Percutaneous balloon mitral valvotomy during pregnancy: A systematic review and meta-analysis

Introduction: The objective of this study was to systematically review the maternal and fetal outcomes in pregnant women who underwent percutaneous balloon mitral valvuloplasty (PBMV) during pregnancy.

Material and methods: A search was conducted on MEDLINE and Embase databases to identify studies published between 2000 and 2018 that reported on maternal and fetal outcomes following PBMV performed in pregnancy. Randomized controlled trials, cohort studies, case-control studies, cross-sectional studies and case series with four or more pregnancies in which PBMV was performed during pregnancy were included. Reference lists from relevant articles were also hand-searched for relevant citations. A successful procedure was defined as one where there was a reported improvement in the valve area or reduction in the mitral valve gradient. A random effects model was used to derive pooled estimates of various outcomes and the final estimates were reported as percentages with a 95% confidence interval (95% CI).

Results: Twenty-one observational studies reporting 745 pregnancies were included in the review, all of them having reported outcomes without a comparison group. Most of the studies fell into the low-risk category as determined using the Joanna Briggs Institute (JBI) critical appraisal checklist for case series. Most of the studies (86%) were reported from low- to middle-income countries and PBMV was mostly performed during the second trimester of pregnancy. Forty-three procedures (5.7%) were unsuccessful, nearly half (n = 19) of them reported among women with the severe subvalve disease (Wilkins subvalve score 3 or more). There were 11 maternal deaths among those with suboptimal valve anatomy (severe subvalve disease or Wilkin score >8). Mitral regurgitation was the most common cardiac complication (12.7%; 95% CI 7.3%-19.1%), followed by restenosis (2.4%; 95% CI 0.02%-7.2%). Pooled incidence of cesarean section was 12.1% (95% CI 3.6%-23.8%), preterm delivery 3.9% (95% CI 0.6%-9.0%), stillbirth 0.9% (95%CI 0.2%-2.2%) and low birthweight 5.4% (95% CI 0.2%-14.7%).

Conclusions: PBMV may be an effective and safe procedure for optimizing outcomes in pregnant women with mitral stenosis in the absence of severe subvalve disease.