Anticoagulation regimens during pregnancy in patients with mechanical heart valves: a protocol for a systematic review and network meta-analysis

IntroductionPregnancy in patients with mechanical heart valves (MHVs) is associated with high maternal complications and fetal complications.Anticoagulation treatments serve to decrease their venous clotting risk. Although some anticoagulation regimens have been used for patients during pregnancy with MHVs, no one is definitively superior among different regimens in recent studies. For a better understanding of the clinical treatment which anticoagulation regimen is more effective and safer during the pregnancy in patients with MHVs, a Bayesian network meta-analysis is necessary.Methods and analysisThis protocol has been reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols. Related studies until April 2019 will be searched in the following databases: PubMed, Embase,SinoMed and the using the OVID interface to search for evidence-based medicine reviews. A clinical trial registry (www.ClinicalTrials.gov) was also searched for unpublished trials. Both experimental studies (randomised clinical trials) and observational studies (cohort studies, case–control studies and case series studies) will be included in this study. Quality assessment will be conducted using Cochrane Collaboration’s tool or Newcastle-Ottawa Scale based on their study designs. The primary outcomes of interest will be the frequencies of serious maternal and fetal events. The additional outcomes of interest will be adverse maternal events, mode of delivery and adverse fetal events. Pairwise and network meta-analysis will be conducted using R (V.3.4.4, R Foundation for Statistical Computing, Vienna, Austria) and Stata (V.14, StataCorp). The ranking probabilities will be estimated at each possible rank for each anticoagulation regimen using the surface under the cumulative ranking curve. Statistical inconsistency assessment, subgroup analysis, sensitivity analysis and publication bias assessment will be performed.Ethics and disseminationEither ethics approval or patient consent is not necessary, because this study will be based on literature. The results of this study will be published in a peer-reviewed journal.PROSPERO registration numberCRD42019130659