Impact of Tortuosity of the V1-Segment Vertebral Artery on Mechanical Thrombectomy

Impact of Tortuosity of the V1-Segment Vertebral Artery on Mechanical Thrombectomy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Impact of Tortuosity of the V1-Segment Vertebral Artery on Mechanical Thrombectomy Zhoucheng Kang, Hanghang Zhao, Dong Wei, Yang Li, Rui Shi, Li Li This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4766966/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Dec, 2024 Read the published version in Scientific Reports → Version 1 posted 16 You are reading this latest preprint version Abstract Background and Objective Tortuosity of the vasculature poses challenges to mechanical thrombectomy (MT); however, only a few studies have reported the impact of vertebral artery (VA) tortuosity on MT. The present study aimed to investigate the impact of tortuosity of the V1-segment VA on MT in patients with acute vertebrobasilar artery occlusion (AVBAO). Methods The patients diagnosed with AVBAO and treated with MT in the Stroke Center of Xijing Hospital from November 2019 to March 2022 were analyzed retrospectively. According to the tortuosity of V1-segment VA, patients were divided into tortuous (coiling and kinking) and non-tortuous groups (straight, single-arc, and multi-arc). A binary logistic regression model was established to analyze the association between the tortuosity of V1-segment VA and successful reperfusion (mTICI ≥ 2b), neurological improvement at 7 days, favorable and poor outcome at 90 days, and symptomatic intracranial hemorrhage (ICH) within 24 h. After adjustment for age, baseline National Institute of health stroke scale (NIHSS) score and puncture-to-recanalization time, the impact of tortuosity of the V1-segment VA on outcomes was analyzed. Results After screening, 35 patients were enrolled in this study. The overall rate of successful reperfusion was 74.3% (26/35), and 40% (14/34) patients achieved favorable outcomes at 90 days. Subsequently, 15/35 (42.9%) patients were included in the tortuous group, and the remaining 20 patients comprised the non-tortuous group. After adjustment for age, baseline NIHSS score, and puncture-to-recanalization time, the rate of 90-day favorable outcome in the tortuous group was significantly lower than that of the non-tortuous group (20% vs . 57.9%, P = 0.034), while the rates of reperfusion (80% vs . 73.7%) and 7-day neurological improvement (33.3% vs . 36.8%) were similar between the two groups. The incidence of 24-h symptomatic ICH in the tortuous group was higher than that in the non-tortuous group (26.7% vs . 15.8%), albeit not significantly. Conclusion In patients with AVBAO, tortuosity of the V1-segment VA was negatively associated with favorable outcomes 90 days after MT. Biological sciences/Neuroscience/Diseases of the nervous system Biological sciences/Neuroscience Health sciences/Medical research ischemic stroke acute vertebrobasilar artery occlusion mechanical thrombectomy vertebral artery tortuosity Figures Figure 1 Figure 2 1 Introduction Compared to acute anterior circulation occlusion, acute vertebrobasilar artery occlusion (AVBAO)-related ischemic stroke is associated with higher rates of disability and mortality. 1 Neither BEST 2 nor BASICS 3 demonstrated that patients with AVBAO would benefit from endovascular treatment (EVT). BASILAR 4 is a multicenter prospective registry study, suggesting that EVT improves clinical outcomes. Despite the lack of high-grade medicine-based evidence, EVT has been widely carried out in clinical practice to assess the disastrous consequences for patients with AVBAO. 1 Until May 2022, BAOCHE 5 study presented at the European Stroke Organization Conference (ESOC 2022) provided evidence-based proof for the posterior circulation EVT, showing that EVT significantly improved the 90-day clinical outcomes compared to the best medical treatment (46.4% vs . 24.3%). Although the technical success rate is about 85%, the benefit rate is only 32–44%. 