• Journal of Korean Neurosurgical Society
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• v.60 no.3
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• pp.335-347
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• 2017

Intravenous recombinant tissue plasminogen activator had been the only approved treatment for acute ischemic stroke since its approval in 1995. However, the restrictive time window, numerous contraindications, and its low recanalization rate were all limitations of this modality. Under those circumstances, endovascular stroke therapy went through a great evolution during the past two decades of intravenous thrombolysis. The results of the 2013 randomized trials for endovascular stroke therapy were neutral, although they were limited by insufficient imaging screening at enrollment, early-generation devices with less efficacy, and treatment delays. Huge progress was made in 2015, as there were five randomized clinical trials which all demonstrated the safety and efficacy of endovascular stroke treatment. Despite differences in detail patient enrollment criteria, all 5 trials employed key factors for good functional recovery; (1) screening with non-invasive imaging to identify the proximal occlusion and exclude a large infarct core, (2) using highly effective modern thrombectomy devices mainly with stent retriever, and (3) establishment of a fast workflow to achieve effective reperfusion. The results of those trials indicate that modern thrombectomy devices can allow for faster and more effective reperfusion, which can lead to improved clinical outcomes compared to intravenous thrombolysis alone. These advances in mechanical thrombectomy are promising in the global fight against ischemic stroke-related disability and mortality. Two current mainstreams among such mechanical thrombectomy techniques, "stent retriever thrombectomy" and "direct clot aspiration", are the topic of this review. Stent retriever thrombectomy using Solitaire and Trevo retriever will be firstly discussed. And, the commonalities and the differences between two major clot aspiration thrombectomy techniques; a direct aspiration first pass technique (ADAPT) and forced arterial suction thrombectomy (FAST), will be additionally explained. Finally, details regarding the combination of direct clot aspiration and stent retriever thrombectomy, the switching strategy and the Solumbra technique, will be described.

• Journal of Korean Neurosurgical Society
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• v.58 no.5
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• pp.419-425
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• 2015

Objective : Acute vertebrobasilar artery occlusion (AVBAO) is a devastating disease with a high mortality rate. One of the most important factors affecting favorable clinical outcome is early recanalization. Mechanical thrombectomy is an emerging treatment strategy for achieving a high recanalization rates. However, thrombectomy alone can be insufficient to complete recanalization, especially for acute stroke involving large artery atheromatous disease. The purpose of this study is to investigate the safety and efficacy of mechanical thrombectomy in AVBAO. Methods : Fourteen consecutive patients with AVBAO were treated with mechanical thrombectomy. Additional multimodal treatments were intra-arterial (IA) thrombolysis, balloon angioplasty, or permanent stent placement. Recanalization by thrombectomy alone and multimodal treatments were assessed by the Thrombolysis in Cerebral Infarction (TICI) score. Clinical outcome was determined using the National Institutes of Health Stroke Scale (NIHSS) at 7 days and the modified Rankin Scale (mRS) at 3 months. Results : Thrombectomy alone and multimodal treatments were performed in 10 patients (71.4%) and 4 patients (28.6%), respectively. Successful recanalization (TICI 2b-3) was achieved in 11 (78.6%). Among these 11 patients, 3 (27.3%) underwent multimodal treatment due to underlying atherosclerotic stenosis. Ten (71.4%) of the 14 showed NIHSS score improvement of >10. Overall mortality was 3 (21.4%) of 14. Conclusion : We suggest that mechanical thrombectomy is safe and effective for improving recanalization rates in AVBAO, with low complication rates. Also, in carefully selected patients after the failure of recanalization by thrombectomy alone, additional multimodal treatment such as IA thrombolysis, balloons, or stents can be needed to achieve successful recanalization.

