Abnormal systolic intraventricular flow velocities after valve replacement for aortic stenosis - Mechanisms, predictive factors, and prognostic significance

Background Dynamic intraventricular flow velocities after valve replacement for aortic stenosis have been associated with high in-hospital morbidity and mortality. The aims of the present study were to determine the mechanisms and preoperative predictors of abnormal flow velocity (AFV) after valve replacement for aortic stenosis and to assess the clinical course of patients with AFV after surgery. Methods and Results One hundred consecutive patients with pure aortic stenosis were studied prospectively before operation by cardiac catheterization and Doppler echocardiography. After surgery, intraventricular flow was studied by Doppler echocardiography at rest, during nipride infusion, and during dobutamine infusion. AFV (defined as a systolic dagger-shaped Doppler spectrum >2 m/s) occurred in 14 patients at rest and in 27 patients during nipride and/or dobutamine infusion. In most patients, AFV was associated with left ventricular cavity squeezing. Left ventricular end-diastolic diameter, preoperative intraventricular flow velocity and septal-to-posterior wall thickness ratio by Doppler echocardiography, and mean transvalvular pressure gradient and ejection fraction by catheterization emerged as predictors of resting postoperative AFV. Patients with resting AFV had a higher incidence of dyspnea or hypotension (64% versus 21%, P<.01) and a longer hospital stay (13.1+/-5.8 versus 11.1+/-2.5, P<.05) than patients without AFV. In contrast, at a 1-year follow-up, no patient with resting AFV died. Conclusions First, AFV occurs in 14% of patients at rest after Valve replacement for aortic stenosis and can be provoked or worsened by ventricular unloading or inotropic stimulation. Second, AFV is related more frequently to cavity squeezing than to systolic anterior motion of the mitral valve apparatus. Third, a typical pattern (small, hyperdynamic, and asymmetrically hypertrophied ventricle) is predictive for postoperative AFV and should be taken into account for the postoperative management. Finally, the presence of AFV at rest is associated with high in-hospital morbidity but good long-term prognosis.