Clinical experience with alteplase in the management of intracardiac and major cardiac vessels thrombosis in pediatrics: a case series

Thrombolysis in Children: A Case Report and Review of the Literature

Thromboembolism (TE), including venous thromboembolism (VTE), arterial TE, arterial ischemic stroke (AIS), and myocardial infarction (MI), is considered a relatively rare complication in the pediatric population. Yet, the incidence is rising, especially in hospitalized children. The vast majority of pediatric TE occurs in the setting of at least one identifiable risk factor. Most recently, acute COVID-19 and multisystem inflammatory syndrome in children (MIS-C) have demonstrated an increased risk for TE development. The mainstay for the management pediatric TE has been anticoagulation. Thrombolytic therapy is employed more frequently in adult patients with ample data supporting its use. The data for thrombolysis in pediatric patients is more limited, but the utilization of this therapy is becoming more commonplace in tertiary care pediatric hospitals. Understanding the data on thrombolysis use in pediatric TE and the involved risks is critical before initiating one of these therapies. In this paper, we present the case of an adolescent male with acute fulminant myocarditis and cardiogenic shock likely secondary to MIS-C requiring extracorporeal life support (ECLS) who developed an extensive thrombus burden that was successfully resolved utilizing four simultaneous catheter-directed thrombolysis (CDT) infusions in addition to a review of the literature on the use of thrombolytic therapy in children.

Clinical experience with recombinant tissue plasminogen activator in the management of intracardiac and arterial thrombosis in children

Thrombotic events may complicate the clinical course of many pediatric diseases. Drugs for therapeutic thrombolysis include streptokinase, urokinase and tissue plasminogen activator (t-PA). There is less experience with recombinant t-PA (rt-PA) in children. We aimed to present our experiences with rt-PA in children with intracardiac or peripheral arterial thrombus. We retrospectively reviewed the children who received rt-PA for thrombus. Twenty-two children (13 boys, 9 girls; age range: 1 day-17 years) with intracardiac (n = 5), prosthetic heart valve (n = 2) and peripheral arterial (n = 15) thrombus were evaluated. Twelve (54%) had congenital heart disease, two (9%) had rheumatic heart disease, three (14%) had leukemia and five (23%) had documented sepsis, prematurity or meconium aspiration syndrome. Ten of the 15 peripheral arterial thromboses were observed following cardiac catheterization. Three of the five intracardiac thrombi were detected in children with leukemia. All children received low-molecular-weight heparin. rt-PA (alteplase) infusion (at a dose of 0.01-0.5 mg/kg per h) was administered for different time periods (3-66 h). Ten of 11 patients with peripheral arterial occlusion and three of five patients with intracardiac thrombus showed full recovery. However, there was no response in two patients with intracardiac thrombus and in two patients with heart valve thrombus. Nose bleeding, melena and decreased serum fibrinogen concentration were observed in seven patients during the rt-PA infusion. All bleedings stopped after cessation of rt-PA infusion, and no blood transfusion was required in any patient. We conclude that rt-PA infusion seems effective and well tolerated in children for the treatment of peripheral arterial and intracardiac thrombus.

Left ventricular thrombus formation after repair of anomalous left coronary artery from the pulmonary artery

Although thrombus formation following myocardial infarction in adults is well known, intracardiac thrombosis in children is uncommon. We report the case of a large left ventricular thrombus in an infant with ischemic cardiomyopathy secondary to anomalous origin of the left coronary artery from the pulmonary artery. Given its mobility and protrusion across the aortic valve, the patient underwent urgent thrombus removal through a transaortic approach. There were no embolic or neurologic complications. This case highlights that thrombectomy may be performed safely and successfully in critically ill pediatric patients.