Transcatheter edge-to-edge repair in severe mitral regurgitation following acute myocardial infarction - aetiology-based analysis

Aims To evaluate the association between transcatheter edge-to-edge repair (TEER) and outcomes in patients with significant mitral regurgitation (MR) following acute myocardial infarction (MI), focusing on the aetiology of acute post-MI MR in high-risk surgical patients. Methods and results The International Registry of MitraClip in Acute Mitral Regurgitation following Acute Myocardial Infarction (IREMMI) includes 187 patients with severe MR post-MI managed with TEER. Of these, 176 were included in the analysis, 23 (13%) patients had acute papillary muscle rupture (PMR) and 153 (87%) acute secondary MR. The mean age was 70 +/- 10 years and 41% were female. PMR patients had fewer cardiovascular risk factors: hypertension (52% vs. 73%, p = 0.04), diabetes (26% vs. 48%, p < 0.01) but a higher left ventricular ejection fraction (45 +/- 15% vs.35 +/- 10%, p < 0.01) compared secondary MR patients. PMR patients were more likely to present in cardiogenic shock (91% vs. 51%, p = 0.001), require mechanical circulatory support (74% vs. 34%, p = 0.01), and had a higher EuroSCORE II (23 +/- 13% vs. 13 +/- 11%, p = 0.011). The median time from MI to TEER was shorter in PMR (6 days) versus secondary MR (20 days) (p < 0.01). Procedural success was similar (87% vs. 92%, p = 0.49) with comparable MR grade reduction. However, PMR patients had significantly higher in-hospital mortality rates (adjusted odds ratio [OR] 3.05, 95% confidence interval [CI] 1.15-8.12, p = 0.02), 30-day mortality rates (unadjusted OR 3.99, 95% CI 1.42-11.26, p = 0.01) and a higher rate of conversion to surgical mitral valve replacement (22% vs. 3%, p < 0.01) (unadjusted OR 8.17, 95% CI 2.15-30.96, p < 0.001). Aetiology of MR, cardiogenic shock, and procedure timing significantly impacted in-hospital mortality. After adjusting for EuroSCORE II and cardiogenic shock, MR aetiology remained the strongest predictor (adjusted OR 6.71; 95% CI 2.06-21.86, p < 0.01). Conclusion Transcatheter edge-to-edge repair may be considered a salvage or bridge procedure in decompensated post-MI MR patients of both aetiologies; however, patients with PMR have a higher risk of mortality and conversion to surgery.