VTE, Thrombophilia, Antithrombotic Therapy, and Pregnancy

Abstract

Summary of RecommendationsNote on Shaded Text: Throughout this guideline, shading is used within the summary of recommendations sections to indicate recommendations that are newly added or have been changed since the publication of Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Recommendations that remain unchanged are not shaded. Abbreviations: APLA 5 antiphospholipid antibody; aPPT 5 activated partial thromboplastin time; HIT 5 heparin-induced thrombocytopenia; INR 5 international normalized ratio; LMWH 5 low-molecular-weight heparin; NNT 5 number needed to treat; PE 5 pulmonary embolism; RR 5 risk ratio; UFH 5 unfractionated heparin

Postpartum venous thromboembolism prophylaxis may cause more harm than benefit: a critical analysis of international guidelines through an evidence‐based lens

“…Similar to the studies by Sultan et al., these findings refute the estimates found in the ninth ACCP VTE guideline 40, 41, 42. During the first week after typical CD, the incidence of VTE is <1/1000 – a magnitude of risk 30 times lower than the 3% minimum felt to counterbalance the harm of LMWH prophylaxis in general surgical patients 12…”

“…Therefore, estimates of the incidence of clinically relevant DVT after CD are markedly inflated: 0.5% and 4% for low‐risk and high‐risk women, respectively. These values are not plausible to experienced obstetricians, who rarely encounter women with clinical VTE 19, 40. It is not known whether postpartum women have an incidence of symptomatic DVT approximately one‐tenth that of asymptomatic DVT.…”

“…Obstetric VTE guidelines from the ACCP, Australia, Canada, New Zealand, Sweden and the Royal College of Obstetricians and Gynaecologists (RCOG) are based on case–control studies reporting relative risks of VTE in women with various risk factors and screening studies that report asymptomatic DVT 19, 20, 21, 22, 23. Risk‐scoring systems based on these data have not been validated.…”

A risk–benefit analysis of factor V Leiden testing to improve pregnancy outcomes: a case study of the capabilities of decision modeling in genomics

“…A genomic test for the FVL mutation has been commercially available since 2003, but recent consensus recommendations differ on the indications that require screening among pregnant women, and the strength of evidence underlying these recommendations is weak. 9,10 The FVL mutation affects an estimated 5% of European Americans, and estimates range from 0.5 to 2.5% among Americans of other ancestries. 11 Heterozygous carriers of the FVL mutation have a three-to eightfold increased risk of experiencing venous thromboembolisms (VTEs) and homozygous carriers are estimated to have a further elevated risk wherein the estimates range from a nine-to 80-fold increased risk as compared with noncarriers.…”

“…13 However, the uncertainty in study findings and strong influence of patient values and preferences for medical treatment during pregnancy have not allowed decision makers to impart strong recommendations on the clinical scenarios that warrant FVL testing and treatment. 9 A risk-benefit analysis of factor V Leiden testing | BAJAJ and VEENSTRA…”