Venous thromboembolism risk in mastectomy and immediate breast reconstruction: analysis of the 2005 to 2011 American College of Surgeons National Surgical Quality Improvement Program data sets

BACKGROUND Venous thromboembolism, including deep venous thrombosis and pulmonary embolism, is a morbid and costly complication following surgical procedures. The authors aim to assess the added risk of venous thromboembolism in patients undergoing immediate breast reconstruction. METHODS The 2005 to 2011 American College of Surgeons National Surgical Quality Improvement Program data sets were used to identify patients undergoing mastectomy with or without immediate breast reconstruction. The dependent variable and our primary outcome was 30-day venous thromboembolism. Venous thromboembolism events were treated as a dichotomous variable. Subgroup analyses were performed with respect to procedure and body mass index stratifications. RESULTS A total of 48,634 patients were identified. Postoperative venous thromboembolism occurred in 184 patients (0.4 percent), including deep venous thrombosis (n = 118) and pulmonary embolism (n = 82). A multivariate regression analysis demonstrated that immediate breast reconstruction, either implant-based (OR, 1.65; p = 0.01) or autologous (OR, 2.14; p = 0.009), was associated with a greater odds of venous thromboembolism. Obesity was also identified as a risk factor for venous thromboembolism: class I (OR, 2.20; p < 0.001), class II (OR, 1.6; p < 0.092), and class III (OR, 2.88; p < 0.001). Impaired patient functional status (OR, 2.56; p = 0.035), recent irradiation (OR, 3.60; p = 0.03), and underlying renal comorbidities (OR, 5.60; p < 0.001) were associated with venous thromboembolism in adjusted analysis. Subgroup analysis of nonobese patients demonstrated that implant reconstruction (0.2 percent versus 0.3 percent; p = 0.383) did not confer an added risk of venous thromboembolism, whereas analysis of obese patients revealed a modality-specific increased risk of venous thromboembolism (0.4 percent versus 0.8 percent versus 1.8 percent; p < 0.001) between mastectomy compared to implant and autologous reconstruction, and for which all intergroup comparisons were significant (p < 0.05). CONCLUSIONS Immediate breast reconstruction is associated with an added risk of venous thromboembolism relative to mastectomy, but this risk is procedure and body mass index dependent. Overall, autologous reconstruction and states of obesity placed patients at significant added risk for venous thromboembolism, particularly when both factors are present. CLINICAL QUESTION/LEVEL OF EVIDENCE Risk, III.