Transcatheter mitral valve repair yielded positive outcomes in functional, degenerative MR

Transcatheter mitral valve repair was associated with strong immediate outcomes and similar 1-year mortality rates in patients with functional and degenerative mitral regurgitation, according to results from the Transcatheter Valve Treatment Sentinel Pilot Registry.

Real-world data for the use of transcatheter mitral valve repair with the MitraClip (Abbott Vascular) remain limited despite widespread use of that approach in Europe, according to the researchers. They conducted the prospective, independent study in a cohort of 628 patients aged 74.2 ± 9.7 years who underwent the procedure during January 2011 through December 2012 at 25 centers in eight countries in Europe.

Functional mitral regurgitation (MR) was the pathogenesis reported in 72% of the cohort. Highly symptomatic patients — defined as NYHA functional class III or higher — comprised 85.5% of patients. These patients had a logistic EuroSCORE of 20.4 ± 16.7%.

The researchers reported a 95.4% procedural success rate. Patients with functional and degenerative MR experienced similar procedural success rates (P=.662).

Only one clip was required for 61.4% of the cohort.

The in-hospital mortality rate was 2.9%. No differences occurred between the groups in terms of in-hospital mortality.

One-year mortality was estimated to be 15.3%, with functional and degenerative MR regurgitation yielding similar rates of estimated 1-year mortality.

Estimated rehospitalization due to HF at 1 year was reported in 22.8% of patients. This rate was 25.8% in the functional MR group and 12% in the degenerative group, which the researchers noted was a significant difference (P =.009).

Clinicians at 15 centers made 1-year paired echocardiographic data available for 368 consecutive patients. These results indicated a persistent reduction in the degree of MR at that time point, with 6% of patients having severe MR.

David R. Holmes Jr., MD, and Charanjit S. Rihal, MD, from the department of cardiovascular diseases and internal medicine at the Mayo Clinic in Rochester, Minn., described the cohort in an accompanying editorial as “a wonderful source of data.”

David R. Holmes Jr.

“It does not, however, afford the reader the chance of having the full denominator of the entire set of experiences in Europe, nor does it offer a glimpse of what carefully adjudicated data by central laboratories might provide,” they wrote.

Holmes and Rihal mentioned the elderly, symptomatic nature of the cohort. “These are not the sort of patients for whom there is a long roster of cardiovascular surgeons waiting outside the room to talk about scheduling for a surgical date,” they wrote, and highlighted the encouraging outcomes. “These improvements in this elderly, frail group of patients make a marked difference in their life. Importantly, we need to bear in mind that most invasive treatments in medicine (eg, procedures such as knee replacements) are performed to improve quality of life and functional status, and that is arguably the greatest goal of technology.”

Charanjit S. Rihal

The editorialists suggested that the complexity of the procedure is one issue that needs to be addressed in the field. “Professional societies need to continue to define parameters of experience for individual operators and institutions to qualify for procedural performance,” they wrote. “Training programs will continue to evolve and include simulation models, exposure to anatomic specimens and often proctored cases. All of these elements will combine to optimize the outcome of the procedure.”

Patient selection should also evolve, they added. Patients with functional MR comprised the majority of the set, but this group required more rehospitalizations. “There were also differences in the severity of MR, change in left atrial size and nonsignificant changes in left ventricular ejection fraction between the [two] groups,” Holmes and Rihal wrote. “The extent to which these changes will help to guide patient selection is unclear. More data will be needed.”

A final concern is that the placement of one or more clips may cause downstream complications, according to the editorialists.

“This multicenter registry experience is an example of the strength of registries in evaluating the application in broader patient groups,” they wrote. “Such an approach may serve as a template in selected circumstances for post-market approval studies.”

For more information:

Holmes DR. J Am Coll Cardiol. 2014;64:885-886

Nickenig G. J Am Coll Cardiol. 2014;64:875-884.

Disclosure: The researchers report financial disclosures with numerous pharmaceutical and device manufacturers. Please see the study for the full disclosures list. Holmes and Rihal report no relevant financial disclosures.