Value of Low Triiodothyronine and Subclinical Myocardial Injury for Clinical Outcomes in Chest Pain

Abstract

Low triiodothyronine (T3) levels and subclinical myocardial injury may be associated with adverse cardiac and cerebrovascular (CCV) events in individuals without clinically apparent coronary heart disease (CHD). The aim of this study was to determine the associations of a low T3 level and subclinical myocardial injury with the development of adverse CCV events in individuals without clinically apparent CHD. T3 and high-sensitivity cardiac troponin T (hs-cTnT) levels were analyzed in 250 patients with chest pain free of CHD and heart failure. The primary end point was the composite of sudden cardiac death, ischemic stroke, newly developed atrial fibrillation, pericardial effusion and thrombosis. Throughout a mean follow-up of 15.6 months, the primary end point happened in 17 patients (6.8%). Kaplan-Meier analysis disclosed a notably higher overall occurrence rate in patients with hs-cTnT levels ≥0.014 ng/mL and in patients with T3 <60 ng/dL. An exaggerated hazard was observed in patients with combined high hs-cTnT and low T3 levels. After adjustment, the hazard ratio for overall events in patients with high hs-cTnT/low T3 versus normal hs-cTnT/T3 was 11.72 (95% confidence interval, 2.83-48.57; P = 0.001). In patients with chest pain without clinically obvious CHD, high hs-cTnT combined with low T3 was associated with adverse cardiac/CCV events and was an independent predictor of overall events even after adjustment. These data suggest the importance of systemic factors, such as low T3 syndrome, in the development of adverse cardiac/CCV events beyond advancing clinical atherosclerotic coronary disease in patients with chest pain.