Complementary Alternative Cardiovascular Medicine
Complementary Alternative Cardiovascular Medicine
Complementary Alternative Cardiovascular Medicine
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190 <strong>Alternative</strong> <strong>Cardiovascular</strong> <strong>Medicine</strong><br />
extremely few, small in size, and poorly designed, offering few conclusions<br />
concerning its effectiveness. If chelation therapy is proved safe and<br />
effective in treating ischemic heart disease or peripheral vascular disease,<br />
it would represent a new therapeutic modality and would gain<br />
widespread application. However, if chelation therapy is ineffective for<br />
coronary artery disease (CAD), these data will provide important information<br />
to the public and allow for informed decision making.<br />
This chapter attempts to put chelation therapy in perspective for the<br />
clinician. It is important for physicians to ask patients who are using or<br />
intending to use chelation therapy to determine their concerns, expectations,<br />
misconceptions, and to discuss treatment options before patients<br />
undergo chelation therapy.<br />
Topics addressed in this chapter include:<br />
1. EDTA pharmacology<br />
2. An evidence-based review of EDTA as a therapy for atherosclerotic<br />
disease<br />
3. Mechanisms of action<br />
4. Clinical applications<br />
EDTA PHARMACOLOGY<br />
EDTA is an amino acid that was first synthesized in 1930. It is currently<br />
approved by the FDA for removal of toxic metal cations, such as<br />
lead. The term chelation derives from the Greek chele, which refers to<br />
the claws of a crab or a lobster. Chelation is the chemical reaction in<br />
which a molecule surrounds and bonds with a metal cation to form a<br />
heterocyclic structure. The compound resulting from a chelating agent<br />
and a metal is described as a metal chelate. Metal chelates are widely<br />
represented in biologic systems. For example, hemoglobin, chlorophyll,<br />
and vitamin B 12 are metal chelates of iron, magnesium, and cobalt,<br />
respectively. EDTA is a tetrabasic acid with four replaceable hydrogen<br />
ions. It is poorly soluble in water, but it is soluble in alkaline hydroxides.<br />
In the United States, the commercially available salts are the disodium<br />
and the calcium disodium salts of EDTA. In these formulations, EDTA<br />
is widely used as an in vitro anticoagulant for blood collection and as an<br />
antioxidant synergist, stabilizer, and preservative for pharmaceutical<br />
preparations. Calcium EDTA is used for lead toxicity, whereas disodium<br />
EDTA is used to treat atherosclerosis.<br />
EDTA binds with divalent and trivalent metal cations, such as iron,<br />
copper, calcium, magnesium, zinc, mercury, aluminum, and lead, with<br />
differing affinities. EDTA is poorly absorbed from the gastrointestinal<br />
(GI) tract. After iv administration, EDTA is found primarily in plasma.