Temporal trends in characteristics and outcomes in patients undergoing percutaneous mitral valve repair for secondary mitral regurgitation
Authors: Kaddoura R , Al-Badriyeh D A O U D , Abushanab D I N A , Al-Hijji M 
Published: November 2023

Abstract

Background and purpose
Several studies have investigated the procedural and clinical outcomes of patients with secondary mitral regurgitation (MR) who underwent percutaneous mitral valve repair. However, temporal trend of patients’ characteristics and outcomes has not been studied in comparison with landmark studies. Thus, this systematic review investigated the temporal trend in patient characteristics and outcomes from observational studies over years in comparison with landmark studies in secondary MR.

Methods
The identified observational studies were grouped into two 5-year periods. The first 5-year period included 36 studies that started recruiting patients at any year between 2008 and 2012, whereas 25 studies in the second 5-year period started recruitment between 2012 and 2018. Pooled data of two every 5-year period were compared with the landmark studies. Multicenter studies with potential overlap in term of recruitment periods were excluded. Variables from observational studies were compared with those of landmark trials using a random-effects model for each variable. R software was used for non-comparative pooling of variables, and the RevMan software was used for the comparative meta-analysis.

Results
EVEREST versus observational studies: In first 5-year period, patients in EVERST program were more likely to have non-ischemic MR aetiology and less likely to be symptomatic at presentation (i.e., NYHA III/IV) or getting implanted cardiac device. They were less likely to have MR grade ≤2+ (OR 0.58, 95% CI:0.44-0.78) post procedure but maintained NYHA class I/II at 12-month follow-up (OR 1.74, 95% CI: 1.38-2.19) with no difference in mortality. In the subsequent 5-year period, there was no change from the former comparisons.
COAPT versus observational studies: In the first period, COAPT patients were more likely to have renal insufficiency and receive beta-blockers and implanted device. They were less likely to present with severe heart failure symptoms or severe MR. There was no difference in post procedure outcomes, but they were more likely to maintain MR grade ≤2+ at follow-up (OR 3.98, 95% CI: 2.15-7.37). In the following period, COAPT patients were more likely to present with MR grade 3+ without a difference in procedural or clinical outcomes except for more chance to maintain procedural success at 12-mont follow-up (i.e., MR grade ≤2+; OR 2.41, 95% CI: 1.27-4.58).
MITRA-FR versus observational studies: In the first period, MITRA-FR patients were less likely to have atrial fibrillation, renal insufficiency, or NYHA class III/IV. They were more likely receive beta-blockers and implanted device. However, there was no difference in post procedure and clinical outcomes. In the second period, there was no major change from the previous comparisons.

Conclusion
Although patients from landmark studies, namely COAPT and MITRA-FR, may have favourable characteristics, this did not translate into better outcome over time.