By Dr Stela Rutovic

ESOC 2023 Session Report – ATTENTION to the BEST and BASIC Controversies of Basilar Artery Occlusion

Chairs: Simona Sacco and Stefania Nannoni

The first lecture in this session was ATTENTION to the Clinical- Anatomical Syndromes of Basilar Artery Occlusion Stroke by Patrik Michel (Lausanne, Switzerland) who presented major differences and similarities between basilar artery occlusion (BAO) strokes and anterior large vessel occlusions (LVO). Frequency of BAO strokes is lower than anterior LVO, its severity has a“ camel distribution „ and  severe BAOs are more often missed than anterior LVOs. Symptoms related to missed strokes are acute stupor/coma, isolated vertigo and acute amnesia. Around 50% of BAO strokes have precurser events. Major similarities between anterior LVO and BAO include stroke mechanisms in LVOs and medium vessel occlusions (MEVOs), poor prognosis if untreated, and  major outcome predictors including NIHSS, age and recanalisation . Most specific deficits in minor posterior circulation strokes are cerebrellar/vestibular, oculomotor brainstem signs, decreased level of consciousness, bilateral or crosses signs and amnesia. Frequency of LVO and (MEVO) is lower in posterior than anterior circulation. Main clinical syndromes of BAO are top of basilar syndrome as a result of distal BAO, locked-in syndome as mid- basilar  occlusion and Wallenberg syndrome as a result of proximal BAO.

The second lecture was The BEST Approach to Imaging Selection of Reperfusion Therapy for Basilar Artery Occlusion by Volker Puetz (Dresden, Germany) . He presented results of recent meta-analysis by Abdalkader et al.  which compared endovascular thrombectomy (EVT) with best medical management (BMM) of patients with BAO . The meta-analysis included several randomised control trials (RCTs) (BAOCHE , ATTENTION , BASICS  and BEST ) and its results favour EVT in contrast to  BMM  in BAO.  Simple imaging selection criteria for EVT are BAO and pc-ASPECTS≥ 6, and pons- midbrain index ≤2.  There is unclear benefit of EVT for BAO  if pc-ASPECTS is <6.   In the rest of the lecture he provided answers to several questions. The first one was about preferred imaging modality, and the conclusion was that non-contrast CT or CT angiography –source images (CTA-SI) are probably sufficient for patient selection. The second question was should we perform EVT if there is large infarct core (pc-ASPECTS<6). Subgroup analysis from BAOCHE and ATTENTION  trial  indicate that patients with pc-ASPECTS <6 may benefit from EVT, but future studies are required. Perfusion imaging  may identify patients who are unlikely to benefit from EVT. The third question was should EVT be performed in extended time window.  Baseline ischemia and collaterals are associated with outcome.  Good collaterals and good pc-ASPECTS (>8) may indicate benefit>24h.  The fourth question was should we perform EVT in patients with minor deficits (NIHSS <10). Results from the previously mentioned meta -analysis have shown that benefit from EVT in those patients is unclear. CT perfusion may identify patients who are likely to benefit from EVT.

The third lecture was The role of Intravenous Thrombolysis for BASILAR  Artery Occlusion, by Daniel Strbian (Helsinki, Finland) who  gave an overview of several RCTs on the BAO.  BASICS registry, BEST and BASIC trials have shown eqvivocal benefit between the treatment of BAO with EVT or IVT, although IVT proved better in BASICS in patients with moderate symptoms. ATTENTION and BAOCHE  trial  showed that in BAO patients with very severe symptoms  EVT is superior to antithrombotics. He pointed out that there is no evidence that EVT is superior to IVT . The only randomised IVT – EVT comparison comes from the BASICS trial in which 80% of patients were treated with IVT,  and this trial showed no difference between these treatment modalities.  The lecturer  further presented observational data from HELSINKI cohort (1995-2022). Favourable outcome in patients treated only with IVT was achieved in 46% of patients (like EVT arms of RCTs). There was no significant difference in outcome between IVT vs EVT, however there was a tendency of more favourable outcome in the IVT group. As a practical guideline he recommended that if you are in a center where you see a patient with very severe BAO symptoms and your standard approach was antiplatelet/anticoagulation  EVTshould be used (BEST, BAOCHE, ATTENTION).However, If you are in a center where IVT is used then you should look at BASICS trial and observational data on IVT from HELSINKI.

