Background: To analyze the outcomes of clipping and coiling for ruptured intracranial aneurysms (RIAs) based on data from the National Health Insurance Service in South Korea, with a focus on variations according to region and hospital size. Methods: This study analyzed the one-year mortality rates for patients with RIAs who underwent clipping or coiling in 2018. Coiling was further categorized into non-stent assisted coiling (NSAC) and stent assisted coiling (SAC). Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs), or semi-general hospitals (sGHs) based on size. South Korea’s administrative districts were divided into 15 regions for analysis. Results: In 2018, there were 2,194 (33.1%) clipping procedures (TRGH, 985; GH, 827; sGH, 382) and 4,431 (66.9%) coiling procedures (TRGH, 1,642; GH, 2076; sGH, 713) performed for RIAs treatment. Among hospitals performing more than 20 treatments, the one-year mortality rates following clipping or coiling were 11.2% and 16.0%, respectively, with no significant difference observed. However, there was a significant difference in one-year mortality between NSAC and SAC (14.3% vs. 19.5%, P = 0.034), with clipping also showing significantly lower mortality compared to SAC (P = 0.019). No significant differences in other treatment modalities were observed according to hospital size, but clipping at TRGHs had significantly lower mortality than at GHs (P = 0.042). While no significant correlation was found between the number of treatments and outcomes at GHs, at TRGHs, a higher volume of clipping procedures was significantly associated with lower total mortality (P = 0.023) and mortality after clipping (P = 0.022). Conclusion Using Korea NHIS data, mortality rates for RIAs showed no significant variation by hospital size due to coiling’s prevalence. However, differences in clipping outcomes by hospital size and volume in TRGH highlight the need for national efforts to improve clipping skills and standardization. Additionally, the higher mortality rate with SAC emphasizes the importance of precise indications for its application.

Objective: : To analyze the outcomes of coil embolization (CE) for unruptured intracranial aneurysm (UIA) according to region and hospital size based on National Health Insurance Service data in South Korea. Methods: : The incidence of complications, including intracranial hemorrhage (ICRH) and cerebral infarction (CI), occurring within 3 months and the 1-year mortality rates in UIA patients who underwent CE in 2018 were analyzed. Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs) or semigeneral hospitals (sGHs) according to their size, and the administrative districts of South Korea were divided into 15 regions. Results: : In 2018, 8425 (TRGHs, 4438; GHs, 3617; sGHs, 370) CEs were performed for UIAs. Complications occurred in 5.69% of patients seen at TRGHs, 13.48% at GHs, and 20.45% at sGHs. The complication rate in TRGHs was significantly lower than that in GHs (p=0.039) or sGHs (p=0.005), and that in GHs was significantly lower than that in sGHs (p=0.030). The mortality rates in TRGHs, GHs, and sGHs were 0.81%, 2.16%, and 3.92%, respectively, with no significant difference. Despite no significant difference in the mortality rates, the complication rate significantly increased as the number of CE procedures per hospital decreased (p=0.001; rho=-0.635). Among the hospitals where more than 30 CEs were performed for UIAs, the incidence of CIs (p=0.096, rho=-0.205) and the mortality rates (3 months, p=0.048, rho=-0.243; 1 year, p=0.009, rho=-0.315) significantly decreased as the number of CEs that were performed increased and no significant difference in the incidence of post-CE ICRH was observed. Conclusion : The complication rate in patients who underwent CE for UIA increased as the hospital size and physicians’ experience in conducting CEs decreased. We recommend nationwide quality control policies CEs for UIAs.

Objective: : Placement of a single transverse stent via the nondominant A1 across the anterior communicating artery (AComA) into the contralateral A2 can provide sufficient neck coverage for wide-necked bifurcation AComA aneurysms. The authors described the feasibility, safety and long-term outcomes of this technique. Methods: : Between January 2015 and February 2018, placement of a single transverse stent via the nondominant A1 was attempted in 17 wide-necked bifurcation AComA aneurysms. The authors reviewed the medical records and radiological studies. Results: : The technical success rate was 94.1% (16/17). Periprocedural thromboembolic complications occurred in one patient (6.3%) without permanent neurological deficits. The mean clinical follow-up duration was 39.9±9.8 months. No deaths or delayed thromboembolic complications occurred. The mean angiographic follow-up duration was 38.9±9.8 months. The immediate and final follow-up complete occlusion rates were 87.4 and 93.7%, respectively. There was no recanalization during the follow-up period. Conclusion : Placement of a single transverse stent via the nondominant A1 across the AComA into the contralateral A2 is a feasible and relatively safe endovascular technique for the treatment of wide-necked bifurcation AComA aneurysms, with good long-term occlusion rates and a reasonable complication rate, if only the nondominant A1 is applicable.

