A 40-year-old male with Becker muscular dystrophy presented with severe mitral regurgitation and underwent mitral valve repair. Following the surgery, the patient became tachycardic, and developed a continuous high grade-fever and hyperbilirubinemia. The patient's condition worsened and we eventually tested his thyroid levels and discovered abnormally high thyroid levels. After diagnosing a severe thyroid storm, the patient was treated with oral administration of Lugol's iodine and thiamazole, as well as an intravenous steroid, which led to an immediate improvement of symptoms. The incidence of thyroid storm after open-heart surgery is extremely rare but highly life-threatening if unrecognized.

Cryoglobulinemia is a cold-reactive autoimmune disease. A 64-year-old man with active cryoglobulinemia presented Stanford type A acute aortic dissection. He had been treated with immunosuppressive drugs and plasma exchange (PE) at our hospital; subsequently, qualitative analysis of cryogobulin (CG) was negative. He underwent emergency ascending aorta replacement using cardiopulmonary bypass (CPB) under deep hypothermia circulatory arrest with selective cerebral perfusion. The total CPB time, aortic cross clamp time, and selective cerebral perfusion time were 255, 153, 56 minutes, respectively, and the minimal nasopharyngeal temperature was 17.3°C. Our patient had no significant perioperative complications. Hence, if PE is performed appropriately and CG is negative, patients with cryoglobulinemia who exhibit severe preoperative symptoms can safely undergo surgery with deep hypothermia.