Abstract 18754: Prognostic Evaluation of Catalytic Iron in Patients with Acute Coronary Syndromes: Observations from OPUS-TIMI 16

Abstract

BACKGROUND: The potential of iron to generate reactive oxygen species (ROS) has motivated a long-standing interest in whether excess iron is causally linked to atherosclerotic heart disease. Catalytic iron, or “free” iron, is the circulating store of iron that is not bound to transferrin or ferritin and is available to generate ROS that may have deleterious vascular effects.

METHODS: We investigated the association of catalytic iron with clinical outcomes in 1701 patients with UA, NSTEMI, or STEMI who were followed for a median of 10 months. All endpoints were adjudicated by a blinded Clinical Endpoints Committee. RESULTS: The median catalytic iron level was significantly higher in those who died, 0.45μmol/L (0.37, 0.57), compared with survivors 0.37μmol/L (0.31, 0.46), p= 0.016. Catalytic iron was associated with a step-wise increased risk of death, with the highest quartile at an almost 4-fold risk compared to baseline (HR 3.94, p=0.035), which persisted after adjustment for age, diabetes, prior MI, prior CHF, ST deviation, CrCl, BNP, and Killip class (adjHR 3.89, p=0.038, FIGURE). There was no association between catalytic iron and risk of myocardial infarction, recurrent ischemia, heart failure, or bleeding. CONCLUSION: Increasing catalytic iron levels were associated with all-cause mortality. Our findings suggest that catalytic iron is not likely to add to currently available tools as a routine clinical biomarker for risk stratification of ischemic events, but its association with mortality is intriguing and leaves open the question of whether cardiovascular therapeutics aimed at catalytic iron may have utility.