Implementation of a Risk-Based Heparin Protocol for Postpartum Venous Thromboembolism Prevention

Abstract

Objective: To evaluate the effect of a postpartum risk-based low-molecular-weight heparin protocol for venous thromboembolism prevention.

Methods: We conducted a retrospective cohort study of postpartum women at a safety net hospital before (2013), during (2014), and after (2015) implementation of a risk-based enoxaparin thromboembolism prevention protocol. The calculated sample size was based on a primary outcome of enoxaparin administration rate. Secondary outcomes included incidence of postpartum thromboembolism, wound complications, and 30-day readmission rates. The prevalence of thromboembolism risk factors and protocol adherence was evaluated in two groups of women before (May 2013) and after (May 2015) protocol implementation. Exact χ or Cochran-Armitage trend tested differences in rates.

Results: Over 3 years, 9,766 deliveries were included. Enoxaparin was administered to 0.28% (95% CI 0.14-0.55) of postpartum women in 2013 (before) compared with 33.46% (95% CI 31.89-35.07%) after protocol implementation (P<.001). Although underpowered to detect a difference in these outcomes, no differences were seen in rates of thromboembolism (0.16%, 0.12%, 0.15%, P=.9), wound complication (0.82%, 1.21%, 0.91%, P=.7), or emergency department visits (8.30%, 7.96%, 8.34%, P=.9), whereas readmissions increased (0.79%, 1.27%, 1.42%, P=.02). Prevalence of thromboembolism risk factors did not differ between women delivered in May 2013 and May 2015. Physician adherence to the protocol was 89.5% in May 2015. Nine women had thromboembolic events after protocol implementation: five received appropriate treatment per protocol, but four did not. In 2014, three of four women with a thromboembolism were inadequately treated compared with one of five in 2015 with the addition of a computerized order set.

Conclusion: Implementation of a low-molecular-weight heparin risk-based protocol for postpartum thromboembolism prevention resulted in high physician adherence and more than 30% of postpartum women receiving enoxaparin. Before implementing such a protocol on a wider scale, a much larger study is needed to evaluate the effect on thromboembolic disease and wound problems.

Figure 1

Algorithm for implemented risk-based, low-molecular-weight heparin venous thromboembolism prevention protocol in postpartum women. Risk factors selected based on the Royal College of Obstetricians and Gynaecologists Green-top Guideline No. 37a.² SCD, sequential compression device; BMI, body mass index; ART, assisted reproductive technology.