Clinical Practice Guideline for the Prehospital Stage of Acute Stroke : III. Initial Decision for Primary Treatment in Subarachnoid Hemorrhage

Composition of the clinical practice guideline committee and multidisciplinary participation

The Clinical Practice Guideline Committee comprises an executive, a working, and internal and external review committees. The executive committee establishes the strategy and direction for guideline development, reviews and approves the budget, coordinates stakeholders, and ensures the independence of the development process. We described more details about members and progress in this guideline (Supplementary Material 1).

Clinical medical guideline development

This study is not the first attempt to develop stroke medical guidelines in Korea. Therefore, we reviewed existing medical guidelines to define the scope and target population of the new guidelines. Stroke is a broad topic; attempting to cover all aspects of stroke in the first edition of the guidelines might lead to an excessively extensive scope and potential overlap with existing international guidelines.

Stroke treatment is categorized into three phases : pre-hospital care, hospital treatment, and post-treatment management. Most previously established Korean guidelines focused on hospital-based treatment and were created by modifying or adapting existing international guidelines.

In Korea, emergency patient transfers are a social concern. Since February 2024, legislative conflicts about the rapid increase in medical school enrollment quotas have exacerbated the shortage of specialists, especially in essential medical services. Consequently, transferring patients between hospitals is challenging. The availability of treatment modalities for SAH, such as surgical clipping and endovascular coiling, varies by region and time; some hospitals are equipped to perform both procedures, while others can offer only one. Therefore, selecting and transferring patients to specialized centers that provide the most appropriate treatment may lead to better clinical outcomes in emergency situations. In Korea, the establishment of multiple stroke-specialized hospitals led to an increasing consideration of endovascular coiling as a viable treatment modality for SAH. However, a substantial gap exists between the expert’s understanding and the general public’s stroke treatment perception. In actual emergency rooms, controversy and confusion remain regarding the initial decision-making between clipping and coiling for SAH. During an emergency, medical staff may not have adequate time to explain the differences and potential benefits of each procedure. Patients and caregivers may experience dissatisfaction or regret regarding treatment decisions, especially when the outcome is unfavorable, regardless of the chosen intervention. Despite successful aneurysm occlusion, the mortality rate remains high. Experienced medical professionals must lead the treatment decision while respecting the values and preferences of patients and their caregivers. Considering the critical importance of early treatment decision-making in the management of SAH, this guideline aims to provide evidence-based recommendations to support the selection between clipping and coiling. We prepared this guideline in accordance with the Institutional Review Board (UC24ZISE0069), and the requirement for informed consent was waived.

Selecting key questions

Two main key questions for each recommendation were formulated based on the PICO (population/patient, intervention, comparison, outcome) framework, and a systematic literature search was conducted accordingly. Our key questions were as follows : 1) how should the choice between coiling and clipping be made in patients with SAH?; 2) when choosing between clipping and coiling as an initial treatment for SAH, which option provides more benefit to the patient?; 3) does endovascular coiling improve functional outcomes compared to surgical clipping in patients with SAH?; and 4) does clipping reduce mortality more than coiling in patients with SAH? The clinical questions addressed in this guideline were structured according to the PICO format; we included patients diagnosed with SAH who underwent either endovascular coiling or surgical clipping. The intervention group consisted of patients who received endovascular coiling, and the comparison group consisted of patients who received surgical clipping. The primary outcomes evaluated were good functional outcome, defined as a modified Rankin scale (mRS) score of less than 3, and all-cause mortality within 1 year (Supplementary Table 1).

Literature search and selection

The literature search was conducted by methodology experts and the development committee members. An initial set of search terms was formulated, and a search strategy was established accordingly. Based on this strategy, searches were conducted on November 11, 2024, across four major databases : MEDLINE (PubMed), Embase, Cochrane Library, and KoreaMed. The selection of relevant studies was conducted separately for each key question, with seven development committee members assigned. Duplicate exclusion and literature selection followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart (Fig. 1). The inclusion and exclusion criteria for each key question were formulated and applied based on the PICO framework.

Fig. 1.

The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flow diagram for systematic reviews and a metaanalysis. Modified from Page et al. [28]

Consensus and recommendation adoption

The guideline recommendations were derived from two major topics, resulting in two recommendations. The principle for determining recommendation grades within the internal committee required that at least 80% of committee members participate; moreover, a minimum of 70% approval was needed for a decision to be considered a consensus. If the approval rate was not up to 70%, the committee engaged in further discussions to draft a revised proposal, followed by a second round of voting. Recommendations that were not approved in the first round were revised and subjected to a second vote. During the second voting round, a consensus was reached regarding the two revised recommendations, and one final recommendation was adopted (Table 1).

