A Case of Acute Microvascular Myocardial Infarction During Cyclophosphamide Infusion

Abstract

BACKGROUNDCyclophosphamide (CYC) is a nitrogen mustard alkylating agent with potent immunomodulatory and immunosuppressive properties. Its cardiotoxicity effects, however, are reported to be dose-dependent, especially at doses above 100 mg/kg. Furthermore, cases of acute myocardial infarction at the time of infusion are rare. Hypotension, arrhythmias, heart failure and myocarditis are more common between two to ten days after infusion. CASE REPORTWe report the case of a 43-year-old black female, with a diagnosis of systemic lupus erythematosus (SLE) in 2022. Treatment with CYC and methylprednisolone followed due to glomerulonephritis. During the CYC infusion, she started having typical chest pain. Asymptomatic in the pre-infusion, she received only 100 mg of CYC until the onset of symptoms. The infusion was interrupted, and the patient received isosorbide dinitrate, with improvement after. Troponin test and electrocardiogram (ECG) were ordered in the emergency room. The patient's ECG was compatible with a subendocardial lesion current in the lateral, high lateral wall, and inferior wall. In addition, her troponin levels went from 40.9 to 1,026 pg/mL. An immediate cardiac catheterization was compatible with the diagnosis of myocardial infarction with nonobstructive coronary arteries (MINOCA). After catheterization, she remained in the intensive care unit until full symptom recovery, being transferred to the infirmary and subsequently discharged from the hospital, with a prescription of clopidogrel 75 mg daily, prednisone 40 mg and hydroxychloroquine 400 mg daily. Due to CYC cardiotoxicity and the risk of new cardiac events, it was decided not to perform new infusions, and mycophenolate mofetil 500 mg 4 tablets/day was started to control renal damage. CONCLUSIONThe knowledge of the cardiotoxicity of CYC is widespread in the medical literature, but the pathophysiology of the myocardial toxicity is not completely understood. Due to the use of different dosages, the side-effects profile and intensity may vary greatly. In this case, we observed endothelial and molecular damage even with low dose CYC, highlighting the importance of its side effects for the Rheumatologist.