Which medication class is most effective at slowing progression of thoracic/abdominal aortic aneurysm?

• A. ACE inhibitors
• B. Beta-blockers
• C. Nitrates
• D. Diuretics

Answer: (B)

The main concept is that slowing the heart’s pulsatile stress on a weakened aortic wall slows its expansion. Aortic wall tension depends on pressure and the rate of pressure change with each beat; by lowering heart rate, contractility, and systolic pressure, beta-blockers reduce dP/dt and the overall wall stress. This reduction in pulsatile stress helps prevent the aneurysm from enlarging as quickly, buying time before surgical repair is needed. This approach is particularly emphasized in conditions like Marfan syndrome, where reducing mechanical stress on the aorta is crucial over the long term.

Other drug classes can help control blood pressure, but they don’t consistently slow aneurysm growth to the same extent. Nitrates can cause reflex tachycardia, which may increase wall stress. Diuretics lower volume but have less impact on peak wall tension. ACE inhibitors or ARBs lower blood pressure and may have remodeling benefits, but beta-blockers remain the class most associated with slowing expansion of thoracic or abdominal aortic aneurysms.