You will be provided with a reference and some statements. Please determine whether each statement is 'supported', 'unsupported', or 'unknown' with respect to the reference. Please note:
First, assess whether the reference contains any valid content. If the reference contains no valid information, such as a 'page not found' message, then all statements should be considered 'unknown'.
If the reference is valid, for a given statement: if the facts or data it contains can be found entirely or partially within the reference, it is considered 'supported' (data accepts rounding); if all facts and data in the statement cannot be found in the reference, it is considered 'unsupported'.

You should return the result in a JSON list format, where each item in the list contains the statement's index and the judgment result, for example:
[
    {
        "idx": 1,
        "result": "supported"
    },
    {
        "idx": 2,
        "result": "unsupported"
    }
]

Below are the reference and statements:
<reference>
Chelation Therapy - Special Subjects - Merck Manual Professional Edition

Chelation Therapy - Explore from the Merck Manuals - Medical Professional Version.

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Integrative, Complementary, and Alternative Medicine
Chelation Therapy
Full Review:
Oct 2025
By
Abhinav Singla
,
MD
,
Mayo Clinic
|
Peer reviewed by
Michael R. Wasserman
,
MD
,
California Association of Long Term Care Medicine (CALTCM)
Last updated: Oct 2025
v21360389

View Patient Education
Drug Information
|
In chelation therapy, a
biologically based practice
, a drug is used to bind with and remove hypothesized excess or toxic amounts of a metal or mineral (eg, lead,
copper
, iron, calcium) from the bloodstream. In conventional medicine, chelation therapy is used to treat lead and other heavy metal poisoning (see table
Chelation Therapy for Heavy Metal Poisoning
).
Heavy metal toxicity, usually due to environmental exposure, may be a risk factor for dementia (
1
), cardiovascular disease (
2
), and chronic kidney disease (
3
).
Chelation therapy with EDTA (ethylene diamine tetraacetic acid) has also been suggested as a way to remove calcium and potentially treat atherosclerosis.
A 2012 trial of chelation therapy (the Trial to Assess Chelation Therapy [TACT]) for subjects with a history of myocardial infarction found a significant benefit for chelation over placebo for a composite outcome of mortality or cardiovascular event (26.5% versus 30% for placebo), but not for individual outcomes (eg, death, cardiovascular events, stroke, hospitalizations) (
4
). The methodological flaws raised with the study did not end the controversy over chelation therapy. A post hoc review of the data showed a significant reduction in the composite end point in patients with diabetes and peripheral artery disease in the chelation group compared to the control group, as well as a reduction in mortality (
5
). A subsequent systematic review of 38 studies showed possible but unclear benefits of chelation in regard to secondary prevention of recurrent cardiac events (
6
). A repeat trial, TACT2, has been initiated to replicate the TACT trial in patients with diabetes and cardiovascular disease (
7
).
The American College of Cardiology, in its 2023 guideline for chronic coronary disease, states that EDTA chelation is not approved by the U.S. Food and Drug Administration (FDA) for prevention or treatment of cardiovascular disease and does not recommend its use outside of research settings (
8
).
Risks
of chelation therapy include
Hypocalcemia (which is potentially serious)
Infusion site reaction, fever, nausea, vomiting
Kidney damage
Delay of more effective treatment
Death
References
1.
Killin LO, Starr JM, Shiue IJ, et al
. Environmental risk factors for dementia: a systematic review.
BMC Geriatr.
16(1):175, 2016. doi: 10.1186/s12877-016-0342-y
2.
Chowdhury R, Ramond A, O'Keeffe LM, et al
. Environmental toxic metal contaminants and risk of cardiovascular disease: systematic review and meta-analysis.
BMJ.
362:k3310, 2018. doi: 10.1136/bmj.k3310
3.
Farkhondeh T, Naseri K, Esform A, et al
. Drinking water heavy metal toxicity and chronic kidney diseases: a systematic review.
Rev Environ Health.
2020 Nov 2:/j/reveh.ahead-of-print/reveh-2020-0110/reveh-2020-0110.xml. doi: 10.1515/reveh-2020-0110
4.
Lamas GA, Goertz C, Boineau R, et al
. Effect of disodium EDTA chelation regimen on cardiovascular events in patients with previous myocardial infarction: the TACT randomized trial.
JAMA.
. 309(12):1241–50, 2013. doi: 10.1001/jama.2013.2107
5.
Ujueta F, Arenas IA, Escolar E, et al
. The effect of EDTA-based chelation on patients with diabetes and peripheral artery disease in the Trial to Assess Chelation Therapy (TACT).
6.
Ibad A, Khalid R, Thompson PD, et al
. Chelation therapy in the treatment of cardiovascular diseases.
J Clin Lipidol.
10(1):58-62, 2016. doi: 10.1016/j.jacl.2015.09.005
7.
Navas-Acien A, Santella RM, Joubert BR, et al
. Baseline characteristics including blood and urine metal levels in the Trial to Assess Chelation Therapy 2 (TACT2).
Am Heart J.
2024;273:72-82. doi:10.1016/j.ahj.2024.04.005
8.
Writing Committee Members, Virani SS, Newby LK, et al
. 2023 AHA/ACC/ACCP/ASPC/NLA/PCNA Guideline for the Management of Patients With Chronic Coronary Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines.
J Am Coll Cardiol.
2023;82(9):833-955. doi:10.1016/j.jacc.2023.04.003.
Correction.
J Am Coll Cardiol
. 2023;82(18):1808. doi:10.1016/j.jacc.2023.09.794
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</reference>

<statements>
1. The 2023 AHA/ACC/ACCP/ASPC/NLA/PCNA Guideline for the Management of Patients With Chronic Coronary Disease provides clear guidance on chelation therapy
2. Disodium EDTA chelation is not approved by the FDA for the prevention or treatment of cardiovascular disease
3. Chelation therapy is explicitly not recommended for clinical use outside authorized research protocols
4. Consequently, EDTA chelation therapy has no role in contemporary cardiovascular prevention or treatment
</statements>

Begin the assessment now. Output only the JSON list, without any conversational text or explanations.