Impact of a risk-stratified thromboprophylaxis protocol on the incidence of postoperative venous thromboembolism and bleeding.

Efforts to reduce postoperative venous thromboembolism are challenging due to heterogeneity in thromboprophylaxis practice. As a result, a 'one-size-fits-all' approach that accounts for surgery-specific risk, but fails to account for patient-level variation, is often adopted by healthcare networks. Updated clinical practice guidelines have advocated an individualised risk-stratified approach that balances the risk:benefit ratio associated with thromboprophylaxis; however, there are limited data confirming effectiveness of these recommendations on the incidence of postoperative venous thromboembolism and bleeding. We developed the surgical-thrombo-embolism-prevention protocol, a novel risk-stratified algorithm that classified patients into low-, intermediate-, and high-risk profiles according to surgical procedure and patient baseline medical risk. Expert-endorsed risk-specific thromboprophylaxis strategies were then applied. A staged quality improvement program was developed to implement the protocol. We postulated that compliance with the protocol would reduce postoperative venous thromboembolism rates without increasing the incidence of postoperative bleeding. Between June 2013 and March 2018, we evaluated the efficacy, safety and sustainability of this risk-stratified approach in 24,953 surgical admissions at a dedicated cancer centre. By final implementation, program compliance was 91%. Postoperative venous thromboembolism rates reduced from 3.1 per 1000 surgical admissions to 0.6 per 1000 surgical admissions (relative risk reduction 79%; p < 0.005). Postoperative bleeding rates also declined from 10.0 per 1000 surgical admissions to 6.3 per 1000 surgical admissions (relative risk reduction 37%; p = 0.02). Sustained improvement was evident more than 3 years after implementation. Implementation of the surgical-thrombo-embolism-prevention protocol significantly reduced the incidence of postoperative venous thromboembolism supporting its validation at other institutions.