JAMA Attack On Chelation Therapy

Context  Chelation therapy using EDTA is an unproven but widely used alternative therapy for ischemic heart disease.

Objective  To determine if current EDTA protocols have a favorable impact on exercise ischemia threshold and quality of life measures in patients with stable ischemic heart disease.

Design  Double-blind, randomized, placebo-controlled trial conducted between January 1996 and January 2000.

Setting  Participants were recruited from a cohort of cardiac catheterization patients and the practices of cardiologists in Calgary, Alberta.

Participants  We screened 3140 patients, performed a qualifying treadmill test in 171, and enrolled 84. Entry criteria included age at least 21 years with coronary artery disease proven by angiography or a documented myocardial infarction and stable angina while receiving optimal medical therapy. The required treadmill test used a gradual ramping protocol and patients had to demonstrate at least 1-mm ST depression.

Interventions  Patients were randomly assigned to receive infusion with either weight-adjusted (40 mg/kg) EDTA chelation therapy (n = 41) or placebo (n = 43) for 3 hours per treatment, twice weekly for 15 weeks and once per month for an additional 3 months. Patients in both groups took oral multivitamin therapy as well.

Main Outcome Measure  Change from baseline to 27-week follow-up in time to ischemia (1-mm ST depression).

Results  Thirty-nine patients in each group completed the 27-week protocol. One chelation patient had therapy discontinued for a transient rise in serum creatinine. The mean (SD) baseline exercise time to ischemia was 572 (172) and 589 (176) seconds in the placebo and chelation groups, respectively. The corresponding mean changes in time to ischemia at 27 weeks were 54 seconds (95% confidence interval [CI], 23-84 seconds; P<.001) and 63 seconds (95% CI, 29-95 seconds; P<.001), for a difference of 9 seconds (95% CI, -36 to 53 seconds; P = .69). Exercise capacity and quality of life scores improved by similar degrees in both groups.

Conclusion  Based on exercise time to ischemia, exercise capacity, and quality of life measurements, there is no evidence to support a beneficial effect of chelation therapy in patients with ischemic heart disease, stable angina, and a positive treadmill test for ischemia.

JAMA. 2002;287:481-486

View Full Text    
 
 
Author/Article Information

 
 
Author Affiliations: Division of Cardiology, University of Calgary and Calgary Regional Health Authority, Calgary, Alberta.
 
Corresponding Author and Reprints: Merril L. Knudtson, MD, Foothills Medical Center, 1403 29th St NW, Calgary, Alberta, Canada T2N 2T9 (e-mail: knudtson@shaw.ca).

Author Contributions: Study concept and design: Knudtson, Wyse, Galbraith, Brant, Hildebrand.

Acquisition of data: Knudtson, Wyse, Galbraith, Hildebrand, Paterson, Richardson, Burkart, Burgess.

Analysis and interpretation of data: Knudtson, Wyse, Galbraith, Brant, Burgess.

Drafting of the manuscript: Knudtson, Wyse, Galbraith, Brant, Hildebrand, Burgess.

Critical revision of the manuscript for important intellectual content: Knudtson, Wyse, Galbraith, Brant, Hildebrand, Paterson, Richardson, Burkart.

Statistical expertise: Wyse, Galbraith.

Obtained funding: Knudtson, Wyse, Galbraith, Brant, Hildebrand.

Administrative, technical, or material support: Knudtson, Wyse, Galbraith, Hildebrand, Paterson, Richardson, Burgess.

Study supervision: Knudtson, Wyse, Galbraith, Paterson, Burkart, Burgess.

Funding/Support: This study was supported by the Alberta Health Services Research and Innovation Fund, Medical Services Incorporated Research Foundation, and the Calgary Regional Health Authority.

PATCH Investigators: Clinical Steering Committee Members: Merril L. Knudtson, MD, D. George Wyse, MD, PhD, Rollin Brant, PhD, Ellen Burgess, MD, James Stone, MD, James Mayhew, MD, Jeanette Soriano, MD, Janet Hammond, P. Diane Galbraith, BN. Safety Monitoring Committee Members: Paul Armstrong, MD, University of Alberta; Koon Teo, MD, McMaster University; G. B. John Mancini, MD, University of British Columbia. Substudy Committee: Merril L. Knudtson, MD, D. George Wyse, MD, PhD, Rollin Brant, PhD, P. Diane Galbraith, BN, Todd Anderson, MD, Ellen Burgess, MD, and Derek Exner, MD, MPH.

Acknowledgment: We gratefully acknowledge David Goodhart, MD, for his supervision during many exercise tests. We thank Cliff Simpson for his computer programming expertise, the University of Calgary Lipid Clinic personnel, Heritage Medical Research Clinic personnel, the Foothills Medical Center pharmacy personnel, and Lu Mann, BN, for her help with the treadmills. Joyce Forster helped with preparation of the manuscript.