Timing of operation in asymptomatic severe aortic stenosis.

Calcific aortic stenosis is now the main cause of aortic stenosis in the majority of patients, due to declining incidence of rheumatic fever. Risk factors such as hyperlipidemia play an important role in the progression of aortic stenosis. According to the most recent American College of Cardiology/American Heart Association guidelines, peak velocity greater than 4 m/sec, a mean gradient of more than 40 mmHg and a valve area of less than 1.0 cm(2) is considered hemodynamically severe aortic stenosis. Aortic valve surgery promptly should be done in symptomatic patients due to dismal prognosis without operation. Features such as high aortic valve calcium and positive exercise test identify asymptomatic patients who would benefit from early aortic valve surgery. Due to improvement in surgical techniques and better prosthesis, aortic valve surgery can now be offered at low risk to a selected group of asymptomatic patients with severe aortic stenosis. Currently percutaneous aortic valves are used in very high-risk patients with severe symptomatic aortic stenosis. Their role may expand in the future, depending on the improvements in design and operator experience. Whether advances in molecular cardiology lead to novel therapies in preventing calcific aortic stenosis in the future remains to be seen.