Chemoprophylaxis for venous thromboembolism in otolaryngology.

Importance: Venous thromboembolism (VTE) causes significant morbidity and mortality in surgical patients. Despite strong evidence that thromboprophylaxis reduces the incidence VTE, guidelines for prophylaxis in otolaryngology are not well established. Key to the development of VTE prophylaxis recommendations are effective VTE risk stratification and evaluation of the benefits and harms of prophylaxis.
Objective: To evaluate the effectiveness and safety of VTE chemoprophylaxis among a population of otolaryngology patients stratified by risk.
Design, Setting, and Participants: Retrospective cohort study of 3498 adult patients admitted for otolaryngologic surgery at a single-institution academic tertiary care medical center between September 1, 2003, and June 30, 2010.
Interventions: Patients were stratified into 2 groups based on whether they received VTE chemoprophylaxis.
Main Outcomes and Measures: Incidence of VTE and bleeding-related complications within 30 days after surgery.
Results: Of 1482 patients receiving VTE chemoprophylaxis, 18 (1.2%) developed a VTE compared with 27 of 2016 patients (1.3%) who did not receive prophylaxis (P = .75). Patients with Caprini VTE risk scores greater than 7 were less likely to have a VTE with perioperative chemoprophylaxis (5.3% vs 10.4%; P = .06). Of patients with VTE chemoprophylaxis, 3.5% developed a bleeding complication compared with 1.2% of patients without prophylaxis (P < .001). Bleeding complications were associated with concomitant use of antiplatelet medications and chemoprophylaxis. Among patients undergoing free tissue transfer, chemoprophylaxis significantly decreased the incidence of VTE (2.1% vs 7.7%; P = .002) and increased bleeding complications (11.9% vs 4.5%; P = .01). In all other patients, VTE chemoprophylaxis did not significantly influence the likelihood of VTE (1.0% vs 0.6%; P = .12) or bleeding (1.5% vs 0.9%; P = .15).
Conclusions and Relevance: Effectiveness and safety of VTE chemoprophylaxis differed between patient subgroups, defined by Caprini risk score and by procedure. Effectiveness was most evident in patients with high Caprini risk scores and microvascular free tissue reconstruction. Bleeding complications were associated with VTE chemoprophylaxis administered in close proximity to potent antiplatelet therapy. The Caprini risk assessment model appears to be an effective tool to stratify otolaryngology patients by risk for VTE. Patients undergoing free tissue reconstruction merit further study before developing recommendations for VTE prophylaxis because of their higher risk of both VTE and bleeding.