SYSTEMIC RESPONSES IN PATIENTS WITH INTERMITTENT CLAUDICATION AFTER TREADMILL EXERCISE

The effect of 5 min treadmill exercise was investigated in claudicant patients and healthy controls; systemic neutrophil count, plasma throm boxane and von Willebrand's factor (a marker for endothelial injury) w ere Median (interquartile range (i.q.r.)) resting count was 5.6 (5.2-6 .0) x 10(6) cells l(-1) in claudicants and 2.8 (2.6-3.2) x 10(6) l(-1) in controls (P< 0.05); this increased in those with claudication to 7 .1 (6.2-7.7) x 10(6) l(-1) immediately after exercise (P<O.05). The re sting plasma thromboxane level was (25.0-60.0) pg ml(-1) in claudicant s and rose to (104.0-141.3) pg ml(-1) 15 min after exercise, compared with a rise from 25.0 (22.0-33.5) to 55.5 (33.0-67.0) pg ml(-1) in con trols (P<O.05). The resting serum von Willebrand's factor level was 12 7 (110-135) units dl(-1) in claudicants compared with 60 (48-71) units dl(-1) in controls; this difference persisted after exercise (P<0.01) . In patients with claudication, the level of von Willebrand's factor increased to 150 (140-156) units dl(-1) 60 min after exercise (P<O.05) . Free radical scavenging capacity was also investigated by measuring the plasma antioxidant activity of glutathione peroxidase and its esse ntial non-metal cofactor selenium. Scavenging capacity was lower in cl audicant patients whose median (i.q.r.) glutathione peroxidase activit y (change in absorbance per min per mi plasma) was 2.84 (2.39-3.61) ve rsus 3.24 (3.06-3.79) in controls (P<O.05). Similarly, plasma concentr ations of selenium were lower in claudicants at a median (i.q.r.) of 7 5.0 (58.0-81.0) mu g l(-1) compared with 88.0 (75.0-92.5) mu g l(-1) i n controls (P< 0.05). Exercise in claudicant patients leads to neutrop hilia and thromboxane production with subsequent endothelial injury. T he antioxidant activity of glutathione peroxidase is reduced in patien ts with claudication and may allow the unopposed action of free radica ls to damage endothelium.