The fourth lecture was Endovascular therapy for BAO: Past,  Present and Future by Wouter Schonewille (Utrecht, Netherlands) who gave an overview of major studies on this topic.  BASICS registry from 2002.- 2007 included  patients with BAO, and showed that there was not favourable outcome of EVT over IVT. Basics Trial from 2012-2019 included patients within 6 hours after stroke onset due to BAO,  who were assigned to receive EVT or standard medical care. Chinese  ATTENTION registry  included patients within 12 hours of estimated BAO, and BAOCHE trial  included patients within 6-24h of symptom onset. Both trials only randomized patients with moderate or severe deficit and limited ischemic changes. There was low use of IVT in both trials.  There are several conclusions from all of these  trials.  EVT is highly effecitve in <24 hours from symptom onset in patients with BAO and NIHSS≥10 with limited early ischemic changes not treated with IV T.  EVT is probably effective in <4.5hours from symptom onset in patients with BAO and a NIHSS≥10 treated with IVT.  The efficacy of additional IVT prior to EVT within 4.5- 24 hours of symptom onset is currently tested in the POST-ETERNAL  trial. As a take home message we should be hesitant to treat patients with minor deficit and BAO with EVT, as EVT is potentially harmful in patients with BAO and a NIHSS<10. The efficacy of EVT in patients with a minor deficit should be tested in a future trial.

The fifth lecture  in this session was Initiation of Anticoagulation After Reperfusion by Apostolos Safoursi (Pireus, Greece). High rates of recurrent cardioembolic strokes within the first days after stroke raise the question if we can initiate anticoagulation early but safely considering the bleeding risk. Results from the studies suggest that during EVT we shoud give as low as possible iv heparin,  and that bridging with heparin is not recommended. NOACs are safer and more efficient than VKAs in preventing recurrent strokes and should be the first choice in subacute ischemic stroke. 2019 ESO guidelines suggest initiation of anticoaguation on days 3-4 of stroke onset in patients with mild stroke and small infarct size, on day 7 in those with moderate stroke, and on day 14 in those with severe stroke and large infarct size. Several large studies  compared efficacy and safety of early vs  late anticogulation in ischemic stroke patients.  Recent results of ELAN trial which also included patients after EVT favour early anticoagulation. In accordance with  the results of this trial in patients with minor/moderate stroke it could be safe to initiate anticoagulation within 2 days , and in patients with severe stroke in 6 days+1. Hemorrhagic infarction after EVT should not cause delay in the initiation of anticoagulation. There is not many data on optimal timing of anticoagulation in patients with parenchimal hemorrhage after EVD, current results suggest that initiation within 14 days seems safe.

By Dr Zdravka Poljakovic

ESOC 2023 Session Report -Neurointervention – Imaging and Reperfusion

First lecture has been given by professor Joachim Fladt, from Canada, dealing with possible impact of brain atrophy/fraility on baseline stroke severity and outcome. Concept of brain fraility was an intriguing insight in brain reserve mechanisms where prof Fladt discussed cortical integrity and synaptic density. He presented the results of ESCAPE-NAI trial where an original way of combined analysis of brain fraility on non-contrast CT has been conducted. The features included global cortical atrophy scale, white matter hyperintensities, subcortical atrophy, lacunes and chronic infarcts in numbers. The results of the study clearly showed that brain fraility has impact on final outcome as well as cortical atrophy and chronic infarct burden. He stressed out that maybe more attention should be paid to the biological versus chronological brain age.

Dr Antje Schmidt Pogoda from Germany gave the next talk, which she herself described as provocative – what it really was. She analysed the problem of failure of neuroprotection  in clinical setting in contrast to the results of animal trials, and presented the possible explanation. According to it, lack of  infarct volume growth in clinical setting after stroke strongly influences the results of neuroprotection as this is the main measure of neuroprotection. According to this theory as infarct growth is the target of neuroprotection in experimental models, and most stroke patients do not experience infarct growth, in clinical setting we actually do not offer a target for neuroprotection.

Two lectures about special features and subgroup analysis from SELECT2 Imaging analysis were given by professor Amrou Saraj and gave a new insight into the study results as well as definitions of some neuroimaging characteristics in the study group of patients. The rational for this subanalysis were the facts that three RCT’s recently demonstrated improved functional outcomes after endovascular treatment (EVT) even in patients with large core, which extended EVT eligibility according to CT/MR-perfusion imaging. The hypothesis is therefore that ischemic core estimates on different imaging modalities correlates with EVT outcomes. However, important is to be aware of possibility of CTP over- and underestimation of ischemic core. So, the investigational group of prof Saraj concluded that ischemic core estimates demonstrated prognostic utility rather than treatment modification, that treatment effect maintained even in patients with very large core, and that reduced infarct growth was present in patients achieving functional independence and independent ambulation.

