PAS-1: MitraClip Posts Positive 1-Year Outcomes Post-Approval

Patrice Wendling

May 02, 2018

Treatment with the MitraClip device provides meaningful improvements in coronary function and quality of life in degenerative mitral regurgitation (MR), results from the first 2000 patients treated after approval in the United States suggest.

"Commercial use of the MitraClip device remains a safe and effective option for select patients and the present study, I don't think, presents any new concerns during the real-world follow-up of this device," James Hermiller Jr, MD, St Vincent Heart Center, Indianapolis, Indiana, said during a press briefing on late-breaking results at the Society for Cardiovascular Angiography and Interventions (SCAI) 2018 Scientific Sessions.

The MitraClip system (Abbott Structural Heart) was approved in October 2013 in the United States for significant symptomatic degenerative MR in patients at prohibitive risk for surgery but is currently not indicated for functional MR.

Last year, the company took voluntary action to reinforce proper procedures used to deploy the device after reports surfaced of improper use requiring surgical intervention.

Outcomes were also reported last year and subsequently published on nearly 3000 MitraClip procedures in the Society of Thoracic Surgeons/American College of Cardiology (STS/ACC) Transcatheter Valve Therapy (TVT) registry linked with Centers for Medicare & Medicaid Services claims data.

The present Post Approval Study-1 (PAS-1) study also used STS/ACC TVT data but is the first and largest report of echocardiographic and clinical outcomes, including functional and quality of life, through 1 year, Hermiller said.

Among these very sick patients (mean age 80 years; STS score 10%), the implant rate was 97.1%. At the time of the procedure, 86% of patients were in NYHA functional class 3/4 and 4.5%, 18%, and 77% had MR grade 2+, 3+, and 4+, respectively.

At 1 year, the proportion of patients with MR grade 2+ or greater was significantly different (5.1% vs 86.6%; P < .0001): 41% of patients had MR grade 1+, 45.6% had grade 2+, and only 7.3% and 6.1% had grades 3+ and 4+, respectively.

Significant changes were also observed from baseline to 1 year in left ventricular volume (Δ = –8.5 mL; P = .0201) and dimension (Δ = –0.20 cm; P < .0001).

One-year survival was 78.1%, which is very similar to what's been seen in other registries and on par with the original studies, Hermiller said.

Perhaps the most striking change from baseline to 1 year, however, was an "impressive" 38-meter gain in 6-minute walk test distance and a "very dramatic" 30-point gain in quality-of-life scores on the Kansas City Cardiomyopathy Questionnaire (KCCQ), he said.

Ted Feldman, MD, NorthShore University Health-Evanston Hospital, Evanston, Illinois, who was not involved in the study, told theheart.org | Medscape Cardiology that an increase in 6-minute walk test distance "like that is the difference between being able and not being able to go to the bathroom independently, so it is meaningful. And the KCCQ also reflected that, where a 5-point change is thought to be meaningful and it almost doubled in these patients."

For a group with predominantly degenerative MR, the 22% 1-year mortality rate is high but also highlights that these patients are appropriately being selected for MitraClip therapy in clinical practice, Feldman said.

"Some people might interpret the mortality results as poor, but I think it's just a reflection of the population," he said.

Going forward, "The questions we all have are, 'What is the lower floor, the lower end of risk that interventionalists can expect comparable results from MitraClip in surgery?'" Feldman said. "The EVEREST II trial looked at higher-risk operable patients and surgery did better in terms of reducing mitral regurgitation, but now we have a decade of experience. The EVEREST II acute procedure success rate was only 77%, compared to approaching 100% in practice today."

In addition, leaflet detachment occurred in almost 7% of the EVEREST II group but is now a 1% problem, and a third of the patients also had Barlow's disease, which is typically excluded today, said Feldman, who headed the trial.

Notably, enrollment recently began in MITRA-HR, a 1:1 randomized comparison of the MitraClip against repair surgery in surgical higher-risk candidates with severe degenerative MR.

Results on MitraClip repair also are eagerly anticipated from the MITRA-FR, MATTERHORN, and COAPT studies in patients with functional MR, who comprised about 10% of the present cohort.

Hermiller reported receiving honoraria, institutional grant/research support, and consultancy for Abbott Vascular. Feldman reported receiving grants and personal fees from Boston Scientific, Abbott, Edwards, and WL Gore.

Society for Cardiovascular Angiography and Interventions (SCAI) 2018 Scientific Sessions. Presented April 27, 2018.

Follow Patrice Wendling on Twitter: @pwendl. For more from theheart.org | Medscape Cardiology, follow us on Twitter and Facebook.

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