title: Postoperative Surveillance and Long-term Outcomes After Endovascular Aneurysm Repair Among Medicare Beneficiaries.
abstract: OBJECTIVE
  The Society for Vascular Surgery recommends annual surveillance with computed tomography (CT) or ultrasonography after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysms. However, such lifelong surveillance may be unnecessary for most patients, thereby contributing to overuse of imaging services.
  
  
  OBJECTIVE
  To investigate whether nonadherence to Society for Vascular Surgery-recommended surveillance guidelines worsens long-term outcomes after EVAR among Medicare beneficiaries.
  
  
  METHODS
  We collected data from Medicare claims from January 1, 2002, through December 31, 2011. A total of 9503 patients covered by fee-for-service Medicare who underwent EVAR from January 1, 2002, through December 31, 2005, were categorized as receiving complete or incomplete surveillance. We performed logistic regressions controlling for patient demographic and hospital characteristics. Patients were then matched by propensity score with adjusting for all demographic variables, including age, sex, race, Medicaid eligibility, residential status, hospital volume, ruptured abdominal aortic aneurysms, and all preexisting comorbidities. We then calculated differences in long-term outcomes after EVAR between adjusted groups. Data analysis was performed from January 1, 2002, through December 31, 2011.
  
  
  METHODS
  Post-EVAR imaging modality, aneurysm-related mortality, late rupture, and complications.
  
  
  RESULTS
  Median follow-up duration was 6.1 years. Incomplete surveillance was observed in 5526 of 9695 patients (57.0%) who survived the initial hospital stay at a mean (SD) of 5.2 (2.9) years after EVAR. After propensity matching, our cohort consisted of 7888 patients, among whom 3944 (50.0%) had incomplete surveillance. For those in the matched cohort, patients with incomplete surveillance had a lower incidence of late ruptures (26 of 3944 [0.7%] vs 57 of 3944 [1.4%]; P = .001) and major or minor reinterventions (46 of 3944 [1.2%] vs 246 of 3944 [6.2%]; P < .001) in unadjusted analysis. Aneurysm-related mortality was not statistically different between groups (13 of 3944 [0.3%] vs 24 of 3944 [0.6%]; P = .07). In adjusted analysis of postoperative outcomes controlling for all patient and hospital factors by the tenth postoperative year, patients in the incomplete surveillance group experienced lower rates of total complications (2.1% vs 14.0%; P < .001), late rupture (1.1% vs 5.3%; P < .001), major or minor reinterventions (1.4% vs 10.0%; P < .001), aneurysm-related mortality (0.4% vs 1.3%; P < .001), and all-cause mortality (30.9% vs 68.8%, P < .001).
  
  
  CONCLUSIONS
  Nonadherence to the Society for Vascular Surgery guidelines for post-EVAR imaging was not associated with poor outcomes, suggesting that, in many patients, less frequent surveillance is not associated with worse outcomes. Improved criteria for defining optimal surveillance will achieve higher value in aneurysm care.
authors.affiliation: Division of Vascular Surgery, Stanford School of Medicine, Stanford, California.
authors.forename: Trit
authors.initials: T
authors.lastname: Garg
authors.affiliation: Department of Health Research and Policy, Stanford School of Medicine, Stanford, California3National Bureau of Economic Research, Cambridge, Massachusetts.
authors.forename: Laurence C
authors.initials: LC
authors.lastname: Baker
authors.affiliation: Division of Vascular Surgery, Stanford School of Medicine, Stanford, California.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Mell
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D057510:Endovascular Procedures / Q000592:standards*; D005260:Female; D019983:Guideline Adherence / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D006278:Medicare; D011159:Population Surveillance; D011182:Postoperative Care; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States