title: Proximal ischemia is a frequent cause of exercise-induced pain in patients with a normal ankle to brachial index at rest.
abstract: BACKGROUND
  Excluding a vascular origin of exercise-related pain is often difficult in clinical practice. Recent papers have underlined the frequent association of concurrent lumbar spine degenerative disease and peripheral arterial disease. Furthermore, even when suspected, isolated exercise-induced proximal ischemia is difficult to diagnose. Measurement of transcutaneous oxygen pressure (tcpO2) is an interesting and accurate method to differentiate proximal (buttock) from distal (calf) regional blood flow impairment (RBFI) during exercise.
  
  
  OBJECTIVE
  We searched for isolated proximal-without-distal RBFI as a possible cause of claudication, in patients with borderline (ABI-b: 0.91 - 0.99) or normal (ABI-n: 1.00 to 1.40) ankle to brachial index at rest.
  
  
  METHODS
  Retrospective cohort design study. We analyzed patients referred to our laboratory with symptom limiting claudication and an ankle brachial index within normal limits.
  
  
  METHODS
  University-based exercise-investigation center.
  
  
  METHODS
  Over a 12-year period, we identified 463 patients referred to our laboratory that had their lowest resting ABI between 0.90 and 1.40. The tcpO2 on chest, buttocks, and calves were recorded during treadmill walking tests (3.2 km/h, 10% slope) in 220 ABI-b and 243 ABI-n unique consecutive patients complaining of limiting claudication (each patient's ABI was the lowest of the 2 legs). Limiting claudication was defined as the reported inability to walk 1 kilometer without stopping. A DROP index (limb tcpO2-changes minus chest tcpO2-changes from rest) below -15 mmHg was used to indicate a positive result (i.e. exercise-induced RBFI).
  
  
  RESULTS
  Treadmill exercise showed evidence for proximal or distal RBFI, of at least one side, in 128 out of 220 patients (58.2%) and in 86 out of 243 (35.4%) patients with ABI-b and ABI-n, respectively. Isolated proximal-without-distal RBFI was found in 32 out of the 128 (25.0 %) positive tests in ABI-b and 32 out of the 86 (37.2%) positive tests in ABI-n patients.
  
  
  CONCLUSIONS
  Study limitations include the absence of systematic follow-up of diagnosed patients and absence of systematic search for cardio-respiratory co-morbid conditions.
  
  
  CONCLUSIONS
  Isolated proximal-without distal RBFI is found in approximately one out of 7 patients complaining of symptom limiting claudication with a borderline or normal resting ABI. Exercise-tcpO2 may help to discriminate patients with arterial claudication that could benefit from invasive vascular investigations and procedures.
authors: Université Angers, CHU Angers, Laboratory for Vascular Investigations, Angers Cedex 09, F-49933. France.
authors: Marie
authors: M
authors: Gernigon
authors: Johann
authors: J
authors: Marchand
authors: Nafi
authors: N
authors: Ouedraogo
authors: Georges
authors: G
authors: Leftheriotis
authors: Jean M
authors: JM
authors: Piquet
authors: Pierre
authors: P
authors: Abraham
mesh_terms: D055109:Ankle Brachial Index; D002081:Buttocks / Q000098:blood supply; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000209:etiology* / Q000503:physiopathology*; D007511:Ischemia / Q000150:complications* / Q000503:physiopathology*; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D012146:Rest; D012189:Retrospective Studies