When is it safe to start thromboprophylaxis after splenic angioembolization?

Background: Thromboprophylaxis after blunt splenic trauma is complicated by the risk of bleeding, but the risk after angioembolization is unknown. We hypothesized that earlier thromboprophylaxis initiation was associated with increased bleeding complications without mitigating venous thromboembolism events.

Methods: All blunt trauma patients who underwent splenic angioembolization within 24 hours of arrival were identified from the American College of Surgeons Trauma Quality Improvement Program datasets from 2017 to 2019. Cases with <24-hour length of stay, other serious injuries, and surgery before angioembolization were excluded. Venous thromboembolism was defined as deep vein thrombosis or pulmonary embolism. Bleeding complications were defined as splenic surgery, additional embolization, or blood transfusion after thromboprophylaxis initiation. Data were compared with χ² analysis and multivariate logistic regression at P < .05.

Results: In 1,102 patients, 84% had American Association for the Surgery of Trauma grade III to V splenic injuries, and 73% received thromboprophylaxis. Splenic surgery after angioembolization was more common in those with thromboprophylaxis initiation within the first 24 hours (5.7% vs 1.7%, P = .007), whereas those with the initiation of thromboprophylaxis after 72 hours were more likely to have a pulmonary embolism (2.3% vs 0.2%, P = .001). Overall, venous thromboembolism increased considerably when thromboprophylaxis was initiated after day 3. In multivariate analysis, time to thromboprophylaxis initiation was associated with bleeding (odds ratio 0.74 [95% confidence interval 0.58-0.94]) and venous thromboembolism complications (odds ratio 1.5 [95% confidence interval 1.20-1.81]).

Conclusion: This national study evaluates bleeding and thromboembolic risk to elucidate the specific timing of thromboprophylaxis after splenic angioembolization. Initiation of thromboprophylaxis between 24 and 72 hours achieves the safest balance in minimizing bleeding and venous thromboembolism risk, with 48 hours particularly serving as the ideal time for protocolized administration.