Table 1.

Summary of key questions and recommendations

Publication and future updates of the clinical practice guideline

This clinical practice guideline will be published in medical journals affiliated with KNS, KEMS, KSCVS, and KoNES. Additionally, it will be made publicly available on the official website, Instagram, and other online platforms of the society, ensuring that physicians, healthcare professionals, and the public can easily download and access the guideline.

The guideline will be registered on the official website of KoNES for promotional purposes. A summary booklet will also be produced and distributed at future academic conferences and events.

The KoNES Academic Committee and the Clinical Practice Guideline Committee will continue to monitor research findings in specific areas, including early diagnosis and transfer of emergency stroke cases, and SAH treatment selection. Further, they will track updates from international clinical guidelines. In the event of new research warranting additions or modifications to the recommendations, a Clinical Guideline Revision Committee under the society will be formed to revise the guideline every 5 years.

Functional outcome

The two primary therapeutic options for SAH, endovascular coiling and surgical clipping, must be carefully evaluated. The appropriate initial treatment should be determined in consultation with a qualified specialist to improve the functional outcome. The final treatment decision for SAH should be tailored to individual patient factors, including aneurysm location, morphology, and expertise available at the treatment center, based on the expertise of neurosurgeons and endovascular neurosurgeons, as well as patient’s status and institutional factors. Such decisions should be explained and shared with the patient and their caregivers, along with the rationale for selecting the most appropriate treatment at the given hospital (level of evidence [LOE], high; grade of recommendation [GOR], A). In centers where both coiling and clipping are feasible based on the judgment of specialists, either modality-coiling or clipping could be considered an appropriate treatment option. When endovascular coiling is feasible as initial treatment, prioritizing coiling is considered a rational and acceptable clinical strategy to obtain a good functional outcome (LOE, high; GOR, A).

A systematic review of the literature identified six RCTs and 58 non-randomized studies comparing clipping and coiling outcomes in acute SAH treatment. These studies investigated functional outcomes within 1 year after treatment, analyzing results based on the mRS and the Glasgow outcome scale. For this analysis, a good functional outcome was defined as an mRS score of 2 and a Glasgow outcome scale score of ≥4. Data were collected and compared to assess the efficacy of both treatment modalities in optimizing patient recovery following SAH. Through a quality assessment, six RCTs and 58 non-randomized studies were selected for analysis. The RCTs included 2940 patients; 1699 (57.7%) demonstrated good functional outcomes.

A meta-analysis of RCTs comparing the functional outcomes of clipping and coiling demonstrated that coiling improved the achievement of good functional outcomes by approximately 9% compared with clipping. This difference was statistically significant (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.86–0.97; Fig. 2). No heterogeneity was observed, and the quality assessment of the included trials indicated a high LOE. In nonrandomized studies, 40386 patients were analyzed; 26222 (64.9%) achieved good functional outcomes. A meta-analysis comparing functional outcomes following clipping and coiling showed that coiling improved the achievement of good functional outcomes by approximately 12% compared with clipping (OR, 0.88; 95% CI, 0.78–0.99; Fig. 3). However, high heterogeneity was observed among the studies, and the LOE was assessed as low. Despite these limitations, the findings from non-randomized studies were consistent with the results from RCTs, supporting the association between coiling and better functional outcomes.

Fig. 2.

Forest plot of functional outcome between clipping and coiling for subarachnoid hemorrhage patients on randomized control study. CI : confidence interval.

Fig. 3.

Forest plot of functional outcome between clipping and coiling for subarachnoid hemorrhage patients on non-randomized control study. CI : confidence interval.

