SINGLE-LUNG TRANSPLANTATION FOR CANINE PULMONARY-HYPERTENSION

Background: In spite of recent reports of the clinical application of single lung transplantation for pulmonary hypertension, there is littl e underlying experimental data because of the lack of a reliable anima l pulmonary hypertensive transplant model. We have established a pulmo nary hypertensive model in beagles with dehydromonocrotaline and have been able to measure cardiopulmonary hemodynamics accurately and use c irculatory assists during procedures. The purpose of this study was to determine whether single lung transplantation could be performed afte r the protocol of clinical procedure. Methods and Results: In six cont rol dogs, allografting was successfully completed without cardiopulmon ary bypass. Because one pulmonary hypertensive recipient dog died of r ight ventricular failure during the procedure without cardiopulmonary bypass, we used bypass for allografting in five pulmonary hypertensive dogs. Cardiopulmonary bypass lowered pulmonary artery pressure, allow ing pulmonary arterial clamping and avoiding right ventricular overloa d. All pulmonary hypertensive dogs undergoing bypass were successfully weaned from bypass, indicating a good hemodynamic response to transpl antation. In pulmonary hypertensive dogs, transplantation resulted in significant decreases in systolic pulmonary artery pressure and pulmon ary vascular resistance, and a significant increase in blood flow to t he graft lung, whereas in controls the results were the reverse. Concl usions: Thus we were able to show that hemodynamics improved after sin gle lung transplantation with cardiopulmonary bypass in a new pulmonar y hypertensive animal model. These relatively larger animals are valua ble for further studies of single, double, bilateral, and heart-lung t ransplantation for pulmonary hypertension.