Delayed respiratory response to exercise of short duration in patients with severe intermittent claudication due to bilateral atherosclerotic vascular disease: normalization after aorto-bifemoral bypass operation

To investigate the respiratory response to exercise in patients with severe intermittent claudication, eight male patients, aged 57 years (range 43-73 ), with bilateral multi-segment atherosclerotic vascular disease, median ma ximum walking distance 50 m (range 20-200) and ankle-to-arm pressure index 0.4 (range 0.3-0.6), were studied before and after aortobifemoral bypass op eration. Ventilation, CO2 output and O-2 intake were recorded in the sittin g position during 20 min of rest, I min of leg exercise on a bicycle ergome ter [4.9 kJ (500 bpm)], and 20 min of recovery and rest. Before operation, maximal ventilation and CO2 output per minute were observed 2-4 min after c essation of work, while afterwards peal; values were found during the work or the first minute of recovery. Pre-operatively, the extra ventilation and CO2 output during the work and recovery period and the recovery times of t he ventilation and CO2 output per minute were markedly increased. Afterward s these values were clearly reduced towards normal. It is concluded that pa tients with Severe intermittent claudication show a characteristic delay an d prolonged rise in the respiratory response to exercise of short duration, which closely corresponds to the previously described pattern of outflow o f hypoxia-generated metabolites from the exercising muscles. The pattern of respiratory response after operation reflects the fact that these patients also suffer from atherosclerotic heart dysfunction.