Considering the results from the RCTs and non-randomized studies, coiling appears to improve functional outcomes compared with clipping in acute SAH treatment. Therefore, coiling may be prioritized as the initial treatment option. In addition to our findings, the 2012 American Heart Association/American Stroke Association (AHA/ASA) Guidelines for the Management of SAH state the following : for patients with ruptured aneurysms judged to be technically amenable to both endovascular coiling and neurosurgical clipping, endovascular coiling should be considered (class I; LOE, B) [6]. Furthermore, according to the updated 2023 AHA/ASA guidelines, in the treatment of good-grade SAH due to ruptured aneurysms located in the anterior circulation suitable for both primary coiling and clipping, primary coiling is recommended over clipping to improve the 1-year functional outcome (class I; LOE, A) [17]. For good-grade SAH from ruptured aneurysm on the anterior circulation, suitable for both primary coiling and clipping, both treatment options are reasonable to achieve a favorable long-term outcome (class I; LOE, B–R). The 2018 SAH guidelines in Korea state that for patients with ruptured aneurysms judged to be technically amenable to both endovascular coiling and neurosurgical clipping, endovascular coiling should be considered (class I; LOE, B in AHA/ASA 2012) [4]. In cases where the aneurysm appears to be equally effectively treated either by coiling or clipping, coiling is the preferred treatment (LOE, I; level A; European Stroke Organisation 2013). These results are consistent with those of established guidelines.

However, in our study, the observed difference was approximately 9%; given the substantial variability in aneurysm location, size, cerebral edema, patient condition at admission, and post-treatment complications, generalizing treatment recommendations for all patients remains challenging. The choice of treatment for SAH is influenced by patient‐specific factors (age, comorbidities, presence of intracerebral hemorrhage, World Federation of Neurosurgical Societies (WFNS) grade, aneurysm size, location, and configuration), the operator’s opinion, and institutional resources. Previous guidelines provided additional detail on these considerations. Microsurgical clipping may receive increased consideration in patients presenting with large (>50 mL) intraparenchymal hematomas and middle cerebral artery (MCA) aneurysms. Endovascular coiling may receive increased consideration in the elderly (>70 years of age), in those presenting with poor-grade (WFNS classification IV/V) SAH, and in those with aneurysms of the basilar apex (class IIb; LOE, C) [6].

Therefore, an expert panel recommended that treatment decisions should be individualized by specialists, considering patient, operator, and institutional factors, to optimize functional outcomes. In centers where both endovascular coiling and microsurgical clipping are technically feasible based on specialist judgment, either modality may be considered an appropriate treatment option. When endovascular coiling is feasible as the initial treatment, prioritizing coiling is a rational and acceptable clinical strategy to achieve favorable functional outcomes (LOE, high; GOR, A).

Mortality

The choice between clipping and coiling does not significantly affect the overall mortality in SAH. While both endovascular coiling and surgical clipping are primary treatment options, surgical clipping may be a reasonable option in selected patients when it is expected to reduce mortality. To suggest that clipping can be beneficial, treatment decisions should be guided by expert specialists and institutional capacity to provide both endovascular and surgical interventions to reduce mortality (LOE, low; GOR, C).

A systematic review of four RCTs and 50 non-randomized studies comparing mortality outcomes after clipping and coiling in patients with acute SAH was conducted. In the RCTs, 439 patients were analyzed, with 73 deaths (16.6%). In the nonrandomized studies, 70,894 patients were included, with 8912 deaths (12.6%). A meta-analysis of RCTs comparing mortality outcomes between clipping and coiling found no statistically significant difference between the two groups (OR, 1.38; 95% CI, 0.91–2.09; Fig. 4). No heterogeneity was observed among the studies, and the LOE was high. Contrarily, a meta-analysis of non-randomized studies showed that clipping was significantly associated with a 22% reduction in mortality compared with coiling (OR, 0.77; 95% CI, 0.69–0.86; Fig. 5). However, significant heterogeneity was observed among the studies, and the LOE was assessed as low. The comparison of mortality outcomes between clipping and coiling yielded different results depending on the study design. As RCTs provide high-quality evidence, we concluded that no significant difference in mortality reduction was observed between both SAH treatment modalities (LOE, high). However, despite the lower LOE, nonrandomized studies indicated that surgical clipping significantly reduced mortality compared with coiling (LOE, low). This finding suggests that in certain patient populations, clipping may offer survival benefits (OR, 0.77; 95% CI, 0.69–0.86). Therefore, although coiling and clipping remain primary treatment options, surgical clipping should be considered in selected cases where it may provide an advantage in reducing mortality (GOR, C).

Fig. 4.

Forest plot of mortality between clipping and coiling for subarachnoid hemorrhage patients on randomized control study. CI : confidence interval.

Fig. 5.

Forest plot of mortality between clipping and coiling for subarachnoid hemorrhage patients on non-randomized control study. CI : confidence interval.

