What is the diagnosis and management of an aortic dissection?

From the Guidelines

Aortic dissection is a life-threatening emergency requiring immediate diagnosis and treatment, with CT angiography being the preferred initial test due to its high sensitivity and specificity, as stated in the most recent guideline 1. The diagnosis of an aortic dissection relies on clinical suspicion in patients presenting with sudden, severe chest or back pain often described as tearing or ripping, combined with imaging studies. Management depends on the location:

• Type A dissections (involving the ascending aorta) require emergency surgical repair to prevent rupture, cardiac tamponade, and aortic valve dysfunction,
• while Type B dissections (limited to descending aorta) can often be managed medically unless complications arise. Initial medical management focuses on pain control and aggressive blood pressure reduction to systolic 100-120 mmHg using IV beta-blockers (esmolol 50-300 μg/kg/min or labetalol 2-8 mg/min) as first-line agents, followed by vasodilators like nicardipine (5-15 mg/hr) if needed, as recommended by the American College of Cardiology/American Heart Association joint committee on clinical practice guidelines 1. Long-term management includes lifelong blood pressure control (target <130/80 mmHg), beta-blockers, regular imaging surveillance every 6-12 months, and lifestyle modifications. Endovascular repair may be considered for complicated Type B dissections. Mortality remains high, particularly for Type A dissections, emphasizing the importance of rapid diagnosis and appropriate intervention, with inhospital mortality reported to be as high as 27% even under optimal conditions 1.

Some key points to consider in the diagnosis and management of aortic dissection include:

• The use of CT angiography as the primary imaging modality for diagnosis, due to its high accuracy and availability 1
• The importance of rapid diagnosis and treatment, with mortality rates increasing by 1-2% per hour after the onset of symptoms for untreated ascending aortic dissections 1
• The need for emergency surgical repair for Type A dissections, and medical management for Type B dissections unless complications arise 1
• The use of IV beta-blockers and vasodilators for blood pressure control, and the importance of lifelong blood pressure control and regular imaging surveillance in long-term management 1

From the Research

Diagnosis of Aortic Dissection

• The diagnosis of aortic dissection can be achieved through various noninvasive imaging procedures, including transthoracic and transesophageal color-flow Doppler echocardiography (TTE and TEE), contrast-enhanced x-ray computed tomography (CT), and magnetic resonance imaging (MRI) 2.
• The sensitivities of MRI, TEE, and x-ray CT for detecting dissection are similar, at 98.3,97.7, and 98.3 percent, respectively, while TTE has a sensitivity of only 59.3 percent 2.
• MRI and x-ray CT are more sensitive than TTE in detecting the formation of thrombus in the entire thoracic aorta, but are not superior to TEE in this regard 2.

Management of Aortic Dissection

• The treatment of aortic dissection depends on the severity and location of the dissection, with open surgical repair being the gold standard of treatment for dissections located to the proximal part of the aorta and the arch 3.
• Endovascular interventions are recommended for most distal or type B aortic dissections 3.
• Beta-blockers are known to protect a vulnerable aorta from acute dissection, as well as reducing the risk of recurrent dissection, and should be used to control blood pressure and heart rate 4.
• Clevidipine, a calcium channel blocker, can be used as a therapeutic and cost-effective alternative to sodium nitroprusside in patients with acute aortic syndromes, with similar efficacy and safety profiles 5.

Imaging Techniques

• MRI is the most appropriate investigation for most patients with chronic aortic disease, while CT scanning is usually the most useful technique in acute situations, with echocardiography added for those with ascending aortic disease or cardiac complications 6.
• A noninvasive diagnostic strategy using MRI in all hemodynamically stable patients and TEE in patients who are too unstable to be moved should be considered the optimal approach to detecting dissection of the thoracic aorta 2.