Next challenging presentation about MR Microscopy in Thrombectomy to assess clot composition given by professor Michael Breckwoldt showed the power of advanced neuroimaging techniques in clot analysis. Knowledge of clot histology may predict outcome or possible endovascular therapy resistance or recurrence of occlusion, or may give additional data about stroke etiology. The data about ex vivo MR microscopy of clots at 9.4 Tesla following thrombectomy already exist, and clot composition can be assessed by MR microscopy. Furthermore, white clots need more recanalization maneuvers, increased time to recanalization and have poorer clinical outcomes. So a preinterventional clot imaging can give valuable data about clot composition and might allow a personalized approach to thrombectomy, prof Breckwoldt  concluded.

Dr Jorge Pagola from Barcelona presented the results of a study about intracranial thrombus composition and possibilities of prediction early reoclussion accordingly. The study was inspired by the fact that certain percentage of patient experience early reoclusion, dr Pagola showed, and this fact has a huge impact on outcome of this patients.The possibility of prediction of this phenomena could be clinically important. According to the results of the study, rich B-lymphocite thrombus is an independent predictor of early unexpected reocclusion even after initial successful thrombectomy. On the other hand,  thromboinflammation is a potential therapeutic target that may decrease early reocclusion.

His collegue from Barcelona as well, dr Roger Collet Vidiella continued the session presenting interesting results of a RES-CAT study, namely clinical and angiographic outcomes after rescue stenting for failed mechanical thrombectomy. He showed the results of a metaanalysis of several studies which mainly showed that intracranial stent is a rescue therapy and that rescue stenting improves outcomes in failed thrombectomy. In the study he presented the group of investigators posed the same question, namely does rescue stenting improve the functional outcome of patients with failed mechanical thrombectomy. The results of the study showed a trend towards better functional outcome with rescue stenting, however, after adjustment this trend was not statistically significant. Furthermore, the results showed that patient with successful recanalization which was achieved after stenting have worse functional outcome in comparison with patients who did not need rescue stenting. However, a good news is that there were no issues in safety outcomes, he concluded.

Finally, professor Thanh N. Nguyen concluded the session with a talk about endovascular thrombectomy for patients with large vessel occlusion stroke beyond 24-hours. In summary of her talk she stated that good ASPECTS and collateral scores can serve as surrogates  for viable brain and slow infarct progression with good functional outcomes after 90.days. Interesting conclusion is by any means the fact that clinical-ASPECT mismatch paradigm can be a simple, more inclusive and more easily incorporated into clinical practice in comparison to perfusion-imaging mismatch paradigm and this approach can guide a therapeutic decision.

By Dr Linxin Li

ESOC 2023 Session Report – SAH and ICH

After the presentations of two positive trials in ICH in the plenary session, the excitement continued in the scientific communication session on ICH this afternoon.

We had a range of high quality studies presented, including randomised controlled trials, individual participant level meta-analysis and hospital as well as population-based cohorts, focusing also on various aspects of ICH management. Here are some of the highlights.

Dr Iain McGurgan presented the results from the Prevention Of Hypertensive Injury to the Brain by Intensive Treatment of blood pressure after IntraCerebral Haemorrhage (PROHIBIT-ICH) trial, which is a randomized trial assessing home telemetry-guided blood pressure treatment in ICH. They demonstrated that centralized home blood pressure monitoring was feasible with excellent patient acceptance. It also resulted in better blood pressure control at 3 months than routine care with a significant group difference of 13.6 mmHg. We look forward to hearing the long-term blood pressure control and imaging marker related results in the near future.

Professor Philip Bath and Dr Shoujiang You presented results using data from the Blood Pressure in Acute Stroke Collaboration (BASC). It was very interesting to see advances in statistical methods to allow the use of a global analysis approach to assess outcomes. On the other hand, this large ICH dataset also made it possible to provide more reliable data showing that there were greater rates of early neurological deterioration in lobar ICH compared to deep ICH, yet after adjustment for baseline ICH volume, deep ICH location was associated with poorer functional outcome at 90 days.

