Clinical Trial Finds Medtronic CoreValve Effective for Extreme Risk Patients

 Lead investigator Dr. Jeffrey J. Popma, director of interventional cardiology at Beth Israel Deaconess Medical Center in Boston, presented results of the Corevalve Extreme Risk Trial at the 25th annual TCT conference. The trial ( funded by Medtronic) which was conducted in 487 patients with symptomatic, severe aortic stenosis, aimed to evaluate the safety and efficacy of the CoreValve in extreme risk patients who, at 30 days, had a greater that 50% risk of predictive operative risk of mortality or serious, irreversible morbidity.

“The primary endpoint was all cause mortality or major stroke at 12 months,” Popma said. In it's final results “The study achieved its primary endpoint of a reduction in all cause mortality or major stroke at one year compared to a rigorously defined OPG.” The study set a performance goal of a 43% composite rate of death or major stroke; results at 12 months showed this rate was at 25.5%.

The CoreValve was also found to reduce paravalvular leak (PVL) in 80% of patients who experienced PVL at one month following implantation. The other 20% stayed the same. “We didn't have anyone that progressed from moderate to severe,” Popma said.

Dr. Michael J. Mack, a cardiac surgeon at Baylor Heart Hospital in Dallas, asked Popma to speculate on the factors that may have contributed to the decreased PVL. “Everybody had their valves sized with CT angiography that allows us to have a three-dimensional picture. So we had a standardized approach to valve selection that, if anything, perhaps put larger valves in for a comparable sizes,” Popma responded. “I think it's primarily due to the fact that the self expanding nitinol frame continued to expand, particularly as it was slightly oversized.” Popma went on to say that the reduction of PVL is “a pretty remarkable finding that needs to be confirmed as everything does.”

The study also showed that the pacemaker rate (which, in this study, was 22.2% of patients who received a pacemaker during the trial) does not impact mortality.

In a separate update on FDA review, Medtronic said FDA has decided to conduct separate reviews for the trials extreme risk and high risk patient studies. “ FDA has determined it has sufficient information to evaluate the safety and efficacy of the Medtronic CoreValve System for this patient group without the need for an external expert panel.”

-Chris Wiltz, Associate Editor, MD+DI
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