Myectomy with mitral valve repair versus replacement in adult patients with hypertrophic obstructive cardiomyopathy: a systematic review and meta-analysis

We evaluated the differences in mitral valve (MV) plasty (MVP) and MV replacement (MVR) with respect to death, postoperative MV dysfunction, reoperation rates and thromboembolic events (DFRE) in patients with hypertrophic obstructive cardiomyopathy and systolic anterior motion of the anterior mitral leaflet-mediated MV regurgitation (HOCM & MR). We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, searching PubMed, Cochrane library and ClinicalTrials.gov for studies that evaluated DFRE in adults with HOCM & MR after MVP/MVR. We used a risk of bias assessment tool for non-randomized studies, and analyses were performed using Cochrane Review Manager 5.3.5 for I-2 statistics, funnel plots and forest plot and the generic inverse variance method for hazard ratios (HRs). We developed qualitative and quantitative syntheses of 35 and 23 studies, respectively, including levels of evidence of 1/2/3/4/5=3/1/11/11/9 and 1/2/3/4/5=0/1/11/11/0, respectively, from January 1980 to August 2017. A statistically significant difference between MVP and MVR favoured MVP for the prevention of DFRE in patients with HOCM & MR, on the basis of a significant reduction of the HR for DFRE: HR=0.68 (0.57, 0.82), I-2=68% (P=0.002). The findings were as follows: (i) MVP should be the first-line treatment in patients with HOCM & MR (accuracy LEVEL A) and (ii) MVR may be harmful if it is used as the first-line treatment (accuracy LEVEL A).