• Journal of Korean Neurosurgical Society
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• v.63 no.4
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• pp.427-432
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• 2020

Three randomized control trials (RCTs), published in 2013, investigated efficacy of mechanical thrombectomy in large vessel occlusions and did not show better results compared to intravenous (IV) recombinant tissue-type plasminogen activator (tPA) alone. However, most clinicians treating stroke consider mechanical thrombectomy as the standard treatment rather than using IV tPA alone. This paradigm shift was based on five RCTs investigating efficacy of mechanical thrombectomy in acute ischemic stroke conducted from 2010 to 2015. They demonstrated that mechanical thrombectomy was effective and safe in acute ischemic stroke with anterior circulation occlusion when performed within 6 hours of stroke onset. There are four reasons underlying the different results observed between the trials conducted in 2013 and 2015. First, the three RCTs of 2013 used low-efficiency thrombectomy devices. Second, the three RCTs used insufficient image selection criteria. Third, following the initial presentation at the hospital, reperfusion treatment required a long time. Fourth, the three RCTs showed a low rate of successful recanalization. Time is the most important factor in the treatment of acute ischemic stroke. However, current trends utilize advanced imaging techniques, such as diffusion-weighted imaging and multi-channel computer tomographic perfusion, to facilitate the detection of core infarction, penumbra, and collateral flows. These efforts demonstrate that patient selection may overcome the barriers of time in specific cases.

• Journal of Korean Neurosurgical Society
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• v.63 no.1
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• pp.14-25
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• 2020

Proximal flow control achieved with a balloon guide catheter (BGC) during endovascular treatment of acute ischemic stroke is reviewed in this article. In clinical practice, BGCs offer a multi-faceted approach for clot retrieval by creating proximal flow arrest, reducing embolic burden, and shortening procedure time. Evaluation of frontline thrombectomy procedures with BGCs revealed advantages of combined use over the conventional guide catheter (CGC), notably in the significant reduction of distal emboli to both the affected and previously unaffected territories. Recently, new measures of early and complete reperfusion at first thrombectomy pass have been identified as independent predictors of improved outcomes, which were consistently demonstrated with use of BGC as a safe and effective option to minimize number of passes during intervention. Prior randomized controlled trials reported the positive correlation between BGC-treated patients and a lower risk of mortality as well as shortened procedure time. While BGC use is more common in stent retriever-mediated mechanical thrombectomy, preliminary data has shown the potential benefit of device application during contact aspiration thrombectomy to achieve successful recanalization. However, the question of which major endovascular strategy reigns superior as a frontline remains to be answered. Along with clinical case assessments, BGC performance during in-vitro simulation was analyzed to further understand mechanisms for optimization of thrombectomy technique.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.352-356
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• 2016

Objective : The efficacy and safety of manual aspiration thrombectomy using Penumbra in an acute occlusion of large intracranial arteries has been proven in many previous studies. Our study aimed to retrospectively assess the efficacy and safety of manual aspiration thrombectomy using Penumbra in patients with small vessel occlusions (M2 segment of the MCA). Methods : We conducted a retrospective review of 32 patients who underwent manual aspiration thrombectomy using the Penumbra 4 MAX Reperfusion Catheter for treatment of an M2 occlusion between January 2013 and November 2014. We evaluated immediate angiographic results and clinical outcomes through review of patient electronic medical records. Results : There were slightly more men in this study (M : F=18 : 14) and the median age was 72.5 (age range : 41-90). The rate of successful recanalization (TICI grade ${\geq}2b$) was 84% (27/32). NIHSS at discharge and favorable clinical outcomes at 3 months were significantly improved than baseline. Median initial NIHSS score was 10 (range : 4-25) and was 4 (range : 0-14) at discharge. Favorable clinical outcomes (mRS score ${\leq}2$ at 3 months) were seen in 25 out of 32 patients (78%). There were no procedure-related symptomatic intracerebral hemorrhages. One patient expired after discharge due to a cardiac problem. Conclusion : Manual aspiration thrombectomy might be safe and is capable of achieving a high rate of successful recanalization and favorable clinical outcomes in patients with distal cerebral vessel occlusion (M2).

