Association of Prophylaxis and Length of Stay With Venous Thromboembolism in Abdominopelvic Surgery

INTRODUCTION:Extended venous thromboembolism prophylaxis (eVTEp) is recommended for select patients who have undergone major abdominopelvic surgery to prevent postdischarge venous thromboembolism (pdVTE). Criteria for selection of these patients are untested for this purpose and may be ineffective. To address this gap, we investigated the effectiveness of eVTEp on pdVTE rates. METHODS:A retrospective cohort study of patients undergoing abdominopelvic surgery from January 2016 to February 2020 was performed using data from the Michigan Surgical Quality Collaborative. pdVTE was the main outcome. Our exposure variable, eVTEp, was compared dichotomously. Length of stay (LOS) was compared categorically using clinically relevant groups. Age, race, cancer occurrence, inflammatory bowel disease, surgical approach, and surgical time were covariates among other variables. Descriptive statistics, propensity score matching, and multivariable logistic regression were performed to compare pdVTE rates. RESULTS:A total of 45,637 patients underwent abdominopelvic surgery. Of which, 3063 (6.71%) were prescribed eVTEp. Two hundred eighty-five (0.62%) had pdVTE. Of the 285, 59 (21%) patients received eVTEp, while 226 (79%) patients did not. After propensity score matching, multivariable logistic regression analysis showed pdVTE was associated with eVTEp and LOS of 5 d or more (P < 0.001). eVTEp was not associated with LOS. Further analysis showed increased risk of pdVTE with increasing LOS independent of prescription of eVTEp based on known risk factors. CONCLUSIONS:pdVTE was associated with increasing LOS but not with other VTE risk factors after propensity score matching. Current guidelines for eVTEp do not include LOS. Our findings suggest that LOS >5 d should be added to the criteria for eVTEp.