EVEREST II Supports Abbott Vascular's MitraClip to Treat Mitral Regurgitation in High-Risk Patients

July 7, 2014—Twelve-month outcomes of percutaneous mitral valve edge-to-edge repair in high-risk patients in the EVEREST II study were published by Donald D. Glower, MD, et al the Journal of the American College of Cardiology (JACC; 2014;64:172–181). 

The EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) High-Risk registry and the EVEREST II REALISM continued-access study’s high-risk arm studied patients who received the MitraClip device (Abbott Vascular) for mitral regurgitation (MR) in the United States. In October 2013, the company announced US Food and Drug Administration approval and launch of the MitraClip in the United States for patients with significant, symptomatic, degenerative MR who are at prohibitive risk for mitral valve surgery.
 
The EVEREST II study enrolled patients with grades 3 to 4+ MR and a surgical mortality risk ≥ 12% based on the Society of Thoracic Surgeons risk calculator or the estimate of a surgeon coinvestigator after prespecified protocol criteria.

MitraClip significantly reduced MR, improved clinical symptoms, and decreased left ventricular (LV) dimensions at 12 months in this high-surgical-risk cohort, concluded the EVEREST II investigators in JACC.

As reported in JACC, 327 of 351 patients completed 12 months of follow-up. Patients were elderly (76 ± 11 years of age), 70% had functional MR, and 60% had previous cardiac surgery. MitraClip reduced MR to ≤ 2+ in 86% of patients at discharge (n = 325; P < .0001). Major adverse events at 30 days included death in 4.8%, myocardial infarction in 1.1%, and stroke in 2.6% of patients. At 12 months, MR was ≤ 2+ in 84% of patients (n = 225; P < .0001). 

From baseline to 12 months, LV end-diastolic volume improved from 161 ± 56 mL to 143 ± 53 mL (n = 203; P < .0001), and LV end-systolic volume improved from 87 ± 47 mL to 79 ± 44 mL (n = 202; P < .0001). The New York Heart Association functional class improved from 82% in class III/IV at baseline to 83% in class I/II at 12 months (n = 234; P < .0001). The 36-item Short Form Health Survey physical and mental quality-of-life scores also improved from baseline to 12 months (n = 191; P < .0001). The annual hospitalization rate for heart failure fell from 0.79% preprocedure to 0.41% postprocedure (n = 338; P < .0001). The Kaplan-Meier survival estimate at 12 months was 77.2%.

In summing up the study, the investigators found that in patients with severe MR who are at high surgical risk, the percutaneous MitraClip device reduced MR, improved symptoms, and decreased LV dimensions 12 months after deployment. Also, patients with severe MR, high surgical risk, and suitable mitral anatomy should be considered for MitraClip placement to reduce the severity of MR and LV volume, improve symptoms and quality of life, and prevent hospitalization for heart failure.

The investigators advised that more information from ongoing randomized trials is needed to clarify the role of the MitraClip procedure in comparison to clearly defined medical therapy in patients with severe MR who are not candidates for surgical valve repair or replacement. Additionally, refinement of patient selection criteria (ie, distinguishing those with functional versus degenerative MR, reduced LVEF, severe pulmonary hypertension, right ventricular dysfunction, tricuspid regurgitation, pulmonary disease, renal impairment, and overall frailty) is needed to identify those who stand to gain the most benefit from the MitraClip procedure.