3, 4 Several studies have shown that prolonged time of reperfusion is a major factor affecting the outcomes of EVT 2, 6 ; therefore, the recanalization of occluded vessels is the primary target of EVT. Tortuous vascular paths are the common causes of complications and even mechanical thrombectomy (MT) failure. The tortuous vascular anatomy hinders the smooth passage of microwires and microcatheters and prolongs the time of reperfusion. 7 In addition, during the pull-back process, the tortuous vessels may lead to the deformation and even collapse of the stent retrievers or aspiration catheters, which would reduce the combination power between the thrombectomy device and thrombosis and reduce the possibility of achieving the mTICI 2b/3 reperfusion. 8 Different from the MT of anterior circulation occlusion, bilateral vertebral arteries can be used as a path to the basilar artery for MT; however, up to 64% of patients with AVBAO have unilateral or bilateral extracranial vertebral artery (VA) stenosis or occlusion, 9 which greatly increases the difficulty of MT. Although the anatomic configuration of V1 segment of the VA has been classified previously, 10 the impact of tortuosity of the V1-segment VA on MT has not yet been reported. This study retrospectively analyzed the patients with AVBAO undergoing MT in the Stroke Center of Xijing Hospital, aiming to investigate the association between the tortuosity of the V1-segment VA and outcomes of MT. 2 Methods 2.1 Study subjects Patients with AVBAO undergoing MT in the Stroke Center of Xijing Hospital from November 2019–March 2022 were consecutively enrolled in this study. The institutional review boards of Xijing Hospital approved the trials (KY20212150-C-1), and written informed consent was obtained from enrolled patients or their surrogates for endovascular treatment (EVT). All methods were performed in accordance with relevant guidelines and regulations. Written informed consent for registration was waived because the study was retrospective in nature and utilized anonymized data. Inclusion criteria: ( 1 ) ≥ 18-years-old; ( 2 ) acute occlusion of the basilar artery or the intracranial VArtery resulting in no forward flow to the basilar artery confirmed by digital subtraction angiography; ( 3 ) MT was performed within 24 h after onset. Exclusion criteria were as follows: ( 1 ) patients who underwent intracranial angioplasty or stenting at the same time; ( 2 ) patients with spontaneous recanalization or no occlusion of the basilar artery by angiography; ( 3 ) patients who only underwent angiography without MT because of the difficulty of placing the microwire or microcatheter or for other reasons; ( 4 ) patients with tandem vertebrobasilar artery occlusion (extracranial VA recanalization or angioplasty must be performed before MT); ( 5 ) incomplete baseline data. 2.2 Mechanical thrombectomy All patients were treated with local anesthesia and conscious sedation. Angiographic catheters were used to identify the vascular pathways and vertebrobasilar artery occlusion, and carotid angiography was used to assess collateral compensation. The MT procedure consisted of stent retriever thrombectomy, thrombus aspiration, or a combination of the two approaches. The aspiration catheters include Sofia (MicroVention, USA) and Catlyst (Stryker, USA), and the stent retrievers include Solitaire (EV3 USA) and Trevo XP Provue (Stryker). Typically, MT is performed less than three times. All endovascular procedures were performed by an experienced neurointervention team. The head computed tomography (CT) scan was performed immediately after MT. 2.3 Baseline data collection The following data were collected: age, sex, medical history (hypertension, diabetes, coronary heart disease, atrial fibrillation, and previous stroke), smoking, drinking, stroke etiologic classification, onset to groin puncture time, admission to groin puncture time, groin puncture to recanalization time, neurological deficits, and intravenous thrombolysis. The National Institution of Health Stroke Scale (NIHSS) 11 was used to assess the degree of neurological deficits. According to TOAST 12 classification, the etiologies of stroke were classified into large artery atherosclerosis, cardiogenic embolism, and other etiologies. 