By Babak Navi, MD, MS
Stroke Center Director, Assistant Professor of Neurology, Weill Cornell Medical College
Dr. Navi reports no financial relationships relevant to this field of study.
Synopsis: A large number of futile transfers take place for consideration of endovascular therapy, and better selection criteria need to be developed.
Source: Fuentes B, et al. Futile interhospital transfer for endovascular treatment in acute ischemic stroke. The Madrid Stroke Network experience. Stroke 2015;46:2156-2161.
Stroke is the fifth leading cause of death in the United States and the leading cause of adult disability. Until recently, the only proven treatment for acute ischemic stroke was intravenous thrombolysis, which increases the odds of excellent neurological outcome by 30%. However, in the past year, five landmark trials have demonstrated that endovascular therapy, primarily with stent-retriever devices for acute stroke from large vessel occlusions, dramatically improve functional outcomes with a number-needed-to-treat of four patients in some studies. Therefore, many community hospitals without endovascular capability are now implementing collaborative systems to transfer acute stroke patients with suspected or confirmed large vessel occlusions to larger hospitals with endovascular capability. Given the strong correlation between time to recanalization and outcomes, the emphasis of these acute stroke transfers is on timely recognition and transport, and thus some patients transferred to comprehensive stroke centers ultimately may not receive endovascular therapy because of absence of proximal occlusion or other contraindications. As hospital transfers are expensive and resources are limited, the authors of this study sought to investigate the frequency and predictors of futile hospital transfers for acute stroke endovascular therapy.
In Northern Madrid, there is a tiered hospital stroke system, whereby three comprehensive stroke centers provide 24-7 endovascular capability for multiple community hospitals serving nearly 3 million inhabitants. A consensus protocol is used to determine which stroke patients should be emergently transferred to the comprehensive stroke centers for possible endovascular therapy. This protocol is primarily based on last-known well time and stroke severity; assessment of large vessel occlusion with noninvasive imaging is recommended but not required. Upon arrival at the receiving endovascular-capable hospital, neurologists use clinical and radiographic criteria to make the final decision about endovascular therapy. From February 2012 to May 2013, 120 patients were transferred to comprehensive stroke centers in Northern Madrid for acute stroke endovascular therapy, 50 (41%) of whom did not receive an intervention and were deemed futile transfers. No clinical characteristics were associated with futile transfer; this included age, baseline NIH Stroke Scale and ASPECTS scores at the transferring hospital, and use of intravenous thrombolysis. The main reasons for ineligibility were clinical improvement or arterial recanalization (48%) and findings on the second neuroimaging test performed at the receiving hospital (32%), which usually was a low ASPECTS score. Interestingly, transport delays were a rare (2%) cause of futile transfer and median transfer times were only 56 minutes. The main limitation of the study was the relatively small sample size and the poor external validity since the patient population and stroke network of Madrid may not generalize to other populations and stroke systems.
Commentary
Fuentes et al have shown that about two in five hyperacute stroke transfers for possible endovascular therapy in Northern Madrid are futile, and the most common reasons for futility are clinical improvement, arterial recanalization, or neuroimaging findings on repeat brain imaging. These findings raise the question of where advanced neuroimaging should be performed and whether it is necessary to repeat neuroimaging at the receiving hospital. This is especially germane since the first positive endovascular trial1 did not exclude patients based on ASPECTS score, although the median ASPECTS score was 9 and very few patients had scores < 5. Furthermore, less than 5% of all ischemic stroke patients receive endovascular therapy, so better systems are needed to increase treatment rates while keeping treatment times low. Future studies will be needed to determine the best hospital system and patient selection criteria for acute stroke patients being considered for endovascular therapy.
REFERENCE
- Berhemer OA, et al; MR CLEAN investigators. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med 2015;372:11-20.
A large number of futile transfers take place for consideration of endovascular therapy, and better selection criteria need to be developed.
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