Breathing Heavy

Obesity in lung transplant recipients may increase odds for transplant dysfunction

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Overweight or obese people undergoing a lung transplant may have increased risk for complications. Lung donors that smoked can hurt the odds too, but don’t refuse their lungs so quickly.

A recent study followed a group of lung transplant patients for three months after surgery.

The results of the study showed that if the lung donor had been a smoker, or if the transplant recipient was overweight or obese, the odds of developing life-threatening lung complications were higher.

The authors noted previous studies have shown that receiving a lung from a donor who had been a smoker was still better than staying on the waiting list to wait for a non-smoking donor.

"Talk to your doctor about weight loss before transplant surgery."

Joshua Diamond, MD, MSCE, professor of medicine in the Division of Pulmonary, Allergy and Critical Care at the University of Pennsylvania’s Perelman School of Medicine, led an investigation into the risks of donor smoking and recipient obesity in lung transplant surgeries.

In lung transplant terms, the word ‘graft’ refers to implanting a new lung or pair of lungs into a patient. ‘Primary graft dysfunction’ refers to the lung not working the way it should after the transplant. Primary graft dysfunction could mean any kind of problem, ranging from an upper respiratory infection to pneumonia to full-on lung failure.

From the time the lungs leave the donor until they are implanted, or grafted, into the recipient, no blood flows through the lungs. Lack of blood flow in the lungs as they are transported between the donor and recipient bodies, followed by re-starting blood flow in the recipient’s body during surgery, can result in damage to the lungs.

Primary graft dysfunction occurs in around 25 percent of lung transplants and is the main cause of early death in transplant recipients.

For the study, 1,255 lung transplant recipients from 10 medical centers enrolled between 2002 and 2010 were followed for 90 days after transplant surgery.

Primary graft dysfunction was measured by comparing the amount of oxygen given to the patient versus the amount of oxygen in the patient’s blood.

If the lung functions normally, the level of oxygen in the blood closely matches the level of oxygen the patient is receiving. If the lung isn’t functioning normally, the level of oxygen in the blood is less than the level of oxygen being given to the patient.

Primary graft dysfunction grades range between zero for no dysfunction to three for severe dysfunction.

The researchers in this study were most concerned with transplant patients with Grade 3 primary graft dysfunction between 48 and 72 hours after transplant.

A total of 17 percent of patients developed Grade 3 primary graft dysfunction after lung transplant.

If the lung donor had been a smoker, the odds of the recipient developing Grade 3 primary graft dysfunction were almost double.

“Even though donor smoking is tied to higher death rates and incidence of Grade 3 primary graft dysfunction, this doesn’t mean we should prohibit smokers from donating lungs,” said Dr. Diamond.

“Although primary graft dysfunction was higher after receiving a lung from a smoking donor compared with a non-smoking donor, other studies show that overall survival is significantly better than remaining on waiting lists for lung transplantation,” Dr. Diamond continued.

If the lung recipient was overweight, the odds of the recipient developing Grade 3 primary graft dysfunction were also almost double. If the recipient was obese, the odds of developing Grade 3 primary graft dysfunction increased 2.3 times compared to normal weight donors.

Final results of the study showed that patients who developed primary graft dysfunction had a 23 percent risk of dying within 90 days of transplant surgery compared to 5 percent in patients without dysfunction.

Patients with primary graft dysfunction had a 34 percent risk of dying within a year of surgery compared to 11 percent of patients that did not develop primary graft dysfunction.

Other factors that contributed to graft dysfunction included various lung diseases and being put on a machine that takes over the heart and lung function during surgery, which is called cardiopulmonary bypass.

This study was published in the March issue of the American Journal of Respiratory and Critical Care Medicine.

The National Institutes of Health provided funding for this project. No conflicts of interest were declared.

Reviewed by: 
Review Date: 
March 10, 2013
Last Updated:
March 14, 2013