Preoperative anemia is an important, modifiable risk factor among surgical patients. However, data is scarce on the impact of preoperative anemia on postoperative outcomes after infrainguinal bypass.
In this multi-institutional analysis, data were retrospectively collected on all infrainguinal bypass procedures performed between 2010 and 2020. Patients were grouped by preoperative hemoglobin according to the National Cancer Institute anemia scale (mild, 10 g/dL – lower limit of normal; moderate, 8.0-9.9 g/dL; severe, 6.5-7.9 g/dL). Multivariable comparisons were performed using logistic regression analysis.
A total of 492 patients underwent bypass for peripheral artery disease over the 10-year study period. Median preoperative hemoglobin was 11.0 g/dL (IQR 9.5-12.7), and median follow-up was 1.7 years. Preoperative anemia was prevalent among bypass patients (mild 52.4% [n=258], moderate 26.4% [n=130], severe 5.1% [n=25]). Women were more likely to have moderate (49.2% [women] vs 50.8% [men]) or severe anemia (52.0% [women] vs 48.0% [men]) compared with normal hemoglobin (17.7% [women] vs 82.3% [men]) (p<0.001). Patients with preoperative anemia were more likely to present with tissue loss (22.8% [normal] vs 47.7% [moderate] vs 52.0% [severe], p=0.01). Bypass target and conduit types were similar between groups. Anemic patients had longer median hospital length of stay (LOS) compared with non-anemic patients (4 days [normal] vs 5 days [mild] vs 6 days [moderate] vs 7 days [severe], p<0.001). Postoperative mortality at 30-days was similar across anemia groups (2.5% [normal] vs 4.6% [moderate] vs 8.0% [severe], p=0.23). On multivariable analysis, however, postoperative mortality was independently associated with severe anemia (OR 7.5 [1.2-48.8], p=0.04) and male gender (OR 7.5 [1.2-26.4], p=0.03).
Preoperative anemia is common among patients undergoing infrainguinal bypass surgery, and is an independent risk factor for postoperative mortality. Future investigation is needed to determine whether correction of anemia improves postoperative outcomes in these high-risk patients.

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