Intermittent claudication and risk of cardiovascular events.

To determine the natural history of intermittent claudication, 110 patients were followed up for a mean period of 24.4 +/- 1.2 months. Four patients died during the follow-up. Of the survivors, 24 experienced a nonfatal cardiovascular event, myocardial infarction being the most frequent. Cumulative cardiovascular morbidity was 29% at 3 years. Cox proportional-hazards analysis showed initial ankle-brachial pressure index (ABPI) as a significant predictor for nonfatal cardiovascular events (p<0.002). With an initial ABPI >0.70, cardiovascular morbidity rate was 12% compared with 33% for those with initial ABPI ranging from 0.70 to 0.50, and 60% for those with ABPI <0.50 (p<0.005). Critical limb ischemia occurred in only four patients, amputation was required in two, and arterial reconstruction in five. Of the 85 patients who participated in the treadmill test, maximum walking capacity worsened in 26% and improved in 27%. This study elucidates the neglected area of cardiovascular morbidity in intermittent claudication. It has shown that ABPI identifies a subgroup of patients for whom the risk of cardiovascular events is especially pronounced. On the other hand, based on objective evaluation of the patient status, the relatively benign prognosis for the claudicant limb has been confirmed.