Response to Letter by Schulte-Altedorneburg et al
Minds are like parachutes—they only function when open.
— —Thomas Dewar
Schulte-Altedorneburg et al comment on our systematic analysis of the available data of intravenous (IVT) and intra-arterial (IAT) thrombolysis in basilar artery occlusion (BAO).1 They emphasize what we had written and there is no real disagreement between their and our opinions. We concluded that centers with an interventional neuroradiology service should pursue IAT, and that there is no reason for centers without interventionists to refrain from IVT. We analyzed the available data and took efforts to include trials with as similar patient cohorts as possible. This is why we excluded studies with a major number of distal vertebral artery occlusions.
In our analysis, there was no difference in the likelihood of good outcome in the 2 treatment modes although recanalization was achieved slightly more frequently after IAT. The logical conclusion from this main finding, as stated in the abstract, was that hospitals not equipped for IAT may set up IVT protocols for BAO thrombolysis, and that its effect is probably not much different from that of IAT. What we did not conclude was that hospitals equipped for IAT should give up their expertise and divert to less resource-consuming IVT protocols. On the contrary, we stated that such hospitals should pursue their service because of higher recanalization rates. Furthermore, rather than having solved this now widely debated issue,2–6 we stressed that a randomized trial would be necessary to prove the relative efficacy of IAT and IVT. Such a trial should compare IVT and endovascular recanalization techniques (ie, combinations of IAT and diverse mechanical recanalizations) and a third arm of a combined or bridging IVT/endovascular approach.
In our analysis it was not possible to include mechanical recanalization techniques because there were too few patients reported. The study by Eckert et al7 with 34% favorable outcomes points in the direction that an endovascular approach combining pharmacological and mechanical recanalization techniques may yield better results than a pharmacological dissolution of the clot alone. This study supports once more the conclusion that endovascular recanalization should be attempted when this service is professional and quickly available. However, looking at the whole world, for every hospital with experienced interventional neuroradiologists there may be, depending on the location on earth, several or several dozen hospitals without the skilled hands to perform endovascular interventions. The doctors in those hospitals would do a service to their BAO patients by starting immediate IVT according to current wisdom.
Schulte-Altedorneburg et al noted that the studies included in our analysis had different methods, ie magnetic resonance angiography versus digital subtraction angiography, to ascertain that BAO was the correct diagnosis. We had commented on that limitation of our study. It is unlikely that there were major differences in the accuracy of the diagnosis of BAO in the IVT and IAT patients. In fact, there were more patients with a clinical and radiological presentation of BAO who were comatose on admission in the IVT (51%) than in the IAT studies (45%). In the largest IVT study,8 46% were unconscious and 76% had to be intubated because of reduced alertness. Sixty percent of those needed mechanical respiratory support, and 18% were totally dependent on mechanical ventilation besides being comatose. That argues strongly against a bias favoring the IVT approach in our analysis.
Schulte-Altedorneburg et al refer to their retrospective analysis of 180 patients with vertebrobasilar occlusions treated with IAT,9 which included distal vertebral occlusions in addition to BAOs. Studies with a major portion of distal vertebral artery occlusions were excluded from our analysis and therefore the patients differ slightly. However, their study echoes the exact same trend of our systematic analysis. Although IAT can achieve respectful recanalization rates, the functional outcome of the patients is not necessarily more favorable than after IVT. Twenty-three percent of their endovascularly treated patients reached an independent functional outcome (mRS 0 to 2), whereas the corresponding numbers of our analysis are 22% after IVT and 24% after IAT. Obviously, there is a balance between the advantages and disadvantages of both approaches. Although IVT can be started more rapidly and has a lower recanalization rate, endovascular treatment achieves better recanalization rates but may require referral to another hospital or more preparation time during which the patient continues to deteriorate. We agree with Schulte-Altedorneburg and coauthors that a bridging concept with combined IVT and endovascular approach may eventually give best results and that this should be tested in a randomized trial. Until such data are available we rely on knowledge from case series and individual beliefs of experienced clinicians.2–4 More data are clearly needed, and until there are data from randomized trials we strongly suggest that BAO patients are entered in a large international database such as the academy driven BASICS registry (www.brains.umcutrecht.nl).
Lindsberg PJ, Mattle HP. Therapy of basilar artery occlusion: a systematic analysis comparing intra-arterial and intravenous thrombolysis. Stroke. 2006; 37: 922–928.
Davis SM, Donnan GA. Basilar artery thrombosis: recanalization is the key. Stroke. 2006; 37: 2440.
Ford GA. Intra-arterial thrombolysis is the treatment of choice for basilar thrombosis: con. Stroke. 2006; 37: 2438–2439.
Schellinger PD, Hacke W. Intra-arterial thrombolysis is the treatment of choice for basilar thrombosis: pro. Stroke. 2006; 37: 2436–2437.
Schonewille W, Wijman C, Michel P; BASICS investigators. Treatment and clinical outcome in patients with basilar artery occlusion. Stroke. 2006; 37: 2206; author reply 2207.
Ciccone A, Scomazzoni F. Intra-arterial thrombolysis for acute ischemic stroke. Stroke. 2006; 37: 1962; author reply 1963.
Eckert B, Koch C, Thomalla G, Kucinski T, Grzyska U, Roether J, Alfke K, Jansen O, Zeumer H. Aggressive therapy with intravenous abciximab and intra-arterial rtPA and additional PTA/stenting improves clinical outcome in acute vertebrobasilar occlusion: combined local fibrinolysis and intravenous abciximab in acute vertebrobasilar stroke treatment (FAST): results of a multicenter study. Stroke. 2005; 36: 1160–1165.
Schulte-Altedorneburg G, Hamann GF, Mull M, Kühne D, Liebetrau M, Weber W, Brückmann H, Mayer TE. Intraarterial thrombolysis in acute vertebrobasilar occlusions: a multicentric retrospective analysis of 180 cases. Am J Neuroradiol. 2006; In press.