Deep venous thrombosis after repair of nonruptured abdominal aneurysm

Objective: To examine venous thromboembolism (VTE) rates, timing, and risk factors after nonruptured open or endoluminal abdominal aortic aneurysm (AAA) repair. Methods: We queried The American College of Surgeons National Surgery Quality Improvement Program dataset from 2005 to 2009 for open or endoluminal AAA repairs using Current Procedural Terminology and International Classification of Diseases, 9th Edition, codes. Operations performed emergently or for ruptured AAA were excluded. VTE was defined as either deep venous thrombosis or pulmonary embolism requiring treatment within 30 days of operation. VTE was classified as occurring in-hospital or postdischarge. Univariate and multivariable analyses of VTE were performed relative to preoperative and operative risks, including type of repair. Results: Query of the dataset yielded 12,469 patients: 8502 endoluminal (68.2%) and 3967 (31.8%) open repairs. Mean patient age was 73.2 ± 8.7 (standard deviation) years, and 19.8% of patients were women. The 30-day VTE rate was 1.1% (n = 135). Of VTE cases, 30% (40/135) were diagnosed after discharge from the surgical hospitalization. The postdischarge VTE rate was 0.3% after both open and endoluminal repairs. The in-hospital VTE rate was higher in the open group (1.6% vs 0.4%; P <.001), as was median length of stay (7 days vs 2 days; P <.001). Independent preoperative predictors of in-hospital VTE were dyspnea, serum albumin (protective), and history of peripheral vascular disease. With preoperative risk adjustment, in-hospital VTE risk increased with duration of operation and number of units of blood transfused. Open repairs were associated with higher risk for VTE than endoluminal repairs (odds ratio, 1.91; 95% confidence interval, 1.10-3.33; P =.022). VTE was associated with increased 30-day mortality from 1.9% (232/12,102) in patients without VTE to 4.4% (6/135) in patients with VTE (χ² P =.035). Conclusions: VTE after AAA repair was infrequent but was associated with higher mortality, and one-third of VTEs were diagnosed after discharge. Open AAA repair increased risk for in-hospital VTE compared with endoluminal repair. Patients with the identified risk factors may benefit from pharmacologic thromboprophylaxis after AAA repair. Pharmacologic thromboprophylaxis may be unnecessary after endoluminal repair.