Impact of Overt Hypothyroidism on Early Outcomes of Coronary Artery Surgery

BACKGROUND The association between preoperative overt hypothyroidism and early outcomes after coronary artery bypass grafting (CABG) is unclear. This study aimed to evaluate the influence of overt hypothyroidism on the outcomes of CABG. METHODS The series included 189 overt hypothyroid patients, who underwent CABG at Fuwai Hospital. These patients were 1:4 matched with 737 euthyroid patients using propensity score matching. The early postoperative outcomes were compared. RESULTS After propensity score matching, the incidences of impaired wound healing, reintubation, and the total complications were higher in hypothyroid patients than euthyroid patients (11.8% vs. 0.9%, P < 0.001; 2.1% vs. 0.4%, P = 0.03; 39.6% vs. 30.3%, P = 0.015, respectively). Multivariate analysis showed overt hypothyroidism was significantly associated with the occurrence of impaired wound healing (odds ratio [OR]=12.29, P < 0.001), reintubation (OR=5.71, P = 0.047), and the total complications (OR=1.31, P = 0.049). The OR of the total complications was 1.43 (P = 0.03) in hypothyroid patients with abnormal thyroid-stimulating hormone compared with euthyroid patients. The proportions of the use of dopamine, adrenaline, milrinone, and dobutamine in hypothyroid patients were higher than euthyroid patients (75.4% vs. 67.6%, P = 0.038; 10.7% vs. 6.1%, P = 0.028; 3.2% vs. 0.3%, P = 0.001; 4.8% vs. 1.2%, P = 0.004, respectively). The total duration of inotropic support and mechanical ventilation time in hypothyroid patients were longer than euthyroid patients (median duration: 4 days vs. 3 days, P = 0.003; 17 hours vs. 15 hours, P < 0.001, respectively). CONCLUSIONS CABG in overt hypothyroid patients is associated with a higher incidence of postoperative complications, stronger postoperative inotropic support, and longer mechanical ventilation time.