Echocardiographic estimation of aortic-valve gradient in aortic stenosis.

Fifty-five consecutive patients with aortic stenosis underwent echocardiography at the time of cardiac catheterization. Left ventricular systolic pressure was estimated from the echocardiogram assuming that peak systolic circumferential was stress was constant. Systolic blood pressure was substracted from the estimated left ventricular pressure to obtain the aortic-valve gradient. Of 44 patients with adequate echocardiograms and catheterization studies, 30 had their aortic gradient accurately estimated by the echocardiogram (r = 0.75). All 30 patients had normal left ventricular systolic function estimated echocardiographically. The echocardiogram underestimated the aortic gradient in all seven patients with poor left ventricular systolic function. An accurate echocardiographic estimate of aortic-valve gradient can be obtained in patients with normal left ventricular function. The technique can identify those patients with insignificant left ventricular outflow obstruction, thereby obviating the need for invasive studies.