The score settles it? maybe not: Navigating postpartum VTE prophylaxis

Abstract Background: The risk of venous thromboembolism (VTE) increases during pregnancy and continues to rise throughout pregnancy with maximum risk in the postpartum period. The guidelines that stratify patients into VTE risk categories are conflicting. Aims: (1) Evaluate the incidence of postpartum VTE (VTE within 3 months of delivery) over 1 year. (2) Determine the number of patients that would have received VTE prophylaxis based on different society recommendations. (3) Determine the number of patients with VTE that would possibly been prevented with different society recommendations. Methods: Characteristics of 3190 patients who underwent delivery at our medical center were investigated for incidence and risk factors for VTE. Data was collected using the International Classification of Diseases codes and by chart review. Descriptive statistics were calculated. Results: The incidence of postpartum VTE in our patient cohort (n=3190) was 0.25% (8/3190). Most patients were aged ≥30 (66.6%), white (61%) and had BMI >30 (61.1%). The number of patients who had previous history of cancer, lupus, inflammatory bowel disease and sickle cell disease were 77 (2.4%), 12 (0.4%), 25 (0.8%), and 2 (0.1%), respectively. Sixteen (0.5%) patients had a history of provoked VTE, and 76 (2.4%) patients had a family history of VTE. The proportion of patients who had cesarean delivery, postpartum hemorrhage, pre-eclampsia, and multiple gestation pregnancy were 571 (17.9%), 340 (10.7%), 295 (9.2%), and 40 (1.3%), respectively. 46 (1.4%) patients had prolonged hospitalization of >3 days, who were deemed to have decreased mobility, which is an important risk factor for VTE. Mechanical prophylaxis was used postpartum in 465 patients (14.4%), low molecular weight heparin in 55 patients (1.7%), and other anticoagulation in 20 patients (0.6%). Two of the patients with a VTE event within 90 days postpartum received prophylaxis in our cohort. The percentage of patients who would have received pharmacologic VTE prophylaxis based on Royal College of Obstetricians and Gynecologists (RCOG) risk factors criteria, Society of Obstetricians and Gynaecologists of Canada (SOGC), and 'Eubanks’ risk scoring criteria was 61.3% (n=1954), 33.8% (n=1077), and 15% (n=513), respectively. RCOG predicted 7 of the 8 VTE events compared to only 2 of the VTE events predicted by Eubanks. Sensitivity of RCOG was high at 87.5% whereas specificity of Eubanks was high at 0.84. SOGC predicted 4 of the VTE events with a specificity of 0.67 and sensitivity of 0.50. Conclusion: The number of postpartum patients recommended to receive peripartum anticoagulation varies widely depending on the risk scoring tool employed. Optimized risk stratification for peripartum VTE prophylaxis is needed.