• Journal of Chest Surgery
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• v.54 no.6
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• pp.500-508
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• 2021

Background: The major limitation of arteriovenous graft access is the high incidence of thrombotic occlusion. This study investigated the outcomes of our salvage strategy for thrombosed hemodialysis arteriovenous grafts (including surgical thrombectomy with balloon angioplasty) and evaluated the efficacy of intragraft curettage. Methods: Salvage operations were performed for 290 thrombotic occluded arteriovenous grafts with clinical stenotic lesions from 2010 to 2018. Of these, 117 grafts received surgical thrombectomy and balloon angioplasty from 2010 to 2012 (group A), and 173 grafts received surgical thrombectomy and balloon angioplasty, with an additional salvage procedure using a curette and a graft thrombectomy catheter, from 2013 to 2018 (group B). Outcomes were described in terms of post-intervention primary patency and secondary patency rates. Results: The post-intervention primary patency rates in groups A and B were 44.2% and 66.1% at 6 months and 23.0% and 38.3% at 12 months, respectively (p=0.003). The post-intervention secondary patency rates were 87.6% and 92.6% at 6 months and 79.7% and 85.0% at 12 months, respectively (p=0.623). Multivariate Cox regression analysis demonstrated that intragraft curettage was a positive predictor of post-intervention primary patency (hazard ratio, 0.700; 95% confidence interval, 0.519-0.943; p=0.019). Conclusion: Surgical thrombectomy and balloon angioplasty showed acceptable outcomes concerning post-intervention primary and secondary patency rates. Additionally, intragraft curettage may offer better patency to salvage thrombotic occluded arteriovenous grafts with intragraft stenosis.

• Journal of Korean Neurosurgical Society
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• v.57 no.5
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• pp.342-349
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• 2015

Background : Higher reperfusion rates have been established with endovascular treatment for acute ischemic stroke patients. There are limited data on the comparative performance of mechanical thrombectomy devices. This study aimed to analyse the efficacy and safety of the stent retriever device (Solitaire stent) by comparing procedure time, angiographic outcome, complication rate and long term clinical outcome with previous chemical thrombolysis and mechanical thrombectomy using penumbra system. Method : A retrospective single-center analysis was undertaken of all consecutive patients who underwent chemical thrombolysis and mechanical thrombectomy using Penumbra or Solitaire stent retriever from March 2009 to March 2014. Baseline characteristics, rate of successful recanalization (modified Thrombolysis in Cerebral Infarction score 2b-3), symptomatic intracerebral hemorrhage, procedure time, mortality and independent functional outcomes ($mRS{\leq}2$) at 3 month were compared across the three method. Results : Our cohort included 164 patients, mechanical thrombectomy using stent retriever device had a significant impact on recanalization rate and functional independence at 3 months. In unadjusted analysis mechanical thrombectomy using Solitaire stent retriever showed higher recanalization rate than Penumbra system and chemical thrombolysis (75% vs. 64.2% vs. 49.4%, p=0.03) and higher rate of functional independence at 3 month (53.1% vs. 37.7% vs. 35.4%, p=0.213). In view of the interrelationships between all predictors of variables associated with a good clinical outcome, when the chemical thrombolysis was used as a reference, in multiple logistic regression analysis, the use of Solitaire stent retriever showed higher odds of independent functional outcome [odds ratio (OR) 2.62, 95% confidence interval (CI) 0.96-7.17; p=0.061] in comparison with penumbra system (OR 1.57, 95% CI 0.63-3.90; p=0.331). Conclusion : Our initial data suggest that mechanical thrombectomy using stent retriever is superior to the mechanical thrombectomy using penumbra system and conventional chemical thrombolysis in achieving higher rates of reperfusion and better outcomes. Randomized clinical trials are needed to establish the actual benefit to specific patient populations.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.654-660
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• 2017

