The role of regional anesthesia in lower extremity revascularization procedures on reducing graft failure and need for reoperation remains unclear. In this study, we will analyze data from the multicenter National Surgical Quality Improvement Program (ACS NSQIP®) to assess the association between regional anesthesia (RA) and graft outcomes, as compared to general anesthesia (GA). Our primary objective is to determine for patients undergoing elective open lower limb revascularization, whether RA (spinal, epidural, and peripheral nerve block), compared to GA or general anesthesia with regional anesthesia (GA+RA), is associated with higher rates of patent graft within 30 days postoperatively (primary outcome).

Lower limb (infrainguinal) revascularization surgeries are performed for patients with blood flow occlusion, with the goals of improving pain and function. Graft patency is associated with higher quality of life scores. However, open lower limb revascularization is associated with a significant risk of graft failure. Multiple anesthesia options exist for elective open lower limb revascularization, including general and regional (spinal, epidural, peripheral nerve block). The literature has shown mixed results regarding the superiority of regional anesthesia over general anesthesia for morbidity and mortality. In this study, we will analyze data from the multicenter National Surgical Quality Improvement Program (ACS NSQIP®) to assess the association between regional anesthesia (RA) and graft outcomes, as compared to general anesthesia (GA).Our primary objective is to determine for patients undergoing elective open lower limb revascularization, whether RA (spinal, epidural, and peripheral nerve block), compared to GA or general anesthesia with regional anesthesia (GA+RA), is associated with higher rates of patent graft within 30 days postoperatively (primary outcome). Our secondary outcomes are major reintervention, amputation, bleeding requiring transfusion or secondary procedure, venous thromboembolism (VTE), myocardial infarction (MI) or stroke, pneumonia, discharge destination, postoperative length of stay, readmission rate, and death, all within 30 days postoperatively. There will be two composite outcomes: thromboembolism, and morbidity and mortality. We hypothesize that the use of RA is associated with increased graft patency after elective lower limb revascularization compared to GA. Compared to GA, RA is associated with decreased rates of major reintervention, amputation, death (30 days), bleeding requiring transfusion or secondary procedure, VTE, MI or stroke, pneumonia, mortality, composite thromboembolism, and composite morbidity and mortality.; Compared to GA, RA is associated with increased rates of discharge destination being home.

Inclusion Criteria:

• All elective cases within the NSQIP Lower Extremity Open (LEO) procedure-targeted dataset (i.e. undergoing Lower extremity open revascularization) from 2014-2019 will be included.
• Hybrid procedures (where patients had both open and endovascular repair) are included, as long as there is an open component.

Exclusion Criteria:

• Patients will be excluded if they underwent urgent or emergency surgery (identified using NSQIP variable EMERGNCY=1 OR ELECTSURG=0)
• local was the only anesthetic technique listed in principal and additional anesthesia technique.
• missing data on exposure, procedure name, or status of elective surgery. This includes having "other" or "unknown" for BOTH principal and additional anesthesia technique
• Patients with INR >= 1.5 on day of surgery

All elective cases within the NSQIP Lower Extremity Open (LEO) procedure-targeted dataset (i.e. undergoing Lower extremity open revascularization) from 2014-2019 will be included. The estimated sample size is 15,000 based on the NSQIP Participant Use Files.

Elective procedures will be identified using the NSQIP variable ELECTSURG=1. Urgent and emergency procedures are not included, as patients may not being offered RA due to insufficient time and/or unable to withhold anticoagulants/antiplatelets due to acute limb ischemia. Note that age 18 years and older is already part of the NSQIP inclusion criteria. Hybrid procedures (where patients had both open and endovascular repair) are included, as long as there is an open component.

NSQIP data would be free to other researchers from central site.