Post-transplant nerve regrowth better with young hearts, quick surgery

July 08, 2002

DALLAS, July 9 - Spontaneous nerve regeneration after a heart transplant is more likely in cases involving young donors, young recipients and fast, uncomplicated surgery, researchers report in today's rapid access issue of Circulation: Journal of the American Heart Association.

Nerve regrowth (reinnervation) to the left ventricle can improve exercise performance, blood flow regulation, and ventricular function. It also allows the sensation of chest pain as an important warning sign of coronary blockage.

Sympathetic nerve fibers are severed during heart transplant surgery. Reinnervation takes time, so it is more frequently observed months or years after surgery. Reinnervation often is partial, but some patients experience no regrowth, explains lead author, Frank M. Bengel, M.D., an assistant professor at Nuklearmedizinische Klink und Polinklinik der Technische Unviersitat in Munchen, Germany. German scientists explored factors that may influence reinnervation in the largest group of patients assessed for ventricular reinnervation to date. The study also investigated the impact of regrowth on transplant survival.

Seventy-seven heart transplant patients (11 of them women) who were not experiencing organ rejection or other severe problems were examined with positron emission tomography (PET scan). A PET scan provides a cross-sectional image of the heart and heart tissue function.

Follow-up ranged from 1.5 years to 19 years after transplantation. Recipients ranged in age from 23 to 60; donor age ranged from 13 to 59. Duration of surgery (measured by the amount of time the recipients' aorta was clamped) varied from about a half hour to nearly 3 hours.

In 52 patients, researchers found partial reinnervation, while 25 patients had no evidence of nerve regrowth when checked at various times after surgery. Among those with regrowth, nerves were restored in 21 percent of the left ventricular heart muscle. Reinnervation was greater with more passage of time after surgery, with hearts from younger donors and in younger recipients. Researchers also noted that recipients who underwent shorter surgery had more reinnervation. Reinnervation did not significantly impact survival.

The molecular mechanisms involved remain unclear. However, researchers note that studies of peripherial nerves show that regeneration of those nerves depend on neural growth factors that may be reduced with increasing age.

"In addition, surgical dissection of the nerves requires nerve fibers to regrow along arteries to reach the new heart," Bengel says. "Extensive scar tissue along this path may impede the regrowth. Hence, extensive reinnervation is more likely if there were few complications during transplant surgery.

"This study suggests that sympathetic reinnervation after heart transplant is not simply a function of time," he says.

While urging that the study be interpreted with caution, researchers conclude that more rapid and intense reinnervation can be expected if hearts of younger donors are chosen and if the procedure is fast and uncomplicated. In addition, transplant recipients who are younger or those with few rejection episodes can expect a higher likelihood of reinnervation and thus higher likelihood for improved exercise capacity and heart function.
-end-
Co-authors of the study are Peter Ueberfuhr, M.D.; Thomas Hesse; Nina Schiepel; Sibylle I. Ziegler, Ph.D.; Siegfried Scholz, M.D.; Stephan G. Nekolla, Ph.D., Bruno Reichart, M.D.; and Markus Schwaiger, M.D.

CONTACT: For journal copies only,
please call: (214) 706-1396
For other information, call:
Bridgette McNeill: (214) 706-1135
Maggie Francis: (214) 706-1397

American Heart Association

Related Heart Transplant Articles from Brightsurf:

Does the new heart transplant allocation policy encourage gaming by providers?
A new national policy was created to make determining who receives a heart transplant more fair.

Tiny biological package gets drug right to the 'heart' of transplant rejection
For patients who receive a heart transplant in the near future, the old adage, 'Good things come in small packages,' may become words to live by.

Survival on heart transplant waiting list
Survival of patients on the heart transplant waiting list was examined in this observational study.

Double surgery improves chances for heart transplant in patients with obesity
Pairing bariatric surgery with LVAD heart surgery may be an effective bridge to heart transplant for obese patients.

Changes in US heart transplant waitlist activity, volume during COVID-19 pandemic
National and regional changes in waitlist inactivations and additions, donor recovery and heart transplant volume during the COVID-19 pandemic are described in this observational study.

Racial, gender disparities observed in heart transplant recipients with COVID-19 infection
Researchers suggest focusing on disparities to help identify which patients with a heart transplant may be at higher risk for a worse course of COVID-19 infection.

Characteristics, outcomes of heart transplant recipients with COVID-19
The characteristics, treatment and outcomes of heart transplant recipients who were infected with COVID-19 in New York City are described in this case series.

PET imaging offers new insights into post-transplant care for heart patients
Myocardial blood flow (MBF) and myocardial flow reserve (MFR) have been identified as accurate indicators for graft failure after cardiac transplantation, according to research published in The Journal of Nuclear Medicine.

Massachusetts General Hospital performs first-of-its-kind heart transplant in New England
Mass General Hospital recently performed the largest number of adult heart transplants in the country using what are known as Donation after Circulatory Death (DCD) donor hearts.

Air pollution may increase mortality risk after heart transplant
Heart transplant recipients who live in areas where particulate matter (PM2.5) air pollution levels reached above national limits for clean air had a 26% higher risk of mortality due to infection, according to a study published today in the Journal of the American College of Cardiology.

Read More: Heart Transplant News and Heart Transplant Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.