Previous guidelines have also addressed the utility of surgical intervention and the necessity of surgical clipping. The 2023 ASA/AHA SAH guideline states that for patients with SAH deemed salvageable and with a depressed level of consciousness due to a large intraparenchymal hematoma, emergency clot evacuation should be performed to reduce mortality outcome (class I; LOE, B–R) [17]. The requirement for surgical treatment to control intracranial pressure in certain patients remains consistent. Although coiling and clipping remains a primary treatment option, surgical clipping should be considered in selected cases where it may provide an advantage in reducing mortality. To suggest that clipping can be beneficial, treatment decision should be guided by expert specialists and institutional capacity to provide both endovascular and surgical interventions to reduce mortality (LOE, low; GOR, C).

Additionally, we reviewed and summarized the advantages and disadvantages of both methods from various perspectives. The factors examined included old age, poor grade SAH, location, rebleeding & retreatment, vasospasm, and shunt-dependent hydrocephalus. The analysis followed a systematic review format, and conclusions were drawn based on expert consensus.

Old age

Young patients exhibit good prognoses with both methods; however, clipping is preferred because of its lower recurrence rate. However, in older patients, postoperative complications and cognitive impairment may hinder recovery, making the risk of complications a more substantial issue than recurrence.

A review of studies comparing coiling and clipping in older patients yielded the following findings : among patients aged ≥65 years, intraoperative complications showed a significant difference only in the incidence of intraoperative aneurysm rupture [1]. Intraoperative aneurysm rupture occurred in 6.4% and 16.7% of patients undergoing coil embolization and surgical clipping, respectively. Among postoperative complications, epilepsy and pneumonia showed significant differences. The incidence of epilepsy was 0.7% and 12.9% in the coil embolization and clipping groups, respectively, while pneumonia occurred in 5.1% and 15.0% of patients, respectively. Similar to the overall patient population, the cohort of patients aged ≥65 years demonstrated that coil embolization was associated with a lower incidence of complications. This suggests that in older patients, the risk of postoperative complications is higher with clipping than with coiling. Thus, the choice of surgical method should be made with careful consideration of the associated risks.

The optimal treatment method may vary depending on the aneurysm location. In the study comparing surgical outcomes in patients aged ≥65 years, the surgical method associated with favorable functional outcomes, depending on aneurysm location, was identified [1]. Regarding aneurysms located in the anterior cerebral artery and anterior communicating artery, no significant difference in functional outcomes (mRS, 0–2) was observed between the two surgical groups. However, regarding aneurysms located in the internal carotid artery (ICA) and posterior communicating artery (PComA), 1-year follow-up results demonstrated that 72% and 52% of patients who underwent coil embolization and clipping, respectively, achieved favorable outcomes, with significant differences. Similarly, regarding aneurysms located in the MCA, 1-year follow-up results showed that 45.5% of patients treated with coil embolization and 86.7% of those treated with clipping had significant favorable outcomes. Based on these findings, in older patients with ruptured aneurysms, the choice between coil embolization and surgical clipping should be based on aneurysm location. Regarding aneurysms in the ICA and PComA, coiling showed better functional outcomes than clipping. Conversely, clipping demonstrated better functional outcomes than coiling for aneurysms in the MCA. Thus, in patients aged ≥65 years, clipping may be considered a viable option for treating MCA aneurysms.

Location

The BRAT compared outcomes in 238 and 233 patients who underwent surgical clipping and endovascular coiling, respectively, finding no significant difference in functional outcomes for anterior circulation aneurysms [2]. However, for posterior circulation aneurysms, patients in the surgical clipping group had significantly worse outcomes (mRS score >2; OR, 5.09; 95% CI, 1.63–15.9; p=0.005).

Furthermore, a retrospective study found that postoperative third cranial nerve palsy was significantly more common in the microsurgical clipping group (7.7% [6/78] vs. 2.0% [3/153], p=0.01).

Surgical access is generally easier in anterior circulation aneurysms than in posterior ones; as such, clipping is performed more frequently than coiling. As studies indicate no significant difference in functional outcomes, either treatment method may be selected based on patient-specific factors.

However, in posterior circulation aneurysms, surgical access is more difficult, and securing an adequate operative space during clipping is challenging. Consequently, clipping tends to yield worse postoperative outcomes than coiling. Therefore, coiling should be prioritized for posterior circulation aneurysms whenever feasible.

