Transfusion Timing and Postoperative Myocardial Infarction and Death in Patients Undergoing Common Vascular Procedures

Background: Perioperative allogenic blood transfusions, specifically packed red bloods cells (pRBC), after vascular surgery procedures are modifiable risk factors that are associated with increased cardiovascular events and 30-day mortality. The aim of this study is to evaluate the effect of transfusion timing (intraoperative vs. postoperative) on the rate of postoperative myocardial infarction (POMI) and death. Methods: Six surgical and endovascular modules within the Vascular Quality Initiative (VQI) from 2013 to 2017 were reviewed at a single institution. Transfusion data on elective and urgent cases were abstracted and all patients who underwent inpatient procedures had routine postoperative troponin/ECG testing. The primary endpoint was POMI utilizing the American Heart Association's third universal definition for myocardial infarction. These criteria include the detection of a rise/and or fall of cTnT with at least one value above the 99th percentile and with at least one of the following 1) symptoms of acute myocardial ischemia, 2) new ischemic ECG changes, 3) development of pathological Q waves, 4) imaging evidence of new loss of viable myocardium or new regional wall motion abnormality in a pattern consistent with ischemic etiology. The secondary endpoint was 30-day all-cause mortality. Multivariable logistic regression analysis was utilized to evaluate the risk of transfusions on POMI and death. Results: We identified 1,154 cases for analysis (299 abdominal aortic aneurysm [EVAR], 117 infrainguinal bypasses, 127 open abdominal aortic aneurysm [AAA], 41 suprainguinal bypasses, 168 thoracic endovascular aortic repair [TEVAR], and 402 peripheral vascular interventions). Overall, the POMI rate was 2% and mortality 1%. Rates of POMI differed by procedure type (P = 0.04), where infrainguinal bypass had the highest rate of POMI at 4%. Death rates did not vary by type of procedure (P = 0.89). Mean number of intraoperative pRBC and postoperative pRBC transfusion was higher for patients with POMI (intraop: 1.3 vs. 0.3, postop: 1.8 vs. 0.4, both P < 0.01) and death (intraop: 1.4 vs. 0.3, postop: 2.5 vs. 0.4, both P < 0.01). In addition, older age and coronary artery disease (CAD) were associated with POMI on univariate analysis. On multivariable analysis for POMI, CAD (odds ratio [OR] = 5.15, 95% confidence interval [CI] [2.00–13.24], P < 0.001), receiving both an intraoperative and postoperative transfusion (OR = 6.20, 95% CI [1.78–21.55], P < 0.01) as well as a postoperative transfusion only (OR = 5.70, 95% CI [1.81–17.94], P < 0.01) compared to no transfusion were associated with higher odds of POMI; however intraoperative transfusion only was not (OR = 3.42, 95% CI [0.88–13.31], P = 0.08). On multivariable analysis, increasing age of the patient was associated with higher odds of death (OR = 1.08, 95% CI [1.01–1.15], P = 0.02) and statin use was highly protective (OR = 0.27, 95% CI [0.10–0.74], P = 0.01), but any intraoperative or postoperative transfusion compared to no transfusion was not associated with death after adjustment. Conclusions: In our series with routine postoperative troponin screening in the inpatient setting, the use of an isolated postoperative transfusion as well as cases requiring both an intraoperative and postoperative transfusion was associated with POMI. However, isolated intraoperative transfusion was not associated with POMI, and we did not identify an association of transfusion with 30-day mortality. These data suggest that the perioperative setting of transfusions is important in its impact on postoperative outcomes and needs to be accounted for when evaluating transfusion outcomes and indications.