Hemodynamic State Early after Prosthetic Replacement of Mitral Valve

Abstract

Cardiac output, stroke volume, and atrial, pulmonary arterial, left ventricular, and systemic arterial pressures were measured preoperatively, during operation, and for 48 hours thereafter in 14 patients undergoing prosthetic replacement of the mitral valve. Cardiac output was usually abnormally low after repair, being lowest 3 to 6 hours after operation. This pattern was different from that in a patient undergoing plication of the posterior leaflet and very different from that in a patient undergoing removal of a left atrial myxoma, who served as controls. Ventricular filling pressure was high, there was no significant diastolic pressure difference across the Starr-Edwards prosthesis, and there was no pressure difference across the left ventricular outflow tract. Blood gas levels and pH were within satisfactory range. The data are interpreted as indicating that impairment of ventricular performance, particularly left, usually contributes significantly to the low cardiac output in these patients. This is probably related in part to preoperative ventricular function. Possible additional contributing factors are discussed.