Response to Letter by Schonewille et al
We thank Schonewille et al for an interesting point. The analysis in our report was limited to basilar artery occlusions (BAO) proven with angiography or magnetic resonance angiography and treated with thrombolytics.1 Because only 30% of the patients (25) with presumed BAO in the referred study by Schonewille et al were confirmed by a comparable imaging study,2 there are still very limited case series data on patients treated with conventional measures (antiplatelets, anticoagulation or their combination) with proven BAO. Because of the phenotypic diversity of BAO and other posterior circulation syndromes, we focused our analysis on series with as similarly diagnosed cases as possible, therefore excluding studies with only clinical judgment as the basis of presumed BAO. Also, we did not include studies without repeat data on recanalization, which is the single most decisive determinant of eventual outcome and in our past experience very seldom ensues after conventional therapy.
The mortality rate of proven acute BAO with no specific recanalization treatment is commonly substantially higher than in the cited report,2 where the follow-up lasted until hospital discharge after a mean of 28 days. Nonrecanalized BAO patients commonly succumb at a subacute stage, often after transfer to a rehabilitation or nursing home, whereas patients with mild or moderate disability at 3 months commonly improve functionally.3 This together with the heterogeneity of diagnostic procedures in the study may explain the comparatively low in-hospital case fatality rate of 40% in the conventionally treated patients.2
We agree with Schonewille et al in that, while we await a multicenter randomized controlled study, a well-organized registry might be the next step in attempt to find a better comparison of the different treatment modes, and we therefore warmly advocate completion of the BASICS registry. However, registries have their limitations and cannot replace a randomized controlled study to compare intravenous thrombolysis with endovascular recanalization techniques.
Lindsberg PJ, Mattle HP. Therapy of basilar artery occlusion: a systematic analysis comparing intra-arterial and intravenous thrombolysis. Stroke. 2006; 37: 922–928.
Schonewille WJ, Algra A, Serena J, Molina CA, Kappelle LJ. Outcome in patients with basilar artery occlusion treated conventionally. J Neurol Neurosurg Psychiatry. 2005; 76: 1238–1241.