Dr David Rodriguez-Luna used data from the RAINS study and showed that achievement of systolic blood pressure target of <140 mmHg within 60min after hospital arrival was associated with lower rate of substantial hematoma expansion and early neurological deterioration, resulting in better function outcomes. This highlights that “time is brain” also holds true for ICH.

We also heard from Dr Bernhard Siepen that there has been a change with regards to the spectrum of anticoagulation-associated ICH in the last decade with a shift towards more DOAC-related ICH. Somewhat reasurringly, the outcome of DOAC-related ICH seemed more comparable to non-anticoagulated ICH.

Finally the session concluded from a promising score to predict death after ICH  presented by Dr Baptiste Alvarez and an interesting finding of an association of CAA and SDH presented by Dr Cyprien Rivier.

By Dr Zdravka Poljakovic

ESOC 2023 Session Report – Organising the Acute Chain of Stroke Care

The session began with two lectures, given by Professors Lars-Pedersen Pallesen and Bojana Zvan dealing with important topic of stroke care in distant parts of the country, and in centres who are not experienced in recanalization therapy where the role of telemedicine and even telethrombolysis makes a change. The lectures clearly showed that telemedical approach can help stroke patients in distant parts of the land to have the same possibility for adequate treatment. Professor Zvan showed even the results from telethrombolysis project in her country, where the outcomes for patients in distant hospitals as well as door-to-needle time were impressive. The main advantages of this approach are constant and progressive increase in the absolute number of patients treated with systemic recanalization therapy due to the possibility of capturing large areas of a country as well as accurate diagnosis of stroke itself .

Professor Rajiv Advani in his lecture emphasized the importance of doing the right things for the stroke patient in the Emergency room, which according to his presentation should contain proper evaluation, diagnostics, therapeutic approach (basically thrombolysis at this point), stabilization and team work. For the evaluation part, the knowledge and clinical setting of prehospital care should be taken into account very seriously he stressed. Also, diagnostic part, which consists of clinical and radiological part, should be done in parallel way, without wasting time for unnecessary actions so that thrombolytic therapy can be delivered as soon as possible, even during the process. The lecture raised some questions about the timeline of the whole process which were discussed in details.

Especially challenging was the lecture of professor Silvia Schonenberger about managing the patient in the angio-suite during which she discussed and presented papers presenting dilemmas about performing thrombectomy in conscious sedation or general anesthesia (GA), which still do not offer a final conclusion, and which my have implication to the blood pressure values. As blood pressure drops and extensive changes may directly influence outcome, they must be avoided and taken care of even in decision making process in choosing the GA or not. Some studies did namely show that decreased blood pressure prior recanalization is associated with larger infarct volume and worse outcome, prof Schonenberger stated. Her team actually made their own algorithm for stroke patients before and after thrombectomy with a clear message about the importance of quick end of sedation/extubation after the procedure. In conclusion, prof Schonenberger stressed the importance of SOP which can prevent complications and save time prior to the intervention,  of specialized neurocritical/neurointerventional/neuroanesthesiological team during the intervention who will take care of the patient especially avoiding hypotension and hypocapnia and of avoiding prolonged ventilation and ICU stay after the procedure.

Finally, professor Valeria Caso gave a comprehensive, but also deeply touching lecture about the importance of organizing stroke care in all European countries, but with special tribute to stroke care organization in Ukraine. She stressed the importance of keeping detailed data about stroke care in order to improve the stroke care system, of having educated prehospital service and network of dedicated hospitals and of keeping records of the treatment results especially mortality, where big differences in rates based on type of the hospital where patients were treated can be observed. Coming to the end of her lecture, prof Caso gave an overview of the situation in Ukraine which is an admirable country being constantly improving its stroke care in spite of the already longlasting and devastating war. The number of hospitals with stroke units constantly grows, and keeps growing. Just as an illustration for this statement, the number of stroke units in 2016 was 21, and today there are 260 units in Ukraine. prof Caso showed. The session ended with this very emotive and motivating presentation which illustrated the importance of keeping the goal even in difficult situations.

