Objective: To survey the association of serum free triiodothyronine (FT3) level with coronary artery calcification and major adverse cardiac events (MACE) in outpatients with suspected coronary artery disease (CAD).
Methods: A total of 577 outpatients with suspected CAD, who underwent dual-source computed tomography and FT3 detection were included, patients were followed up for 8-29 months for the major adverse cardiac events (death, MI, PCI, CABG). These patients were divided into low FT3 ( < 3.5 pmol/L, n = 126) and normal FT3 ( ≥ 3.5 pmol/L, n = 451) group based on the FT3 level, and divided into CACS > 100 (n = 235) and CACS ≤ 100 (n = 342) group based on the coronary artery calcium score (CACS). Related factors to CACS and MACE were analyzed using logistic regression (stepwise) analysis.
Results: CACS (146.7 (55.8, 599.1) vs. 34.8 (0, 261.9), P < 0.001) and MACE (7.9% (10/126) vs. 2.0% (9/451) , P = 0.003) were significantly higher in the low FT3 group than in normal FT3 group. Logistic regression analysis demonstrated that the FT3 levels are inversely associated with the CACS (OR = 0.442, 95%CI = 0.317-0.618, P < 0.001). Kaplan-Meier analysis displayed that patients with low FT3 levels had a lower cumulative survival rate than patients with normal FT3 levels (P = 0.005), and patients with CACS > 100 also had a lower cumulative survival rate than patients with CACS ≤ 100(P < 0.001).
Conclusions: FT3 levels are associated with coronary artery calcification scores and the incidence rate of MACE in patients with suspected coronary artery disease. A low FT3 level is considered as an important risk factor of high calcification scores and MACE.