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

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.

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.

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).

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.