Impact of the learning curve on outcomes after percutaneous mitral valve repair with MitraClip and lessons learned after the first 75 consecutive patients.

Aims: Mitral valve regurgitation plays a significant role in the aetiology and course of heart failure. We investigated the impact of the learning curve on outcomes after percutaneous mitral valve repair with MitraClip.

Methods And Results: Outcomes of the first 75 consecutive patients treated with MitraClip at our centre were stratified by subsequent treatment periods (25 patients each). Median total procedure time and device time decreased from 180 and 105 min in period 1 to 95 and 55 min in period 3 (P < 0.005 each). There was an excess of total safety events in period 1 (n = 16) that decreased in periods 2 and 3 (n = 6 and 3, P = 0.0003). Acute procedural success [APS; clip successfully placed and mitral regurgitation (MR) grade ≤2+ at discharge] was 80% in periods 1 and 2, but 92% in period 3 (P = 0.46). At 6 months, improvement in durability and completeness of mitral valve repair was evident: 89.4% of patients in period 3 and 65.0% in period 1 had MR ≤2+ at 6 months (P = 0.03). Within 30 days, no patient sustained myocardial infarction or stroke, and mortality was 2.7% for all patients without significant differences regarding periods. Furthermore, while treatment period did not affect mid-term survival and hospitalization for heart failure, failure of APS, STS (Society of Thoracic Surgeons) score ≥15%, and overt right heart failure at baseline predicted increased mortality.

Conclusion: MitraClip showed a learning curve regarding mid-term durability and completeness of mitral valve repair, and APS predicted mortality. Recently published studies should be interpreted in consideration of these findings.