Thoracic Aortic Aneurysm and Dissection

Perspective:

This state-of-the-art review summarizes our current understanding of the pathophysiology and treatment of thoracic aortic disease. The following are 10 key points to remember:

1. There are two main categories of risk factors for aortic dissection. The first category is factors that cause medial degeneration of the aortic wall, which include genetic abnormalities and inflammatory diseases. Factors that increase wall stress form the second category, and include hypertension and physical trauma.

2. The most important principle in treating aortic aneurysms is excellent blood pressure control, which may slow expansion and reduce the risk for dissection. Blood pressure should be treated to the lowest tolerated level. Smoking cessation, treatment of hyperlipidemia, and avoidance of strenuous resistive exercise may be helpful.

3. The clinical benefit of beta-blockers in patients with a thoracic aortic aneurysm remains unclear. While early studies in Marfan syndrome patients reported reduced rates of dilatation in those treated with beta-blockers, a meta-analysis suggested no benefit or potentially harm. However, in patients with type A acute aortic dissection, beta-blockers have been associated with improved survival and appear to have a clear clinical benefit.

4. Several studies have suggested that angiotensin-II receptor blockers may reduce the rate of aortic dilatation in patients with Marfan syndrome, but further studies are needed and are currently underway.

5. Routine surveillance of aortic aneurysms is important to determine when asymptomatic patients may benefit from prophylactic surgery.

6. Increased aortic size is associated with a greater risk of aortic dissection or rupture. Consensus guidelines recommend that individuals with an aortic root ≥5.5 cm in diameter should be referred for surgery (or ≥5.0 cm in patients with a bicuspid valve plus a family history of dissection or rapid growth). Surgery is recommended at smaller aortic diameters for individuals with Marfan syndrome or Loeys-Dietz syndrome.

7. It is important to note that many patients with aortic dissection have aortic diameters smaller than these cutoffs. Independent predictors of dissection at smaller diameters include hypertension, increased age, and radiating pain.

8. Type A acute aortic dissection is associated with a high rate of mortality, and all patients should be considered for urgent surgery. Medical stabilization before surgery has no role, and coronary angiography is generally not recommended.

9. Aneurysms and dissections of the ascending aorta are treated surgically, while endovascular repair can be considered for aneurysms of the descending aorta. Consideration of endograft repair depends on suitable anatomy, vascular access, and risk for embolism of atheroma.

10. Uncomplicated type B aortic dissection should generally be treated medically. Thoracic endovascular aortic repair is recommended only for patients with complicated type B dissections.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Dyslipidemia, Prevention, Vascular Medicine, Aortic Surgery, Cardiac Surgery and CHD & Pediatrics, Congenital Heart Disease, CHD & Pediatrics and Interventions, CHD & Pediatrics and Prevention, CHD & Pediatrics and Quality Improvement, Hypertension

Keywords: Angiotensin Receptor Antagonists, Aortic Aneurysm, Thoracic, Endovascular Procedures, Plaque, Atherosclerotic, Hyperlipidemias, Dilatation, Blood Pressure, Risk Factors, Pain, Loeys-Dietz Syndrome, Marfan Syndrome, Aneurysm, Dissecting, Embolism, Hypertension, Mitral Valve, Smoking Cessation


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