PC2138: A Heart-wrenching Case of Ischemic Stroke Secondary to Left Ventricular Thrombus Formation in MIS-C

Introduction: Left ventricular thrombus formation, most commonly seen in adults, occurs in the setting of severely reduced ejection fraction (EF). Throughout the COVID-19 pandemic, thrombosis in previously healthy children has become more common, with incidence of clot formation up to 2.5% in children with COVID-19. Venous thromboembolism is most common, with few reports of arterial thrombosis or intra-cardiac thrombus formation in children. While prothrombotic state most often occurs in multi-system inflammatory syndrome in children (MIS-C), thrombus formation also occurs in patients with Covid-19 but no diagnosis of MIS-C. Currently, there are few reported cases of ischemic stroke secondary to left ventricular thromboembolism in MIS-C.

Case Description: A 4 year-old previously healthy female developed altered mental status, difficulty ambulating, and right facial droop 8 days after reportedly testing positive for COVID-19. Patient was somnolent on arrival to the emergency department, requiring intubation for airway protection. SARS-CoV-2 Nucleic Acid Amplification Test was negative. MRA brain revealed total occlusion of the left internal carotid artery and MRI brain was consistent with left MCA stroke. 2D echo revealed 5 left ventricular (LV) thrombi and mildly reduced left ventricular systolic function, EF 47%. Patient was started on milrinone and heparin drip. Her LV function improved gradually with complete recovery and continued reduction in left ventricular thrombus size. Prothrombotic workup was significant for positive ANA (1:320), and mildly depressed protein C activity, thought to reflect inflammatory state and clot-induced consumption. She was continued on anticoagulation with enoxaparin and treated with steroids for MIS-C. Post extubation, she was found to have expressive dysphagia and right hemiplegia. She required intensive therapies in an inpatient rehabilitation facility and continues therapy as an outpatient. She recovered her speech, right-sided muscle strength, and ability to ambulate unassisted.

Discussion: LV thrombi are typically seen in severely depressed cardiac function, where EF is < 30%. Although this patient's function was significantly higher, it is suspected that she developed MIS-C leading to a hypercoagulable state that increased her risk for thrombosis and ultimately, resulted in her stroke. Per the American College of Rheumatology clinical guidelines, patients with ejection fraction less than 35% should receive prophylactic low dose aspirin and therapeutic low molecular weight heparin until ejection fraction recovers.

Conclusion: Hypercoagulability with thromboembolism, a phenomenon historically seen in primarily adults, has become more prevalent in children throughout the COVID-19 pandemic. Although literature shows COVID-19 and MIS-C leading to prothrombotic states, there are few case reports of children with LV thrombus secondary to COVID-19. This phenomenon is rare and attributed to the prothrombic state associated with MIS-C. This case demonstrates that a mildly reduced EF or dilated cardiomyopathy may also be risk factors for LV thrombus formation in MIS-C and consideration to initiate prophylactic anticoagulation should be given in all patients.