Flow Diverter Treatment Using a Flow Re-Direction Endoluminal Device for Unruptured Intracranial Vertebral Artery Dissecting Aneurysm: Single-Center Case Series and Technical Considerations / 신경중재치료의학

Purpose@#This study aimed to evaluate the effectiveness, safety, and technical considerations of flow diverter (FD) treatment using a Flow Re-direction Endoluminal Device (FRED) for unruptured intracranial vertebral artery dissecting aneurysms (VADAs). @*Materials and Methods@#We conducted a retrospective study of 23 patients with unruptured intracranial VADAs who underwent FD treatment using a FRED between June 2017 and August 2021. Symptoms, imaging findings, treatment strategies, and angiographic and clinical outcomes were evaluated. Dissections were categorized according to the dominance of the VA in which they occurred: dominant VA, co-dominant VA, and non-dominant VA. @*Results@#All patients successfully underwent FD treatment with either a FRED (n=11) or FRED Jr. (n=12). Complete occlusion rates were 78.3% at 6-month follow-up magnetic resonance angiography and 91.3% at 12-month. There were no instances of complications, recurrence, or retreatment during a median follow-up of 20 months. Dissections occurred in the dominant VA in 3 cases (13.0%), the co-dominant VA in 13 cases (56.5%), and the non-dominant VA in 7 cases (30.4%). Intimal flap and true lumen stenosis were observed in 39.1% and 30.4% of cases, respectively. Four cases required a bilateral VA approach due to technical difficulties, all in the non-dominant VA. @*Conclusion@#Flow diversion treatment using a FRED for unruptured intracranial VADAs proved feasible and safe, yielding satisfactory occlusion rates. Technical challenges were more likely in lesions involving non-dominant VAs in the acute or subacute stage, mainly due to associated intraluminal lesions compromising the arterial lumen.

Whole Exome Sequencing in Patients with Phenotypically Associated Familial Intracranial Aneurysm

Objective@#Familial intracranial aneurysms (FIAs) are found in approximately 6%–20% of patients with intracranial aneurysms (IAs), suggesting that genetic predisposition likely plays a role in its pathogenesis. The aim of this study was to identify possible IA-associated variants using whole exome sequencing (WES) in selected Korean families with FIA. @*Materials and Methods@#Among the 26 families in our institutional database with two or more IA-affected first-degree relatives, three families that were genetically enriched (multiple, early onset, or common site involvement within the families) for IA were selected for WES. Filtering strategies, including a family-based approach and knowledge-based prioritization, were applied to derive possible IA-associated variants from the families. A chromosomal microarray was performed to detect relatively large chromosomal abnormalities. @*Results@#Thirteen individuals from the three families were sequenced, of whom seven had IAs. We noted three rare, potentially deleterious variants (PLOD3 c.1315G>A, NTM c.968C>T, and CHST14 c.58C>T), which are the most promising candidates among the 11 potential IA-associated variants considering gene-phenotype relationships, gene function, co-segregation, and variant pathogenicity. Microarray analysis did not reveal any significant copy number variants in the families. @*Conclusion@#Using WES, we found that rare, potentially deleterious variants in PLOD3, NTM, and CHST14 genes are likely responsible for the subsets of FIAs in a cohort of Korean families.

Etiology-Related Outcome of Endovascular Therapy in Posterior Circulation Stroke Compared to Anterior Circulation Stroke / 대한뇌졸중학회지

