Day 3. Wednesday, 9 September
Guidelines in 2015
This last day began by a lecture from Dr J. Gralla (Bern, Switzerland) focusing on the latest guidelines for endovascular treatment of ischemic stroke. The “unhappy triad” studies (IMS III, Synthesis, MR-Rescue) were reviewed and two crucial points were emphasized: that these studies did not reflect the clinical results of stent retrievers and that patient selection was not based on imaging studies.
The main results of the “magnificent seven” (MR-CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, THRACE, THERAPY) which have revolutionized interventional neuroradiology regarding stroke therapy, were nicely presented. Based on these data, the recommendations provided by the ESO-ESMINT, ESNR and AHA were summarized. Mechanical thrombectomy (MT) is recommended as first-line treatment up to six hours for large vessel occlusion in the anterior circulation (with association of IV fibrinolysis within a 4.5 hour range). Despite the validation of MT by stent retrievers (level 1A), the efficacy of other devices or aspiration still has a lack of proof (Level 2A). The assessment of both brain parenchyma and vessels (and not only brain OR vessels) before endovascular treatment was also well underscored.
The morning case session began with a left MCA stroke presented by the Charleston, SC, USA team. Treatment for this patient began very early, 1 hour after symptom onset, and the CT imaging showed a MCA M1 segment occlusion with an ASPECT 10 score. The case did not present any difficulties for treatment and resulted in a TICI3 recanalization by one attempt using aspiration. What was of great interest was how this team demonstrated that optimal patient workflow allows for better management of stroke patients.
The Bern, Switzerland interventional neuroradiology team presented the second case. A wake-up stroke of vertebrobasilar territories secondary to a basilar occlusion pointed out the difficulties in patient selection for symptoms onset strokes after an undetermined time. As well, interest in this case was also related to the stroke etiology: intracranial stenosis evoked quickly as shown by both angiographic and epidemiologic data (basilar arterial chronic stenosis frequently involves the lowest parts of the vessel). A first stent retrieval and recanalization of the basilar artery was performed. However, the question of whether to stent or not to stent the basilar artery remains unanswered. Could a percutaneous balloon angioplasty (PTA) be considered in this case? An open debate followed with a very rich exchange between the expert panel and the audience. At the end, several passes of stent retriever followed by four PTAs were performed on two stenotic locations after administration of antiplatelet agent (anti GpIIb/IIIa).
On the Cutting Edge: biomechanical behavior of Stent Retrievers
The cutting-edge topic session gave us the opportunity to hear two very original, break-through presentations.
Dr Paolo Machi (Brussels, Belgium) shared with us his original research work with video supports focusing on the biomechanical behavior of stent retrievers in relation to anatomy and thrombus composition. His work is of great interest and will certainly help us understand treatment planning related to the specific patient anatomy. The main results include the following observations: that white clots are stiffer than red ones preventing their penetration by either the guidewire or the stent retriever. In addition, the best thrombectomy results on silicone models are obtained using large sized and incomplete section devices which present radial force increases with their shortening. These results are of great interest in understanding certain of the failures encountered in practice. However, their transposition to clinical practice still needs further study.
On the Cutting Edge: biological aspect of intracranial thrombus
Dr C. Dargazanli (Montpellier, France) presented an interesting work focusing on the biological aspects of intracranial thrombus. This area of research is seeing increased interest as it is critical in deepening our understanding of ischemic stroke disease. Dr C. Dargazanli and his collaborators set up an original protocol to obtain and analyze by immunohistochemical staining fresh thrombus retrieved by mechanical thrombectomy. His aim was to study the content of intracranial thrombi T-cells in relation to stroke etiology. He concluded that atherothrombotic thrombi contain more T-cells than cardioembolic ones. This original approach could have an impact on the secondary prevention of ischemic stroke patients, especially when dealing with unknown etiology.
