Lungs' pressure needn't threaten heart transplant survival

Heart surgeons at Johns Hopkins say people who need heart transplants can largely avoid transplant failure due to elevated blood pressure in their lungs with the help of proper drug treatment.

Of the more than 2,000 heart transplants performed each year in the United States, up to 20 percent of the patients die or reject their organ within a year due to right heart failure brought on by pulmonary hypertension, infection or immune response.

In a study to be presented Nov. 6 at the American Heart Association's (AHA) annual Scientific Sessions in Orlando, Fla., the Hopkins team found that transplant recipients who needed and got commonly used blood-vessel-opening drugs, such as adenosine, prostaglandins, nitric oxide, and nitroprusside, had the same survival rates as those without high pressure (at 88.8 percent and 89.7 percent, respectively.) Those who did not respond to therapy had a somewhat reduced survival rate (of 84.6 percent).

The findings bring new hope, researchers say, to hundreds more whose physicians fear they are not good candidates for transplant because they have severe pulmonary hypertension.

Results come from a review of patient records provided by the United Network for Organ Sharing (UNOS), on 10,331 men and women who received a heart transplant between 2000 and 2006. UNOS is a national network that allocates donated organs across the United States, including more than 150 medical centers that perform heart transplants.

“These findings are really good news for heart transplant patients and their physicians who are fearful of organ failure from pulmonary hypertension,” says lead researcher Lois Nwakanma, M.D.

“If the pressure buildup in the lungs is effectively controlled, chances of survival are comparable and physicians should not feel constrained about recommending patients with pulmonary hypertension for heart transplantation,” adds Nwakanma, a cardiac surgery and critical care fellow at The Johns Hopkins University School of Medicine and its Heart Institute.

Until now, she says, surgeons were unsure whether drug therapy was of significant benefit to any, some or all patients.

Historically, severe pulmonary hypertension, measured at above 5 Wood units, has carried a high risk of heart failure and death, with or without transplantation. An acceptably safe value, researchers say, is a level of 2.5 Wood units, a calculation of how much pressure is in the lung blood vessel relative to the amount of blood being pumped out by the heart.

“What our data show is really emblematic of the dramatic improvement over the last decade in how we care for heart transplant patients,” says senior study investigator and cardiac surgeon John Conte, M.D.

“Improved technology, such as the use of heart pumps, and better management of drug therapy have really bought us time to help our patients get better and lead long-lasting lives,” says Conte, director of the heart and lung transplantation at Hopkins and an associate professor of surgery.

According to UNOS, average survival rates in men and women one year after heart transplantation were 85 percent in 2006.