Impact of Device Iterations in MitraClip and PASCAL Systems on Outcomes for High-Risk Degenerative Mitral Regurgitation with Complex Anatomy: Findings from the PRIME-MR Registry

Background: Degenerative mitral regurgitation (DMR) has traditionally been managed with surgical repair as the gold standard. For high or prohibitive surgical risk patients, mitral transcatheter edge-to-edge repair (M-TEER) is a minimally invasive, effective alternative. Since the pivotal EVEREST trial, successive iterations of the MitraClip device (Abbott Vascular) and the newer PASCAL system (Edwards Lifesciences) have aimed to enhance procedural precision, safety, and MR reduction, especially in complex anatomies.

Purpose: This study evaluates the efficacy and safety various MitraClip (MC) iterations and the PASCAL device (PD) in M-TEER patients for relevant DMR using data from a large, multicenter registry.

Methods:
The PRIME-MR (Outcomes of Patients Treated with Mitral Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation) Registry includes 1,926 DMR patients undergoing M-TEER with MC (all iterations) or PD between 2008 and 2022 across 27 European and North American centres. The primary endpoints were residual MR at discharge for efficacy and complication rates per MVARC (Mitral Valve Academic Consortium Criteria) criteria for safety.

Results:
Of 1,926 patients (median age: 82 [interquartile range (IQR) 76; 86] years; 54.1% male; mean EuroSCORE II: 5.3% ± 4.3), age was the main reason for surgical ineligibility (41.9%). The mean effective regurgitant orifice area (EROA) was 0.4 cm² (0.2-0.5 cm²). Leaflet prolapse was the predominant pathology (52.9%), with an eccentric jet in 46.1% of patients. Patients were stratified into cohorts based on device iterations: 821 received MC generation 1 or 2, 677 received MC generation 3, and 349 were treated with either MC generation 4 or PD (Ace/P10). Baseline anatomical complexity, including greater anterior-posterior diameter (MC 1 & 2: 34.0 mm [30.9-39.0] vs. MC 3: 37.0 mm [33.0-41.0] vs. MC 4 & PD: 36.0 mm [32.3-39.5]; p < 0.001), flail gaps (MC 1 & 2: 5.0 mm [3.5-7.0] vs. MC 3: 6.0 mm [4.0-8.0] vs. MC 4 & PD: 5.5 mm [4.0-8.0]; p < 0.001), and flail width (MC 1 & 2: 10.0 mm [7.1-13.0] vs. MC 3: 12.0 mm [10.0-15.0] vs. MC 4 & PD: 11.0 mm [8.0-15.0]; p<0.001) differed significantly among the subgroups.
Technical success was consistent across all device subgroups, with higher rates of none/trace MR at discharge in later iterations (MC 1 & 2: 12.8% vs. MC 3: 16.6% vs. MC 4 & PD: 22.7%; p<0.001). Rates of significant residual MR at discharge (MR severity ≥2+ at discharge) were similar across groups (MC 1 & 2: 37.6% vs. MC 3: 32.9% vs. MC 4 & PD: 32.7%; p=0.10), though newer device iterations showed reduced bleeding and vascular complications (freedom from bleeding complication according to MVARC: MC 1 & 2: 90.4% vs. MC 3: 94.1% vs. MC 4 & PD: 96.0%; p<0.001; freedom from vascular complications: MC 1 & 2: 85.9% vs. MC 3: 96.5% vs. MC 4 & PD: 96.6%; p<0.001). Residual MR was the primary reason for reintervention (MC 1 & 2: n=70 [85.4%] vs. MC 3: n=30 [61.2%] vs. MC 4 & PD: n=9 [39.1%]; p<0.001).
At one-year follow-up, patients treated with newer devices iterations demonstrated better functional outcomes, with a higher likelihood of achieving NYHA class ≤II (MC 1 & 2: 75.7% vs. MC 3: 83.9% vs. MC 4 & PD: 81.7%; p=0.02).

Conclusion:
Advancements in MC iterations and the PD have improved procedural efficacy and reduced complications, enhancing patient outcomes and supporting their use in high-risk DMR populations, even in situations with a complex mitral valve anatomy.

Impact of Device Iterations in MitraClip and PASCAL Systems on Outcomes for High-Risk Degenerative Mitral Regurgitation with Complex Anatomy: Findings from the PRIME-MR Registry

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