Nerve Regrowth after Heart Transplant

Researchers have found that spontaneous nerve regeneration following a heart transplant is more likely in cases involving young donors, young recipients, and fast, uncomplicated surgery. Their study was published in the July 9, 2002, rapid access issue of Circulation.

Nerve regrowth to the left ventricle can improve exercise performance, blood-flow regulation, and ventricular function. It also allows the patient to feel the sensation of chest pain, an important warning sign of coronary blockage. Sympathetic nerve fibers are severed during transplant surgery. Nerve regrowth takes months or years to develop, and some patients never experience it.

The study involved 77 heart transplant patients (23-60 years old) without organ rejection or other severe problems, who were examined with positron emission tomography (PET) to obtain a cross-sectional image of the heart and heart tissue function. Donor age ranged from 13-59. Follow-up occurred from 1.5 years to 19 years after transplantation. In 52 patients, researchers found partial reinnervation, while 25 patients had no evidence of nerve regrowth. Among those with regrowth, nerves were restored in 21% of the left ventricular heart muscle. Reinnervation was greater as more time passed and in hearts from younger donors and in younger recipients. Patients who had shorter surgery had more regrowth. Reinnervation was not shown to affect survival.

"In addition, surgical dissection of the nerves requires nerve fibers to regrow along arteries to reach the new heart,” said Frank M. Bengel, M.D., assistant professor at the Technical University in Munich (Germany) and lead author. "Extensive scar tissue along this path may impede the regrowth. Hence, extensive reinnervation is more likely if there were few complications during transplant surgery.”