Abstract
BackgroundThyroid function is closely involved in cardiovascular diseases. The free triiodothyronine (fT3) to free thyroxine (fT4) ratio has been reported as a risk factor for coronary artery disease, but its prognostic value in euthyroid patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) remains unclear.MethodsA total of 1162 euthyroid patients with MINOCA were enrolled and divided according to decreased tertiles of fT3/fT4 ratio. The study endpoint was major adverse cardiovascular events (MACE), including all-cause death, nonfatal MI, nonfatal stroke, revascularization, and hospitalization for unstable angina or heart failure. Kaplan-Meier, Cox regression, and receiver-operating characteristic analyses were performed.ResultsPatients with lower fT3/fT4 tertile levels had a significantly higher incidence of MACE (10.0%, 13.9%, 18.2%; p=0.005) over the median follow-up of 41.7 months. The risk of MACE increased with the decreasing fT3/fT4 tertiles even after multivariate adjustment (tertile1 as reference, tertile2: HR 1.58, 95% CI: 1.05-2.39, p=0.030; tertile3: HR 2.06, 95% CI: 1.17-3.11, p=0.006). Lower level of fT3/fT4 ratio remained a robust predictor of MACE in overall (HR 1.64, 95% CI: 1.18-2.29, p=0.003) and in subgroups. When adding fT3/fT4 ratio [area under the curve (AUC) 0.61] into the thrombolysis in myocardial infarction (TIMI) risk score (AUC 0.69), the combined model (AUC 0.74) yielded a significant improvement in discrimination for MACE (ΔAUC 0.05, p=0.023).ConclusionsLow level of fT3/fT4 ratio was strongly associated with a poor prognosis in euthyroid patients with MINOCA. Routine assessment of fT3/fT4 ratio may facilitate risk stratification in this specific population.
Highlights
Acute myocardial infarction (AMI) remains the leading cause of high morbidity and mortality of cardiovascular (CV) diseases worldwide [1]
Patients were diagnosed with myocardial infarction with nonobstructive coronary arteries (MINOCA) if they met the 4th universal definition of AMI [23] and the coronary angiography did not show a stenosis of ≥50% in epicardial coronary arteries [2]
There were no significant differences in Body mass index (BMI), dyslipidemia, prior MI, LDL-C, creatinine levels, and in-hospital medication among the 3 groups
Summary
Acute myocardial infarction (AMI) remains the leading cause of high morbidity and mortality of cardiovascular (CV) diseases worldwide [1]. A distinct population with myocardial infarction with nonobstructive coronary arteries (MINOCA) has been increasingly recognized due to the widespread use of coronary angiography. The predictive value of fT3/fT4 ratio in euthyroid patients with MINOCA remains unclear. We investigated the association between fT3/fT4 ratio and long-term outcomes after MINOCA and explored whether this ratio might provide significant prognostic information in this population. The free triiodothyronine (fT3) to free thyroxine (fT4) ratio has been reported as a risk factor for coronary artery disease, but its prognostic value in euthyroid patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) remains unclear
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