Postapproval Registry Shows Continued Benefit of Abbott Vascular's MitraClip TMVR Device

March 15, 2015—Findings from a United States registry of the MitraClip transcatheter mitral valve repair (TMVR) system (Abbott Vascular) show that TMVR outcomes in commercial use compare favorably with preapproval reports. TMVR with the MitraClip is approved for patients at high risk for surgery. The data were presented at the 64th annual scientific session of the American College of Cardiology (ACC) in San Diego, California.

As noted in the ACC’s press release, the US Food and Drug Administration (FDA) approved the MitraClip TMVR system for treatment of patients with degenerative mitral regurgitation who face prohibitive risk from open heart surgery. FDA approval came with a requirement for all patients treated with this system to be enrolled in the American College of Cardiology/Society of Thoracic Surgeons (ACC/STS) Transcatheter Valve Therapy Registry; coverage by the Centers for Medicare and Medicaid Services carries the same stipulation. 

The MitraClip, which remains the only commercially approved alternative to surgical repair of mitral regurgitation, is available in Europe and at approximately 100 centers in the United States. 

According to ACC, this is the first study of outcomes with TMVR outside of a clinical trial since the system was approved. Analyses are based on data from the ACC/STS registry, gathered from 61 hospitals for 564 patients who underwent the procedure between November 2013 and August 2014. Paul Sorajja, MD, Director of the Center for Valve and Structural Heart Disease at Minneapolis Heart Institute in Minneapolis, Minnesota, is the study’s Principal Investigator.

In the ACC announcement, Dr. Sorajja commented, “Our results show that the transcatheter MitraClip system is a safe and effective valve repair treatment for patients with symptomatic mitral regurgitation whose surgical risk is prohibitive. Similar to other transcatheter therapies, TMVR with MitraClip has an operator learning curve, which directs interest to outcomes now that the procedure is being performed outside the context of a clinical trial.” 

The study’s main outcome was success of the procedure, defined as a reduction in mitral regurgitation to a level of moderate or less without later heart surgery or in-hospital death. By this measure, valve repair was successful for 518 patients, or 91.8%, and also reduced mitral regurgitation to mild or less in 63.7%. The investigators found that institutional experience with the procedure and case volume had a bearing on procedural success but not on major adverse outcomes, complications, or device-related events. 

In-hospital mortality was 2.3%, and four of the 13 patient deaths were from heart-related causes. Other outcomes of interest were clinically significant events within 30 days of the procedure. The rate for stroke or transient ischemic attack was 1.2%, and there were no heart attacks. Procedural complications arose in 7.8% of patients, and device-related events appeared in 2.7%. At 30 days of follow-up, 5.8% (26 patients) had died, 15 from heart events; the stroke rate was 1.6%; and 8% had re-entered the hospital for heart failure, noted the ACC announcement.

Dr. Sorajja observed, “Overall, procedure success rates were high, procedural complication and device-related event rates were low, and hospital stays were quite short at an average of 3 days. In addition, 82% of the patients were discharged directly to home from the hospital, with another 10% discharged directly to extended care. These results are remarkable, especially when one considers that these patients are elderly with significant morbidities.” 

Although surgery reduces mitral regurgitation more effectively—when patients are eligible for either TMVR or surgery—Dr. Sorajja emphasized that TMVR is approved for patients at prohibitive risk from open heart surgery. The study’s findings are not applicable to lower-risk patients, although smaller studies have shown similar survival rates for TMVR and surgery in lower-risk patients with different degrees of decrease in mitral regurgitation. 

Limitations of this study include dependence on site reporting of outcomes and its focus only on the in-hospital and early outcomes. Dr. Sorajja advised, “More long-term follow-up is needed to address the clinical significance of residual mitral regurgitation in these and other TMVR-treated patients, but these data give considerable insight into the commercial use of this procedure in the United States. The Transcatheter Valve Registry will allow us to continue to collect and analyze data to improve our understanding of the impact of this treatment option.”