Impact and predictors of thyroid dysfunction among patients with stenotic coronary artery lesion during late postacute coronary syndrome

Objective
Thyroid dysfunction (TD) is a risk factor for coronary heart disease (CHD) events. We study the prevalence and predictors of TD and its impact on characteristics, cardiac function, and ischemic severity of patients with manifest CHD.
Patients and methods
A total of 200 patients 6–12 months after acute coronary syndrome had at least one vessel − significant stenotic coronary artery lesion. Before elective angiography, patients underwent anthropometric measurement, routine biochemical assay, thyroid hormones, and thyroid peroxidase antibody.
Results
The prevalence of TD was 17.5%: 12% for hypothyroidism (9.5% subclinical, 2.5% overt) and 5.5% for hyperthyroidism (2.5% subclinical, 3% overt). Compared with the euthyroid group, the hypothyroid group had a significantly higher age, BMI, diastolic blood pressure (BP), atherogic lipid profile, and impaired cardiac functions and higher pulmonary artery systolic pressure (PASP), and the hyperthyroid group had significantly higher systolic BP, ejection fraction (EF), and PASP and significantly lower diastolic BP and lipid profile. Independent predictors for hypothyroidism were age, bradycardia, increased BMI, lower EF, diastolic dysfunction, and atherogenic lipid profile, whereas increased PASP was an independent predictor for hyperthyroidism. Thyroid-stimulating hormone (TSH) was positively correlated and both free triiodothyronine and free thyroxine were negatively correlated to BP, BMI, lipid profile, impaired EF, and coronary atherosclerosis severity. TSH and free thyroxine were positively correlated to PASP, which increased significantly through hypothyroidism to hyperthyroidism. TSH and free triiodothyronine were independent predictors of severity of CHD.
Conclusion
Age, obesity, impaired cardiac function, and atherogenic lipid profile are predictors of hypothyroidism, and PASP is the predictor of hyperthyroidism among manifest CHD. Thyroid hormones are predictors of severity of coronary atherosclerosis and correlated to cardiac functions and PASP.