Ultimately, treatment selection should not only consider aneurysm location but also complication risks, ensuring that the most appropriate approach is selected.

Poor-grade SAH

Patients with poor-grade SAH, defined as WFNS grades IV and V, present a substantial challenge in aneurysm management. The optimal treatment method remains elusive owing to controversial evidence [5]. Coiling may be advantageous in poorgrade patients owing to its less invasive nature and potential for faster recovery [7,36]. However, clipping has shown benefits in achieving more complete aneurysm occlusion and reducing rebleeding rates [8].

A multicenter study specifically focusing on poor-grade aneurysms found no significant difference in long-term outcomes between coiling and clipping in selected patients [5]. The choice between coiling and clipping for patients with poor-grade SAH should be based on multiple factors, including patient age, aneurysm location and morphology, presence of intraparenchymal hemorrhage, and available expertise at the treatment center.

Rebleeding and retreatment

Clipping and coiling are widely utilized treatment modalities for intracranial aneurysms, demonstrating efficacy in preventing rebleeding. However, a higher recurrence and retreatment rate has been observed in coiling.

The ISAT investigated the need for retreatment within 1 year among 2143 patients, reporting that 121 cases occurred after coiling, whereas only 33 occurred in the clipping group [8]. During the 1st year, rebleeding from the target aneurysm was reported in 45 patients undergoing coiling and 39 undergoing clipping. Beyond the 1st year, rebleeding was identified in seven patients in the coiling group, compared with only two in the clipping group. Although this difference was not significant, a higher recurrence rate following coiling was observed. The BRAT reported no rebleeding cases within the 1st year following coiling [3]. However, among 113 patients who underwent coiling, 12 (10.62%) required retreatment within the 1st year, a significantly higher rate than that observed in the clipping group (OR, 2.57; 95% CI, 0.98–6.55; p=0.03). In a 7-year followup study, the retreatment rate remained significantly higher in the coiling group, with 20% (23/115) of patients requiring additional intervention, compared with <1% (2/241) in the clipping group [10].

This highlights the need for long-term follow-up evaluations following coiling, as an increased risk of recurrence and retreatment may exist. Thus, adopting a patient-specific risk assessment strategy that considers factors such as age, aneurysm size, packing density ratio, and treatment modality is imperative. Regular imaging surveillance is recommended to monitor recurrence and guide clinical decision-making, ensuring optimal long-term outcomes after coiling [9,11-14].

Vasospasm

Vasospasm is a risk factor for complications in patients with SAH [15]. However, no clear consensus on the most effective treatment exists.

The ISAT randomly assigned 2,143 patients to either surgical clipping (n=1070) or endovascular coiling (n=1073) [16]. The incidence of vasospasm showed no significant differences between the two groups. Even in patients with poor-grade subarachnoid hemorrhage, no clear difference was observed in the incidence of vasospasm between the two treatment modalities [18].

Imamura et al. [19] analyzed nine studies comparing surgical clipping with endovascular coiling, reporting no significant difference in vasospasm risk techniques (risk ratio [RR], 1.21; 95% CI, 0.99–1.48). Jones et al. [20] reviewed eight RCTs involving 3585 patients with SAH (1792 underwent coiling, and 1773 underwent clipping). Their comprehensive quantitative analysis indicated that the coiling group had a significantly lower rate of vasospasm (OR, 0.58; 95% CI, 0.36–0.92; p=0.02).

Surgical clipping may contribute to hematoma removal in the arachnoid space, which could influence vasospasm development. Contrarily, endovascular coiling involves minimal manipulation of cerebral blood vessels, which aids in vasospasm prevention [21].

Given the conflicting findings across studies, the risk of vasospasm alone should not be the primary factor in treatment method selection [22-25]. The decision should be based on available resources, patient’s overall condition, and surgeon expertise to ensure selection of the most appropriate approach.

Shunt-dependent hydrocephalus

Hydrocephalus is a complication of SAH due to a ruptured aneurysm. In clipping, thick subarachnoid hematomas can be removed during surgery; however, this procedure may induce an inflammatory response in the arachnoid space. Coiling does not allow for the direct removal of thick subarachnoid hematomas but may have a relatively lesser direct impact on cerebrospinal fluid circulation.

To evaluate the impact of treatment modality on shunt-dependent hydrocephalus development, data were collected based on its established definition. Several studies have investigated the comparative effects of clipping and coiling on shunt-dependent hydrocephalus incidence; however, the findings remain inconclusive.

