EVIDENCE FOR PARTIAL SYMPATHETIC CARDIAC REINNERVATION FOLLOWING CARDIAC TRANSPLANTATION

Heart transplantation causes total cardiac denervation. Measurements o f plasma concentrations of the main presynaptic noradrenal metabolite, dihydroxyphenylglycol (DOPEG, exclusively neuronal in origin), were u sed to examine the possibility of sympathetic reinnervation of the tra nsplanted human heart. We determined arterial and coronary-venous plas ma concentrations of DOPEG in 15 heart transplant recipients (28-68 ye ars of age at the time of transplantation with the transplant ageing f rom 0.5 to 4 years at the time of investigation) and in nine control p atients (45-75 years of age). In each of the control patients the DOPE G concentration was higher in coronary venous plasma than in arterial plasma (mean arteriovenous increment: 60 +/- 10%; P < 0.001). In the h eart transplant recipients nine patients showed an arteriovenous incre ment in plasma DOPEG. For the mean group results it was found that the ratio of the coronary-venous to arterial DOPEG concentration was posi tively correlated with the time after transplantation (r = 0.92; n = 5 ; P < 0.05). Thus, our data provide neurochemical evidence for partial sympathetic reinnervation in some of the heart transplants. Moreover, it is suggested that the time after transplantation is unlikely to be the only determinant for the occurrence and extent of sympathetic rei nnervation.