3.4 V1-segment vertebral artery tortuosity Classification of the V1-segment VA tortuosity was conducted independently by two experienced neurointerventionists. In case of disputes, another neurointerventionist was invited to review the radiographs and determine the classification. All the experts were blinded to clinical data. According to the classification of extracranial internal carotid artery (ICA) tortuosity, 13 the V1-segment VA was classified as follows: straight, single-arc tortuosity (single curve), multi-arc tortuosity (≥ 2 arcs, S-shaped curve or wave-shaped curve), coiled (folded VA forming arterial loop), and kinked (folded VA forming acute [< 90°] angulation) (Fig. 1 ). Previous studies have shown that when the folded VA forms an arterial loop or acute angulation, the hemodynamics of VA are significantly disordered. 10 Therefore, in this study, patients were divided into two groups (tortuous and non-tortuous) according to the tortuous degree of V1-segment VA. The tortuous group included patients with coiled or kinked VA, while other patients were included in the non-tortuous group. 2.5 Outcomes The outcomes included successful reperfusion, post-stroke neurological improvement at 7 days, favorable outcomes and poor outcomes, and symptomatic ICH within 24 h post-operation. The modified thrombolysis in cerebral infarction (mTICI) scale was used to evaluate the reperfusion after MT, and successful reperfusion was defined as the achievement of mTICI score 2b/3. 14 The neurological improvement was defined as a ≥ 10-point decrease of the NIHSS score from baseline or the score of 0 at 7 days from onset. 15 Head CT was used to evaluate the ICH within 24 h post-operation, including parenchymal hemorrhage and subarachnoid hemorrhage. Symptomatic ICH was defined as intracranial hemorrhage-associated neurological deterioration with ≥ 4-point increase in the NIHSS score. 16 The functional prognosis was evaluated by modified Rankin scale (mRS). 17 At 90 days post-operation, the mRS scores were assessed by experienced neurologists by telephone or outpatient follow-up to evaluate the functional prognosis of the patients. The mRS scores of 0–2 and 5–6 were defined as favorable and poor outcomes, respectively. 15 2.6 Statistical analysis Herein, we compared the baseline characteristics, treatment profiles, and outcomes between the tortuous and the non-tortuous groups. Means ± standard deviations ( \(\:\stackrel{-}{X}\pm\:S)\) were calculated for continuous variables with normal distribution, and t -test was used for comparison between groups. Median and quartiles [ M ( P 25 , P 75 )] were used for continuous skewed distribution, and Mann-Whitney U test was used for comparison between groups. Categorical parameters were presented as numbers and percentages, and chi-square test or Fisher’s exact test was performed for comparison between groups. Binary logistic regression models were established to analyze the statistical association between the tortuosity of the V1 segment VA and each outcome, and the odds ratios (OR) with 95% confidence intervals (CIs) were calculated for the tortuous group using the non-tortuosity group as the reference. After adjustment for age, baseline NIHSS score, and groin puncture to reperfusion time, the impact of tortuosity of the V1-segment VA on each outcome was analyzed. Cohen’s kappa coefficient was used to analyze the consistency of VA classification between the two experts. Two-sided P <0.05 was considered significant. Statistical analyses were carried out using the SPSS software package (version 25.0). 3 Results 3.1 Patients’ characteristics From November 2019–March 2022, a total of 35 patients (21 men [60%]; median age, 65 [52, 70] years; median NIHSS score, 18.5 [6.75, 32.75]) were included in this study. A total of 12 patients (34.3%) underwent intravenous thrombolysis (IVT) prior to MT. Ten patients (28.6%) were treated by thrombus aspiration, and 25 patients were treated by stent retriever combined with aspiration thrombectomy. Of the 35 patients, 18 (51.4%) had large artery atherosclerosis, 14 (40%) presented cardiogenic embolism, and the remaining 3 (8.6%) showed other etiologies. Successful reperfusion (final mTICI score ≥ 2b) was achieved in 26 patients (74.3%); the median time from groin puncture to reperfusion was 135 min (95,210). 