TCT: PARTNER shines for TAVI method, long-term durability questions linger

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Sapien transcatheter aortic valve
Image source: Edwards Lifesciences

WASHINGTON, D.C.—Balloon-expandable transcatheter aortic valve implantation (TAVI) should be the new standard of care for patients with aortic stenosis who are not suitable candidates for surgery, despite the higher incidence of major strokes and major vascular events, according to the researchers of the PARTNER trial, which was presented as a late-breaking clinical trial at the 22nd annual Transcatheter Cardiovascular Therapeutics (TCT) conference today. However, the long-term durability of the valves remains an unanswered question.

Martin B. Leon, MD, associate director of the Center for Interventional Vascular Therapy at New York Presbyterian Hospital/Columbia Medical Center in New York City, and the PARTNER investigators randomly assigned patients with severe aortic stenosis, whom surgeons considered not to be suitable candidates for surgery, to standard therapy or transfemoral transcatheter implantation of a balloon-expandable bovine pericardial valve (Sapien, Edwards Lifesciences).

A total of 358 patients underwent randomization at 21 centers (17 in the U.S.) in two arms of 179 patients. The primary endpoint was the rate of death from any cause.

The inclusion criteria included patients with severe calcific aortic stenosis defined as an echo-derived valve area of <0.8 cm 2 (EOA index <0.5cm2) and a mean gradient of >40 mm Hg or jet velocity >4.0 m/s; NYHA functional class II or greater; and a risk of death or serious irreversible morbidity as assessed by a cardiologist and two surgeons that must exceed 50 percent.

The average age of these patients was 83 years, and 20 percent of them were over 90 years.

At 30 days, the rate of all-cause mortality was 5 percent in the TAVI arm compared with 2.8 percent in the standard therapy arm. At one year, the rate was 30.7 percent with TAVI, compared with 50.7 percent with standard therapy.

The rate of repeat hospitalization was 5.6 percent at 30 days and 22.3 percent at one year in the TAVI arm, compared with 10.1 percent at 30 days and 44.1 percent at one year in the standard therapy arm.

Among survivors at one year, the rate of cardiac symptoms (NYHA class III or IV) was lower among patients who had undergone TAVI than among those who had received standard therapy (25.2 vs. 58 percent).

At 30 days, TAVI, as compared with standard therapy, was associated with a higher incidence of major strokes (5 vs. 1.1 percent) and major vascular complications (16.2 vs. 1.1 percent). At one year, TAVI, compared with standard therapy, was associated with a higher incidence of major strokes (7.8 vs. 3.9 percent) and major vascular complications (16.8 vs. 2.2 percent).

For major bleeding complications, the incidence rates were 16.8 percent at 30 days and 22.3 percent at one year in the TAVI arm, compared with 3.9 percent at 30 days and 11.2 percent at one year in the standard therapy arm.

During his presentation, Leon noted that the study incorporated many centers that were on the earliest arch of the learning curve. Of the 17 U.S. centers, only three had any experience with the TAVI technique. “Therefore, it is difficult to assess how much that contributed to the stroke or complication rates,” he said.

In the year after TAVI, there was no deterioration in the functioning of the bioprosthetic valve, as assessed by evidence of stenosis or regurgitation on an echocardiogram. In a video interview with Cardiovascular Business News, Leon said that one caveat is that durability is an important consideration with valve therapies.

“I would just caution people to realize that while the median follow-up time for PARTNER was 1.6 years, valve durability needs to be considered out to five, 10 and 15 years,” he said in the video, “so we need careful follow-up with echocardiograms to ensure that these valves are as durable as the expectation of surgical valves.”

The researchers concluded that in patients with severe aortic stenosis who were not suitable candidates for surgery, TAVI, as compared with standard therapy, significantly reduced the rates of death from any cause, the composite endpoint of death from any cause or repeat hospitalization and cardiac symptoms, despite the higher