Safety and outcomes of thrombolysis with tissue plasminogen activator for treatment of intravascular thrombosis in children.

OBJECTIVES: In this study, we tried to determine the safety and outcomes of thrombolysis with tissue plasminogen activator of intravascular thrombus. STUDY DESIGN: Eighty consecutive children were treated between 1985 and 1999 in a tertiary care setting in a retrospective case series. There were 65 arterial thrombi (56 after cardiac catheterization) and 15 venous thrombi treated with tPA at an average dose of tPA of 0.5 mg/kg/hour for a median duration of 6 hours. RESULTS: Clot resolution was complete in 65% of children, partial in 20%, and there was no effect in 15%. There were major complications in 40%, minor complications in 30%, and no complications in 30%. Two patients had cerebral ischemia secondary to hypotension because of profound bleeding, with intracranial hemorrhage in 2 additional patients. Clot resolution was not related to patient age or weight, dose, and duration of tPA therapy and fibrinogen levels. However, complications were more likely in patients who weighed less, had a longer duration of therapy, a greater decrease in fibrinogen levels, and who failed to have resolution of their clot. CONCLUSIONS: tPA therapy can be effective in the thrombolysis of intravascular thrombus in children, but is associated with a low margin of safety and an unknown risk-benefit ratio.

Diagnosis and management of stenotic aorto-arteriopathy in childhood.

Stenotic aorto-arteriopathy is an uncommon vascular lesion characterized by segmental arterial stenoses. We reviewed the experience with several management algorithms to define the most effective management course. The clinical records of 14 pediatric patients with acquired SAA who presented over a 16-year period were reviewed. Most patients presented with a mid-thoracoabdominal coarctation and were diagnosed with Takayasu arteritis. Differentiating between Takayasu arteritis and fibromuscular dysplasia was difficult on clinical grounds or by angiography. Medical management of the end-organ disease and renovascular hypertension was only palliative. Selective percutaneous transluminal balloon angioplasty of the stenotic renal arteries had only transient benefits; renal autotransplantation had slightly better success. Dilation of stenosed aortic segments with balloon-expandable endovascular stents and subsequent renal autotransplantation proved useful. Distinguishing SAA resulting from fibromuscular dysplasia caused by Takayasu arteritis in the chronic vaso-occlusive phase may be unnecessary for effective treatment. Therapy should focus on interventions to minimize the end-organ damage caused by the vaso-occlusive manifestations of the disorders.

Assessment of myocardial perfusion and function in childhood systemic lupus erythematosus.

OBJECTIVES: To determine the prevalence of abnormalities in myocardial perfusion or function in children with systemic lupus erythematosus (SLE), and describe potential factors that may predict their development. STUDY DESIGN: Patients (n = 40; 30 female) were enrolled through the Lupus Clinic at The Hospital for Sick Children between 1990 and 1992. Resting and exercise thallium myocardial perfusion scans, radionuclide angiography with multiple gated acquisition (MUGA), and resting M-mode and two-dimensional echocardiography were performed. RESULTS: All patients were free of symptoms, and none had a history of ischemic heart disease. Their median age was 15.9 years (range 10.5 to 19.8 years) at enrollment. Abnormalities of coronary perfusion were found in 5 (16%) of 31 patients (95% confidence interval: 3%, 29%) and included a large fixed perfusion defect in 1; 5 of 27 MUGA scans showed marginally low left ventricular ejection fractions at rest, whereas all had normal exercise responses. In the group with abnormal thallium scans, three of five patients had antiphospholipid antibodies detected, and two of four had an abnormal plasma lipid profile. This group tended to have a shorter disease duration and had received a lower cumulative dose of corticosteroids; these differences were not statistically significant compared with the group with normal scans. CONCLUSION: Asymptomatic abnormalities of myocardial perfusion occur in children with SLE and are more common than previously suspected. Patients with these abnormalities of myocardial perfusion may be predisposed to the previously recognized early-onset ischemic heart disease seen in adults with SLE.

Outcome of coronary artery aneurysms after Kawasaki disease.

From 1974 through 1991, a total of 583 children with Kawasaki disease were seen at the Hospital for Sick Children, in Toronto, of whom 80 (13.7%) had coronary artery involvement. There were 55 boys and 25 girls, whose mean age at onset was 2.9 +/- 2.5 years, followed for a mean period of 4.0 +/- 3.6 years. Giant aneurysms (maximum diameter > or = 8 mm) were found in 22 children, moderate-sized aneurysms (> or = 4 to < 8 mm) in 44, and dilation lesions (< 4 mm) in 14. Myocardial infarction occurred in 9 (1.5%), all of whom had giant aneurysms. The persistence rate for aneurysms was 72% at 1 year and 41% at 5 years of follow-up. In multivariate analysis, the regression of an aneurysm was significantly related to the severity of coronary artery lesions, initial treatment, and gender. Although > 80% of small or moderate-sized aneurysms regressed within 5 years, giant aneurysms did not regress during the follow-up period. In patients who received immune globulin therapy, coronary lesions tended to resolve more rapidly than in those treated with salicylate therapy alone, because 91% of the lesions in the former were small or moderate. These findings suggest that the severity of coronary artery involvement during the initial stages of Kawasaki disease influences the regression of these lesions, and that immune globulin treatment may improve outcome by reducing the incidence of severe lesions.

Tissue plasminogen activator for the treatment of thromboembolism in infants and children.

We report our experience with the use of tissue plasminogen activator to treat 12 infants and children with various thromboembolic states after conventional thrombolytic agents had failed. The dosage range was between 0.1 to 0.5 mg/kg per hour. Complete clot dissolution occurred in seven cases after 2 hours to 3 days of therapy. Partial clot dissolution and clinical improvement were noted in another four patients. Bleeding complications were noted in 6 of the 12 patients and included bruising, oozing from various venipuncture sites, and bleeding; these complications were controlled by clinically available means. In all cases with bleeding the dose rate was in the higher range (0.46 to 0.50 mg/kg per hour). In one patient, restlessness, agitation, and screaming were noted during administration of tissue plasminogen activator and when it was reinstituted. We conclude that tissue plasminogen activator is effective in inducing clot lysis in children. Because the effective dose appears to overlap with those causing bleeding, we recommend that a dose of 0.1 mg/kg per hour be started and increased gradually if clot dissolution does not occur, with close monitoring for bleeding.