Anesthesia Technique and Lower Limb Revascularization Patency
Condition: Regional Anesthesia, Vascular Grafting, Vascular Patency
Study type: Observational

Summary: 
      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).
    

Detailed description: 
      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.
    

Intervention name(s): NSQIP Lower Extremity Open (LEO) procedure-targeted dataset (i.e. undergoing Lower extremity open revascularization) from 2014-2019
Intervention type(s): Procedure
Intervention description(s): Infrainguinal, open lower extremity revascularization procedures
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        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.