title: Regional Variation in Postoperative Myocardial Infarction in Patients Undergoing Vascular Surgery in the United States.
abstract: BACKGROUND
  The aim of this study is to assess for regional variation in the incidence of postoperative myocardial infarction (POMI) following nonemergent vascular surgery across the United States to identify potential areas for quality improvement initiatives.
  
  
  METHODS
  We evaluated POMI rates across 17 regional Vascular Quality Initiative (VQI) groups that comprised 243 centers with 1,343 surgeons who performed 75,057 vascular operations from 2010 to 2014. Four procedures were included in the analysis: carotid endarterectomy (CEA, n = 39,118), endovascular abdominal aortic aneurysm (AAA) repair (EVAR, n = 15,106), infrainguinal bypass (INFRA, n = 17,176), and open infrarenal AAA repair (OAAA, n = 3,657). POMI was categorized by the method of diagnosis as troponin-only or clinical/ECG and rates were investigated in regions with ≥100 consecutive cases. Regions with significantly different POMI rates were defined as those >1.5 interquartile lengths beyond the 75th percentile of the distribution. Risk-adjusted rates of POMI were assessed using the VQI Cardiac Risk Index all-procedures prediction model to compare the observed versus expected rates for each region.
  
  
  RESULTS
  Overall rates of POMI varied by procedure type: CEA 0.8%, EVAR 1.1%, INFRA 2.7%, and OAAA 4.2% (P < 0.001). Significant variation in POMI rates was observed between regions, resulting in differing ranges of POMI rates for each procedure: CEA 0.5-2.0% (P = 0.001), EVAR 0.3-3.1% (P < 0.001), INFRA 1.1-4.8% (P < 0.001), and OAAA 2.2-10.0% (P < 0.001). A single region in 3 of the 4 procedure-specific datasets was identified as a statistical outlier with a significantly higher POMI rate after CEA, EVAR, and OAAA; this region was identical for the EVAR and OAAA datasets but was a different region for the CEA dataset. No significant variation in POMI was noted between regions after INFRA. Procedure-specific clinical POMI rates (mean; range) were significantly different between regions for EVAR (0.4%; 0-1.1%, P = 0.01) and INFRA (1.4%; 0.5-2.9%, P = 0.01), but not for CEA (0.4%; 0-0.8%, P = 0.53) or OAAA (1.6%; 0-3.8%, P = 0.23). Procedure-specific troponin-only POMI rates (mean; range) were significantly different between regions for all procedures: CEA (0.4%; 0.1-1.2%, P < 0.001), EVAR (0.7%; 0-2.1%, P < 0.001), INFRA (1.3%; 0.4-2.5%, P = 0.001), and OAAA (2.5%; 0-8.5%, P < 0.001). After risk adjustment, regional variation was again noted with 3 regions having higher and 4 regions having lower than expected rates of POMI.
  
  
  CONCLUSIONS
  Significant variation in POMI rates following major vascular surgery exists across VQI regions even after risk adjustment. These findings may present an opportunity for focused regional quality improvement efforts.
authors.affiliation: Division of Vascular Surgery, University of Vermont Medical Center, Burlington, VT.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Steely
authors.affiliation: Division of Vascular Surgery, University of Vermont Medical Center, Burlington, VT.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Callas
authors.affiliation: Division of Vascular Surgery, University of Florida College of Medicine, Gainesville, FL.
authors.forename: Daniel
authors.initials: D
authors.lastname: Neal
authors.affiliation: Division of Vascular Surgery, University of Florida College of Medicine, Gainesville, FL.
authors.forename: Salvatore T
authors.initials: ST
authors.lastname: Scali
authors.affiliation: Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
authors.forename: Philip P
authors.initials: PP
authors.lastname: Goodney
authors.affiliation: Division of Vascular Surgery, University of Massachusetts Medical School, Worcester, MA.
authors.forename: Andres
authors.initials: A
authors.lastname: Schanzer
authors.affiliation: Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
authors.forename: Jack L
authors.initials: JL
authors.lastname: Cronenwett
authors.affiliation: Division of Vascular Surgery, University of Vermont Medical Center, Burlington, VT. Electronic address: daniel.bertges@uvmhealth.org.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Bertges
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D005260:Female; D006301:Health Services Needs and Demand / Q000639:trends; D054625:Healthcare Disparities / Q000639:trends*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology*; D020380:Needs Assessment / Q000639:trends; D017064:Process Assessment, Health Care / Q000639:trends*; D058996:Quality Improvement / Q000639:trends; D019984:Quality Indicators, Health Care / Q000639:trends*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014656:Vascular Surgical Procedures / Q000009:adverse effects* / Q000639:trends*