IMPACT OF ACUTE PULMONARY REJECTION ON CARDIAC-FUNCTION

Background Experiments were designed to define cardiac function in dog s with single lung allografts during acute rejection of the allografte d lung. Methods and Results Left lungs were either autotransplanted (n =4) or allotransplanted (n=8) in adult male mongrel dogs. All allotran splanted animals were maintained on triple-drug immunosuppression (cyc losporine, azathioprine, and steroids) for 5 days after the operation. In 4 allotransplanted animals, treatment was discontinued, allowing t he animals to reject (usually after a further 3 days; rejecting group) ; 4 other allotransplanted animals were maintained on immunosuppressio n for an additional 3 days (immunosuppressed group). Another group of dogs were not operated on but were maintained on the same immunosuppre ssion as the rejecting group (controls). All experimental animals unde rwent fast computed tomographic scanning with measurement of left vent ricular pressure and calculation of ventricular chamber volumes, cross -sectional areas of coronary arteries, myocardial perfusion, and intra myocardial blood volume. Neither cardiac output, left ventricular mass , left ventricular pressure, nor myocardial oxygen consumption was alt ered during acute rejection of lung allografts. However, left ventricu lar contractility (systolic elastance, E(max)) and ejection fraction w ere depressed to approximately one half (P<.05) in acutely rejecting a nimals compared with other groups. The cross-sectional area of the cor onary arteries was less in autotransplanted and allotransplanted treat ed animals than in animals that were not operated on. Cross-sectional area of the coronary arteries was decreased by an additional 30% in th e rejecting group (P<.05). Conclusions The results of this study indic ate that acute rejection of a single lung allograft decreases cardiac performance and reduces diameter of coronary arteries in the recipient . Alterations of circulating humoral factors and activated leukocytes may contribute to these changes.