Major adverse cardiac events in patients with amiodarone-induced thyrotoxicosis undergoing thyroidectomy: a multicenter study.

Objective: Amiodarone-induced thyrotoxicosis (AIT) affects 5-10% of patients on amiodarone therapy, increasing cardiovascular (CV) risk. Total thyroidectomy is proposed for refractory cases, but its long-term impact on major adverse cardiovascular events (MACEs) remains uncertain. This study evaluates post-operative MACEs and cardiac mortality in AIT patients with and without pre-operative left ventricular ejection fraction (LVEF) impairment. Methods: Patients undergoing total thyroidectomy for AIT from 2010 to 2023 in two French referral centers were retrospectively included. They were divided into two groups based on pre-operative LVEF (<40% vs ≥40%). The main outcomes were the post-operative MACEs and cardiac mortality at one and five years. Results: Among 101 patients, 26 had LVEF < 40% (group 1), while 75 had LVEF ≥ 40% (group 2). Patients in group 1 were younger, had higher ASA (American Society of Anesthesia) scores, and had more severe cardiac conditions. The median duration of exposure to AIT was 2.7 (Q1; Q3 1.3; 4.7) months. Overall, perioperative mortality was 2.0%. Group 1 showed higher 5-year MACE occurrence (61.4 vs 24.0%, P = 0.0005) and higher cardiac mortality (30.8 vs 1.3%, P = 0.0001). Multivariate regression identified younger age at AIT diagnosis and baseline LVEF < 40% as significantly associated with a higher 5-year MACE rate. Among patients with baseline LVEF < 40%, those with early post-operative LVEF improvement displayed a lower rate of 5-year MACEs (47.1 vs 100%, P = 0.022). Conclusion: Patients with LVEF < 40% carries a high long-term CV risk despite early thyroidectomy. Post-operative LVEF assessment may help identify high-risk patients. In contrast, those with LVEF ≥ 40% have a favorable prognosis.