ties [85]. More importantly, delineating ischemic core and pen­umbra may be of importance, as previous early time window LVO trials failed to demonstrate any volume cutoff below which EVT was no longer benecial. Moreover, present EVT guidelines for LVO patients in the early time window exclusively rely on NCCT ASPECTS to estimate the degree of irreversible tissue damage [86]. Despite this, using ASPECTS in MeVO stroke may be prob­lematic, since the anterior and posterior cerebral artery territories are not represented at all.

Perez-Garcia etal. [89] addressed this issue by comparing the safety and efcacy of EVT using mini stent retrievers alone (used

earlier in the study period) versus mini stent retrievers combined with low-prole distal aspiration catheters through the blind exchange/mini-pinning (BEMP) technique in patients with MeVO in M2/M3/A1/A2/A3/P1 and distal posterior cerebral artery seg­ments. The authors studied the procedural, safety (emboli to unwanted territories and hemorrhagic complications), and clinical outcomes. Out of the 102 enrolled patients (106 MeVO in differ­ent arteries), 56 were treated with the BEMP technique, and 50 were treated with the mini stent retriever alone. The authors found improved outcomes with the BEMP technique, including a higher rate of rst-pass extended thrombolysis in cerebral ischemia 2c/3 recanalization (57% vs. 34%) and lower rates of rescue therapy (7.1% vs. 22%). Multivariable logistic regression analysis dem­onstrated the BEMP technique to be the sole independent factor associated with rst-pass recanalization, with no difference in mortality or functional independence between the groups. Moreover, although clinical outcomes were comparable in both groups, mini stent retriever technique was associated with an unacceptably high rate of emboli to new territory (1.8% vs. 12%) and symptomatic intracerebral hemorrhage (1.9% vs. 12.8%). For future studies replicating this, patient selection is crucial, espe­cially identifying patients with an M2 occlusion.

good functional outcome is acceptable for LVO population, den­ing primary outcome as 90-day mRS score of 0–2 is impractical and suboptimal for patients with MeVO. Domain-specic out­come measures or quality of life assessments can also be consid­ered for these trials. Furthermore, since the median presenting NIHSS score is much lower in these patients, the traditionally used ECASS (European Cooperative Acute Stroke Study) and SITS-MOST (Safe Implementation of Thrombolysis in Stroke­Monitoring Study) denitions of symptomatic intracerebral hem­orrhage outcome for patients with LVO need modication to account for lesser clinical worsening in NIHSS that might be seen in patients with MeVO.

Neuroprotection to prevent infarct progression as a potential treat­ment for AIS is associated with a rather lackluster history. The failures of these prior neuroprotection trials may be attributable to problems with the preclinical assessment of these drugs and the design/implementation of clinical trials.

via IA delivery into the ICA for cerebral vasospasm, making it an attractive potential agent due to its established safety prole. Fraser etal. then followed these experiments up with a phase 1 clinical trial entitled Superselective Administration of VErapamil During Recanalization in Acute Ischemic Stroke (SAVER-I) (NCT02235558). Subjects undergoing mechanical thrombectomy with thrombolysis in cerebral infarction (TICI) 2a or better recan­alization received 10mg verapamil in 20cc of normal saline over 20minutes via microcatheter injection directly into the previously occluded artery. Eleven patients were included, and IA delivery was technically successful in all. The authors concluded that the IA delivery of verapamil immediately following thrombectomy is safe and feasible [95, 97].

A 2010 US study delivered saline at 15°C and 7°C into the internal carotid artery (ICA) of 18 patients undergoing follow-up routine angiograms at 33ml/minute for 10 minutes. The jugular bulb temperatures demonstrated a drop of 0.84°C, compared to

The future of neuroprotection in stroke will likely involve combination therapy utilizing multiple agents. Presently, one completed phase 1 clinical trial (SAVER-I) has demonstrated the safety and feasibility of IA delivery of neuroprotective drugs immediately after reperfusion in large vessel occlusion ischemic stroke patients. Two additional clinical trials are ongoing. Furthermore, two published human clinical pilot studies have supported the safety and feasibility of infusing cold saline directly into the carotid artery in patients undergoing angiograms and in stroke patients. As additional clinical trials come to fruition, the safety prole of these techniques will become established, and the ideal ratio for neuroprotection will need to be reassessed [99,

leptomeningeal anastomosis (LMA) can signicantly inuence outcomes.

Another recent study also reported that the texture of the clot, or radiomic features (RFs), is predictive of recanalization follow­ing treatment with intravenous alteplase for AIS. This suggests that the extraction of pretherapeutic RF from radiological imag­ing may contain valuable information related to the composition of the clot, with an impact on the future success of MTB.

Attempts in another recent study to use pretherapeutic com­puted tomography (CT) to extract RF from the clot to investigate their capacity to predict the success of the MTB strategy were done in order to identify patients with rst-attempt recanalization with thromboaspiration and to predict the overall number of pas­sages with an MTB device required for successful recanalization [103].

Over the past few years, evidence has also supported the idea that factors like the biological clot composition should be consid­ered when choosing the fastest method to remove a clot. Recently, the use of AI to characterize the thrombus and guiding thrombec­tomy was utilized in Clotild®, a neurovascular guidewire equipped with the Sensome proprietary impedance sensor.

update Clotild®'s database and thus improve the prediction accu­racy of the model in providing physicians with insights for mechanical thrombectomy.