Background@#and Purpose We investigated the impact of stroke etiology on the endovascular treatment (EVT) procedure and clinical outcome of posterior circulation stroke (PCS) patients with EVT compared to anterior circulation stroke (ACS) patients. @*Methods@#We retrospectively analyzed ischemic stroke patients who underwent EVT between January 2012 and December 2020. Enrolled ACS and PCS patients were compared according to etiologies (intracranial arterial steno-occlusion [ICAS-O], artery-to-artery embolic occlusion [AT-O], and cardioembolic occlusion [CA-O]). EVT procedure and favorable clinical outcomes at 3 months (modified Rankin Scale 0–2) were compared between the ACS and PCS groups for each etiology. @*Results@#We included 419 patients (ACS, 346; PCS, 73) including 88 ICAS-O (ACS, 67; PCS, 21), 66 AT-O (ACS, 50; PCS, 16), and 265 CA-O (ACS, 229; PCS, 36) patients in the study. The onset-to-recanalization time was longer in the PCS group than in the ACS group (median 628.0 minutes vs. 421.0 minutes, P=0.01). In CA-O patients, the door-to-puncture time was longer, whereas the puncture-to-recanalization time was shorter in the PCS group than in the ACS group. The proportions of successful recanalization and favorable clinical outcomes were similar between the ACS and PCS groups for all three etiologies. Low baseline National Institutes of Health Stroke Scale (NIHSS) scores and absence of intracerebral hemorrhage at follow-up imaging were associated with favorable clinical outcomes in both groups, whereas successful recanalization (odds ratio, 11.74; 95% confidence interval, 2.60 to 52.94; P=0.001) was only associated in the ACS group. @*Conclusions@#The proportions of successful recanalization and favorable clinical outcomes were similar among all three etiologies between PCS and ACS patients who underwent EVT. Initial baseline NIHSS score and absence of hemorrhagic transformation were related to favorable outcomes in the PCS and ACS groups, whereas successful recanalization was related to favorable outcomes only in the ACS group.

Outpatient Day-Care Management of Unruptured Intracranial Aneurysm: A Retrospective Cohort Study

Objective@#This study aimed to assess the outcomes of outpatient day-care management of unruptured intracranial aneurysm (UIA), and to present the risks associated with different management strategies by comparing the outcomes and adverse events between outpatient day-care management and management with longer admission periods. @*Materials and Methods@#This retrospective cohort study used prospectively registered data and was approved by a local institutional review board. We enrolled 956 UIAs from 811 consecutive patients (mean age ± standard deviation, 57 ± 10.7 years; male:female = 247:564) from 2017 to 2020. We compared the outcomes after embolization among the different admission-length groups (1, 2, and ≥ 3 days). The outcomes included pre- and post-modified Rankin Scale (mRS) scores and rates of adverse events, cure, recurrence, and reprocedure. Events were defined as any cerebrovascular problems, including minor and major stroke, death, or hemorrhage. @*Results@#The mean admission period was 2 days, and 175 patients (191 aneurysms), 551 patients (664 aneurysms), and 85 patients (101 aneurysms) were discharged on the day of the procedure, day 2, and day 3 or later, respectively. During the mean 17-month follow-up period (range 6–53 months; 2757 patient years), no change in post-mRS was observed compared to pre-mRS in 99.6% of patients. Cure was achieved in 95.6% patients; minimal recurrence that did not require re-procedure occurred in 3.5% patients, and re-procedure was required in 2.3% (22 of 956) patients due to progressive enlargement of the recurrent sac during follow up (mean 17 months, range, 6–53 months). There were eight adverse events (0.8%), including five cerebrovascular (two major stroke, two minor strokes and one transient ischemic stroke), and three non-cerebrovascular events. Statistical comparison between groups with different admission lengths (1, 2, and ≥ 3 days) revealed no difference in the outcomes. @*Conclusion@#This study revealed no difference in outcomes and adverse events according to the admission period, and suggested that UIA could be managed by outpatient day-care embolization.

