Radionuclide angiography in the management of asymptomatic aortic regurgitation

Left ventricular systolic function is an important determinant of long-term prognosis in patients with chronic aortic regurgitation. In patients undergoing aortic valve replacement, those with preoperative left ventricular dysfunction have a greater risk of postoperative congestive heart failure and death than do those in whom preoperative left ventricular systolic function is normal. However, patients with preoperative left ventricular dysfunction are not a homogeneous group but may be further stratified according to risk on the basis of the severity of symptoms, exercise intolerance, and temporal duration of left ventricular dysfunction. Therefore, asymptomatic patients with reproducible and definite evidence of impaired left ventricular function should undergo operation without waiting for the development of symptoms or more severe left ventricular dysfunction. In addition, among asymptomatic patients with normal systolic function, indexes of left ventricular function are also helpful, especially when measured serially, in predicting the development of symptoms and the need for valve replacement surgery over the course of the next 5 to 10 years. Noninvasive imaging techniques should play a major role in this evaluation, and radionuclide angiography is ideally suited for the quantitative evaluation of systolic function in the volume-overloaded left ventricle. Although the prognostic value of left ventricular ejection fraction at rest is well established, ejection fraction during exercise has little value once age and left ventricular function at rest are accounted for and is of minor importance in formulating patient management decisions.