Two novel risk factors for postoperative venous thromboembolism: A reconsideration of standard risk assessment and prophylaxis

Background: Postoperative venous thromboembolism (VTE) is usually preventable with adequate prophylaxis. In an institutional study, patients with emergency operations (EO), multiple operations (MO), and perioperative sepsis (PS) were more likely to develop VTE despite standard prophylaxis. Methods: General surgery patients in the NSQIP database from 2011 to 2014 were stratified into VTE and non-VTE groups, and statistical analyses were performed. Results: Among 1,610,086 patients, 13,673 (0.8%) were diagnosed with VTE. The VTE odds ratios for patients with EO, MO and PS were 1.4 (95%CI:1.3-1.5), 1.9 (95%CI:1.7-2.0), and 2.4 (95%CI:2.2-2.5), respectively. VTE odds ratios increased with concurrence of two factors (EO+PS: 2.0 (95%CI:1.9-2.2)) (EO+MO: 2.3 (95%CI:1.9-2.7)) (MO+PS: 2.5 (95%CI:2.2-2.7)) and further still for patients with all three factors (2.7, 95%CI:2.4-3.0). Conclusion: General surgery patients with EO, MO, or PS have a greater likelihood of developing post-operative VTE. These factors are not necessarily captured in contemporary risk assessment models that guide chemoprophylaxis, and so these high-risk patients may receive insufficient prophylaxis. (C) 2020 Elsevier Inc. All rights reserved.