This study looked at those with previous MIs. This study found a reduction in recurrent events in those receiving EDTA chelation versus placebo. The authors of this study looked at the Hazard ratio, which was reduced in every end point that this study was designed to evaluate.
Only abstract available here, but EDTA chelation found to reduce risk of death, reinfarction, stroke, hospitalization, angina in individuals with diabetes and prior MI from 38% to 25%.