In general, however, the efficacy of chelation therapy in athero- sclerotic disease is not supported by clinical trials. Studies in patients with intermittent claudication have failed to demon- strate improvements in exercise measures,823,824 ankle- brachial index,823,824 or digital subtraction angiograms with chelation.825 The only RCT examining the effectiveness of chelation therapy on SIHD826 studied 84 patients with stable angina and a positive treadmill test for ischemia. Those randomized to active therapy received weight-adjusted diso- dium EDTA chelation therapy for 3 hours per treatment, twice weekly for 15 weeks and then once monthly for an additional 3 months. There were no differences between groups in changes in exercise time to ischemia, exercise capacity, or quality-of-life scores. The National Center of Complementary and Alternative Medicine and the National Heart, Lung, and Blood Institute have sponsored TACT (Trial to Assess Chelation Therapy),842 an RCT comparing chela- tion to placebo in patients who had experienced an MI. There is insufficient evidence to support chelation therapy for improving symptoms or preventing adverse outcomes in patients with SIHD. Moreover, this therapy is costly and time consuming, can result in harm, and could result in patients failing to pursue proven treatment strategies. 4.4.2.5.5. Garlic, Coenzyme Q10, Selenium, and Chromium. Nu- tritional supplements for the prevention and treatment of cardiovascular disease have grown increasingly popular in the United States. These alternative therapies often are promoted with anecdotal claims of efficacy but have not been studied rigorously. When data are available, they often conflict and consist of results of small, open-label trials. At present, there is no definitive evidence to recommend treat- ment with garlic, coenzyme Q10, selenium, or chromium for improving cardiovascular outcomes in patients with SIHD. 4.4.3. Medical Therapy for Relief of Symptoms 4.4.3.1. Use of Anti-ischemic Medications: Recommendations Class I 1. 