Zusammenfassung
Die systemische Thrombolysetherapie beim akuten Schlaganfall führt zu einer signifikanten Verbesserung des klinischen Outcomes. Dabei werden das starre Zeitfenster und die fest definierte Medikamentendosierung der Heterogenität ischämischer Insulte kaum gerecht. Daher besteht großer Bedarf, das Thrombolysemanagement zu individualisieren und dadurch dessen Effizienz zu steigern. In dieser Übersicht werden verschiedene Ultraschall(US)techniken vorgestellt, die sowohl in diagnostischer als auch in therapeutischer Hinsicht einen signifikanten Beitrag zur Thrombolyseoptimierung leisten können. Dabei sollen sowohl bereits etablierte als auch noch in der Entwicklung befindliche Modalitäten berücksichtigt werden. Mit Einführung sog. Echokontrastverstärker wurde nicht nur die Ausbeute und Verlässlichkeit in der Akutdiagnostik intrakranieller Gefäßverschlüsse gesteigert, sondern auch eine Perfusionsmessung auf Gewebeebene (sog. US-Perfusionimaging) erst ermöglicht. Dadurch könnte die spezifische Auswahl geeigneter Thrombolysekandidaten künftig verbessert werden. Durch engmaschiges US-Monitoring während der Lysetherapie kann der Zeitpunkt der Gefäßrekanalisation am Krankenbett verfolgt und damit die Wirksamkeit der Rekanalisationstherapie nichtinvasiv bestimmt werden. Mit der US-assisistierten Thrombolyse befindet sich ein Instrument in der Entwicklung, das die frühe Rekanalisation beim akuten Gefäßverschluss beschleunigen könnte. Dadurch könnte ein modifiziertes Dosisregime ermöglicht und so das Blutungsrisiko weiter reduziert werden. Als weitere Therapieoption wird intensiv an der US-gesteuerten Freisetzung „verpackter” Pharmaka gearbeitet, wodurch eine thrombusspezifische, lokale Lysetherapie trotz systemischer Applikation in ferner Zukunft realisierbar erscheint. Diese modernen Werkzeuge der Neurosonographie besitzen ein großes Potenzial, die Thrombolysetherapie des akuten Hirninsultes künftig auf breiter Basis zu optimieren.
Abstract
Systemic thrombolysis of acute ischaemic stroke leads to significant improvement in clinical outcome. The rigid therapeutic window and the fixed medical dosage, however, are less than optimal with respect to the heterogeneity of ischaemic strokes. There is great demand for establishing more individualised treatment strategies to further increase the efficiency of thrombolytic therapy. In this review, new diagnostic and therapeutic ultrasound (US) techniques will be presented that could contribute significantly to this process. Echocontrast agents have led to improvement in the detection of vessel occlusion and have enabled brain perfusion measurements on the tissue level. Thereby the selection of candidates most suitable for recanalisation therapy could be guided. Transcranial US monitoring of time point and extent of revascularisation allows to judge the efficacy of thrombolysis which may result in individualised dose regimens. US-assisted thrombolysis has been demonstrated to potentiate purely pharmacological revascularization in various experimental settings. The delivery of encapsulated drugs via US, another exciting therapeutic tool, is currently under experimental investigation. It could provide thrombus-specific local revascularisation of occluded vessels in the distant future. Through recent progress, multimodal neurosonography has the potential to optimise thrombolytic therapy on a broad basis.
Key words
Ultrasound - Sonothrombolysis - Perfusion imaging - Echocontrast agents - Drug delivery
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Priv.-Doz. Dr. med. Darius G. Nabavi
Klinik und Poliklinik für Neurologie · Westfälische Wilhelms-Universität
Albert-Schweitzer-Straße 33
48129 Münster
Email: nabavi@uni-muenster.de
