Short-term survival is no longer the pivotal issue after heart transplantation but, most heart-transplant patients (Htx) still present with reduced exercise capacity. Besides central factors, peripheral factors such as impaired vasomotricity might play a key role. Particularly, increased endothelin 1 in Htx might limit both their exercise-induced vasodilation and blood flow redistribution toward acting muscles. Similarly, an impaired nitric oxide pathway might participate in exercise capacity reduction after heart transplantation. Indeed, exercise limitation is associated with attenuated endothelium dependant-vasodilation of the peripheral microcirculation.

After presenting data concerning exercise capacity, we will discuss both endothelin and the nitric oxide pathway at rest and during exercise after heart transplantation.