3.2 Comparison of baseline data between groups In the present study, Cohen’s Kappa coefficient was used to analyze the consistency of two experts’ evaluation of tortuosity of the V1-segment VA in 35 patients. Both experts agreed that 10 patients should be assigned to the tortuous group and 18 to the non-tortuous group. However, 3 patients were identified as a tortuous group by expert 1, but as non-tortuous group by expert 2; also, 4 patients were identified as a tortuous group by expert 2, but non-tortuous by expert 1. The overall Cohen’s kappa coefficient was 0.578 ( P = 0.001), showing moderate consistency. The discussion was required for 7 cases; 5 were classified as the tortuous group and 2 as the non-tortuous group. Finally, 15 (42.9%) patients were included in the tortuous group, and the remaining 20 (57.1%) in the non-tortuous group. After stratification by group, the time from admission to groin puncture in the non-tortuous group was longer than that in the tortuous group (46 min vs . 32 min, P = 0.039). Notably, compared to the non-tortuous group, the tortuous group had a higher median age (68 years vs . 63 years), higher baseline NIHSS score (24.5 vs . 18), and longer time from groin puncture to reperfusion (165 min vs . 125 min), although the differences were not statistically significant. Factors, such as medical history, classification of etiology, thrombectomy method, and intravenous thrombolysis, were similar between groups (Table 1 ). Table 1 Comparison of baseline characteristics between groups All (n = 35) Tortuous group (n = 15) non-Tortuous group (n = 20) P Age, years 65.0 (52.0, 70.0) 68.0 (57.0, 74.0) 63.0 (47.0, 67.0) 0.067 Men 21 (60.0%) 7 (46.7%) 14 (70.0%) 0.163 Smoking 13 (37.1%) 6 (40.0%) 7 (35.0%) 0.762 Drinking 4 (11.4%) 1 (6.7%) 3 (15.0%) 0.619 Hypertension 17 (48.6%) 6 (40.0%) 11 (55.0%) 0.380 Diabetes 10 (28.6%) 5 (33.3%) 5 (25.0%) 0.712 Coronary heart disease 3 (8.6%) 1 (6.7%) 2 (10.0%) 1.000 Atrial fibrillation 5 (14.3%) 3 (20.0%) 2 (10.0%) 0.631 Previous stroke 7 (20.0%) 3 (20.0%) 4 (20.0%) 1.000 Etiology of stroke 0.771 Large artery atherosclerotic 18 (51.4%) 7 (46.7%) 11 (55.0%) Cardiac embolism 14 (40.0%) 7 (46.7%) 7 (35.0%) Other or unknown 3 (8.6%) 1 (6.6%) 2 (10.0%) MT strategy 0.276 Aspiration 10 (28.6%) 6 (40.0%) 4 (20.0%) Aspiration + stent retriever 25 (71.4%) 9 (60.0%) 16 (80.0%) Intravenous thrombolysis 12 (34.3%) 4 (26.7) 8 (42.1) 0.350 Time from onset to puncture 330.0 (271.3, 454.0) 330.0 (255.0, 437.0) 330.0 (275.0, 505.0) 0.837 Time from door to puncture 42.0 (26.0, 53.0) 32.0 (22.0, 44.0) 46.0 (32.0, 80.0) 0.039 Time from puncture to reperfusion 135.0 (95.0. 210.0) 165.0 (100.0, 205.0) 125.0 (65.0, 210.0) 0.151 Baseline NIHSS score 18.5 (6.8, 32.8) 24.5 (6.5, 32.8) 18.0 (8.0, 35.0) 0.821 NIHSS score at 24 h 16.0 (3.5, 25.0) 9.0 (2.0, 33.5) 17.0 (7.0, 24.0) 0.957 Data are n (%) or median (P25, P75); NIHSS, National Institutes of Health Stroke Scale. 3.3 Comparison of outcomes between groups Table 2 shows the rate of favorable outcomes in the tortuous group was significantly lower than that in the non-tortuous group (20% vs . 57.9%), and the difference was statistically significant after adjustment for age, baseline NIHSS score, and the time from groin puncture to reperfusion ( P = 0.034). The rates of successful recanalization, poor outcomes, and neurological improvement at 7 days did not reach statistical significance. The rate of symptomatic ICH was higher in the tortuous group than in the non-tortuous group (26.7% vs . 