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To evaluate safety endpoints in pregnant women with mechanical heart valves treated with traditional treatment (vitamin-K antagonists throughout pregnancy) and sequential treatment (first trimester heparin followed by vitamin-K antagonists).
We searched in Medline, Embase, Cochrane databases, and proceedings of major international meetings for clinical trials that comparing traditional treatment and sequential treatment. We conducted the search until January 2017. Two independent reviewers reviewed the titles, abstracts and collected the data from studies that met the inclusion criteria. Conflicts between reviewers were resolved by consensus. We extracted study duration, patient characteristics and clinical outcomes. Internal validity was assessed. The primary safety outcomes were maternal mortality, thromboembolic complications, live births and neonatal adverse events. Odds ratios(OR) and 95% confidence interval(CI) were used as the summary statistic. Random-effects model was used for this meta-analysis.
We finally identified 22 trials published in English. It was indicated that traditional treatment had a better performance than sequential treatment in maternal mortality (OR:0.45; 95% CI: 0.12-1.01, p=0.06). Meanwhile, it was showed that there were less thromboembolic complications with traditional treatment(OR: 0.52; 95% CI: 0.32-0.96; p=0.02). We noticed a trend towards favoring sequential treatment for live births (OR:0.82; 95% CI:0.56-1.17;p=0.25). However, we found no statistically significant difference in neonatal adverse events.(OR: 0.93; 95% CI:0.62-2.14; p=0.52).
In broad terms, it is indicated that traditional treatment is associated with significantly lower rates of maternal mortality and also with less live births. Traditional treatment seemed to bring less thromboembolic complications probably due to the risk from crossover therapy in sequential treatment. Last but not the least, there is no significant difference in neonatal adverse events between traditional treatment and sequential treatment. Considering the swing of anticoagulation strategy, further studies are still needed to clarify the ideal treatment for pregnant women with mechanical valves.