Modern Lower Extremity Bypass Outcomes by Anesthesia Type in the Veteran Population

Lower extremity bypass (LEB) revascularization can be performed under general (GA) or neuraxial anesthesia (NA). Studies show that the use of NA may decrease morbidity, 30-day mortality, and hospital length-of-stay (LOS). The goal of our analysis is to examine the differences in postsurgical outcomes following LEB between patients who undergo GA compared to NA in the Veteran Affairs Surgical Quality Improvement Program (VASQIP) database.

After IRB approval, the VASQIP database was assessed for patients who underwent LEB between 1998-2018. Only infrainguinal bypass procedures and anesthesia type classified as "general," "epidural," or "spinal" were included. The neuraxial cohort includes both spinal and epidural anesthesia patients. The Risk Analysis Index (RAI), a validated measure of frailty, was additionally calculated for each patient. Chi squared, paired t-test, and binary logistic regression were used to compare the cohorts.

During this period, 22,960 veterans underwent LEB recorded in VASQIP. Compared to those who underwent surgery under GA, patients with procedures performed using NA were older (66.4 ± 9.6 years vs. 65.3 ± 9 years respectively; P <0.001) and more frail (average RAI score 25.7 ± 7.0 vs. 24.9 ± 6.7; P < 0.001). Operative time was shorter in the NA group (4.1 ± 1.7 hrs vs. 4.7 ± 3.0 hrs; P < 0.001) and fewer cases were emergent (1.55% vs. 4.13%; P <0.001). Patients in the GA group had higher rates of postoperative prolonged ileus (0.31% vs. 0.00%; P = 0.03), pneumonia (1.60% vs. 1.06%; P = 0.025), deep wound infection (2.67% vs. 2.61%; P = 0.01), sepsis (1.68% vs. 0.79%; P < 0.001), reintubation (1.80% vs. 1.30%) (P = 0.04),and number of packed red blood cell (pRBC) transfused intraoperatively (0.39 ± 1.21 units vs. 0.22 ± 0.79 units; P <0.001). There was no significant difference in rate of graft failure, return to the OR, myocardial infarction, death, or LOS. In regression analysis, those undergoing NA were less likely to require pRBC transfusion intraoperatively (OR: 0.43; 95% CI: 0.31-0.61; P < 0.001), however no other outcomes reached statistical significance.

Although younger and less frail, veteran patients undergoing GA for lower extremity revascularization had higher rates of postoperative ileus, pneumonia, deep wound infection, sepsis, and need for transfusion as compared to those undergoing NA. There was no significant difference in the rate of other major complications, myocardial infarction, death or LOS. After adjustment, only intraoperative transfusion remained statistically significant, likely reflecting longer and more complex cases for those that undergo general anesthesia rather than the effect of anesthetic choice itself.