15.8%), although not significantly. Figure 2 shows the overall distribution of the mRS scores at 90 days in the tortuous and non-tortuous groups. Table 2 Comparison of outcomes between groups Tortuous group (n = 15) non-Tortuous group (n = 20) Unadjusted Adjusted OR (95% CI) P OR (95% CI) P mTICI score 2b/3 12 (80.0) 14 (73.7) 1.429 (0.281–7.261) 0.667 1.014 (0.166–6.202) 0.988 Favorable outcome 3 (20.0) 11 (57.9) 0.182 (0.038–0.864) 0.032 0.106 (0.013–0.846) 0.034 Poor outcome 8 (53.3) 6 (31.6) 2.476 (0.610–10.058) 0.205 2.461 (0.489–12.392) 0.275 Neurological improvement at 7 d 5 (33.3) 7(36.8) 1.167 (0.282–4.835) 0.832 0.603 (0.094–3.854) 0.593 Symptomatic ICH within 24 h 4 (26.7) 3 (15.8) 1.939 (0.361–10.430) 0.440 1.344 (0.187–9.678) 0.769 mTICI, modified thrombolysis in cerebral infarction scale; NIHSS, National Institutes of Health Stroke Scale; ICH, intracranial hemorrhage; Adjusted for age, baseline NIHSS score, and time from puncture to reperfusion. 4 Discussion Hitherto, only a few studies have reported data on the impact of tortuosity of the V1-segment VA on MT outcomes in patients with AVBAO. The main finding of this study was that the rate of favorable outcome at 90 days was significantly lower in patients with than without coiled or kinked V1-segment VA ( P = 0.034). The tortuous group had a higher incidence of symptomatic ICH than the non-tortuous group (26.7% vs . 15.8%). The rate of successful reperfusion did not differ between the groups. In the present study, none of the baseline characteristics showed statistical differences, except for the time from admission to groin puncture. Notably, the age and female proportion of patients in the tortuous group were higher than those in the non-tortuous group, which is consistent with previous studies. 18 Also, the stroke severity was higher in the tortuous group than in the non-tortuous group (baseline NIHSS score of 24.5 vs . 18), which might be due to the older age and multiple comorbidities. The groin puncture to reperfusion time was longer in the tortuous group than in the non-tortuous group (165 min vs . 125 min), which was considered to be one of the factors leading to poor outcomes. 15 In addition, the shorter time from admission to groin puncture (32 min vs . 46 min) in the tortuous group might reduce the difference in the clinical outcomes between the groups. The difference in clinical outcomes between groups may be the result of the combined effect of clinical characteristics. In the present study, a large difference was detected quantitatively in some baseline parameters between groups, but it did not reach statistical significance, which was related to the small sample size. Furthermore, the rates of successful reperfusion were similar between groups (80% vs . 73.3%, P = 0.998), but the rate of favorable outcomes of the tortuous group was significantly lower than that of the non-tortuous group, which may be related to futile recanalization after MT. Futile recanalization refers to the failure of patients to achieve functional independence at 90 days after MT (mRS score > 2) despite successful recanalization of occluded vessels on imaging (mTICI 2b/3). 19 RESCUE-RE 6 showed that the rate of futile recanalization after MT in patients with acute ischemic stroke was up to 49%. BEST 2 showed that 46% of patients with AVBAO, who received EVT within 8 h after symptom onset, underwent futile recanalization. ANGEL-ACT 20 is a real-world study comparing the safety and efficacy of MT vs . combined IVT and MT, suggesting that futile recanalization after MT was associated with advanced age, high baseline NIHSS score, and prolonged recanalization time. In this study, the overall rate of futile recanalization was 57.7% (15/26): 66.7% (8/12) in the tortuous group and 50% (7/14) in the non-tortuous group. The high rate of futile recanalization in the tortuous group may be related to older age, high baseline NIHSS scores, and prolonged recanalization time. With the improvement in devices, we might be able to successfully navigate tortuous vessels and establish a stable thrombectomy path in most cases, potentially at the expense of prolonged recanalization time. Another previous study has shown that extracranial internal carotid artery (ICA) tortuosity is not correlated to the number of thrombectomies and successful recanalization but is correlated with neurological improvement. 