Fibrinolysetherapie beim Hörsturz mir rt-PA (Recombinant Tissue-Type Plasminogen Activator)

Abstract

In the course of a pilot study, the effects of fibrinolysis treatment with rt-PA (Actilyse, Thomae, Biberach; 100 mg) on the recovery of hearing and hemorheologic parameters were investigated in 12 patients suffering from sudden hearing loss. The authors' approach was based on two considerations, (1) the possibility that, in cases of sudden hearing loss, the oxygen supply to the cochlea is totally or partially blocked by a microthrombus which could be dissolved by rt-PA and (2) the fact that lysis markedly improves the flow characteristics of the blood (as has been demonstrated in studies with streptokinase and urokinase). This human-plasminogen activator, produced by genetic engineering, is superior (also in terms of possible side-effects) to other lysin enzyme preparations (streptokinase, urokinase) because of its highly selective effects on thrombi (low activation of plasma plasminogen) and its short half-life (approx. 4 min). In nine of 12 patients, the treatment brought about a marked improvement in hearing or its complete restitution (three of the patients has initially been deaf in the affected ear). In the three nonresponders there was serologic evidence of an inner-ear infection (neuroborreliosis, cytomegaly, influenza B). The most interesting rheologic effect was the reduction of plasma viscosity (average decrease about 18%), since such a reduction cannot be attained with other, comparable rheologic measures (isovolemic or hypervolemic hemodilution). In spite of the convincing hemorheologic effects, fibrinolysis cannot yet be recommended as treatment for sudden hearing loss. Further studies have still to be done on spontaneous healing, the effects of hemorheologic measures on the blood circulation of the inner ear, and on the oxygen requirements of the ear affected by hearing loss.