Evidence for structural sympathetic reinnervation after orthotopic cardiac transplantation in humans.

Abstract

Early after CT, neither tyramine nor handgrip exercise caused a significant cardiac release of NE, suggesting sympathetic denervation. Late after CT, most patients had a significant, but subnormal, NE release in response to pharmacological or reflex stimuli, suggesting that limited sympathetic reinnervation occurs in most patients after orthotopic CT.

Myocardial Efficiency and Sympathetic Reinnervation After Orthotopic Heart Transplantation

“…It has also been shown that reinnervation remains regionally heterogeneous. 6,7,9,28 Consistently, with the use of PET methodology, which allows direct detection of reappearing myocardial catecholamine uptake and storage, evidence of incomplete reinnervation was found in the present study. Previous work has shown that sympathetic reinnervation contributes to partial restoration of exercise capacity 29 and plays a role for regulation of myocardial blood flow and metabolism.…”

“…Prolonged hypothermic ex vivo storage, 1 episodes of rejection, 2 effects of immunosuppressive therapy, 3 and transplant vasculopathy 4 may all alter the functional and metabolic state. Myocardial sympathetic denervation as the result of surgical interruption of postganglionic nerve fibers 5 is another factor that has been discussed to influence allograft performance by a reduction of local myocardial catecholamine uptake, storage, and release 6,7 and an impaired responsiveness to adrenergic stimulation. 8 Conversely, reappearance of innervation, which has been demonstrated late after transplantation, 6,7 may resolve changes in the denervated heart.…”

“…Myocardial sympathetic denervation as the result of surgical interruption of postganglionic nerve fibers 5 is another factor that has been discussed to influence allograft performance by a reduction of local myocardial catecholamine uptake, storage, and release 6,7 and an impaired responsiveness to adrenergic stimulation. 8 Conversely, reappearance of innervation, which has been demonstrated late after transplantation, 6,7 may resolve changes in the denervated heart. Reinnervation, however, has been shown to remain incomplete and regionally limited.…”

Decreased heart rate and blood pressure in a recent cardiac transplant patient after spinal anesthesia

“…11,[14][15][16] In addition, experiments suggest catecholamine uptake, storage or release from presumed cardiac sympathetic postganglionic neurons in the transplanted heart. 15,[17][18][19] Evidence for parasympathetic reinnervation derives from reports of a high-frequency variability in HR in a small number of transplants, 20,21 and the demonstration of atropine-sensitive reflex changes in HR. 22 In addition, there are a few reports describing vasovagal syncopal-like episodes in cardiac transplant patients.…”

“…Such changes in HR are of particular interest when considered in the context of the controversy regarding reinnervation of the transplanted organ. 1 As the patient had undergone transplantation only five months previously, and, as reinnervation of the transplanted heart (when demonstrable) is not evident before one year after transplantation, 14,18,19,26 the response is unlikely to have been mediated by reflex activation of the sinoatrial (SA) node directly via the central nervous system. Because the patient underwent transplantation using the bicaval anastomosis technique, changes in donor HR could not have been mediated by altered rate of contraction of remnant innervated atrial tissue.…”