A Medical Device Daily

A small, implantable device that helps the heart pump blood offers the promise of keeping alive more women with advanced heart failure until a donor heart is available for transplant, researchers said at this week’s American Heart Association (Dallas) conference in Orlando.

Researchers said Thoratec’s (Pleasanton, California) HeartMate II device performed as well in women as in men.

According to the company, the HeartMate II offers the advantage of being much smaller than the bulkier devices that now perform the same function. Those devices, intended to keep alive patients in need of a heart transplant, previously were too large to be implanted in many women and some smaller men, the company noted.

The findings were presented at an AHA meeting ahead of a FDA review of Thoratec’s application seeking approval of the device. Thoratec funded the study.

FDA reported earlier this week that its outside experts would meet Nov. 30 to consider approving the HeartMate II mechanical heart device (Medical Device Daily, Nov. 6, 2007).

The company said the devices are considered a “bridge” until a donor heart becomes available.

“If we didn’t have a donor heart available, many of these women previously died,” said Roberta Bogaev, MD, medical director of heart failure and cardiac transplantation at the Texas Heart Institute (Houston), who headed the study.

This device is about the size of a D battery, removing those size barriers, the researchers said. It may benefit twice as many women who are waiting for heart transplants, they noted.

The HeartMate II, powered by a battery-run unit outside the body, is an implantable left ventricular assist device for people with severe congestive heart failure and few medical options, the company said.

The study involved 231 patients with advanced heart failure, 52 of them women, treated at 40 U.S. heart transplant hospitals. The women generally had a weakened heart from cancer chemotherapy, a viral infection, pregnancy or unknown cause.

Among 194 patients with six-month follow-up data, survival was virtually identical for men and women.

The study showed 79.5% of women and 80.6% of men survived at the six-month mark, having undergone a transplant, having had the device removed after regaining heart function without a transplant, or having remained on the device still awaiting a transplant.

Women remained on the pump for an average of 175 days, while men did for an average of 130 days.

“The women benefited equally well,” Bogaev said. “We now have a technology that is small enough to offer women and smaller men the opportunity to benefit from mechanical circulatory support.”

In other news from the AHA conference:

• St. Jude Medical (St. Paul, Minnesota) reported that the Resynchronization Therapy In Normal QRS (RethinQ) trial, which studied a subgroup of heart failure patients, most of whom are currently not indicated for cardiac resynchronization therapy (CRT), did not reach its primary effectiveness endpoint of improved oxygen consumption at peak exercise (peak VO₂). While there was a statistically significant improvement in NYHA class, a secondary endpoint, there was no improvement in quality-of-life, six-minute walk or echocardiographic measures in the patients who received CRT, the company said.

John Beshai, MD, director of Pacemaker and Defibrillator Services, and assistant professor of medicine at the University of Chicago School of Medicine, was the principal investigator of the trial.

The RethinQ study, which followed 172 patients for six months, was designed to determine whether CRT could help heart failure patients with a narrow QRS complex (the time required for the heart muscle to contract, as measured by electrocardiogram) and left ventricular mechanical dyssynchrony (when the heart’s main pumping chambers, the ventricles, do not contract together efficiently). Patients with a wide QRS already are indicated for CRT therapy. In the RethinQ study, narrow QRS was defined as 130 milliseconds or less (120 milliseconds or less is considered normal).

St. Jude also reported the one-year results from its 409-patient Management of Atrial Fibrillation Suppression in AF-HF Comorbidity Therapy (MASCOT) trial.

The MASCOT trial was designed to determine whether the St. Jude Atrial Fibrillation (AF) Suppression pacing algorithm prevents permanent AF — the most severe stage of AF — in patients receiving CRT. This AF Suppression algorithm already has been shown to decrease symptoms of paroxysmal AF (where patients experience episodes of AF) in certain pacemaker patients, the company said. MASCOT was a European multi-center, prospective, randomized trial designed to evaluate the development of AF in CRT patients.

The incidence of permanent AF in the control group was much lower (3.3%, representing six patients) than anticipated, according to St. Jude. The incidence of permanent AF was also low, 3.3% (seven patients), in the study group. The low incidence in both groups made it difficult to measure the impact, or to draw conclusions, about AF Suppression therapy’s effects in this subgroup of heart failure patients, the company said. Based on previous studies, the incidence of permanent AF in the control group was expected to be 8% to 9%.