Reversible Symptom Aggravation by Intake of Taurine-Rich Foods in Patients with Venous Congestive Myelopathy: Controlled Case Series Study / 신경중재치료의학

Purpose@#Reversible aggravation of myelopathy symptoms was observed after the intake of taurine-rich foods in patients with venous congestive myelopathy (VCM) caused by a spinal arteriovenous shunt (SAVS), and the taurine-challenge test was applied to demonstrate an association between taurine and VCM. @*Materials and Methods@#The current study reviewed any aggravation history of myelopathy symptoms, including walking difficulty, after consuming taurine-rich foods among 133 consecutive patients with a SAVS from a prospective institutional database from June 2013 to February 2021. The type of taurine-rich foods, demographic data, arteriovenous shunt level, and follow-up periods were obtained. For the controlled taurine challenge test, Bacchus® (Dong-A Pharmaceutical, Seoul, Korea), a taurine-rich drink, was given to patients who fulfilled test criteria of recovered VCM (pain-sensory-motor-sphincter scale ≥2, improvement of spinal cord signal intensity on magnetic resonance imaging, and follow-up >6 months after SAVS treatment) to confirm the disappearance of such aggravation. @*Results@#Ten patients had an aggravation history related to food. Webfoot octopus, small octopus, squid, crab, scallop, and taurine-rich energy drink (Bacchus®) were related to such aggravation in patients with VCM. Aggravation appeared about 30 minutes after food intake followed by expressions such as ‘I could not walk and collapsed to the ground’ and usually lasted for about 3 hours, followed by a slow recovery after taking rest. Four patients who met the test criteria underwent the taurine challenge with Bacchus® and revealed no further symptom aggravation, suggesting that taurine did not affect patients after recovery from VCM. @*Conclusion@#The association between taurine-rich food and reversible symptom aggravation can appear in patients with VCM and disappear after VCM treatment. Aggravation of venous hypertension in the spinal cord is suggested as a mechanism but further elucidation is needed.

Clinical Manifestation and Radiologic Patterns of Spontaneous Cervicocephalic Dissection According to the Anatomic Location: A Single-Center Analysis in Korean Patients / 신경중재치료의학

Purpose@#Spontaneous cervicocephalic dissection (SCAD) is an important cause of stroke and shows various lesion locations and clinical features. The purpose of this study was to analyze the location of SCAD and its clinical and radiologic patterns in Korean patients. @*Materials and Methods@#Patients with SCAD who were evaluated between 2013 and 2018 at a tertiary center in Korea were reviewed. We classified and compared the morphological (aneurysm or steno-occlusion) and presenting (hemorrhage or infarction) patterns according to the lesion locations (anterior circulation [AC] vs. posterior circulation [PC]; intradural [ID] vs. extradural [ED]). @*Results@#A total of 166 patients were included in this study. The SCAD most commonly occurred in the PC-ID location (65.1%), followed by AC-ID (13.3%), AC-ED (13.3%), and PC-ED (8.4%). Aneurysm and steno-occlusion patterns were observed in 66.9% and 57.8% of the cases, respectively. The aneurysm pattern was significantly more common in the PC-ID location (78.7%) than in other locations. As for the presenting pattern, cerebral infarction was the most common pattern (39.8%), and intracranial hemorrhage was observed only in the ID location (7.2%). @*Conclusion@#In Korean patients, PC-ID, especially ID vertebral artery, was the most common location of SCAD, and most cases were accompanied by an aneurysm. It also suggested that these location trends differ by population or ethnicity.

Rare Neurovascular Diseases in Korea: Classification and Related Genetic Variants

Rare neurovascular diseases (RNVDs) have not been well-recognized in Korea. They involve the central nervous system and greatly affect the patients’ lives. However, these diseases are difficult to diagnose and treat due to their rarity and incurability. We established a list of RNVDs by referring to the previous literature and databases worldwide to better understand the diseases and their current management status. We categorized 68 RNVDs based on their pathophysiology and clinical manifestations and estimated the prevalence of each disease in Korea. Recent advances in genetic, molecular, and developmental research have enabled further understanding of these RNVDs. Herein, we review each disease, while considering its classification based on updated pathologic mechanisms, and discuss the management status of RNVD in Korea.

