results, and no definitive benefit has been shown. Surgical aortic valve replacement, on the other hand, normalizes the life expectancy of patients with aortic stenosis to that of age- and sex-matched controls and remains the gold standard therapy for patients who have symptoms.

Traditionally, valve replacement has involved open heart surgery, since it requires direct visualization of the valve while the patient is on cardiopulmonary bypass. Unfortunately, many patients have multiple comorbid conditions and therefore are not candidates for open heart surgery. Options for these patients include aortic valvuloplasty and transcatheter aortic valve replacement. While there is considerable experience with aortic valvuloplasty, transcatheter aortic valve replacement is relatively new. In large randomized trials and registries, the transcatheter procedure has been shown to significantly improve longterm survival compared with medical management alone in inoperable patients and to have benefit similar to that of surgery in the high-risk population.

##### CASE 1: SEVERE, SYMPTOMATIC STENOSIS IN A GOOD SURGICAL CANDIDATE

Mr. A, age 83, presents with shortness of breath and peripheral edema that have been worsening over the past several months. His pulse rate is 64 beats per minute and his blood pressure is 110/90 mm Hg. Auscultation reveals an absent aortic second heart sound with a late peaking systolic murmur that increases with expiration.

On echocardiography, his left ventricular ejection fraction is 55%, peak transaortic valve gradient 88 mm Hg, mean gradient 60 mm Hg, and effective valve area 0.6 cm2. He undergoes catheterization of the left side of his heart, which shows normal coronary arteries.

Mr. A also has hypertension and hyperlipidemia ; h i s re n a l a n d pulmonary functions are normal.

##### How would you manage Mr. A's aortic stenosis?

Symptomatic aortic stenosis leads to adverse clinical outcomes if managed medically without mechanical intervention, but patients who undergo aortic valve replacement have age corrected postoperative survival rates that are nearly normal. Furthermore, thanks to improvements in surgical techniques and perioperative management, surgical mortality rates have decreased significantly in recent years and now range from 1% to 8%. The accumulated evidence showing clear superiority of a surgical approach over medical therapy has greatly simplified the therapeutic algorithm.

Consequently, the current guidelines from the American College of Cardiology and American Heart Association (ACC/AHA) give surgery a class I indication (evidence or general agreement that the procedure is beneficial, useful, and effective) for symptomatic severe aortic stenosis. This level of recommendation also applies to patients who have severe but asymptomatic aortic stenosis who are undergoing other types of cardiac surgery and also to patients with severe aortic stenosis and left ventricular dysfunction (defined as an ejection fraction < 50%).

##### CASE 2: SYMPTOMS AND LEFT VENTRICULAR DYSFUNCTION

Ms. B, age 79, has hypertension and hyperlipidemia and now presents to the outpatient department with worsening shortness of breath and chest discomfort. Electrocardiography shows significant left ventricular hypertrophy and abnormal repolarization. Left heart catheterization reveals mild nonobstructive coronary artery disease.