Value of echocardiography and nuclear techniques in assessment of valvular heart lesions.Cardiovasc Clin. 1986; 17(1):181-200.CC
Assessment of the severity of valvular regurgitation is possible by nuclear techniques, but overlap with mild, moderate, or severe degrees of valvular regurgitation has been reported. For the individual patient, if a baseline correlation is established between RNA measurements and catheterization derived measurements, RNA may then be used serially to follow the patients. Controversy still persists in defining the optimum time for aortic valve replacement. We do not recommend aortic valve replacement in an asymptomatic patient whose end-systolic dimension is greater than 55 mm and fractional shortening is less than 25 percent. No single measurement at one point in time including a greater than or equal to 5 percent decrease in EF during exercise in the presence of a normal resting EF should be used as an indication for aortic valve replacement. It is our belief that these patients can be followed safely and that aortic valve replacement should be recommended only when symptoms appear or resting LV function deteriorates. Conflicting results have been reported with regard to left ventricular function after aortic valve replacement. In the majority of patients with pure AR, a decrease in left ventricular dimensions and improvement in resting EF and exercise EF does occur. However, the improved exercise EF is still lower than that observed in normal subjects. Regression of left ventricular hypertrophy occurs in the vast majority of patients with aortic stenosis in the late postoperative period following aortic valve replacement. In most patients with pure aortic regurgitation, significant regression of hypertrophy has been reported following aortic valve replacement. However, in some patients with isolated aortic regurgitation or mixed aortic stenosis and aortic regurgitation, the increased left ventricular mass and abnormal left ventricular function persist even after successful aortic valve replacement. With regard to patients with mitral regurgitation undergoing mitral valve replacement, a decrease in LVEF occurs early in the postoperative period and the decrease persists in the late postoperative period. In patients undergoing mitral valve replacement and using intraoperative echocardiographic techniques, patients with significant decreases in ejection fraction can be identified in the operating room. These patients can be treated immediately with drug therapy and/or intraaortic balloon counterpulsation support to ensure maximal opportunity for survival.