Current Recommendations of the American Society of Hematology for the Prevention of Thromboembolic Disease and Duration of Prophylaxis in Patients Undergoing Major Surgery

Introduction

Thromboembolic disease is a common cause of perioperative morbidity and mortality in hospitalized patients. The risk of developing deep vein thrombosis and pulmonary embolism increases with the extent of the surgical procedure.

Operations with the highest risk of developing VTE include extensive limb surgeries, especially orthopedic procedures (hip and knee replacements) or trauma surgeries on the lower limbs. Major surgeries in abdominal, urological, or gynecological surgery also carry a significant risk of thromboembolic disease. The risk of VTE further increases with the accumulation of risk factors such as immobilization, dehydration, infection, or cancer.

Currently, the gold standard for perioperative prophylaxis of thromboembolic disease is the administration of low-molecular-weight heparins. The question remains, however, how long to continue prophylaxis after the procedure. The new ASH guidelines compared short-term and extended prophylaxis after major surgeries.

Recommendations for the Duration of Prophylaxis in Extensive Procedures

To create new recommendations, data from 9 systematic reviews were analyzed, including 14 relevant clinical studies. Additionally, 6 other appropriate randomized controlled clinical trials not cited in the systematic reviews were included. The studies generally compared shorter cycles of pharmacological prophylaxis (lasting 4–14 days) with extended cycles of pharmacological prophylaxis (lasting 19–42 days), followed by a monitoring period of 3–9 months for potential bleeding complications and thromboembolic disease.

No significant difference in mortality was observed between the different modalities (relative risk [RR] 0.94; 95% confidence interval [CI] 0.64–1.39). A slight reduction in the risk of symptomatic pulmonary embolism (RR 0.44; 95% CI 0.22–0.85), symptomatic proximal deep vein thrombosis (RR 0.30; 95% CI 0.21–0.42), and distally localized deep vein thrombosis (RR 0.57; 95% CI 0.37–0.87) was described in patients undergoing extended prophylaxis.

With a low degree of certainty in the evidence, a similar risk of severe bleeding (RR 1.00; 95% CI 0.59–1.70) and reoperations (RR 0.82; 95% CI 0.34–1.99) was observed in both regimens.

Conclusion

The American Society of Hematology, in the guidelines published in 2019, recommends an extended cycle of pharmacological prophylaxis for patients undergoing major surgery. Extended prophylaxis generally refers to the administration of anticoagulant preparations for typically longer than 3 weeks, ranging from 19–42 days.

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Source: Anderson D. R., Morgano G. P., Bennett C. et al. American Society of Hematology 2019 guidelines for management of venous thromboembolism: prevention of venous thromboembolism in surgical hospitalized patients. Blood Adv 2019 Dec 10; 3 (23): 3898-3944, doi: 10.1182/bloodadvances.2019000975.