A last afternoon of cases
The afternoon case session allowed the Montpellier, France interventional neuroradiology team to present a vertebrobasilar ischemic stroke (NIHSS = 9). Because of patient agitation during the MRI scan, only the DWI was performed and the patient underwent a CT and CTA. CTA showed a distal and top basilar occlusion. Interestingly, the DWI appeared normal despite a clear neurological deficit. The case illustrates very well the delay of positive DWI lesions in posterior fossa strokes compared to anterior circulation territories strokes. The case and its management by mechanical thrombectomy allowed for the complete recanalization of the basilar arteries and its branches, also gave rise to several questions still hotly debated. We were reminded that in a posterior fossa ischemic stroke which presents within 4.5 hours, the indication of IV fibrinolysis is formal, if there are no contraindications. However, one should always keep in mind that in posterior fossa strokes the onset of clinical symptoms are often not as clear as in anterior circulation.
The fourth and last case of the day but also of the SLICE meeting was by the Barcelona, Spain team of interventional neuroradiologists. They reported on a 55-year-old male with a vertebrobasilar ischemic stroke, suffering from fluctuating symptoms NIHSS (3-5) mainly with dysarthria and dizziness and without consciousness impairment. The performed imaging showed restricted lesions in the left PICA medial branch territory and a V4 vertebral artery segment lesion which was difficult to characterize. The accurate diagnosis was subject to an intense discussion between the expert panel and the audience: and agreement was hard to find. Dissection? Acute thrombosis on the culprit atheromatous plaque? The questions remained. The case and the discussion that followed underscored the difficulties in making an accurate emergency diagnosis, especially for posterior fossa lesions affecting the V4 segments of vertebral arteries. The initial angiographic pictures confirmed the atheromatous etiology. A first aspiration through an intermediate catheter, followed by PTA and successful stenting were performed allowing for the complete recanalization of the arterial tree. The antiplatelet regimen for such procedure was then discussed, highlighting the various practical practices. Unfortunately, imaging at follow-up showed constituted ischemic lesions of the contralateral cerebellar hemispheres.
Future perspectives in Stroke Research and Management
To close this rich last day of SLICE, futures perspectives in stroke research were discussed.
Dr T. Jovin (Pittsburgh, PA, USA) described the DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention (DAWN) trial, which represents the next main trial on endovascular treatment of ischemic stroke. This multicenter study (up to 50 centers worldwide), has the primary objective of evaluating whether Trevo thrombectomy associated with medical management leads to superior clinical outcomes at 90 days when compared to medical management alone in appropriately selected subjects experiencing an acute ischemic stroke when treatment is initiated within 6-24 hours after last being seen in good health. The trial explores recovery by an original approach consisting of a weighted mRS designed to capture health state transitions across the entire spectrum of original mRS.
The DEFUSE 3 study was also briefly presented. It proposes a paradigm shift based on an imaging selection of patients who will benefit from endovascular therapy rather than a time-based selection. The automated post-processing and quantification of the perfusional mismatch will be a cornerstone of both DAWN and DEFUSE 3 trials. To conclude, Dr T. Jovin presented the FRONTIER study focusing on a neuroprotective agent shown to reduce stroke volume in primates and in humans (NA-1, a PSD-95 inhibitor).
Until next year…
This first successful SLICE Meeting ended with the unique opportunity exploring and discussing many aspects of ischemic stroke patients, from their diagnosis to their treatment, including anesthesiology as well as patient workflow at local and regional levels. It allowed the different contributors and attendees to share their experience. It underscored the importance and benefits of endovascular treatment as a first line therapy based on data from recent literature. And it left us all with the impression that there is still a lot to be done to better understand ischemic stroke and improve its treatment. The perspectives of a vast range of challenging future research were presented. Increasing collaboration between key players in many different specialties is needed to rise these challenges.
One thing is certain: SLICE will be there and ready to help, bringing us together to better understand and improve care for all!
Thank you all for your participation, and to have made this Course so alive.
See you at SLICE 2016!
Omer Eker, MD & Cyril Dargazanli, MD
The social media and report team