title: Adding ischaemic hand exercise during occlusion of the brachial artery increases the flow-mediated vasodilation in ultrasound studies of endothelial function.
abstract: A non-invasive method has been introduced to study endothelial function by evaluating flow-mediated, endothelium-dependent vasodilation of the brachial artery. One weakness of this method is that the post-occlusion vasodilation response is very small in subjects above the age of 60 years, which is a problem when quantifying endothelial dysfunction above this age. We have therefore evaluated whether a higher post-occlusion flow stimulus and a larger vasodilation response can be achieved by adding ischaemic hand exercise during the occlusion of the brachial artery. The subject population was men (n = 12), aged 60 years, free from cardiovascular disease. B-mode ultrasound images for the measurement of lumen diameter of the brachial artery were recorded before and after reactive hyperaemia induced by occlusion of the artery. Blood flow velocity was recorded intermittently using a Doppler technique. Hyperaemia was induced in two different ways: first by occlusion only and then by adding ischaemic hand exercise during the occlusion. The results showed that flow velocity was higher and the duration of flow increase was longer after ischaemic hand exercise compared with occlusion only. Two minutes after cuff pressure release, the increase in blood flow velocity was significantly higher after ischaemic hand work compared with occlusion only (P < 0.01). The corresponding maximal lumen diameters after cuff pressure release were 4.63 +/- 0.35 and 4.45 +/- 0.34 respectively (P < 0.01). The flow-mediated vasodilation increased significantly from 2.24 +/- 2.00% after occlusion only to 7.42 +/- 3.32% after occlusion plus ischaemic hand exercise (P < 0.01). In conclusion, this study showed that a maximal endothelial-dependent vasodilation was not achieved after occlusion only in these 60-year-old men. Adding ischaemic hand exercise may therefore be of value when quantifying endothelial dysfunction in this age group.
authors.affiliation: Wallenberg Laboratory for Cardiovascular Research, Sahlgrenska University Hospital, Göteborg University, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Wendelhag
authors.forename: B
authors.initials: B
authors.lastname: Fagerberg
authors.forename: J
authors.initials: J
authors.lastname: Wikstrand
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D006801:Humans; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology; D013997:Time Factors; D018608:Ultrasonography, Doppler; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D005996:Nitroglycerin