ABNORMAL SYSTOLIC INTRAVENTRICULAR FLOW VELOCITIES AFTER VALVE-REPLACEMENT FOR AORTIC-STENOSIS - MECHANISMS, PREDICTIVE FACTORS, AND PROGNOSTIC-SIGNIFICANCE

Background Dynamic intraventricular flow velocities after valve replac ement for aortic stenosis have been associated with high in-hospital m orbidity and mortality. The aims of the present study were to determin e the mechanisms and preoperative predictors of abnormal flow velocity (AFV) after valve replacement for aortic stenosis and to assess the c linical course of patients with AFV after surgery. Methods and Results One hundred consecutive patients with pure aortic stenosis were studi ed prospectively before operation by cardiac catheterization and Doppl er echocardiography. After surgery, intraventricular flow was studied by Doppler echocardiography at rest, during nipride infusion, and duri ng dobutamine infusion. AFV (defined as a systolic dagger-shaped Doppl er 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 en d-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 cath eterization emerged as predictors of resting postoperative AFV. Patien ts 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 1 1.1+/-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 oc curs in 14% of patients at rest after Valve replacement for aortic ste nosis and can be provoked or worsened by ventricular unloading or inot ropic stimulation. Second, AFV is related more frequently to cavity sq ueezing than to systolic anterior motion of the mitral valve apparatus . Third, a typical pattern (small, hyperdynamic, and asymmetrically hy pertrophied ventricle) is predictive for postoperative AFV and should be taken into account for the postoperative management. Finally, the p resence of AFV at rest is associated with high in-hospital morbidity b ut good long-term prognosis.