Safety and Effectiveness of a Modified ASAP Technique during Mechanical Thrombectomy for Acute Ischemic Stroke: Initial Clinical Experience

Current Approaches and Methods to Understand Acute Ischemic Stroke Treatment Using Aspiration Thrombectomy

Acute ischemic stroke occurs when a blood clot occludes a cerebral artery. Mechanical interventions, primarily stent retrievers and aspiration thrombectomy, are used currently for removing the occluding clot and restoring blood flow. Aspiration involves using a long catheter to traverse the cerebral vasculature to reach the blood clot, followed by application of suction through the catheter bore. Aspiration is also used in conjunction with other techniques such as stent retrievers and balloon guide catheters. Despite the wide use of aspiration, our physical understanding of the process and the causes of the failure of aspiration to retrieve cerebral clots in certain scenarios is not well understood. Experimental and computational studies can help develop the capability to provide deeper insights into the procedure and enable development of new devices and more effective treatment methods. We recapitulate the aspiration-based thrombectomy techniques in clinical practice and provide a perspective of existing engineering methods for aspiration. We articulate the current knowledge gap in the understanding of aspiration and highlight possible directions for future engineering studies to bridge this gap, help clinical translation of engineering studies, and develop new patient-specific stroke therapy.

Tortuosity of middle cerebral artery M1 segment and outcomes after mechanical thrombectomy

BACKGROUND

We aimed to quantify the tortuosity of the middle cerebral artery (MCA) and assess its effects on radiological and clinical outcomes in patients with acute MCA occlusions who received mechanical thrombectomy (MT).

METHODS

This retrospective study enrolled 53 patients with acute ischemic stroke due to MCA M1 or M2 segment occlusion who underwent MT using stent retrievers (SRs). Tortuosity index (TI) was defined to quantify the tortuosity of the MCA M1 segment using the following formula: (actual distance / straight distance) × 100. For each patient, four TIs were measured in the anteroposterior and caudal views for both ipsilateral and contralateral sides to the occluded site (TI-APi, TI-APc, TI-CAUi, and TI-CAUc, respectively) using magnetic resonance angiography (MRA) or computed tomography angiography (CTA). We defined the first-pass effect (FPE) as first-pass mTICI classification ≥2b reperfusion.

RESULTS

Patients who did not achieve FPE had significantly higher TI-APi (112 vs. 106; P = 0.004), TI-APc (111 vs. 105; P = 0.005), TI-CAUi (110 vs. 105; P = 0.002), and TI-CAUc (110 vs. 105; P = 0.001) than those who achieved FPE. In multivariable analysis, higher TI-APi, TI-CAUi, and TI-APc were independently associated with an increased rate of unsuccessful FPE (odds ratio (OR) [95% confidence interval (CI)]: 1.25 [1.02-1.61], 1.21 [1.01-1.45], and 1.27 [1.03-1.73], respectively). TI-CAUi, TI-APc, and TI-CAUc were also independent predictors of the occurrence of intracranial hemorrhage after MT (OR [95% CI]: 1.15 [1.01-1.38], 1.14 [1.01-1.38], 1.25 [1.02-1.52], respectively).

CONCLUSIONS

The TIs of the MCA M1 segment on both ipsilateral and contralateral sides were associated with unfavourable outcomes after MT.

A novel remote hands-on training for neuroendovascular-based treatment in the era of the COVID-19 pandemic

The COVID-19 pandemic has demanded a change in learning modalities, which led us to develop a remote personal training system for clinicians performing neuroendovascular procedures. A portable vascular model designed for practicing catheter navigation guidance, thrombus retrieval, and intracranial aneurysm coil embolisation was established. We created an environment that enabled interactive dialogue and communication across long distances using the Internet. The instructor conducted approximately 2 h of hands-on training with two to four trainees at a time. Despite the restrictions enforced by the Government of Japan due to the COVID-19 pandemic, 17 online hands-on training were successfully conducted throughout Japan over 1 year for a total of 48 trainees. The developed remote training programme, to avoid the aggregation of a large number of trainees at a developed time, proved to be at par with the conventional learning system. The training was well-received since the operation time was longer and the question and answer sessions were more fulfilling compared to the conventional format in which a group of trainees had got a brief opportunity to receive actual hands-on experience.