Thyroid Hormone and Coronary Artery Disease: From Clinical Correlations to Prognostic Implications

Abstract

Background: Overt thyroid dysfunction, hypothyroidism in particular, may lead to coronary artery disease (CAD). Whether more subtle anomalies of thyroid hormone metabolism influence the progression of CAD remains a matter of speculation. Hypothesis: The occurrence of CAD and long-term prognosis in patients without a history of either primary thyroid disease, myocardial infarction, or chronic heart failure is related to serum levels of biologically active free triiodothyronine (fT3). Methods: The cohort consisted of 1047 clinically and biochemically euthyroid patients (median age 65.6 y and 69% male) who underwent coronary angiography in our institute for suspected CAD. Results: Lower fT3 levels were predictive of both single-vessel (p = 0.012) and multivessel (p = 0.009) CAD. Through a multivariate logistic regression analysis, fT3 was still linked to the presence of CAD (hazard ratio [HR]: 0.48, 95% confidence interval [CI]: 0.34-0.68, p < 0.001). After a mean follow-up of 31 months, the survival rate was 95% and total mortality (log-rank 6.75, p = 0.009), as well as cardiac mortality (log-rank 8.26, p = 0.004), was greater among patients with low T3 (fT3<2.10 pg/mL) syndrome. At subsequent multivariate Cox regression analysis, the association between low T3 syndrome and survival was maintained (total mortality HR: 1.80, 95% CI: 1.05-3.10, p = 0.034; cardiac mortality HR: 2.58, 95% CI: 1.13-5.93, p = 0.025). Conclusions:In this selected population, fT3 levels were inversely correlated to the presence of CAD and low T3 syndrome conferred an adverse prognosis, even after adjusting for traditional coronary risk factors.

Association of Thyroid Function with Severity of Coronary Artery Disease in Euthyroid Patients

“…However we did not find an association between FT4 and CAD [12]. Coceani et al, studied 1047 clinically and biochemically euthyroid patients reported that serum FT3 levels were inversely correlated with the presence of CAD and the low T3 syndrome conferred an adverse prognosis, even after adjusting for the traditional coronary risk factors [13]. Coceani et al, conducted a study on 2344 patients and have recently advanced the hypothesis that low T3 exerts an adverse impact on prognosis in LV function, which is not influenced by concomitant amiodarone therapy [14].…”

Thyroid hormones and the heart

“…This pathological state perpetuates the deleterious cardiac remodeling and contributes to heart failure progression. In euthyroid patients with coronary artery disease, a similar pattern of low T 3 was observed and correlates with outcome [14].…”

‘Low — T3 syndrome’ among patients with acute myocardial infarction

“…Experimental and clinical analyses have shown, that thyroid hormone (TH) has a fundamental role in cardiovascular homeostasis, influencing cardiac contractility, heart rate, diastolic function and systemic vascular resistance [11]. Abnormal metabolism of TH may lead to various heart diseases, like accelerated coronary atherosclerosis [12]. Coceani et al have demonstrated that free triiodothyronine (T3) levels are inversely correlated with the presence of coronary artery disease (CAD), whereas Low -triiodothyronine (T3) syndrome causes an adverse prognosis for CAD [13].…”