9370 Thinking Outside the Box: A Rare Case of Using Plasmapheresis Treatment of Amiodarone-Induced Thyrotoxicosis in Preparation For CABG

Abstract Disclosure: K. Shaik: None. A. Kartoumah: None. J. Alsheikh: None. A. Nayeem: None. M.H. Horani: None. Introduction: Amiodarone, a standard treatment for arrhythmias, poses a risk of disrupting thyroid function and causing amiodarone-induced thyrotoxicosis (AIT). In critical cases where AIT is refractory to first-line treatment, plasmapheresis can be a vital option to rapidly lower thyroid hormone levels, which is essential for pre-surgical stabilization. This case report describes plasmapheresis in managing AIT in a patient undergoing coronary artery bypass grafting, highlighting its role in preventing potential thyrotoxic crises. Case Presentation: A 75-year-old male with a past medical history of diabetes mellitus, coronary artery disease, arrhythmias treated with amiodarone, and a ninety-pack-year history of tobacco presented to the ED with complaints of chest pressure and dyspnea. Initial troponin levels were normal at 24 ng/mL but trended upward toward 66 ng/mL. In the ED, he was not tachycardic and denied recurrent pain, fever, or chills. A CT angiogram of his chest showed no pulmonary embolus. The patient was found to have low TSH (0.005), and his T3 and T4 were both elevated (3.89/1.96, respectively), confirming thyrotoxicosis; however, he was negative for Graves’ disease. While in the hospital, his amiodarone was discontinued, and he was started on prednisone 10 mg for 14 days and methimazole 5 mg for 14 days. He was ultimately discharged on the same prednisone and methimazole regimen and told to follow up with outpatient endocrinology. However, the patient reappeared a week later with dyspnea on exertion; blood work performed after admission revealed a higher free T4 at 2.87. The patient was admitted, and angiography showed three-vessel disease; however, a coronary artery bypass graft (CABG) procedure was delayed over the concern of a potential thyroid storm. Thus, CABG was planned for when free T4 was less than 2, and the patient underwent two rounds of plasmapheresis, which initially decreased free T4 to 1.7 and finally to 1.4. Ultimately, a CABG was performed and well tolerated. Discussion: Amiodarone-induced thyrotoxicosis (AIT) poses a challenge in patient management, especially in patients requiring urgent surgeries. Plasmapheresis is shown to be a valuable option for rapidly lowering thyroid hormone levels and stabilizing the patient in the pre-operative stages. This case demonstrates the effectiveness of plasmapheresis in reducing free thyroxine levels, facilitating a safe and successful CABG. Due to its ability to quickly remove circulating thyroid hormones, plasmapheresis has excellent potential in managing refractory AIT. It is crucial to carefully time plasmapheresis relative to surgery and monitor for complications throughout. Further research is required to optimize proper plasmapheresis protocols in AIT. Conclusion: This case study highlights plasmapheresis as a promising adjunctive therapy in managing AIT and preventing potential thyrotoxic crises. Presentation: 6/1/2024