Objective : Mechanical thrombectomy is increasingly being used for the treatment of acute ischemic stroke. The population over 80 years of age is growing, and many of these patients have acute infarction; however, these patients are often excluded from clinical trials, so the aim of this study was to compare the functional outcomes and complication rates in very elderly patients (age ${\geq}80$ years) and aged patients (60-79 years) treated with mechanical thrombectomy. Methods : Between January 2010 and June 2015, we retrospectively reviewed 113 senior patients (over 60 years old) treated at our institution for acute ischemic stroke with mechanical thrombectomy. They were divided into a very elderly (${\geq}80$ years) and aged (60-79 years) group, with comparisons in recanalization rates, complications, death and disability on discharge be reported. Results : The mean age was 70.3 years in the aged group and 83.4 years in the very elderly group. Elderly patients had higher rates of mechanical thrombectomy failure than the younger group (40% vs. 14%; odds ratio [OR] 4.1; 95% confidence interval [CI] 1.4-11.9; p=0.012). Results from thrombolysis in cerebral ischemia and modified Rankin scale at discharge were worse in the older group (p=0.005 and 0.023 respectively). There were no differences in mortality rate or other complications, but infarction progression rates were significantly higher in the very elderly group. (15% vs. 2.2%; OR 8.0; 95% CI 1.2-51.7; p=0.038). The majority (92.3%) of the patients who failed in aged group were not successful after several trials. However, in half (4 of 8) of the very elderly group, the occlusion site could not be accessed. Conclusion : Patients older than 80 years of age undergoing mechanical thrombectomy for acute infarction were more difficult to recanalize due to inaccessible occlusion sites and had a higher rate of infarction progression, However, mortality and other complications were similar to those in younger patients.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.635-643
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• 2017

Objective : Acute basilar artery occlusion (BAO) is associated with severe neurological dysfunction and high mortality rates. The benefits of mechanical thrombectomy in BAO have not been explored in recent clinical trials. Therefore, we analyzed outcomes of stent retriever mechanical thrombectomy for BAO, and compared with anterior circulation occlusions (ACO). Methods : In total, 161 consecutive patients (24 BAO, 137 ACO) who underwent mechanical thrombectomy with the stent retriever between January 2013 and August 2016 enrolled in our study. All patients underwent clinical assessment with the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS). Radiological results were used to evaluate thrombolysis in cerebral infarction (TICI) scores and successful recanalization was defined by TICI 2b or 3. Results : Mean NIHSS scores at 24 hours and 30 days were significantly higher in the BAO group than the ACO group (p=0.021, p=0.001). mRS at 90 days was significantly higher in the BAO group (4.2) compared with the ACO group (3.0) (p=0.003). The BAO group (2.0) performed fewer stent retriever passages than the ACO group (2.7) (p=0.049). There were no significant differences between the two groups in terms of complications, but the BAO patients experienced a higher mortality (16.6%) rate than ACO patients (5.8%) (p=0.001). In subgroup analysis of BAO, patients with short procedure times achieved successful recanalization (p=0.001) and successfully recanalized patients exhibited more favorable mRS at 90 days (p=0.027). Conclusion : In our study, mechanical thrombectomy of BAO patients showed worse clinical outcome and higher mortality rate than ACO patients. However, mechanical thrombectomy with a stent retriever in BAO is an effective treatment, because successfully recanalized patients showed good clinical outcome in BAO patients.

• Journal of Korean Neurosurgical Society
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• v.59 no.5
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• pp.518-520
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• 2016

Cerebral venous sinus thrombosisis an uncommon entity and its clinical presentations are highly variable. We present the case of superior sagittal sinus thrombosis. Although it was medical refractory, successfully treated with mechanical thrombectomy using the Solitaire FR device. A 27-year-old man who presented with venous infarction accompanied by petechial hemorrhage secondary to the superior sagittal sinus (SSS) thrombosis. Due to rapid deterioration despite of anticoagulation therapy, the patient was taken for endovascular treatment. We deployed the Solitaire FR device ($4{\times}20mm$) in the anterior portion of the thrombosed SSS, and it was left for ten minutes before the retraction. Thus, we removed a small amount of thrombus. But the sinus remained occluded. We therefore performed the thrombectomy using the same methods using the Solitaire FR ($6{\times}20mm$). Thus, we were successful in removing larger clots. Our case highlights not only that the mechanical thrombectomy using the Solitaire FR is effective in achieving revascularization both rapidly and efficiently available, but also that it might be another option in patients with cerebral venous sinus thrombosis who concurrently had rapid clinical deterioration with devastating consequences.