How can aortic dissection be excluded in a patient with chest pain?

From the Guidelines

To exclude aortic dissection in a patient with chest pain, urgent and definitive imaging of the aorta using CT angiography is recommended due to its high sensitivity and specificity, as evidenced by a Class II large retrospective study 1. This approach is crucial for promptly identifying or excluding thoracic aortic dissection, especially in patients at high risk for the disease. The diagnostic process should start with a thorough history and physical examination, focusing on risk factors like hypertension, Marfan syndrome, previous cardiac surgery, and family history of aortic disease.

Initial Assessment

• An electrocardiogram should be obtained on all patients who present with symptoms that may represent acute thoracic aortic dissection 1.
• The role of chest x-ray in the evaluation of possible thoracic aortic disease should be directed by the patient’s pretest risk of disease 1.
• Selection of a specific imaging modality to identify or exclude aortic dissection should be based on patient variables and institutional capabilities, including immediate availability 1.

Imaging Modalities

• CT angiography is the preferred imaging modality due to its high sensitivity (99%) and specificity (100%) 1.
• Alternatives include transesophageal echocardiography, MRI, or transthoracic echocardiography if CT is unavailable or contraindicated.
• If a high clinical suspicion exists for acute aortic dissection but initial aortic imaging is negative, a second imaging study should be obtained 1.

Clinical Considerations

• While evaluating for aortic dissection, it's essential to simultaneously consider other life-threatening causes of chest pain such as acute coronary syndrome, pulmonary embolism, and tension pneumothorax.
• The clinical presentation can help guide suspicion - sudden, severe, tearing chest pain radiating to the back is classic for dissection, though presentations can vary.
• Hemodynamic stabilization should be prioritized throughout the diagnostic process, with blood pressure control using beta-blockers (such as labetalol 10-20mg IV or metoprolol 5mg IV) followed by vasodilators if needed, while arranging for definitive imaging 1.

From the Research

Excluding Aortic Dissection in Patients with Chest Pain

To exclude aortic dissection in a patient with chest pain, several diagnostic approaches can be considered:

• Imaging Tests: Computed tomography angiography (CTA) is the most frequently used imaging modality for diagnosing type A aortic dissection, with a high degree of sensitivity and specificity 2.
• Point-of-Care Ultrasound (POCUS): POCUS can be a useful diagnostic tool to help differentiate aortic dissection from a primary myocardial infarction, especially in patients presenting with ST-elevation myocardial infarction (STEMI) symptoms 3.
• Transesophageal Echocardiography (TEE): TEE can be used to confirm the diagnosis of aortic dissection, especially when the clinical suspicion is high and complications such as aortic regurgitation are present 4.
• Magnetic Resonance Imaging (MRI): MRI can also be used to diagnose aortic dissection, with a sensitivity of 95-100% 5.
• D-dimer Assay: While the D-dimer assay can be helpful in diagnosing aortic dissection, it may not always be reliable, and a negative result does not rule out the condition 6, 5.

Considerations for Diagnosis

When diagnosing aortic dissection, it is essential to consider the following:

• High-Risk Patients: Patients with a history of hypertension, aortic aneurysm, or other risk factors for aortic dissection should be evaluated promptly and thoroughly 6, 5.
• Clinical Presentation: Patients presenting with severe thoracic pain, hypertension, and other symptoms suggestive of aortic dissection should be evaluated promptly 5.
• Imaging Results: Even if initial imaging studies are negative, surgeons should consider early operation in patients with recent onset chest pain and an ascending aortic aneurysm 2.
• Multimodality Imaging: Using multiple imaging modalities, such as CTA, TEE, and MRI, can help confirm the diagnosis of aortic dissection and rule out other conditions 4.