21 Similar conclusions were reached in this study, the rates of successful recanalization were similar between groups, but the rate of favorable outcomes at 90 days in the tortuous group was significantly lower than that in the non-tortuous group. This phenomenon indicated that further shortening the time from onset to recanalization may be crucial to improving the outcomes of patients with AVBAO. Previous studies have shown that aspiration catheters and stent retrievers damage the intima and artery walls. 22 Excessive tortuous vessels increase the difficulty of the intravascular operation and passage times, as well as the risk of vascular injury. In addition, excessive tortuous vessels prolong the operation time and the recovery time of cerebral blood perfusion, which further aggravates the damage to the blood-brain-barrier. It is prone to reperfusion injury following successful recanalization, which increases the risk of symptomatic ICH. 23 The present study showed that there was no significant difference in the incidence of symptomatic ICH between groups. A recent study from Japan demonstrated that although ICA tortuosity was associated with ICH after MT, it was not associated with symptomatic ICH. 15 This negative result could be attributed to the small sample size of symptomatic ICH. Currently, only 7 cases of symptomatic ICH have been reported in the present study, and only 14 were included in the Japanese study. How to improve the favorable outcomes of patients with VA tortuosity after MT is challenging in clinical practice, and only a few studies have addressed this concern. When the aspiration catheter or stent retriever is pulled back, excessive tortuous vessels lead to the deformation or even collapse of the thrombectomy device, thus weakening the combination power between the device and thrombus, resulting in the rupture and escape of thrombus and even failure of MT. 15 In the future, how to overcome the adverse effects of vascular tortuosity on MT might become an effective means to improve the outcomes of patients. Notably, the vascular tortuosity can be straightened out by stenting or surgery; 24 on the other hand, the design of thrombectomy devices should be updated to improve the performance to adapt to different vascular anatomy. 25 Nevertheless, the present study has several limitations. First, this was a single-center retrospective study, and the inherent bias could not be avoided. Second, to avoid the influence of device updates on the results, the time span of the cases included in this study was short; hence, the sample size was small, which may lead to the instability of the results. Third, tortuosity in other relevant vessels, especially V3-segment VA was not assessed. The unevaluated confounding factors may affect the results. Thus, large-scale clinical trials are needed to study the effect of VA tortuosity on MT in the future. 5 Conclusions The tortuosity of V1-segment VA was independently associated with a lower rate of favorable outcome at 90 days following MT. The tortuosity of V1-segment VA had no significant effect on successful reperfusion and symptomatic ICH. Improving device performance to accommodate the tortuous vessels or straightening out the tortuous vascular anatomy may be an effective tool to improve the outcomes of MT. Declarations Competing interests The authors declare no conflicts of interest. Patient consent for publication Not applicable. Funding This study was funded by the Xijing Hospital’s Discipline Booster Program (XJZT19Z24). Author Contribution Zhou-cheng Kang, Hang-hang Zhao: Conception and design of the study. Data Curation. Data and statistical analysis. Writing- Original Draft. Writing - Review & Editing. Rui Shi: The operation assistant. Conception and design of the study. Data Curation. Supervision. Writing - Review &Editing. Dong Wei: Primary operator. Yang Li and Li Li: The operation assistant. Acknowledgements We gratefully thank Dr. Shuai Kang of department of Stomatology, the 989th Hospital for his contribution to the statistical support. Data Availability Data are available upon reasonable request. Data related to the analysis are