Blood transfusion during lower-extremity revascularization: NSQIP database outcome analysis

Background: Worse outcomes in transfused patients have been observed in various settings, but little is known about the significance of RBC transfusion in patients with peripheral arterial disease. We queried the NSQIP database to examine the effect of intraoperative blood transfusion on the morbidity and mortality in patients who underwent lower-extremity revascularization. Methods: We analyzed the data from the Participant Use Data File containing vascular surgical cases submitted to the ACS NSQIP in 2005, 2006 and 2007. CPT-4 codes were used to select lower-extremity revascularization procedures. Thirty-day outcomes analyzed were: 1) mortality; 2) composite morbidity; 3) graft/prosthesis failure; 4) return to the operating room for any reason within 30 days; 5) wound occurrences; 6) sepsis or septic shock; 7) pulmonary occurrences; and 8) renal insufficiency or failure. Outcome rates were compared between the transfused and non-transfused groups using the chi2 test. Patients were ranked into five equal-sized groups (quintiles) based on their transfusion propensity. Results: The database contained 8,799 patients who underwent lower-extremity revascularization between 2005 and 2007. Transfusion rates ranged from 4.4% in the lowest propensity quintile to 52.9 in the high propensity quintile. The mortality rate was significantly higher in transfused patients versus non-transfused (chi2 < 0.05) for all but the lowest propensity quintile. After adjustment for transfusion propensity and patient and procedural risks, transfusion of 1 or 2 units remained significantly predictive of mortality, composite morbidity, sepsis/shock, pulmonary occurrences, renal insufficiency/failure and return to the operating room. Risks for these outcomes increased with level of transfusion. The adjusted odds ratios for 30-day mortality ranged from 1.92 (95 C.I. 1.36-2.70) for 1-2 units to 2.48 (95 C.I. 1.55-3.98) for 3 or more units. Conclusion: In a large number of patients undergoing lower-extremity revascularization we have found that there is higher risk of postoperative mortality, pulmonary, renal and infectious complications after receiving intraoperative RBC transfusion. The risk for adverse outcomes increases with higher number of units transfused. Additional studies are necessary to better define transfusion triggers that balance the risk/benefit ratio for blood transfusion.