Does preoperative anemia affect outcomes after lower extremity open bypass?
Al Adas Z, Weaver MR, Nypaver T, Shepard A, Galusca D, and Kabbani L. Does preoperative anemia affect outcomes after lower extremity open bypass? J Vasc Surg 2018; 67(6):e142.
Journal of Vascular Surgery
Objective: Preoperative anemia has been shown in several surgical disciplines to increase adverse events, overall hospital costs, and 30-day mortality. The association between postoperative complications and preoperative anemia has not been fully established in vascular surgery. By using the Michigan State Vascular Quality Initiative (VQI) data for patients who underwent open bypasses for peripheral arterial disease, we sought to determine whether preoperative anemia is a risk factor for postoperative complications in patients undergoing open bypasses for peripheral arterial disease. Methods: A retrospective analysis of a prospectively collected database was performed using VQI data from the Michigan region for all open suprainguinal and infrainguinal bypasses performed between April 2011 and March 2017. Anemia was defined by theWorld Health Organization definition, hemoglobin concentration <13 g/dL for men and <12 g/dL for women, and classified into three groups based on its severity: mild, 10 to 13 g/dL for men and 10 to 12 g/dL for women; moderate, 8 to 10 g/dL; and severe, <8 g/dL. Association between preoperative anemia and postoperative complications was analyzed using univariate and then multivariate analysis, specifically looking at cardiac complications (composite of myocardial infarction, dysrhythmia, and congestive heart failure), acute kidney injury (AKI), and 30-day mortality. Results: During the study period, 1755 bypass procedures, 1288 infrainguinal and 467 suprainguinal, were recorded in the regional VQI registry. Average age was 65 years, and men composed 68% of the cohort. Seventy-nine percent were white. Forty-seven percent (827) were anemic: 70% (n = 584) with mild anemia, 26% (n = 213) with moderate anemia, and 4% (n = 30) with severe anemia. After adjustment for other variables using multivariate regression, mild and moderate preoperative anemia was not associated with cardiac complications, AKI, or 30-day mortality. The incidence of severe preoperative anemia was very low, and the study was not powered enough to detect any association with outcomes for the severe anemia group. However, postoperative blood transfusion was associated with cardiac complications, AKI, and 30-day mortality. Conclusions: Preoperative anemia, at least in its mild and moderate forms, was not associated with postoperative complications or mortality after open bypass for arterial occlusive disease.