The feasibility of resection and prosthetic replacement of left ventricular myocardium as a therapeutic adjuvant in myocardial infarction was assessed in a series of 72 dogs. Intracardiac pressures and cardiac output were measured in each dog several days preoperatively. During temporary cardiopulmonary bypass a large segment of the anterolateral wall of the left ventricle was excised. The defect was closed with either Teflon felt, woven Teflon cloth, or a pedicled diaphragmatic flap. Cardiac outputs and intracardiac pressures were measured immediately before and for several hours after myocardial replacement. Survivors were evaluated for periods up to three years by cardiac catheterization at appropriate intervals and pathological observation.
Forty-four dogs survived longer than 24 hours. The immediate hemodynamic consequences of myocardial replacement were a diminished systemic arterial pressure and a low, fixed cardiac output. The arterial pressure and cardiac output gradually increased over a period of weeks, occasionally attaining preoperative levels. Left ventricular end-diastolic pressures were always within normal limits.
The most common cause of death in the first two postoperative weeks was graft detachment. Observations of healing characteristics revealed Teflon felt to be the most satisfactory prosthesis. The diaphragmatic flap frequently necrosed, and woven Teflon produced intraventricular thrombus and incomplete healing.
This study demonstrated the feasibility of resection and prosthetic replacement of large segments of left ventricular myocardium. Complications of the procedure were related to a temporarily diminished cardiac output and inadequate healing of the prosthesis to myocardium.
- © 1968 American Heart Association, Inc.