title: Prevalence and Causes of Normal Exercise Oximetry in the Calf in Patients with Peripheral Artery Disease and Limiting Calf Claudication.
abstract: OBJECTIVE
  In patients with claudication, an ankle brachial index (ABI) under 0.90 is considered to be abnormal and a sufficient argument for the arterial origin of exercise induced pain. Exercise transcutaneous oxygen pressure (Ex-tcpO2) can provide evidence of exercise induced regional blood flow impairment (RBFI) and confirm the arterial origin of walking induced pain. The frequency with which calf Ex-tcpO2 remains apparently normal in patients with claudication and abnormal ABI is unknown. Causes of these discrepant results have yet to be analysed.
  
  
  METHODS
  A retrospective analysis of 4575 Ex-tcpO2 tests performed on 3,281 patients was conducted. The focus was on patients with a history of calf claudication and ABI under 0.90. Duplicate or non-standard tests were excluded, as were patients with no pain or those able to walk more than 15 minutes (on a treadmill). Searches were conducted for possible explanations of normal calf Ex-tcpO2 in the selected patients.
  
  
  RESULTS
  Cardiorespiratory limitation was identified in 50 patients and isolated non-calf ischemia in 36 of the 106 patients selected. There was no obvious explanation during Ex-tcpO2, but clinical improvement after non-vascular treatment or total absence of improvement after a technically successful revascularisation was noted in 12 patients. Four patients were lost on follow up. Four patients improved after revascularisation, which suggests that the Ex-tcpO2 result was false negative.
  
  
  CONCLUSIONS
  Ex-tcpO2 is negative in more than 20% of tests performed in patients with an ABI under 0.90 and a history of calf claudication. In most cases, when excluding re-tests and non-limiting or non-calf claudication on the treadmill, non-calf ischemia or a non-vascular limitation occurring during the test were observed. This observation supports both the value of treadmill testing in patients with calf claudication assumed to be of arterial origin (ABI<0.90) and the use of Ex-tcpO2 to detect non-calf ischemia.
authors.affiliation: Department of Sports Medicine and Vascular Investigations, University Hospital, Angers, France.
authors.forename: I
authors.initials: I
authors.lastname: Signolet
authors.affiliation: Department of Sports Medicine and Vascular Investigations, University Hospital, Angers, France.
authors.forename: S
authors.initials: S
authors.lastname: Henni
authors.affiliation: Department of Sports Medicine and Vascular Investigations, University Hospital, Angers, France.
authors.forename: C
authors.initials: C
authors.lastname: Colas-Ribas
authors.affiliation: Ecole supérieure d'électronique de l'Ouest, Institute of Science & Technology, Angers, France; LAUM - UMR CNR6613, Angers, France.
authors.forename: M
authors.initials: M
authors.lastname: Feuilloy
authors.affiliation: Department of Vascular and Thoracic Surgery, University Hospital, Angers, France; UMR INSERM 1083/CNRS 6214, Angers University, Angers, France.
authors.forename: J
authors.initials: J
authors.lastname: Picquet
authors.affiliation: Department of Sports Medicine and Vascular Investigations, University Hospital, Angers, France; UMR INSERM 1083/CNRS 6214, Angers University, Angers, France. Electronic address: Piabraham@chu-angers.fr.
authors.forename: P
authors.initials: P
authors.lastname: Abraham
mesh_terms: D000368:Aged; D055109:Ankle Brachial Index; D001785:Blood Gas Monitoring, Transcutaneous; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D007383:Intermittent Claudication / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D011237:Predictive Value of Tests; D015995:Prevalence; D012039:Regional Blood Flow; D012189:Retrospective Studies; D013997:Time Factors; D016138:Walking
keywords: Ankle brachial pressure index; Arterial pressure; Exercise; Pain; Peripheral vascular disease; Transcutaneous oxygen pressure