Microcatheter Stabilization Technique Using Partially Inflated Balloon for Coil Embolization of Paraclinoid Aneurysms / 신경중재치료의학

Purpose@#Coil embolization of paraclinoid aneurysms should be simple, safe, and effective considering the benign nature of the aneurysm. Here, we present a microcatheter stabilization technique using a partially inflated balloon for the treatment of paraclinoid aneurysms. @*Materials and Methods@#This retrospective study included 58 patients who underwent balloon-assisted coiling (BAC) for unruptured paraclinoid aneurysms at a tertiary neuro-intervention center between January 2019 and March 2020. We applied a technique to stabilize the microcatheter’s position using the modified BAC technique in paraclinoid aneurysms showing various projections around the ophthalmic curve of the internal carotid artery. The basic concept of the technique is to place a partially inflated balloon just distal to the aneurysm neck and support the distal curve of the microcatheter using the proximal bottom of the balloon. Immediate radiological outcomes were analyzed, and clinical outcomes were evaluated with modified Rankin Scale (mRS) scores. @*Results@#The BAC was successfully performed in 51 of 58 patients (88%). We treated the remaining seven patients by switching to stent-assisted coiling. We obtained a 37% mean packing density resulting in favorable occlusion in all 58 aneurysms (complete occlusion in 35 and residual neck in 23). There were no intraprocedural thromboembolic or hemorrhagic events except one that revealed an asymptomatic infarction after the procedure (1.7%). Magnetic resonance angiography follow-up was performed in 37 patients at an average of 11.8 months, in which 11 minor recurrences (29.7%) were found. There was no major recurrence nor retreatment. The mRS score was 0 in all patients during a mean follow-up of 17.7 months (range, 12–25 months). @*Conclusion@#The modified balloon-assisted coiling technique using a partially inflated balloon was safe and effective and could serve as an option for treating paraclinoid aneurysms.

Embolization Tactics of Spinal Epidural Arteriovenous Fistulas / 신경중재치료의학

Purpose@#Spinal epidural arteriovenous fistulas (SEDAVFs) show an epidural venous sac often with venous congestive myelopathy (VCM) due to intradural reflux at a remote level to which a transarterial approach would be difficult. We present 12 cases of SEDAVF with VCM and describe 3 main tactics for effective transarterial embolization. @*Materials and Methods@#Among 152 patients with spinal vascular malformations diagnosed in our tertiary hospital between 1993 and 2019, 12 SEDAVF patients with VCM were included. Three different transarterial embolization tactics were applied according to the vascular configuration and microcatheter accessibility. We evaluated treatment results and clinical outcomes before and after treatment. @*Results@#Transarterial embolization with glue (20–30%) was performed in all patients. The embolization tactics applied in 12 patients were preferential flow (n=2), plug-and-push (n=6), and filling of the venous sac (n=4). Total occlusion of the SEDAVF, including intradural reflux, was achieved in 11 (91.7%) of 12 patients, and partial occlusion was achieved in 1 patient. No periprocedural complications were reported. Spinal cord edema was improved in all patients for an average of 18 months after treatment. Clinical functional outcome in terms of the pain, sensory, motor, and sphincter scale and modified Rankin scores improved during a mean 25-month follow-up (6.3 vs. 3.3, P=0.002; 3.6 vs. 2.3, P=0.002, respectively). @*Conclusion@#Endovascular treatment for 12 SEDAVF patients with VCM achieved a total occlusion rate of 91.7% without any periprocedural complication. The combined embolization tactics can block intradural reflux causing VCM, resulting in overall good clinical outcomes.

