title: The increased use of computed tomography angiography and magnetic resonance angiography as the sole imaging modalities prior to infrainguinal bypass has had no effect on outcomes.
abstract: BACKGROUND
  Angiography remains the gold standard imaging modality before infrainguinal bypass. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have emerged as noninvasive alternatives for preoperative imaging. We sought to examine contemporary trends in the utilization of CTA and MRA as isolated imaging modalities before infrainguinal bypass and to compare outcomes following infrainguinal bypass in patients who underwent CTA or MRA versus those who underwent conventional arteriography.
  
  
  METHODS
  Patients undergoing infrainguinal bypass within the Vascular Study Group of New England were identified (2003-2012). Patients were stratified by preoperative imaging modality: CTA/MRA alone or conventional angiography. Trends in utilization of these modalities were examined and demographics of these groups were compared. Primary end points included primary patency, secondary patency, and major adverse limb events (MALE) at 1 year as determined by Kaplan-Meier analysis. Multivariable Cox proportional hazards models were constructed to evaluate the effect of imaging modality on primary patency, secondary patency, and MALE after adjusting for confounders.
  
  
  RESULTS
  In 3123 infrainguinal bypasses, CTA/MRA alone was used in 462 cases (15%) and angiography was used in 2661 cases (85%). Use of CTA/MRA alone increased over time, with 52 (11%) bypasses performed between 2003 and 2005, 189 (41%) bypasses performed between 2006 and 2009, and 221 (48%) bypasses performed between 2010 and 2012 (P < 0.001). Patients with CTA/MRA alone, compared with patients with angiography, more frequently underwent bypass for claudication (33% vs. 26%, P = 0.001) or acute limb ischemia (13% vs. 5%, P < 0.0001), more frequently had prosthetic conduits (39% vs. 30%, P = 0.001), and less frequently had tibial/pedal targets (32% vs. 40%, P = 0.002). After adjusting for these and other confounders, multivariable analysis demonstrated that the use of CTA/MRA alone was not associated with a significant difference in 1 year primary patency (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.78-1.16), secondary patency (HR 1.30, 95% CI 0.99-1.72), or MALE (HR 1.08, 95% CI 0.89-1.32).
  
  
  CONCLUSIONS
  CTA and MRA are being increasingly used as the sole preoperative imaging modality before infrainguinal bypass. This shift in practice patterns appears to have no measurable effect on outcomes at 1 year.
authors.affiliation: Division of Vascular and Endovascular Surgery, University of Massachusetts Medical Center, Worcester, MA. Electronic address: bing.shue@umassmemorial.org.
authors.forename: Bing
authors.initials: B
authors.lastname: Shue
authors.affiliation: Department of Surgery, University of Massachusetts Medical Center, Worcester, MA.
authors.forename: Rachelle N
authors.initials: RN
authors.lastname: Damle
authors.affiliation: Department of Surgery, University of Massachusetts Medical Center, Worcester, MA.
authors.forename: Julie
authors.initials: J
authors.lastname: Flahive
authors.affiliation: Division of Vascular and Endovascular Surgery, Boston University Medical Center, Boston, MA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kalish
authors.affiliation: Division of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
authors.forename: David H
authors.initials: DH
authors.lastname: Stone
authors.affiliation: Division of Vascular Surgery, Massachusetts General Hospital, Boston, MA.
authors.forename: Virendra I
authors.initials: VI
authors.lastname: Patel
authors.affiliation: Division of Vascular and Endovascular Surgery, University of Massachusetts Medical Center, Worcester, MA.
authors.forename: Andres
authors.initials: A
authors.lastname: Schanzer
authors.affiliation: Division of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA.
authors.forename: Donald T
authors.initials: DT
authors.lastname: Baril
mesh_terms: D000368:Aged; D019917:Blood Vessel Prosthesis Implantation / Q000639:trends; D016009:Chi-Square Distribution; D005260:Female; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D018810:Magnetic Resonance Angiography / Q000706:statistics & numerical data / Q000639:trends*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009511:New England; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D010818:Practice Patterns, Physicians' / Q000639:trends*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data / Q000639:trends*; D016896:Treatment Outcome; D058017:Vascular Grafting / Q000009:adverse effects / Q000706:statistics & numerical data / Q000639:trends*; D014654:Vascular Patency