title: Asymptomatic peripheral arterial disease is associated with more adverse lower extremity characteristics than intermittent claudication.
abstract: BACKGROUND
  This study assessed functional performance, calf muscle characteristics, peripheral nerve function, and quality of life in asymptomatic persons with peripheral arterial disease (PAD).
  
  
  RESULTS
  PAD participants (n=465) had an ankle brachial index <0.90. Non-PAD participants (n=292) had an ankle brachial index of 0.90 to 1.30. PAD participants were categorized into leg symptom groups including intermittent claudication (n=215) and always asymptomatic (participants who never experienced exertional leg pain, even during the 6-minute walk; n=72). Calf muscle was measured with computed tomography. Analyses were adjusted for age, sex, race, ankle brachial index, comorbidities, and other confounders. Compared with participants with intermittent claudication, always asymptomatic PAD participants had smaller calf muscle area (4935 versus 5592 mm(2); P<0.001), higher calf muscle percent fat (16.10% versus 9.45%; P<0.001), poorer 6-minute walk performance (966 versus 1129 ft; P=0.0002), slower usual-paced walking speed (P=0.0019), slower fast-paced walking speed (P<0.001), and a poorer Short-Form 36 Physical Functioning score (P=0.016). Compared with an age-matched, sedentary, non-PAD cohort, always asymptomatic PAD participants had smaller calf muscle area (5061 versus 5895 mm(2); P=0.009), poorer 6-minute walk performance (1126 versus 1452 ft; P<0.001), and poorer Walking Impairment Questionnaire speed scores (40.87 versus 57.78; P=0.001).
  
  
  CONCLUSIONS
  Persons with PAD who never experience exertional leg symptoms have poorer functional performance, poorer quality of life, and more adverse calf muscle characteristics compared with persons with intermittent claudication and a sedentary, asymptomatic, age-matched group of non-PAD persons.
authors.affiliation: Feinberg School of Medicine, Northwestern University, Chicago, Ill, USA. mdm608@northwestern.edu
authors.forename: Mary M
authors.initials: MM
authors.lastname: McDermott
authors.forename: Jack M
authors.initials: JM
authors.lastname: Guralnik
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: Lu
authors.initials: L
authors.lastname: Tian
authors.forename: Kiang
authors.initials: K
authors.lastname: Liu
authors.forename: Yihua
authors.initials: Y
authors.lastname: Liao
authors.forename: David
authors.initials: D
authors.lastname: Green
authors.forename: Robert
authors.initials: R
authors.lastname: Sufit
authors.forename: Frederick
authors.initials: F
authors.lastname: Hoff
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishida
authors.forename: Leena
authors.initials: L
authors.lastname: Sharma
authors.forename: William H
authors.initials: WH
authors.lastname: Pearce
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Schneider
authors.forename: Michael H
authors.initials: MH
authors.lastname: Criqui
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001916:Brachial Artery; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000503:physiopathology* / Q000523:psychology; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D016491:Peripheral Vascular Diseases / Q000503:physiopathology* / Q000523:psychology; D011788:Quality of Life; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D016138:Walking