Staged Approach for Stent-Assisted Coiling of Cerebral Aneurysms after Failure of Initial Intra-Saccular Catheterization / 신경중재치료의학

Purpose@#Microcatheter navigation into an aneurysm sac can present difficulties through negative interactions between the deployed stent mesh and microcatheter. We hypothesized that endothelialization of the stent mesh would minimize these interactions. We aimed to assess the feasibility of staged coiling after stenting by reviewing our experiences with unavoidably staged embolization cases. @*Materials and Methods@#Between 2011 and 2019, 7 patients (mean age 57.2 years, range 49–76 years) including 5 females, experienced 9 unruptured aneurysms treated with staged stenting and coiling due to unstable microcatheter navigation into the aneurysm after stent placement. The aneurysms were in the paraclinoid internal carotid artery (ICA) (n=3), ophthalmic origin ICA (n=1), superior cerebellar artery origin (n=2), basilar tip (n=2), and the middle cerebral artery bifurcation (n=1). The stents used were the Neuroform Atlas (n=4), Neuroform EZ (n=2), and Low-profile Visualized Intraluminal Support Blue (n=1). @*Results@#The mean interval between stenting and coiling was 15 weeks (range, 12–21 weeks). The average navigation time between the first roadmap imaging and microcatheter insertion in the sac was 14 minutes (range, 8–20 minutes). One aneurysm was occluded without further coiling on follow-up. Staged coiling successfully treated the remaining aneurysms (n=8). No complications were identified. @*Conclusion@#In cases of difficult intra-saccular catheterization, intentional staged coiling may be a feasible option for stent-assisted coiling of the cerebral aneurysms.

Rare Neurovascular Diseases in Korea: Classification and Related Genetic Variants

Rare neurovascular diseases (RNVDs) have not been well-recognized in Korea. They involve the central nervous system and greatly affect the patients’ lives. However, these diseases are difficult to diagnose and treat due to their rarity and incurability. We established a list of RNVDs by referring to the previous literature and databases worldwide to better understand the diseases and their current management status. We categorized 68 RNVDs based on their pathophysiology and clinical manifestations and estimated the prevalence of each disease in Korea. Recent advances in genetic, molecular, and developmental research have enabled further understanding of these RNVDs. Herein, we review each disease, while considering its classification based on updated pathologic mechanisms, and discuss the management status of RNVD in Korea.

Microcatheter Stabilization Technique Using Partially Inflated Balloon for Coil Embolization of Paraclinoid Aneurysms / 신경중재치료의학

Purpose@#Coil embolization of paraclinoid aneurysms should be simple, safe, and effective considering the benign nature of the aneurysm. Here, we present a microcatheter stabilization technique using a partially inflated balloon for the treatment of paraclinoid aneurysms. @*Materials and Methods@#This retrospective study included 58 patients who underwent balloon-assisted coiling (BAC) for unruptured paraclinoid aneurysms at a tertiary neuro-intervention center between January 2019 and March 2020. We applied a technique to stabilize the microcatheter’s position using the modified BAC technique in paraclinoid aneurysms showing various projections around the ophthalmic curve of the internal carotid artery. The basic concept of the technique is to place a partially inflated balloon just distal to the aneurysm neck and support the distal curve of the microcatheter using the proximal bottom of the balloon. Immediate radiological outcomes were analyzed, and clinical outcomes were evaluated with modified Rankin Scale (mRS) scores. @*Results@#The BAC was successfully performed in 51 of 58 patients (88%). We treated the remaining seven patients by switching to stent-assisted coiling. We obtained a 37% mean packing density resulting in favorable occlusion in all 58 aneurysms (complete occlusion in 35 and residual neck in 23). There were no intraprocedural thromboembolic or hemorrhagic events except one that revealed an asymptomatic infarction after the procedure (1.7%). Magnetic resonance angiography follow-up was performed in 37 patients at an average of 11.8 months, in which 11 minor recurrences (29.7%) were found. There was no major recurrence nor retreatment. The mRS score was 0 in all patients during a mean follow-up of 17.7 months (range, 12–25 months). @*Conclusion@#The modified balloon-assisted coiling technique using a partially inflated balloon was safe and effective and could serve as an option for treating paraclinoid aneurysms.

