SAN FRANCISCO—Heart attack patients given a combination of high-dose oral vitamins and minerals do not exhibit a significant reduction in recurrent cardiac events, according to research presented March 10 at the American College of Cardiology (ACC) scientific session. However, the results of one component of the Trial to Assess Chelation Therapy (TACT) study showed that when combined with active chelation therapy, high-dose vitamins and minerals may provide some additional benefit.
The TACT study attempted to determine the impact of chelation therapy, which is typically paired with high-dose vitamin and mineral supplements, for individuals with prior MIs.
Previous results presented at the American Heart Association meeting in November 2012 suggested that chelation treatment, with or without supplements, provided a modest reduction in cardiac events compared to a placebo treatment, explained Gervasio A. Lamas, MD, chief of cardiology at Mount Sinai Medical Center in Miami Beach, Fla. These cardiac events were combined and included recurrent heart attack, stroke, coronary revascularization and hospitalization for angina and death.
The investigators examined chelation and high-dose vitamins as separate and combined components to determine potential individual and synergistic effects of the two treatments. TACT enrolled 1,708 patients with prior heart attacks who were randomly assigned to an active or placebo chelation group and an active or placebo vitamin group. The 2x2 factorial design allowed the investigators to clarify the independent contributions of each treatment.
Patients received 40 intravenous chelation treatments or placebo during an 18-month period. They also were assigned to take three pills twice daily, which contained either high-dose vitamins and minerals or placebo. Average follow-up was 55 months.
Patients were 82 percent male, 94 percent Caucasian and about half were obese. Thirty-two percent had diabetes, 68 percent had high blood pressure and 83 percent had previously undergone bypass surgery, stent implantation or balloon angioplasty.
The primary comparison of the study, oral vitamins and minerals versus an oral placebo, did not show a significant reduction in the primary endpoint: 27 percent in the vitamin group and 30 percent of those receiving placebo.
“Interestingly, patients who received both high-dose vitamins and active chelation compared to placebo of both appeared to have additional benefit, but more research is needed to understand the results,” said Lamas. The analysis of the four groups showed that the chelation/vitamin arm had a 26 percent event rate and the placebo/placebo arm had a 32 percent rate.
Upon entering the study, many patients were already taking evidence-based medications: 84 percent took daily aspirin to reduce risk of stroke and MI, 72 percent were on beta-blockers to treat high blood pressure and 73 percent took statins to treat high cholesterol.
One of the limitations of the study was relatively poor patient adherence with the vitamin regimen. About half of the patients enrolled in the trial stopped taking the vitamins during the study follow-up; 75 percent of participants took vitamins for a least one year.
During a panel discussion after the presentation, Lamas explained that cardiologists are far from applying the vitamin/mineral treatment as adjunct therapy in practice. Panelists were puzzled given the statistically significant finding.
Although chelation therapy has been used since 1956, according to Lamas, it remains an alternative therapy. “We have treatments that are known to work. The results are early and bespeak mechanisms we don’t understand… These are unexpected results that merit further research. The results are not enough to carry this [treatment] into daily use.”
The trial was sponsored by the National Institutes of Health, with the National Heart, Lung, and Blood Institute as lead agency, and the National Center for Complementary and Alternative Medicine as co-sponsors.