Trial Data Show Benefits for Mitral Valve Clip After Two Years
April 6, 2011 – Data from the EVEREST II study show that patients with significant mitral regurgitation (MR) continue to show benefits from treatment with a catheter-based valve-clip system at one year out to two years. The study investigated Abbott’s MitraClip, which also showed improvements in heart function and reductions in symptoms.
EVEREST II is the first randomized clinical trial to compare a catheter-based mitral valve device to mitral valve surgery. Data from the study were published in The New England Journal of Medicine and presented in a late-breaking clinical trial session at the American College of Cardiology's (ACC) 60th Annual Scientific Session and i2 Summit 2011 in New Orleans.
At two years after treatment, data from 279 patients from the trial demonstrated a clinical success rate of 51.7 percent for patients treated with the MitraClip device compared to a clinical success rate of 66.3 percent for surgery patients (p=0.04) on an Intention-to-Treat (ITT) basis. These results compare with the one-year data, which demonstrated a clinical success rate of 55.2 percent for patients who received the MitraClip device, compared to a clinical success rate of 73.0 percent for surgery patients (p=0.0007). The clinical success rate is defined as freedom from death, from surgery for valve dysfunction, and from moderate to severe MR (3+ or 4+).
In The New England Journal of Medicine, the study authors, who represent a variety of specialties including cardiac surgery and interventional cardiology, state that "although percutaneous repair was less effective at reducing mitral regurgitation than surgery before hospital discharge, at 12 and 24 months the rates of reduction in mitral regurgitation were similar, and percutaneous treatment was associated with increased safety, improved left ventricular dimensions, and clinical improvements in NYHA class and quality of life."
"These results reinforce that the MitraClip device continues to be effective out to two years, confirming the durability of the clinical benefit and the safety profile of the therapy. Surgery also performed well in the trial," said Ted Feldman, M.D., FSCAI, director, cardiac catheterization laboratory, and The Mr. and Mrs. Charles R. Walgreen Chair in Interventional Cardiology, NorthShore University HealthSystem, Evanston, Ill. "The MitraClip system offers an option that addresses the unmet need for a percutaneous approach to treating MR, which may be especially important for many patients who are considered high-risk surgical candidates."
Feldman served as co-principal investigator of the EVEREST II trial, was the lead author of The New England Journal of Medicine publication, and presented the two-year data at ACC.
"In the EVEREST II study, the MitraClip device demonstrated strong safety and meaningful clinical benefits," said Donald Glower, M.D., professor of surgery, cardiovascular and thoracic surgery division, Duke University School of Medicine, Durham, N.C., co-principal investigator of the EVEREST II trial and an author of The New England Journal of Medicine publication. "The MitraClip system's positive risk-benefit profile supports its use as a treatment choice for patients who are not good candidates for surgery and have few other options, including elderly or frail patients, those who are at high risk for surgery, and certain patients with functional MR."
The system includes a catheter-based device that is delivered to the heart through the femoral vein, a blood vessel in the leg. The therapy is designed to reduce significant MR by clipping together the leaflets of the mitral valve, one of the four valves of the heart.
The most common type of heart valve insufficiency, MR affects more than 4 million people in the United States – a prevalence of 11.7 percent of those aged 75 years and older. Significant MR is a debilitating condition in which the heart's ability to function continues to deteriorate over time and may lead to irregular heartbeats, heart failure, stroke, heart attack or death. The condition traditionally has been managed with medications, which can relieve symptoms but do not address the underlying cause of the condition, or open-heart surgery. Many people who suffer from MR are not treated surgically because they are not referred to surgery, are not sick enough, or are too frail for an invasive procedure.
In addition to the clinical success rate at one and two years, data from the study showed the following on an ITT basis:
• At 30 days, the MitraClip system demonstrated superior safety compared to surgery, with 15.0 percent of MitraClip patients and 47.9 percent of surgery patients experiencing a major adverse event (MAE) (p<0.001). Major adverse events are defined as a composite of 12 pre-specified adverse events.
• At one and two years, both the MitraClip and surgery groups experienced a significant reduction (p<0.05) in the end systolic and end diastolic volume of the left ventricle heart chamber compared to baseline, indicating an improvement in heart function. In both groups, the decrease in end diastolic volume that was observed between baseline and one year continued to decrease between years one and two.
• Both the MitraClip device and surgery experienced a statistically significant reduction in New York Heart Association (NYHA) Functional Class symptoms at one year that was sustained through two years. NYHA Functional Class provides a scale that assists in the determination of functional ability in patients with heart disease.
• At two years, 78 percent of patients randomized to the MitraClip device were free from surgery.
For more information: www.abbott.com
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