Given the progressive improvements in antithrombotic strategies, management of cardiovascular disease has become sophisticated/refined. However, the optimal perioperative management of antithrombotic therapy in patients with acute coronary syndrome or who are scheduled for percutaneous coronary intervention remains unclear. Assessments of the thrombotic and hemorrhagic risks are essential to reduce the rates of mortality and major cardiac events. However, the existing guidelines do not mention these topics. This case-based consensus document deals with common clinical scenarios and offers evidence-based guidelines for individualized perioperative management of antithrombotic therapy in the real world.

The prevalence of ischemic heart disease is steadily growing as populations age. Antithrombotic treatment is a key therapeutic modality for the prevention of secondary cerebro-cardiovascular disease. Patients with acute coronary syndrome or who are undergoing percutaneous coronary intervention must be treated with dual antiplatelet therapy for a mandatory period. The optimal perioperative antithrombotic regimen remains debatable; antithrombotics can cause bleeding. Inadequate antithrombotic regimens are associated with perioperative ischemic events, but continuation of therapy may increase the risks of perioperative hemorrhagic complications (including mortality). Many guidelines on the perioperative management of antithrombotic agents have been established by academic societies. However, the existing guidelines do not cover all specialties, nor do they describe the thrombotic and hemorrhagic risks associated with various surgical interventions. Moreover, few practical recommendations on the modification of antithrombotic regimens in patients who require non-deferrable interventions/surgeries or procedures associated with a high risk of hemorrhage have appeared. Therefore, cardiologists, specialists performing invasive procedures, surgeons, dentists, and anesthesiologists have not come to a consensus on optimal perioperative antithrombotic regimens. The Korean Platelet-Thrombosis Research Group presented a positioning paper on perioperative antithrombotic management. We here discuss commonly encountered clinical scenarios and engage in evidence-based discussion to assist individualized, perioperative antithrombotic management in clinical practice.

Objective: : Endovascular treatment of large, wide-necked intracranial aneurysms by coil embolization is often complicated by low rates of complete occlusion and high rates of recurrence. A flow diverter device has been shown to be safe and effective for the treatment of not only large and giant unruptured aneurysms, but small and medium aneurysms. However, in Korea, its use has only recently been approved for aneurysms <10 mm. This study aims to compare the safety and efficacy of flow diversion and coil embolization for the treatment of unruptured aneurysms ≥7 mm. Methods: : The participants will include patients aged between 19 and 75 years to be treated for unruptured cerebral aneurysms ≥7 mm for the first time or for recurrent aneurysms after initial endovascular coil embolization. Participants assigned to a flow diversion cohort will be treated using any of the following devices : Pipeline Flex Embolization Device with Shield Technology (Medtronic, Minneapolis, MN, USA), Surpass Evolve (Stryker Neurovascular, Fremont, CA, USA), and FRED or FRED Jr. (MicroVention, Tustin, CA, USA). Participants assigned to a coil embolization cohort will undergo traditional endovascular coiling. The primary endpoint will be complete occlusion confirmed by cerebral angiography at 12 months after treatment. Secondary safety outcomes will evaluate periprocedural and post-procedural complications for up to 12 months. Results: : The trial will begin enrollment in 2022, and clinical data will be available after enrollment and follow-up. Conclusion : This article describes the aim and design of a multi-center, randomized, open-label trial to compare the safety and efficacy of flow diversion versus traditional endovascular treatment for unruptured cerebral aneurysms ≥7 mm.

Objective: : Stent-assisted coil embolization (SAC) has been increasingly used to treat various types of intracranial aneurysms. Delayed thromboembolic complications are major concerns regarding this procedure, so dual antiplatelet therapy with aspirin and clopidogrel is needed. However, clinicians vary the duration of dual antiplatelet therapy after SAC, and no randomized study has been performed. This study aims to compare the safety and efficacy of long-term (12 months) dual antiplatelet therapy and shortterm dual antiplatelet therapy (6 months) after SAC for patients with unruptured intracranial aneurysms (UIAs). Methods: : This is a prospective, randomized and multicenter trial to investigate the optimal duration of dual antiplatelet therapy after SAC in patients with UIAs. Subjects will receive dual antiplatelet therapy for 6 months (short-term group) or 12 months (longterm group) after SAC. The primary endpoint is the assessment of thromboembolic complications between 1 and 18 months after SAC. We will enroll 528 subjects (264 subjects in each group) and perform 1 : 1 randomization. This study will involve 14 topperforming, high-volume Korean institutions specializing in coil embolization. Results: : The trial will begin enrollment in 2022, and clinical data will be available after enrollment and follow-up. Conclusion : This article describes that the aim of this prospective randomized multicenter trial is to compare the effect of short-term (6 months) and long-term (12 months) dual antiplatelet therapy on UIAs in patients undergoing SAC, and to find the optimal duration.

