Increase of walking capacity after acute aminophylline administration in intermittent claudication

In the presence of peripheral atherosclerotic disease, inappropriate adenosine release during exercise might promote excessive arteriolar dilation leading to steal phenomena and ischemia. In order to test this hypothesis, IV aminophylline (6 mg/kg over fifteen minutes), a dosage known to effectively block adenosine receptors, was acutely administered--in a double-blind, placebo-controlled study design--in 13 patients with intermittent claudication and documented atherosclerotic disease. All patients performed two treadmill exercise tests at the same hour on two consecutive days, five minutes after aminophylline or placebo administration randomly allocated. Pain-free time was 109 +/- 133 (mean +/- SD) seconds after placebo and 173 +/- 165 seconds after aminophylline (p less than .01); maximum time to claudication was 273 +/- 191 seconds after placebo and 397 +/- 318 seconds after aminophylline (p less than .05). The authors conclude that intravenous aminophylline markedly increases the walking capacity in patients with intermittent claudication, possibly by preventing flow maldistribution phenomena through adenosine receptors blockade.