A meta-analysis including 10 high-quality studies revealed a significant higher incidence of shunt-dependent hydrocephalus in the clipping than in the coiling group (17.1% vs. 14.8%; RR, 1.16; 95% CI, 1.09–1.23) [26,27,29-35,37]. A single-center retrospective study by Zaidi et al. [38] showed a trend toward a higher incidence of shunt-dependent hydrocephalus in the clipping group; however, the difference was not significant (early surgery : 23.2% [29 of 125] vs. early endovascular treatment : 17.7% [11 of 62]; p=0.45). Zeng et al. [39] reported a higher incidence of shunt-dependent hydrocephalus in the clipping group than in the coiling group; however, the difference was not significant (clipping vs. coiling: 37.1% vs. 29.7%).

Zhao et al. [40] conducted a meta-analysis on shunt-dependent hydrocephalus incidence based on treatment modality (clipping vs. coiling) in patients with SAH. The analysis included 13 studies with 13751 patients (8444 clipped and coiled aneurysms, respectively), reporting no significant difference between the groups (clipping vs. coiling, 11.4% vs. 12.0%, respectively; RR, 0.92; 95% CI, 0.84–1.01). This trend persisted when RCTs were analyzed separately (shunt-dependent hydrocephalus rate : clipping vs. coiling, 23.3% vs. 20.1%; RR, 1.12; 95% CI, 0.91–1.38). Ultimately, the direct impact of clipping and coiling on shunt-dependent hydrocephalus incidence remains controversial and inconclusive. The predictability of hydrocephalus does not appear to be a primary factor in treatment modality selection. Individual patient characteristics, aneurysm location, and institutional expertise should be prioritized when selecting the optimal intervention strategy.

Status of emergency transfers and hospital selection for treatable conditions in South Korea

Between February 26 and December 31, 2024, 650 cardiovascular and cerebrovascular emergency patients were transferred nationwide via the regional network provided by the National Cardiovascular Center. Among them, 244 (37.5%) were hemorrhagic strokes, 213 (32.8%) were ischemic strokes, 164 (25.2%) were myocardial infarctions, and 29 (4.5%) were aortic syndromes. The ratio of hemorrhagic to ischemic stroke cases transferred through the platform was 1.15 : 1. By region, hemorrhagic stroke referrals exceeding 20 cases per year occurred in the following order : Gyeonggi, Seoul, Jeonnam, Daegu, Gangwon, and Busan (source : Kang-min Kim). These results indicate a high demand for hospitals capable of performing both craniotomy and endovascular procedures and the urgent need for neurosurgeons on duty. In fact, a national survey in Korea showed that neurosurgeons were responsible for nearly 100% of key treatments for cerebral hemorrhages—including craniotomies, endovascular procedures, and patient care—and that a high dependence on on-call specialists existed [41].

In SAH, promptly occluding the cerebral aneurysm is crucial, making rapid medical judgment and the choice of a hospital capable of either coiling or clipping treatment extremely important. As such, the KSCVS has implemented a certification system for cerebrovascular surgeons capable of performing clipping procedures (https://www.kscvs.org/certification/index1.html?gubun=4; Supplementary Table 2). Further, the KoNES has established certification systems for neuro-endovascular surgeons and stroke intervention-certified hospitals capable of performing coiling procedures (https://www.konesonline.or.kr/certification/certiList.php; Supplementary Table 3).

As of November 29, 2024, 311 certified stroke interventionists and 106 certified institutions existed. In Korea, the treatment of SAH is structured around a system of certified hospitals and qualified specialists. Based on this infrastructure, a cooperative network—comprising KSCVS, KoNES, KSEM, and the Ministry of Health and Welfare—has been established to facilitate the timely transfer and management of SAH patients. This national collaboration plays a vital role in improving public health outcomes for patients with SAH.

Following expert consensus, the following recommendation can be made. When a hospital is equipped to perform both clipping and coiling procedures, coiling is considered as one of the initial treatment options, as well as clipping. Both clipping and coiling are appropriate and standard initial treatments for SAH. Therefore, the optimal treatment strategy should be determined by a neurosurgical specialist, considering the specific clinical situation and institutional capabilities of hospitals. This approach could help reduce overcrowding in the emergency departments of specific hospitals. Effective coordination between certified physicians and institutions and the national emergency service (119) is crucial for faster and more efficient patient transfers.