Co-variation between walking ability and circulatory alterations in patients with intermittent claudication

Unselected patients ( n = 183) with subjective symptoms of intermittent claudication were examined clinically and by various circulatory tests (calf blood-flow, ankle, toe pressures). The aims of the present study were to evaluate to what extent the central or peripheral circulation is limiting in unselected patients with subjective symptoms of intermittent claudication, to determine the co-variation between the maximum walking capacity and traditional haemodynamical measures mentioned above and to evaluate to what extent a traditional bicycle ergometer exercise test and treadmill walking test give similar information regarding maximum performance. Eighty-five per cent of all patients were or had been smokers and 16% were diabetics. The mean ankle/brachial blood pressure index was 0.58 ± 0.02 and the average post-ischemic maximum calf bloodflow was 13.3 ± 0.6 ml/min/100 ml tissue. Leg arterial insufficiency was the limiting factor of walking capacity in 90% of all patients at 87 ± 2W corresponding to a walking distance of 282 ± 13 m, while leg exhaustion was the limiting factor in 80% of the patients during test on the bicycle ergometer at maximum 84 ± 2W. The mean maximum walking capacity for all patients was 86 ± 3 Wand the mean maximum capacity on the bicycle ergometer was 87 ± 2W. The ankle/brachial index showed only a weak correlation ( r = 0.30, p < 0.002) to walking capacity. Our results demonstrate that the maximum walking capacity on a treadmill agrees with mean values of maximum exercise capacity on a bicycle ergometer. The results re-emphasise that conventional leg circulatory measures (ankle, toe pressure, post-ischaemic maximal calf blood flow) are not useful to predict walking disability in patients with intermittent claudication.