Procedure-specific venous thromboembolism prophylaxis: a paradigm from colectomy surgery.

BACKGROUND: Colectomy patients are at high-risk for venous thromboembolism (VTE), but associated risk factors and best prophylaxis in this defined population are only generalized.

METHODS: Fifteen hospitals prospectively collected pre-, peri-, and postoperative variables related to VTE and prophylaxis, in addition to the variables defined by the National Surgical Quality Improvement Program between 2008 and 2009 concerning open and laparoscopic colectomy patients with 30-day outcomes. Symptomatic VTE was the primary outcome, and risk factors were tested for association with VTE using multiple logistic regression.

RESULTS: The cohort included 3,464 patients with a mean age of 65; 53% were female. Overall, the 30d incidence of VTE was 2.2%. VTE prophylaxis included sequential compression devices (SCDs, 11%) alone; pharmacologic prophylaxis alone (15%); and both SCDs and pharmacologic prophylaxis (combined prophylaxis, 74%). VTE was associated with each additional year of age (OR, 1.05; 95% CI 1.02-1.06, P < .001); increased body mass index (OR 1.03; CI 1.01-1.05; P = .02); preoperative anemia (OR 2.4; CI 1.2-4.8; P = .011); contaminated wound (OR 3.4; CI 1.6-7.3; P < .01); postoperative surgical site infection (OR 2.5; CI 1.2-5.2; P < .011); and postoperative sepsis/pneumonia (OR 3.6;CI 1.9-6.7; P < .01). Postoperative factors alone accounted for 32% of VTE risk. When controlling for all other factors, only combination prophylaxis was protective against VTE (OR 0.48; CI 0.27-0.9; P = .02). Operative time, presence of disseminated malignancy, anastomotic leak, transfusion, urinary tract infection, and laparoscopic procedure were not significantly associated with VTE. Propensity matching showed that unfractionated heparin was equivalent to low molecular weight heparin, and the transfusion rate was not increased with pharmacologic prophylaxis compared to SCDs alone.

CONCLUSION: Regardless of preoperative factors, VTE prophylaxis using a combination of SCDs and chemoprophylaxis was associated with significant reduction in VTE and should be standard care for patients after colectomy.