[Combined first-pass-/equilibrium radionuclide ventriculography for non-invasive evaluation of aortic valve incompetence]

In 15 patients with pure aortic valve incompetence and 5 patients with normal valvular function we determined cardiac output by first-pass-radionuclide ventriculography. In addition, left ventricular stroke volume was evaluated by equilibrium radionuclide ventriculography. The difference between those two volumes in relation to left ventricular stroke volume is the regurgitant fraction. Stroke volume index was calculated as the ratio of enddiastolic-endsystolic count differences of left and right ventricle. Patients with aortic insufficiency demonstrated a regurgitant fraction between 20 and 88%, whilst controls never exceeded 10% (on average-2%). Sensitivity therefore was 100%. In contrast, 2 of 15 patients with aortic valve incompetence showed a stroke volume index within normal range (sensitivity 87%). Regurgitant fraction correlated well with aortographically determined severity of valvular incompetence (r = 0.94). We conclude that combined first-pass-/equilibrium radionuclide ventriculography is a highly sensitive quantitative method for evaluation of aortic insufficiency.