German Society of Neurosurgery Section on Vascular Neurosurgery: Position Statement on the International Subarachnoid Hemorrhage Trial (ISAT)

Abstract

The outcome after a specific treatment (clipping or coiling) of ruptured intracranial aneurysms is determined by both the periprocedural complication rate and the success of preventing re-bleeding from the treated aneurysm. The latter is associated with a cumulative risk over many years, particularly in incompletely treated aneurysms. Incomplete occlusion of the aneurysm is not infrequently seen after endovascular coiling, even in cases with a perfect anatomical configuration. Therefore, we believe that the 1-year outcome as reported in the ISAT is not an appropriate endpoint for the comparison of both methods. There has also been a tendency to apply the 1-year ISAT data to all patients harbouring intracranial aneurysms. It is inappropriate and dangerous to be less critical when selecting the endovascular approach as the method of choice for treating an aneurysm. This will ultimately result in a higher complication rate of coiling. Another striking finding is the poor surgical outcome in the ISAT. This good-grade patient population (94 % were WFNS grade 1-3 and 89 % were WFNS grade 1-2) had an almost 10 % higher rate of poor outcome compared to other good-grade patients in large prospective surgical studies or the same outcome as trials that included up to 20 % poor-grade patients.
Neurosurgeons should acknowledge that endovascular coiling is a safe method associated with less complications than clipping in experienced hands (Fig. [1]). Endovascular radiologists should acknowledge that the success of complete obliteration is higher after surgery, that incompletely occluded aneurysms have a higher rate of re-rupture and that the definitive long-term re-rupture rate still remains unknown. Therefore, we await with interest the angiographic and clinical follow-up data that will provide evidence about the final patient outcome.

Zusammenfassung

Das langfristige Behandlungsergebnis eines rupturierten Aneurysmas wird sowohl von der Rate der perioperativen bzw. periprozeduralen Komplikationen als auch von der Rate der Reblutungen nach Behandlung des Aneurysmas bestimmt. Diese Rerupturrate zeigt besonders bei inkomplett behandelten Aneurysmen ein kumulatives Verhalten. Da nach einer endovaskulären Therapie das Aneurysma nicht selten nur inkomplett verschlossen ist, kann ein 1-Jahres Outcome - wie publiziert im ISAT - nur als vorläufiges Ergebnis der Studie angesehen werden. Des Weiteren muss vor einer unkritischen Erweiterung der Indikationsstellung zum Coiling gewarnt werden. Die Therapie anatomisch nicht optimal geeigneter Aneurysmen wird sonst zwangsläufig zu höheren Komplikationsraten und schlechteren Ergebnissen im Vergleich zur ISAT-Studie führen. Betont werden muss die hohe Rate an schlechtem Outcome in der chirurgischen Gruppe. Im Vergleich zu anderen prospektiven Studien mit dem gleichen Anteil an Patienten im klinisch guten Zustand, schneidet der chirurgische Arm des ISAT mit einer Häufigkeit eines schlechten Outcomes von > 30 % ausnehmend schlecht ab. Die Ursachen dafür werden diskutiert. Zum jetzigen Zeitpunkt sollte anerkannt werden, dass die endovaskuläre Behandlung in erfahrenen Händen eine komplikationsarme Methode der Aneurysmabehandlung darstellt, die aber selterer zum Erfolg des kompletten Aneurysmaverschlusses führt und deren Rerupturraten im Langzeitverlauf bisher unbekannt sind. Wir erwarten daher mit Spannung das Ergebniss der langfristigen Nachuntersuchungen, um eine definitive Antwort auf die Frage nach dem besseren Behandlungsergebnis zu erhalten.

Key words

Subarachnoid hemorrhage - cerebral aneurysm - clipping - coiling

Schlüsselwörter

Subarachnoidalblutung - Aneurysma - mikrochirurgische Therapie - endovaskuläre Therapie

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