The Annals of Thoracic Surgery, Vol 53, 1062-1067, Copyright © 1992 by The Society of Thoracic Surgeons
Efficacy of isoproterenol on the failing transplanted heart during early acute rejection
E De Broux, G Lagace and C Chartrand
Service de Chirurgie Cardiovasculaire, Hopital Ste-Justine, Montreal, Quebec, Canada.
Acute rejection often leads to severe myocardial failure and death. The
beneficial hemodynamic effects of isoproterenol in improving immediate
postoperative heart failure have prompted its routine use after
transplantation. However, because of the physiopathological alterations
documented during rejection, an inappropriate response of the graft to
isoproterenol administration could be expected. Six dogs received
orthotopic transplants and were prepared with implantable devices for
serial hemodynamic studies. The studies were performed on the resting
unanesthetized subject 3 hours after operation when transient heart failure
was present and repeated when myocardial failure secondary to rejection
occurred. After basal state measurement, various doses of isoproterenol
were infused and the hemodynamic responses during each period were
compared. During rejection, the hemodynamic response to 0.05 and 0.10
micrograms.kg-1.min-1 was significantly lower when compared with the
response in the postoperative period. To achieve similar postoperative
chronotropic and inotropic effects, 0.35 microgram.kg-1.min-1 of
isoproterenol was necessary. Isoproterenol is therefore effective in
controlling myocardial failure during acute rejection despite a reduced
sensitivity of the sinoatrial node and myocardial tissue.
