2011 ACC: Aortic Valve Replacement Approach Called Groundbreaking

NEW ORLEANS — April 3, 2011 – High-risk patients with aortic stenosis treated with a minimally invasive approach for aortic valve replacement (AVR) fared as well as their surgical counterparts in overall mortality at one year, reported Craig R. Smith, MD, chief, division of cardiothoracic surgery, New York-Presbyterian Hospital/Columbia, Columbia University, New York, NYin a late-breaking news conference here today.

The study, High Risk Patients with Aortic Stenosis: The Randomized PARTNER,“is the first report of a randomized trial of the conventional AVR versus a minimally invasive system called transcather aortic valve replacement (TAVR) that enrolled candidates whose age and overall health posed high risks for surgery,” he said.

Researchers presented a demonstration of the procedure at the session and focused on the importance of a “hybrid” approach of putting “a surgical and cardiovascular specialist team together, to gain optimal results.”

They estimate that aortic stenosis affects up to 9% of the population older than age 65 years.

TAVR involves delivering an expandable wire mesh stent made from cow tissue via a balloon through the leg artery, or through the ribs if the peripheral arteries are not large enough.

The trial randomized 698 (median age, 81 years) high-risk older patients with severe aortic stenosis among 26 centers to TAVR or AVR. The TAVR group had 348 patients, and there were 350 in the AVR group. Endpoints included all-cause mortality, stroke, and major vascular events.

Mortality (30 day) rates were higher for TAVR (3.4% vs 6.5%) and as far as “improvement in symptoms, both rates were similar.”

High risk was defined as having a 30-day mortality rate of less than or equal to 15%.

Complications, including stroke, were higher for the TAVR at both 30 days (3.8% vs 2.1%) and at one year (5.1 % vs 2.4%).

At thirty days, major CVD complications occurred in 11.0% compared to 3.2 percent for the .AVR group.

However, the TAVR rates were lower for major bleeding (9.3% vs 19.5%) and new onset atrial fibrillation was lower (8.6 vs 16.0, respectively).

Researchers say future directions are to carve out a model to address the risks and benefits, particularly the stroke risks.

The device is not FDA approved, and researchers emphasize the importance of developing a multidisciplinary team and risk models that show the trade offs.

In the companion study of cost effectiveness—Lifetime Cost Effectiveness of Transcatheter Aortic Valve Implantation Compared with Standard Care among Inoperable Patients with Severe Aortic Stenosis: Results from the Randomized PARTNER Trial (Cohort B)—Matthew R. Reynolds, MD, director of economics and quality of life, Harvard Clinical Research Institute, Boston, reported that the life expectancy gain was 1.9 years in TAVR versus AVR, at an “incremental cost effectiveness ratio of about $50,200 for each additional year of life gain, or about $62,000 per each quality-adjusted life year gained.

Commenting of the results, American Heart Association spokesperson Robert Bonow, MD, professor of medicine, Northwestern University, Chicago, said the number of potential candidates could be “fifty to sixty thousand. This is a major breakthrough and will be benefiting those patients who are sick, and would not normally be referred for surgery.”

Some physicians may be concerned about the stroke risks.“It was twice as high in the minimally invasive group,” Dr. Bonow said in an interview.

The trial was funded by Edwards Lifesciences, Inc.