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.