Thyroid arterial embolization in a patient with congenital heart disease and refractory amiodarone-induced thyrotoxicosis.

Introduction: Amiodarone-induced thyrotoxicosis (AIT) can sometimes lead to life-threatening complications, especially in patients with congenital heart disease (CHD). We report the case of a patient with refractory AIT that was successfully treated with thyroid arterial embolization (TAE).

Case Report: A 34-year-old man with complex cyanotic CHD complicated with heart failure (HF), pulmonary hypertension, and supraventricular tachyarrhythmias, was treated with amiodarone since 2013. In March 2019, he presented worsening of his cardiac condition and symptoms of thyrotoxicosis that were confirmed by laboratory assessment. Thiamazole 30 mg/day and prednisolone 40 mg/day were prescribed, but the patient experienced worsening of his cardiac condition with several hospital admissions in the next 5 months, albeit increasing dosages of thionamide and glucocorticoid and introduction of cholestyramine and lithium. Thyroidectomy was excluded due to the severity of thyrotoxicosis, and plasmapheresis was contraindicated due to the cardiac condition. TAE of the four thyroid arteries was then performed with no immediate complications. Progressive clinical and analytical improvement ensued with gradual reduction and suspension of medication with the patient returning to euthyroid state and his usual cardiac condition previous to the AIT.

Conclusion: For patients with medication refractoriness and whose condition precludes thyroidectomy, embolization of thyroid arteries may be an effective and safe option.

Established Facts: Amiodarone-induced thyrotoxicosis (AIT) can be refractory to a combination therapy of thionamides and glucocorticoids. Restoration of euthyroidism is of paramount importance in heart failure (HF) patients. Emergency thyroidectomy for AIT unresponsive to medical therapy is recommended in patients with severe underlying cardiac disease or deteriorating cardiac function.

Novel Insights: Thyroid arterial embolization (TAE) appeared as a salvage therapy in this patient. To the best of our knowledge, few case reports in the literature have described the embolization of the four thyroid arteries in AIT context. Endovascular embolization techniques are a valuable therapeutic option and can be considered in cases where standard forms of treatment are ineffective or involve unacceptable risks.