Endovascular Treatment in Patients with Cerebral Artery Occlusion of Three Different Etiologies / 대한뇌졸중학회지

Background@#and Purpose The outcome of endovascular treatment (EVT) may differ depending on the etiology of arterial occlusion. This study aimed to assess the differences in EVT outcomes in patients with intracranial arterial steno-occlusion (ICAS-O), artery-to-artery embolism (AT-O), and cardiac embolism (CA-O). @*Methods@#We retrospectively analyzed 330 patients with ischemic stroke who underwent EVT between January 2012 and August 2017. Patients were classified according to the etiology. The clinical data, EVT-related factors, and clinical outcomes were compared. The modified Rankin Scale (mRS) score at 3 months, determined using ordinal logistic regression (shift analysis), was the primary outcome. @*Results@#CA-O (n=149) was the most common etiology, followed by ICAS-O (n=63) and AT-O (n=49). Age, initial National Institutes of Health Stroke Scale (NIHSS) score, and rate of hemorrhagic transformation were significantly higher in patients with CA-O compared to AT-O and ICAS-O. The time from onset-to-recanalization was the shortest in the CA-O (356.0 minutes) groups, followed by the AT-O (847.0 minutes) and ICAS-O (944.0 minutes) groups. The rates of successful recanalization, mRS distribution, and favorable outcomes at 3 months (mRS 0–2; CA-O, 36.9%, AT-O, 53.1%; and ICAS-O, 41.3%) did not differ among the three groups. Baseline NIHSS score (odds ratio, 0.87; 95% confidence interval, 0.83 to 0.91) could independently predict a favorable shift in mRS distribution. @*Conclusions@#The functional outcomes of ICAS-O and AT-O were similar to those of CA-O, despite the delay in symptom onset-to-recanalization, suggesting that the therapeutic time window may be extended in these patients.

International Survey on Criteria for Training and Accreditation in Interventional Neuroradiology / 신경중재치료의학

Purpose@#With the rapid expansion of the field of interventional neuroradiology (INR) and the diverse background of aspiring neuro-interventionists, there is an ever increasing need to establish consensus criteria for training and accreditation in INR. @*Materials and Methods@#We performed a survey to explore the current state of criteria for training and accreditation in INR. The questionnaire consisting of 11 questions was emailed to the members of World Federation of Interventional and Therapeutic Neuroradiology (WFITN) worldwide. It was focused on the training charter, training program, qualifying examination, and education after training program as perceived by practitioners in each country. @*Results@#A total of 52 WFITN members in 19 countries responded to the questionnaire. There was a huge variation internationally and nationally due to the unique situation and challenges in each country and institution. Criteria for training and accreditation in INR were well established in some countries of Europe, North America, and Asia but not specified in other countries. @*Conclusion@#It is critical to establish consensus criteria for training and accreditation in INR in order to ensure safe practice and continued expansion and development of INR as a specialty.

Low-dose Prasugrel in Patients with Resistance to Clopidogrel for the Treatment of Cerebral Aneurysms: Follow-up of over 6 Months / 신경중재치료의학

No abstract available.

Cigarette Smoking Preferentially Affects Intracranial Vessels in Young Males: A Propensity-Score Matching Analysis / 신경중재치료의학