Objective: The trend in the initial severity of aneurysmal subarachnoid hemorrhage (SAH) is unclear. This study aimed to evaluate whether there was an improvement in the initial severity of SAH over time. Methods: From January 1, 2005, to December 31, 2020, we identified patients who visited the emergency department of our institution with SAH due to intracranial aneurysm rupture. We identified the Hunt Hess (HH) grade and modified Fisher grade of each patient from the medical records, and the Mann-Kendal method was used to estimate the trend of each grade system. Results: A total of 547 patients with SAH were identified. The mean age of the patients was 59.3 years (standard deviation (SD), 14.6). The mean aneurysm size was 6.9 mm (SD, 4.6 mm). The most frequent aneurysm location was the anterior communicating artery (28.7%). In the Mann-Kendal estimates for the analysis of the trend, there was no statistically significant grade throughout the HH and modified Fisher grades. Similarly, there was no improvement throughout all grades in the modified Fisher grade over time. Conclusions The initial severity of SAH due to cerebral aneurysm rupture did not improve over time.

Background: We aimed to analyze outcomes of clipping and coiling in treating unruptured intracranial aneurysms (UIAs) in elderly patients and to identify the age at which perioperative risk increases based on national cohort data in South Korea. Methods: The incidence of perioperative intracranial hemorrhage (ICRH), perioperative cerebral infarction (CI), mortality, and moderate to severe disability data of the patients who underwent coiling or clipping for UIAs were retrieved. Estimated breakpoint (EBP) was calculated to identify the age at which the risk of treatment increases. Results: A total of 38,207 patients were treated for UIAs. Among these, 22,093 (57.8%) patients underwent coiling and 16,114 (42.2%) patients underwent clipping. The incidence of ICRH, requiring a secondary operation, within 3 months in patients ≥ 65 years that underwent coiling and clipping was 1.13% and 4.81%, respectively, and that of both groups assessed were significantly higher in patients ≥ 75 years (coiling, P = 0.013, relative risk (RR) 1.81; clipping, P = 0.015) than younger patients. The incidence of CI within 3 months in patients aged ≥ 65 was 13.90% and 9.19% in the coiling and clipping groups, respectively. The incidence of CI after coiling in patients aged ≥ 75 years (P < 0.001, RR 1.96) and after clipping in patients aged ≥ 70 years (P < 0.001, RR 1.76) was significantly higher than that in younger patients. The mortality rates within 1 year in patients with perioperative ICRH or CI were 2.41% and 3.39% for coiling and clipping groups, respectively, in patients ≥ 65. These rates increased significantly at age 70 in the coiling group and at age 75 for the clipping group (P = 0.012 and P < 0.001, respectively). Conclusion The risk of treatment increases with age, and this risk increases dramatically in patients aged ≥ 70 years. Therefore, the treatment decisions in patients aged ≥ 70 years should be made with utmost care.

Background: We aimed to analyze outcomes of clipping and coiling in treating unruptured intracranial aneurysms (UIAs) in elderly patients and to identify the age at which perioperative risk increases based on national cohort data in South Korea. Methods: The incidence of perioperative intracranial hemorrhage (ICRH), perioperative cerebral infarction (CI), mortality, and moderate to severe disability data of the patients who underwent coiling or clipping for UIAs were retrieved. Estimated breakpoint (EBP) was calculated to identify the age at which the risk of treatment increases. Results: A total of 38,207 patients were treated for UIAs. Among these, 22,093 (57.8%) patients underwent coiling and 16,114 (42.2%) patients underwent clipping. The incidence of ICRH, requiring a secondary operation, within 3 months in patients ≥ 65 years that underwent coiling and clipping was 1.13% and 4.81%, respectively, and that of both groups assessed were significantly higher in patients ≥ 75 years (coiling, P = 0.013, relative risk (RR) 1.81; clipping, P = 0.015) than younger patients. The incidence of CI within 3 months in patients aged ≥ 65 was 13.90% and 9.19% in the coiling and clipping groups, respectively. The incidence of CI after coiling in patients aged ≥ 75 years (P < 0.001, RR 1.96) and after clipping in patients aged ≥ 70 years (P < 0.001, RR 1.76) was significantly higher than that in younger patients. The mortality rates within 1 year in patients with perioperative ICRH or CI were 2.41% and 3.39% for coiling and clipping groups, respectively, in patients ≥ 65. These rates increased significantly at age 70 in the coiling group and at age 75 for the clipping group (P = 0.012 and P < 0.001, respectively). Conclusion The risk of treatment increases with age, and this risk increases dramatically in patients aged ≥ 70 years. Therefore, the treatment decisions in patients aged ≥ 70 years should be made with utmost care.