Program to Assess Alternative Treatment Strategies to Achieve Cardiac Health - PATCH
The goal of this study was to assess the safety and efficacy of chelation therapy with enzyme-linked immunosorbent assay (EDTA) among patients with stable ischemic heart disease.
EDTA is a widely used alternative medical therapy; however, there is no good evidence that chelation therapy with EDTA is clinically useful in patients with stable ischemic heart disease. It was hypothesized that since EDTA binds calcium and calcium is found in atheromatous plaques, EDTA might favorably change the properties of these plaques.
Patients Screened: 3,140
Patients Enrolled: 84
Mean Follow Up: 27 weeks
Mean Patient Age: Over 21 years
Participants had to be at least 21 years of age and have known coronary artery disease diagnosed by coronary angiography or a documented myocardial infarction. Additionally, participants had to have stable angina while on optimal medical therapy and have a treadmill test, using a gradual ramping protocol, demonstrating at least 1 mm of horizontal or downsloping ST-segment depressions 80 ms after the J point detectible between two and 14 minutes from the onset of exercise.
Exclusion criteria included: planned coronary revascularization, prior chelation therapy, evidence of congestive heart failure, inability to walk on a treadmill, baseline ECG changes that would interfere with interpretation of ischemia, abnormal liver or kidney function, and untreated dyslipidemia.
The primary endpoint was the change in time required to achieve a minimum of 1 mm ST-segment depression on a treadmill test 27 weeks after randomization.
Secondary endpoints included functional reserve, as determined by VO2 max and time to anaerobic threshold. Additionally, quality of life was assessed using the Duke Activity Status Index, Health Status Survey Short Form, and Seattle Angina Questionnaire.
Eligible patients were randomized to receive either weight-based EDTA chelation therapy or placebo two times per week for 15 weeks followed by one time per month for three months for a total of 33 treatments. The EDTA was given as a weight-adjusted (40 mg/kg) infusion up to a maximum dose of 3 g for each treatment. Both the EDTA and placebo solutions were infused over three hours.
The EDTA and placebo solutions were mixed with 750 mg of magnesium sulfate, 5 g ascorbic acid, 5 g sodium bicarbonate, and 80 mg lidocaine. Patients in both groups also took two multivitamin tablets three times per day on nontreatment days.
Patients in the placebo group increased their mean time to ischemia by an average of 54 seconds (95% confidence interval [CI] 23-84, p<0.001) and those in the EDTA group increased their time to ischemia by 63 seconds (95% CI 29-95, p<0.001). The mean difference between the two groups was not statistically significant at nine seconds (95% CI -36 to 53, p=0.69). Additionally, there was no significant difference between the two groups in VO2 max, time to anaerobic threshold, Duke Activity Status Index, Seattle Angina Questionnaire, or Health Status Survey Short Form.
Among patients with coronary artery disease and stable angina, chelation therapy with EDTA was not associated with a significant improvement in quality of life or exercise capacity compared to placebo. These findings suggest that chelation therapy with EDTA is not effective in patients with chronic, stable, ischemic heart disease.
Knudtson ML, Wyse DG, Galbraith PD, et al. Chelation therapy for ischemic heart disease: a randomized controlled trial. JAMA 2002;287:481-6.
Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Stable Ischemic Heart Disease, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging, Chronic Angina
Keywords: Coronary Artery Disease, Myocardial Infarction, Plaque, Atherosclerotic, Angina, Stable, Anaerobic Threshold, Enzyme-Linked Immunosorbent Assay, Calcium, Chelation Therapy, Edetic Acid, Coronary Angiography, Quality of Life, Questionnaires, Confidence Intervals, Health Status, Exercise Test
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