PURPOSE: Cigarette smoking (CS) is one of the major risk factors of cerebral atherosclerotic disease, however, its level of contribution to extracranial and intracranial atherosclerotic stenosis (ECAS and ICAS) was not fully revealed yet. The purpose of our study was to assess the association of CS to cerebral atherosclerosis along with other risk factors. MATERIALS AND METHODS: All consecutive patients who were angiographically confirmed with severe symptomatic cerebral atherosclerotic disease between January 2002 and December 2012 were included in this study. Multivariate logistic regression analyses were performed to identify risk factors for ECAS and ICAS. Thereafter, CS group were compared to non-CS group in the entire study population and in a propensity-score matched population with two different age-subgroups. RESULTS: Of 1709 enrolled patients, 794 (46.5%) had extracranial (EC) lesions and the other 915 (53.5%) had intracranial (IC) lesions. CS group had more EC lesions (55.8% vs. 35.3%, P<0.001) whereas young age group (<50 years) had more IC lesion (84.5% vs. 47.6%, P<0.001). In multivariate analysis, seven variables including CS, male, old age, coronary heart disease, higher erythrocyte sedimentation rate, multiple lesions, and anterior lesion were independently associated with ECAS. In the propensity-score matched CS group had significant more EC lesion compared to non-CS group (65.7% vs. 47.9%) only in the old age subgroup. CONCLUSION: In contrast to a significant association between CS and severe symptomatic ECAS shown in old population, young patients did not show this association and showed relatively higher preference of ICAS.

Current Status of Clinical Diagnosis and Genetic Analysis of Hereditary Hemorrhagic Telangiectasia in South Korea: Multicenter Case Series and a Systematic Review / 신경중재치료의학

PURPOSE: Hereditary hemorrhagic telangiectasia (HHT), a rare genetic vascular disorder, has been rarely reported in South Korea. We investigated the current prevalence and presenting patterns of genetically confirmed HHT in South Korea. MATERIALS AND METHODS: We defined HHT patients as those with proven mutations on known HHT-related genes (ENG, ACVRL1, SMAD4, and GDF2) or those fulfilling 3 or 4 of the Curaçao criteria. A computerized systematic search was performed in PubMed and KoreaMed using the following search term: (“hereditary hemorrhagic telangiectasia” AND “Korea”) OR (“Osler-Weber-Rendu” AND “Korea”). We also collected government health insurance data. HHT genetic testing results were collected from three tertiary hospitals in which the genetic tests were performed. We integrated patient data by analyzing each case to obtain the prevalence and presenting pattern of HHT in South Korea. RESULTS: We extracted 90 cases from 52 relevant articles from PubMed and KoreaMed. An additional 22 cases were identified from the three Korean tertiary hospitals after excluding seven cases that overlapped with those in the published articles. Finally, 112 HHT patients were identified (41 males and 71 females, aged 4–82 years [mean±standard deviation, 45.3±20.6 years]). The prevalence of HHT in South Korea is about 1 in 500,000, with an almost equal prevalence among men and women. Forty-nine patients underwent genetic testing, of whom 28 had HHT1 (ENG mutation) and 19 had HHT2 (ACVRL1 mutation); the other two patients were negative for ENG, ACVRL1, and SMAD4 mutations. CONCLUSION: The prevalence of HHT is underestimated in Korea. The rate of phenotypic presentation seems to be similar to that found worldwide. Korean health insurance coverage is limited to representative genetic analysis to detect ENG and ACVRL1 mutations. Further genetic analyses to detect HHT3, HHT4, and other forms of HHT should be implemented.

Low-Dose Prasugrel in Patients with Resistance to Clopidogrel for the Treatment of Cerebral Aneurysms / 신경중재치료의학

Thromboembolism is one of the major complications of stent assisted coiling in treatment of cerebral aneurysm. Clopidogrel resistance is so common and prasugrel is more effective in its rapid and potent effect. We investigated changes in the value of P2Y12 resistance unit (PRU) when prasugrel was administered to patients with clopidogrel resistance. One hundred mg of aspirin and 75 mg of clopidogrel were administered for 5 days before the procedure, and PRU were examined. The resistance to clopidogrel was defined as the inhibition of PRU was less than 20%. PRU was re-examined after loading 20 mg of prasugrel. We treated 98 consecutive patients between January 2018 and July 2018, and 24 patients (24.5%) had resistance to clopidogrel. Nineteen patients were female. The mean PRU value at admission was 238.5±36.9 and the percentage inhibition value was 4.8±6.3%. After the use of prasugrel, the mean PRU and percentage inhibition values were measured as 124.9±49.9 and 48.0±19.24, respectively. All patients except one patient had a PRU inhibition value as a responder. There was no hemorrhage or thromboembolic complication during mean 1.5 months follow-up after embolization procedure. In conclusion, in patients resistant to clopidogrel, the low dose prasugrel seems to be effective in keeping the percentage inhibition value of PRU within the normal range in treatment of cerebral aneurysm. Further study will be needed to determine the optimal dose of prasugrel to enhance prevention effect of thromboembolism and to reduce hemorrhagic complications during stent assisted coiling.

