• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.311-316
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• 2011

Objective : Stroke is the third leading cause of death in the Republic of Korea. Time is the most important factor in hyperacute stroke. Yet, there had been no protocol for mechanical thrombolysis. We have treated patients with hyperacute stroke by mechanical thrombolysis for 3 years. In current study, we analyzed the outcome of mechanical thrombolysis. Methods : From March 2008 to February 2011, 36 patients were treated with mechanical thrombolysis. Initially we treated the patients by aggressive mechanical clot disruption (AMCD) who were admitted within 6 hours after the symptom onset. If revascularization was not achieved, balloon angioplasty was performed, followed by stenting or temporary endovascular bypass was performed. The result in 15 cases was not so successful. Since then, we started using the thromboaspiration method as the first line treatment of the mechanical thrombolysis. Results : After using the thromboaspiration, we had better results in recanalization rate, modified Rankin Score (mRS) and reperfusion injury compared to AMCD. The recanalization rate was 80.85%, mRS is 2.85, and there was only 0.09% hemorrhagic formation. Conclusion : Even though thromboaspiration is not statistically significant due to the limited numbers of patients enrolled in this study, we think it is a good way in mechanical thronbolysis for hyperacute stroke.

• Journal of Korean Neurosurgical Society
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• v.45 no.6
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• pp.360-368
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• 2009

Objective : The objectives of this study were to analyze the recanalization rates and outcomes of multimodal therapy that consisted of sequential intravenous (IV)/intra-arterial (IA) thrombolysis, mechanical thrombolysis including mechanical clot disruption using microcatheters and microwires, balloon angioplasty, and stenting for acute ischemic stroke, and to evaluate the prognostic factors related to the outcome. Methods : Fifty patients who were admitted to the hospital within 8 hours from ischemic symptom onset were retrospectively analyzed. Initial IV thrombolysis and subsequent cerebral angiography were performed in all patients. If successful recanalization was not achieved by IV thrombolysis, additional IA thrombolysis with mechanical thrombolysis, including balloon angioplasty and stenting, were performed. The outcomes were assessed by the National Institute of Health Stroke Scale (NIHSS) change and modified Rankin scale (mRS) and prognostic factors were analyzed. Results : Successful recanalization was achieved in 42 (84%) of 50 patients, which consisted of 8 patients after IV thrombolysis, 19 patients after IA thrombolysis with mechanical clot disruption, and 15 patients after balloon angioplasty or stenting. Symptomatic hemorrhage occurred in 4 (8%) patients. Good outcomes were achieved in 76% and 70% of patients upon discharge, and 93% and 84% of patients after 3 months according to the NIHSS change and mRS. The initial clinical status, recanalization achievement, and presence of symptomatic hemorrhage were statistically related to the outcomes. Conclusion : Multimodal therapy may be an effective and safe treatment modality for acute ischemic stroke. Balloon angioplasty and stenting is effective for acute thrombolysis, and produce higher recanalization rates with better outcomes.

• International Journal of Vascular Biomedical Engineering
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• v.4 no.2
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• pp.13-18
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• 2006

Direct injection of a fibrinolytic agent to the intra-arterial thrombosis may increase the effectiveness of thrombolysis by enhancing the permeation of thrombolytic agents into the blood clot. Permeation of fibrinolytic agents into a clot is influenced by the surface pressure, which is determined by the injection velocity of fibrinolytic agents. Computational fluid dynamic methods were used in order to predict clot lysis for different jet velocities and nozzle arrangements. Firstly, thrombolysis of a clot was mathematically modeled based on the pressure and lysis front velocity relationship. Direct injection of a thrombolytic agent increased the speed of thrombolysis significantly and the effectiveness was increased as the ejecting velocity increased. The nine nozzles model showed about 20% increase of the lysed volume, and the one and seventeen nozzles models did not show significant differences. Secondly, thrombolysis was modeled based on the enzyme transport and the fluid flow equations, and quasi steady numerical analysis was performed. Clot lysis efficiency was also increased as injection velocity increased.

