Any vascular punctures or invasive procedures should be avoided as far as possible during, and immediately before and after urokinase therapy and if unavoidable done with great care. External chest compression. Caution in conditions eg, possibility of left heart thrombus, subacute bacterial endocarditis, coagulation defects, cerebrovascular disease, diabetic retinopathy and any conditions in which bleeding could be dangerous. Monitor for reperfusion arrhythmias when used in MI.