Diagnosis of Cerebral Aneurysm Via Magnetic Resonance Angiography Screening: Emphasis on Legal Responsibility Increases False Positive Rate / 신경중재치료의학

PURPOSE: False positive diagnoses of cerebral aneurysm via magnetic resonance angiography (MRA) screening may increase unnecessary cerebral catheter angiography. The purpose of this study was to investigate the effects of medical liability on medical decision-making during radiologic interpretation. MATERIALS AND METHODS: We included 56 consecutive patients who were referred with suspected aneurysm based on MRA or computed tomography angiography (CTA) and showed no aneurysm on subsequent digital subtraction angiography (DSA). MRA and CTA were reviewed twice by two neuroradiology fellows who were blind as to whether the suspected lesions were true aneurysms or not. The second review was repeated after proposing that their decision was subject to legal liability and they would be responsible for medico-legal problems related to their diagnoses. Diagnostic differences based on each review were analyzed, focusing on changes in false positive diagnosis rates. RESULTS: A total of 63 suspected aneurysmal lesions detected via MRA or CTA were found to be negative based on DSA. At first review, 32 lesions were diagnosed as true aneurysms by observer 1 and 27 by observer 2, corresponding to false positive rates of 51% and 43% respectively. At the second review, 39 lesions (62%) were diagnosed by observer 1, and 30 (48%) by observer 2. Thus, there was an overall increase in false positive aneurysm diagnosis of 11% for observer 1 and 5% for observer 2, after emphasizing their responsibilities in the context of medical litigation. CONCLUSION: Concerns about medical liability could result in increased false positive diagnoses of cerebral aneurysms via MRA screening. Whether repeated follow-up of the suspected lesion or catheter angiographic confirmation is better with regard to long-term patient outcomes requires further study.

Adjuvant Coil Assisted Glue Embolization of Vein of Galen Aneurysmal Malformation in Pediatric Patients / 신경중재치료의학

PURPOSE: Adjuvant coils may offer advantages in flow control during glue embolization of high flow vein of Galen aneurysmal malformation (VGAM) patients but involves specific issues such as feasibility, durability and coil mass effect. The purpose of this study is to assess the outcome of adjuvant coils in addition to transarterial glue embolization for treatment of these patients. MATERIALS AND METHODS: Five pediatric VGAM patients (age range; 11 weeks to 2 yrs 2 mos) with high flow fistulous angioarchitecture were treated with adjuvant coils 1) in the distal feeding artery and/or 2) in the vein of Galen followed by glue embolization of the shunt. The angiographic / clinical outcomes were assessed. RESULTS: Adjuvant coils were deployed in the distal feeding artery (n=3), vein of Galen pouch plus distal feeding artery (n=2). Additional transarterial glue embolization of the fistulae was successfully performed (n=4). Complete occlusion was achieved with coils in one case. Complete occlusion was achieved for all mural type cases (n=4). Residual feeders remained in a case of choroidal type of VGAM. No complications were noted related to the treatment. All patients showed normal development on follow up (range: 7.6 to 88.8 mo, mean 49.3 mo). Initial hydrocephalus improved on follow up despite coil mass effect in dilated vein of Galen. CONCLUSION: Adjuvant coils for flow control with glue embolization may be a safe and effective treatment method for VGAM patients with high flow fistulous feeders.