High-dose urokinase therapy in newborn infants with major vessel thrombosis.

The effectiveness of urokinase therapy for thrombosis in children, particularly in newborn infants, has not been established. We report our experience with the local administration of high-dose intrathrombus urokinase in two newborn infants. One infant had aortic thrombosis and the other, thrombosis of the right femoral artery. The known abnormalities in the newborn's fibrinolytic mechanism provide the rational basis for the therapeutic use of high doses of plasminogen activators. No significant abnormalities of our patients' fibrinolytic systems were found, and effective thrombolysis was achieved. A literature review of the use of urokinase therapy for thrombosis in children reveals great disparities in dosage and outcome. We believe that fixed-dose regimens should be replaced by individually adjusted thrombolytic therapy and that the need for higher doses of urokinase in newborns should be studied further.