title: Proximal superficial femoral artery occlusion, collateral vessels, and walking performance in peripheral artery disease.
abstract: OBJECTIVE
  We studied associations of magnetic resonance imaging (MRI)-measured superficial femoral artery (SFA) occlusions with functional performance, leg symptoms, and collateral vessel number in peripheral artery disease (PAD). We studied associations of collateral vessel number with functional performance in PAD.
  
  
  BACKGROUND
  Associations of MRI-detected SFA occlusion and collateral vessel number with functional performance among individuals with PAD have not been reported.
  
  
  METHODS
  A total of 457 participants with an ankle brachial index (ABI) <1.00 had MRI measurement of the proximal SFA with 12 consecutive 2.5-μm cross-sectional images. An occluded SFA was defined as an SFA in which at least 1 segment was occluded. A nonoccluded SFA was defined as absence of any occluded slices. Collateral vessels were visualized with magnetic resonance angiography. Lower extremity functional performance was measured with the 6-min walk, 4-m walking velocity at usual and fastest pace, and the Short Physical Performance Battery (SPPB) (0 to 12 scale, 12 = best).
  
  
  RESULTS
  Adjusting for age, sex, race, comorbidities, and other confounders, the presence of an SFA occlusion was associated with poorer 6-min walk performance (1,031 vs. 1,169 feet, p = 0.006), slower fast-paced walking velocity (1.15 vs. 1.22 m/s, p = 0.042), and lower SPPB score (9.07 vs. 9.75, p = 0.038) compared with the absence of an SFA occlusion. More numerous collateral vessels were associated with better 6-min walk performance (0 to 3 collaterals-1,064 feet, 4 to 7 collaterals-1,165 feet, ≥8 collaterals-1,246 feet, p trend = 0.007), faster usual-paced walking speed (0 to 3 collaterals-0.84 m/s, 4 to 7 collaterals-0.88 m/s, ≥8 collaterals-0.91 m/s, p trend = 0.029), and faster rapid-paced walking speed (0 to 3 collaterals-1.17 m/s, 4 to 7 collaterals-1.22 m/s, ≥8 collaterals-1.29 m/s, p trend = 0.002), adjusting for age, sex, race, comorbidities, ABI, and other confounders.
  
  
  CONCLUSIONS
  Among PAD participants, MRI-visualized occlusions in the proximal SFA are associated with poorer functional performance, whereas more numerous collaterals are associated with better functional performance. (Magnetic Resonance Imaging to Identify Characteristics of Plaque Build-Up in People With Peripheral Arterial Disease; NCT00520312).
authors: Department of Medicine, Northwestern University's Feinberg School of Medicine, Chicago, IL 60611, USA. dm608@northwestern.edu
authors: Mary M
authors: MM
authors: McDermott
authors: Timothy J
authors: TJ
authors: Carroll
authors: Melina
authors: M
authors: Kibbe
authors: Christopher M
authors: CM
authors: Kramer
authors: Kiang
authors: K
authors: Liu
authors: Jack M
authors: JM
authors: Guralnik
authors: Aoife N
authors: AN
authors: Keeling
authors: Michael H
authors: MH
authors: Criqui
authors: Luigi
authors: L
authors: Ferrucci
authors: Chun
authors: C
authors: Yuan
authors: Lu
authors: L
authors: Tian
authors: Yihua
authors: Y
authors: Liao
authors: Jarett
authors: J
authors: Berry
authors: Lihui
authors: L
authors: Zhao
authors: James
authors: J
authors: Carr
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D055109:Ankle Brachial Index; D016009:Chi-Square Distribution; D002641:Chicago / Q000453:epidemiology; D003097:Collateral Circulation; D015897:Comorbidity; D003251:Constriction, Pathologic; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology*; D006801:Humans; D016015:Logistic Models; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D012307:Risk Factors; D016138:Walking
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