Complementary Alternative Cardiovascular Medicine

Chapter 12 / Chelation Therapy and CVD 193
relating to general health and effect of poor circulation on life activities,
chelation patients scored better on two scales that rated the level of
physical activity (p < 0.05 for between-groups differences) 3 mo after
therapy. Despite the quality of this study, the small number of patients
enrolled precludes any definitive conclusion concerning the efficacy of
chelation therapy in peripheral vascular disease.
The Program to Assess Alternative Treatment Strategies to Achieve
Cardiac Health (PATCH) was a 6-mo randomized trial that measured
exercise capacity in 84 stable patients with angina randomized to receive
either EDTA treatment or placebo (24). Patients were eligible to participate
in the trial if they were over the age of 21 had proved CAD, and
stable angina pectoris, and 1 mm ST-segment depression within 2–14
min on a gradually ramping treadmill test. A total of 39 patients were
ultimately randomized to the treatment groups, receiving iv solutions of
EDTA 40 mg/kg, up to a maximum of 3.0 g, or placebo (0.9% sodium
chloride). Patients received treatment 2 times/wk for 15 wk, then once
per month for 3 mo, for a total of 33 treatments. Importantly, both groups
received iv magnesium (750 mg) and ascorbic acid (5 g) in the infusate.
All patients were given oral multivitamins. There were no significant
differences in clinical outcomes or quality-of-life scores between the
treatment groups. There were no deaths and no myocardial infarctions
(MIs), and there were nine hospitalizations for worsening angina (six in
the chelation group and three in the placebo group). Both groups increased
their exercise times approx 1 min, an improvement that the investigators
attributed to placebo or “training” effect. Unfortunately, in this trial, the
“placebo” contained vitamin C (antioxidant effect) and magnesium
(vasodilator and antiarrhythmic effects), and the study was underpowered
to assess clinical event rates.
MECHANISMS OF ACTION
The original hypothesis underlying the use of chelation therapy was
that EDTA would remove calcium from atheromatous plaques producing
favorable effects (25,26). Unfortunately, there are little data to support
the decalcifying hypothesis. Other postulated mechanisms of EDTA
action include (1) inhibition of platelet aggregation, (2) parathormone
(PTH) release stimulation that, in turn, mobilizes calcium from plaques
and reduces progressive calcification; (3) an antioxidant effect by
complexing with transitional metals thus interfering with free radical
production and lipid peroxidation; (4) effects on serum iron, and (5)
transient lowering of serum cholesterol (27–30). Some of these hypotheses
may be valid, but there are no confirmatory mechanistic studies.