NEW ORLEANS — A next-generation heart pump outperformed an older version in advanced heart failure patients, early results from a new study found.

The pumps, called left ventricular assist devices, or LVADs, take on the function of pumping blood to the body. For some of the thousands of people who have received one, the device is temporary as they await a heart transplant. For others, it is permanent.

Placed next to the heart and attached to the aorta, the device connects to an external, wearable controller and battery. But LVADs can lead to serious problems, such as blood clots, embolisms and bleeding complications.

In the new study, called MOMENTUM 3, researchers compared two LVADs: the currently available HeartMate II and the newer HeartMate 3. The trial included 294 patients getting the device either permanently or as a “bridge to transplant.”

After six months, 86 percent of patients with the newer device survived without it malfunctioning or causing a disabling stroke compared with 77 percent of patients receiving the current model.

“We were surprised with the findings,” said the study’s lead investigator Mandeep R. Mehra, M.D., medical director of the Brigham and Women’s Hospital Heart and Vascular Center in Boston.

He expected the new device would be at least as good as the previous model, but didn’t anticipate the clear superiority.

The study was presented Wednesday at the American Heart Association’s Scientific Sessions and published online in the New England Journal of Medicine.

Experts said there’s a rising demand for LVADs.

“We’ve hit a ceiling of available donor hearts at the same time the population of patients with advanced heart failure has continued to increase,” said heart surgeon Timothy Gardner, M.D., medical director of the Center for Heart & Vascular Health at Christiana Hospital in Newark, Delaware, who was not part of the study.

Last year in the United States, there were about 2,800 heart transplants. Nearly 4,100 people are currently on the waiting list.

HeartMate 3 stands to be “incrementally better than the prior generation,” Gardner said. “With earlier VADS, many, many patients, maybe most, had complications.”

Researchers will continue to follow patients for up to two years, along with about 700 other patients who enrolled.

HeartMate 3 is approved in Europe. Its manufacturer, Thoratec, a division of St. Jude Medical, said it plans to apply for Food and Drug Administration approval for use in bridge-to-transplant patients.

New features of the HeartMate 3 were engineered to reduce common LVAD complications, Mehra said. The device uses a fully magnetic levitation system to “float” the pump rotor, which helps eliminate friction from moving parts that can damage blood cells and cause clots. The same technology has been used in high-speed Japanese bullet trains, he said.

The new pump also can temporarily speed up and slow down to help prevent stagnation of blood in the pump. Mehra compared the progress of LVAD technology to the “evolution of cars from Model Ts to self-driving cars.”

Longer-term results are needed to show whether the new device can reduce the risk of gastrointestinal bleeding, said Mark Slaughter, M.D., chief of the department of Thoracic and Cardiovascular Surgery at the University of Louisville. Gastrointestinal bleeding risk was the same — 15 percent — with both devices.

LVADs “may be an almost immediate rescue” of patients who are essentially dying, Gardner said. “These are people who can’t get out of a chair or bed and have extreme difficulty breathing.”

The HeartMate 3 is smaller, “with better mechanical properties that can be expected to make it safer and implanted much more easily than previous generations,” Gardner said.

Heart failure specialist Clyde Yancy, M.D., said the new device gives people with advanced heart failure hope.

“For a disease that is otherwise absolutely fatal, that’s a good story,” said Yancy, chief of cardiology at Northwestern University Feinberg School of Medicine, who was not part of the study. “I’m delighted that we now have more confidence that the care we are providing to desperately ill patients will help them more and more.”

Mehra said, “Given what I’ve seen, if I were to need an LVAD today, I would want the HeartMate 3.”