I Signolet1, S Henni1, C Colas-Ribas1, M Feuilloy2, J Picquet3, P Abraham4. 1. Department of Sports Medicine and Vascular Investigations, University Hospital, Angers, France. 2. Ecole supérieure d'électronique de l'Ouest, Institute of Science & Technology, Angers, France; LAUM - UMR CNR6613, Angers, France. 3. Department of Vascular and Thoracic Surgery, University Hospital, Angers, France; UMR INSERM 1083/CNRS 6214, Angers University, Angers, France. 4. 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.
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.
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 calfEx-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 calfEx-tcpO2 in the selected patients. RESULTS: Cardiorespiratory limitation was identified in 50 patients and isolated non-calfischemia 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-calfischemia 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-calfischemia.