Pathophysiology of valvular aortic stenosis in the elderly

Aortic stenosis in the elderly is related to calcification of either a bicuspid valve or a morphologically normal tricuspid valve. There is increasing evidence that factors relating to atherosclerosis are involved in valvular calcification and that it is an actively regulated process rather than a degenerative one. With severe aortic stenosis left ventricular hypertrophy occurs, decreasing wall stress and supporting the left ventricular ejection fraction. However, with pathologic hypertrophy there is a dropout of myocardial cells, subendocardial ischemia, and fibrosis. Eventually, symptoms of angina, non-Q wave myocardial infarction, exertional syncope, and heart failure occur. Once symptoms begin, the prognosis is poor, with sudden death occurring in about one third of patients who die. In the elderly, symptoms can be recognized very late in the course of the disease since they can be attributed to other problems and since the elderly patient may have reduced physical activity to a minimum. The more comorbidities that exist, the greater the risk of valve replacement. Symptomatic patients with severe aortic stenosis even over age 80 can be operated upon with a relatively low mortality and morbidity. In patients over age 80, prolongation of life for any meaningful length of time is not as important as relief of symptoms and improvement in the quality of life. Thus, it is unlikely that any truly asymptomatic patient over age 80, even with severe aortic stenosis, should be sent to surgery.