• Journal of Biomedical Engineering Research
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• v.26 no.3
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• pp.157-161
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• 2005

Direct injection of a fibrinolytic agent to the intraarterial thrombosis may increase the effectiveness of thrombolysis by enhancing the permeation of thrombolytic agents into the blood clot. Permeation of fibrinolytic agents into a clot is influenced by the surface pressure, which is determined by the injection velocity of fibrinolytic agents. In order to calculate the pressure distribution on the clot surface for different jet velocities (1, 3, 5 m/sec) and nozzle arrangements (1, 9, 17 nozzles), computational fluid dynamic methods were used. Thrombolysis of a clot was mathematically modeled based on the pressure and lysis front velocity relationship. Direct injection of a thrombolytic agent increased the speed of thrombolysis significantly and the effectiveness was increased as the ejecting velocity increased. The nine nozzles model showed about $20\%$ increase of the lysed volume, and the one and seventeen nozzles models did not show significant differences. The wall shear stress decreased as the number of nozzles increased, and the wall shear stress in most vessel wall was lower than 25 Pa. The results implied that thrombolysis could be accelerated by direct injection of a drug with the moderate velocity without damaging the blood vessel wall.

• 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 Biomedical Engineering Research
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• v.27 no.5
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• pp.267-273
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• 2006

Numerical analysis was performed on the enzyme transport and the flow fields in order to predict the effectiveness of urokinase injection regimens in clot dissolution. The species and momentum transport equations were numerically solved for the case of uniform perfusion of enzyme into a fibrin clot for an arterial thrombus and a deep vein thrombus models. In order to predict the thrombus lysis efficiency of continuous and forced intermittent injections, enzyme perfusion and clot lysis were simulated for the different injection velocities. Intermittent injection showed faster clot lysis compared to continuous perfusion, and lysis efficiency was increased as injection velocity increased.

• 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 Yeungnam Medical Science
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• v.31 no.1
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• pp.28-32
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• 2014

Pulmonary thromboembolism (PTE) increases the pressure of the right ventricle and leads to symptoms and signs, such as dyspnea and hypoxia. If PTE causes hemodynamic instability, thrombolytic therapy should be considered. A mechanical thrombectomy is an alternative treatment to thrombolytic therapy and should be considered when thrombolytic therapy is contraindicated. Various devices are used in mechanical maceration and catheter-directed thrombolysis, but there is no standard mechanical device for PTE as yet. We report here on 2 clinical experiences of mechanical thrombectomy using the Arrow-Trerotola percutaneous thrombolytic device to remove residual clots after systemic thrombolysis in patients with massive PTE.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.22-30
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• 2009

• Journal of Korean Neurosurgical Society
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• v.58 no.3
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• pp.192-196
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• 2015

Objective : The aim of this study is to investigate good prognostic factors for an acute occlusion of a major cerebral artery using mechanical thrombectomy. Methods : Between January 2013 to December 2014, 37 consecutive patients with acute occlusion of a major cerebral artery treated by mechanical thrombectomy with stent retrievers were conducted. We analyzed clinical and angiographic factors retrospectively. The collateral flow and the result of recanalization were sorted by grading systems. Outcome was assessed by National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) at 90 days. We compared the various parameters between good and poor angiographic and clinical results. Results : Twenty seven patients demonstrated good recanalization [Thrombolysis in Cerebral Infarction (TICI) 2b or 3] after thrombectomy. At the 90-day follow up, 19 patients had good (mRS, 0-2), 14 had moderate (3-4) and four had poor outcomes (5-6). The mRS of older patients (${\geq}75years$) were poor than younger patients. Early recanalization, high Thrombolysis in Myocardial Infarction risk score, and low baseline NIHSS were closely related to 90-day mRS, whereas high TICI was related to both mRS and the decrease in the NIHSS. Conclusion : NIHSS decreased markedly only when recanalization was successful. A good mRS was related to low initial NIHSS, good collateral, and early successful recanalization.