COMPARISON OF HEMODYNAMICS AND EJECTION FRACTION DURING LEFT HEART BYPASS

Temporary mechanical circulatory support during the postcardiotomy period has seen widespread application over the past 5 years. Recovery of sufficient cardiac function to allow removal of such support has usually been assessed by bedside hemodynamic variables during stepwise decrement of assist flows. To assess the efficacy of this approach and obtain prognostic information, 12 patients who required left heart bypass after coronary operations and who showed an indication of ventricular recovery, as evidenced by return of a pulsatile wave on arterial pressure tracing, were studied using blood pool radionuclide angiography during stepwise decrement of assisted flows. Hemodynamic variables (mean arterial pressure, heart rate, central venous pressure, pulmonary artery pressure, cardiac index, and systemic vascular resistance) did not correlate with survival during reduction of assist flows. Pulmonary artery pressure at maximum assisted flows and measured ejection fraction at flows of 60% or less of maximum flows correlated with survival; furthermore, if ejection fraction increased as assist flows were decreased, prognosis appeared excellent. Measurement of left ventricular ejection fraction during stepwise decrement of assisted flows in the postcardiotomy setting may provide valuable prognostic information and more clearly identify those patients who may be successfully separated from mechanical circulatory support.