By Dr Zdravka Poljakovic

ESOC 2023 Session Report -Neurointervention – Imaging and Reperfusion

First lecture has been given by professor Joachim Fladt, from Canada, dealing with possible impact of brain atrophy/fraility on baseline stroke severity and outcome. Concept of brain fraility was an intriguing insight in brain reserve mechanisms where prof Fladt discussed cortical integrity and synaptic density. He presented the results of ESCAPE-NAI trial where an original way of combined analysis of brain fraility on non-contrast CT has been conducted. The features included global cortical atrophy scale, white matter hyperintensities, subcortical atrophy, lacunes and chronic infarcts in numbers. The results of the study clearly showed that brain fraility has impact on final outcome as well as cortical atrophy and chronic infarct burden. He stressed out that maybe more attention should be paid to the biological versus chronological brain age.

Dr Antje Schmidt Pogoda from Germany gave the next talk, which she herself described as provocative – what it really was. She analysed the problem of failure of neuroprotection  in clinical setting in contrast to the results of animal trials, and presented the possible explanation. According to it, lack of  infarct volume growth in clinical setting after stroke strongly influences the results of neuroprotection as this is the main measure of neuroprotection. According to this theory as infarct growth is the target of neuroprotection in experimental models, and most stroke patients do not experience infarct growth, in clinical setting we actually do not offer a target for neuroprotection.

Two lectures about special features and subgroup analysis from SELECT2 Imaging analysis were given by professor Amrou Saraj and gave a new insight into the study results as well as definitions of some neuroimaging characteristics in the study group of patients. The rational for this subanalysis were the facts that three RCT’s recently demonstrated improved functional outcomes after endovascular treatment (EVT) even in patients with large core, which extended EVT eligibility according to CT/MR-perfusion imaging. The hypothesis is therefore that ischemic core estimates on different imaging modalities correlates with EVT outcomes. However, important is to be aware of possibility of CTP over- and underestimation of ischemic core. So, the investigational group of prof Saraj concluded that ischemic core estimates demonstrated prognostic utility rather than treatment modification, that treatment effect maintained even in patients with very large core, and that reduced infarct growth was present in patients achieving functional independence and independent ambulation.

Next challenging presentation about MR Microscopy in Thrombectomy to assess clot composition given by professor Michael Breckwoldt showed the power of advanced neuroimaging techniques in clot analysis. Knowledge of clot histology may predict outcome or possible endovascular therapy resistance or recurrence of occlusion, or may give additional data about stroke etiology. The data about ex vivo MR microscopy of clots at 9.4 Tesla following thrombectomy already exist, and clot composition can be assessed by MR microscopy. Furthermore, white clots need more recanalization maneuvers, increased time to recanalization and have poorer clinical outcomes. So a preinterventional clot imaging can give valuable data about clot composition and might allow a personalized approach to thrombectomy, prof Breckwoldt  concluded.

Dr Jorge Pagola from Barcelona presented the results of a study about intracranial thrombus composition and possibilities of prediction early reoclussion accordingly. The study was inspired by the fact that certain percentage of patient experience early reoclusion, dr Pagola showed, and this fact has a huge impact on outcome of this patients.The possibility of prediction of this phenomena could be clinically important. According to the results of the study, rich B-lymphocite thrombus is an independent predictor of early unexpected reocclusion even after initial successful thrombectomy. On the other hand,  thromboinflammation is a potential therapeutic target that may decrease early reocclusion.

His collegue from Barcelona as well, dr Roger Collet Vidiella continued the session presenting interesting results of a RES-CAT study, namely clinical and angiographic outcomes after rescue stenting for failed mechanical thrombectomy. He showed the results of a metaanalysis of several studies which mainly showed that intracranial stent is a rescue therapy and that rescue stenting improves outcomes in failed thrombectomy. In the study he presented the group of investigators posed the same question, namely does rescue stenting improve the functional outcome of patients with failed mechanical thrombectomy. The results of the study showed a trend towards better functional outcome with rescue stenting, however, after adjustment this trend was not statistically significant. Furthermore, the results showed that patient with successful recanalization which was achieved after stenting have worse functional outcome in comparison with patients who did not need rescue stenting. However, a good news is that there were no issues in safety outcomes, he concluded.

Finally, professor Thanh N. Nguyen concluded the session with a talk about endovascular thrombectomy for patients with large vessel occlusion stroke beyond 24-hours. In summary of her talk she stated that good ASPECTS and collateral scores can serve as surrogates  for viable brain and slow infarct progression with good functional outcomes after 90.days. Interesting conclusion is by any means the fact that clinical-ASPECT mismatch paradigm can be a simple, more inclusive and more easily incorporated into clinical practice in comparison to perfusion-imaging mismatch paradigm and this approach can guide a therapeutic decision.