Experimental orthotopic heart and bilateral lung transplantation completed without cardiopulmonary bypass.

INTRODUCTION

Most experimental studies of orthotopic heart and lung graft failure are complicated by an inability to eliminate the rejection-specific inflammatory mediator from the cardiopulmonary bypass.

METHODS

The following model was developed in our laboratory to investigate the feasibility of performing an orthotopic heart and bilateral lung transplantation without performing a cardiopulmonary bypass. Nineteen transplants were attempted using 19 pairs of mongrel dogs. The recipient dog (mean weight, 23 kg) was anesthetized, and the ascending aorta, the superior vena cava (SVC), the inferior vena cava (IVC), and the main bronchus were dissected. Then, the donor dog (mean weight, 20 kg) was anesthetized, and the heart and lung block was prepared and explanted from the chest under cardioplegic arrest. A Gore-tex shunt (W. L. Gore; Flagstaff, AZ) was placed side-to-side between the recipient IVC and SVC, and then the donor right atrium was anastomosed to the Gore-tex shunt. The donor ascending aorta was anastomosed to the recipient ascending aorta with a partial clamp. On completion of these anastomoses, the donor heart was reperfused by the recipient heart and allowed to beat. When hemodynamic conditions were stable with double hearts, the recipient SVC and IVC were ligated just proximal to the venous anastomosis and the recipient aorta was ligated proximal to the anastomotic site. The recipient trachea was anastomosed to the donor trachea with an end-to-end anastomosis. Finally, the recipient heart and lungs were removed from the chest and the sternum was closed.

RESULTS

Four of the 19 transplants failed. Three died due to left ventricular dysfunction, and one died due to bleeding. Mean (+/- SD) ischemic time was 67 +/- 11 min with a mean (+/- SD) anastomotic time of 54 +/- 12 min. The 15 survivors were hemodynamically stable with or without the minimal use of inotropic support (dopamine, 2 to 3 microg/kg/min) 6 h after grafting, with normal cardiac output, satisfactory oxygenation, and normal wall motion. The sternotomy was repaired without loss of cardiopulmonary function.

CONCLUSIONS

On the basis of our experiences, the experimental model of orthotopic heart and bilateral lung transplantation completed "off pump" can be technically feasible without the loss of cardiac and pulmonary functions.