Chelation therapy for ischemic heart disease: a randomized controlled trial.
BACKGROUND
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.


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


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


METHODS
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.


METHODS
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.


METHODS
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.


CONCLUSIONS
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.
Knudtson
Merril L
ML
Foothills Medical Center, 1403 29th St NW, Calgary, Alberta, Canada T2N 2T9. knudtson@shaw.ca
Wyse
D George
DG
Galbraith
P Diane
PD
Brant
Rollin
R
Hildebrand
Kathy
K
Paterson
Diana
D
Richardson
Deborah
D
Burkart
Connie
C
Burgess
Ellen
E
D000368:Aged; D002614:Chelating Agents / Q000627:therapeutic use*; D015913:Chelation Therapy; D004311:Double-Blind Method; D004492:Edetic Acid / Q000627:therapeutic use*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000628:therapy*; D011788:Quality of Life
D002614:Chelating Agents; D004492:Edetic Acid