RESUMO
BACKGROUND: Pregnancy in women with mechanical valves has a high risk of both valve thrombosis and bleeding as well as adverse effects on the foetus. There is limited data on achieving optimal anticoagulation in pregnancy and management of valve thrombosis, to achieve a successful foetal outcome, while prioritizing the mother's health. While warfarin may carry a lower risk of valve thrombosis, warfarin is teratogenic in the first trimester and is associated with increased foetal loss throughout the pregnancy. Heparin does not cross the placenta but is associated with increased maternal morbidity and mortality. CASE SUMMARY: We describe the case of a pregnant patient with thrombosis of a mechanical mitral valve presenting with an embolic stroke at 22 weeks of pregnancy. The stroke was treated with clot retrieval and resulted in no residual neurological deficit. Two previous pregnancies had been managed with low molecular weight heparin, and both resulted in foetal loss. The patient was determined to continue this pregnancy. She was treated with intravenous unfractionated heparin during the remainder of the pregnancy. She developed worsening heart failure due to persisting valve thrombosis despite maintenance of therapeutic anticoagulation. The patient deteriorated rapidly prior to a planned early elective delivery. Emergency Caesarean section was required followed by valve replacement using extracorporeal membrane oxygenation support with an ultimately successful maternal and foetal outcome. Anticoagulation regimes and treatment of mechanical valve thrombosis in pregnancy are discussed. DISCUSSION: The management of pregnant patients with mechanical valves is complex, especially when valve thrombosis and other complications occur. A multidisciplinary approach is essential and in this case led to successful outcome.
RESUMO
BACKGROUND: Dabigatran is prescribed to increasing numbers of patients with atrial fibrillation (AF). Although routine monitoring is not considered to be useful, measuring drug concentrations can be clinically relevant in specific situations. The aim of this study was the comparison of different functional and non-functional assays for determination of dabigatran concentrations at different timepoints in a real-life patient population with AF. We focused on the differences between assays in identifying patients with low drug concentrations. Furthermore, we studied the effect of glucuronidation on the established concentration as determined with different assays. METHODS: This study established dabigatran concentration ranges in 40 real-life AF patients by an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) reference method and compared these with results from coagulation assays (Hemoclot dTT, LD-dTT and ECA). Samples were taken just before and 2 and 4 h after taking the drug. RESULTS: A wide range of concentrations at different time points was found in this patient group. Coagulation assays correlate best with UPLC-MS/MS results that include the glucuronidated metabolites, showing that the pharmacologically active glucuronides are also measured in coagulation testing. The LD-dTT has the best agreement with UPLC-MS/MS and combines good sensitivity with high specificity. Several patients show consistently low or high drug concentrations, implying that drug exposure differs between patients. CONCLUSIONS: Based on the association of dabigatran concentrations with bleeding and thromboembolic risk, we believe that dabigatran monitoring could be beneficial for further optimizing anticoagulation therapy in AF.
