and enhance patient safety. This collaborative approach ensures that all providers are aware of the patient’s current clinical status, recent interventions, and any changes in management plans. Effective communication is particularly critical during transitions of care, such as from the emergency department to the operating room or ICU, and from inpatient to outpatient settings.

Care coordination extends beyond the acute inpatient phase. Outpatient follow-up and rehabilitation planning are guided by the team’s collective expertise, including input from social workers and psychologists to address psychosocial needs, emotional support, and facilitate the patient’s return to daily life and functional recovery. Rehabilitation specialists and physical therapists assist in restoring physical function and exercise capacity post-operatively or after prolonged hospitalization. Social workers and case managers help coordinate discharge planning, arrange for home healthcare services if needed, and connect patients with community resources and support groups.

By effectively integrating the unique skills and perspectives of each healthcare professional, maintaining open channels of communication, fostering a collaborative and respectful team environment, and emphasizing patient-centered care, the interprofessional team can deliver comprehensive, high-quality care that enhances patient outcomes, improves patient experience, and optimizes overall team performance in the management of aortic dissection, from initial diagnosis of aortic dissection through long-term follow-up and rehabilitation.

Review Questions

[Link to review questions on the original article page]

Figure: Stanford Classification of Aortic Dissection. Visual representation of Stanford Type A and Type B aortic dissections, crucial for understanding diagnosis of aortic dissection. Image courtesy of Npatchett, Public Domain, via Wikimedia Commons.

Figure: Type A Aortic Dissection. Illustrative example of a Type A dissection, highlighting the ascending aorta involvement, a key factor in diagnosis of aortic dissection. Contributed by F Farci, MD.

Figure: Aortic Dissection, Type A. Another visual depiction of Type A aortic dissection, emphasizing the tear location and ascending aorta involvement, important for diagnosis of aortic dissection. Contributed by F Farci, MD.

Figure: Histologic Image of Aortic Dissection. Microscopic view of aortic dissection, showing the tear within the aortic media, relevant to understanding the pathophysiology and diagnosis of aortic dissection. Contributed by F Farci, MD.

Figure: Aortic Dissection Seen in Histology. Histological image showing blood flow in the false lumen of an aortic dissection, confirming diagnosis of aortic dissection at the microscopic level. Image contributed by F Farci, MD.