An experimental minimally invasive technique developed by Abbott Laboratories to repair the most common type of heart valve problem appeared to be as durable as surgical repair two years after the procedure, according to analysis of data presented on Tuesday.
Abbott is currently awaiting a U.S. approval decision for its MitraClip mitral valve-repair device, which is already available in Europe.
The company unveiled the primary results of the pivotal MitraClip study in March, but presented new longer-term data and a sub-analysis of patients with mitral regurgitation, or MR, from differing causes at a heart conference in Paris.
The need for subsequent valve surgery was virtually identical between those who experienced successful MR reduction with MitraClip placement or through open-heart surgery, according to preliminary two-year results evaluating 86 of the 217 patients in the trial, researchers said.
About 5 to 7 percent in each group required subsequent surgery, they said.
The data adds to confidence in the long-term durability of the clip, which is delivered to the heart via a catheter through a blood vessel in the leg, researchers said. The clip had proved to be far safer and nearly as effective as open heart surgery when measured after 30 days.
"If we get a good result to begin with, then those patients are going to do pretty well for at least a couple of years," Dr. Ted Feldman, one of the study's lead investigators, said in a telephone interview.
"We have non-randomized data out to three years and many individual patients out beyond five (years after clip placement), so our confidence level is growing even beyond the two years," added Feldman, director of the cardiac catheterization laboratory at NorthShore University HealthSystem in suburban Chicago.
MR, which affects more than 8 million people in the United States and Europe, is caused by a faulty mitral valve that does not close tightly enough, allowing blood to leak backward in the heart. It is a debilitating condition in which the heart's ability to function deteriorates over time, and can lead to serious heart problems or death.
The condition falls into two categories — functional MR, in which the structure of the valve is normal but not working properly due to heart disease, and degenerative MR, caused by a deterioration of the valve tissue.
MitraClip was designed as an alternative to surgery typically used to repair degenerative MR. But a subanalysis of data from the Phase III trial showed the device was equally safe and effective for both types of MR.
The major adverse event rate (MACE) — a composite of 12 serious problems including major stroke, re-operation of mitral valve, urgent cardiovascular surgery, heart attack, kidney failure, and major bleeding — was 8.1 percent for degenerative MR MitraClip patients and 8.2 percent for functional MR 30 days after the procedure.
That compared with a MACE rate of 42.6 percent in the open-heart surgery group.
The functional and degenerative MR groups both showed significant improvement from baseline measures of heart function, symptoms, and quality of life one year after receiving the clip procedure, Abbott said.
"Every analysis reinforces what we found in the first cut we reported; that safety is a remarkable feature of the procedure and that for the right patients this appears to be effective in reducing symptoms. And now as time passes, we're seeing additional evidence of durability," Feldman said.
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