available to researchers on request to reproduce the results or replicate the procedure by directly contacting the corresponding author. References Buchman SL, Merkler AE. Basilar Artery Occlusion: Diagnosis and Acute Treatment. Current treatment options in neurology 2019;21:45. Liu X, Dai Q, Ye R, et al. Endovascular treatment versus standard medical treatment for vertebrobasilar artery occlusion (BEST): an open-label, randomised controlled trial. The Lancet Neurology 2020;19:115–122. Langezaal LCM, van der Hoeven E, Mont'Alverne FJA, et al. Endovascular Therapy for Stroke Due to Basilar-Artery Occlusion. The New England journal of medicine 2021;384:1910–1920. Zi W, Qiu Z, Wu D, et al. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4766966","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":341768617,"identity":"d0f7d8e8-0a32-424c-b65d-d75b21f3df29","order_by":0,"name":"Zhoucheng Kang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAqElEQVRIiWNgGAWjYFCCBGYgYcPDz99AmpY0GckZB0jTctjGoCGBSA3m7OmPDX/UnOcxYDjA+OFjDhFaLHveGCdIHLvNY87cwCw5cxsRWgxu5DAfMGy4zWPZcICNmZc4LemPDyQ2nOMxOJBAtJYE44SDDQdI0ALyi2HDsWQeyRkHm4nzCyjEJH/U2Nnz8zcf/PCRKIchmIwNRKhH1TIKRsEoGAWjAAcAAHvPNjo2po49AAAAAElFTkSuQmCC","orcid":"","institution":"No.989 Hospital of Joint Logistic Support Force of PLA","correspondingAuthor":true,"prefix":"","firstName":"Zhoucheng","middleName":"","lastName":"Kang","suffix":""},{"id":341768618,"identity":"f7f20cd3-29c7-4d06-8115-aae9637bd1e3","order_by":1,"name":"Hanghang Zhao","email":"","orcid":"","institution":"the First Affiliated Hospital of Air Force Medical University","correspondingAuthor":false,"prefix":"","firstName":"Hanghang","middleName":"","lastName":"Zhao","suffix":""},{"id":341768619,"identity":"447bc220-db64-48a3-a977-d60aa639d06b","order_by":2,"name":"Dong Wei","email":"","orcid":"","institution":"the First Affiliated Hospital of Air Force Medical University","correspondingAuthor":false,"prefix":"","firstName":"Dong","middleName":"","lastName":"Wei","suffix":""},{"id":341768620,"identity":"aea2e297-c458-4178-91c7-37ca34d34b72","order_by":3,"name":"Yang Li","email":"","orcid":"","institution":"the First Affiliated Hospital of Air Force Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"Li","suffix":""},{"id":341768621,"identity":"ce1dcbdf-6de9-4050-a5ec-b1568ab6ddb7","order_by":4,"name":"Rui Shi","email":"","orcid":"","institution":"the First Affiliated Hospital of Air Force Medical University","correspondingAuthor":false,"prefix":"","firstName":"Rui","middleName":"","lastName":"Shi","suffix":""},{"id":341768622,"identity":"297f213d-d60f-4deb-8050-daa75f28a926","order_by":5,"name":"Li Li","email":"","orcid":"","institution":"Xi’an International Medical Center Hospital，Xi’an","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2024-07-19 08:20:59","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4766966/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4766966/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-80396-0","type":"published","date":"2024-12-02T15:57:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":63280126,"identity":"92a9be7c-8e22-4e74-9e48-4cabc881ec23","added_by":"auto","created_at":"2024-08-26 12:49:16","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":98890,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eClassification of the V1-segment VA.\u003c/strong\u003e The V1-segment VA was classified into five types as follows: straight, single-arc tortuosity (single curve), multi-arc tortuosity (≥2 arcs, S-shaped curve or wave-shaped curve), coiled (folded VA forming an arterial loop), and kinked (folded VA forming acute [\u0026lt;90°] angulation).\u003c/p\u003e","description":"","filename":"figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4766966/v1/12b05c5d143b8b7e720f422a.jpg"},{"id":63280127,"identity":"03b3b110-72aa-4309-986d-551ab7698c5b","added_by":"auto","created_at":"2024-08-26 12:49:16","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":77982,"visible":true,"origin":"","legend":"\u003cp\u003eFunctional outcomes in the tortuous and the non-tortuous groups at 90 days. Functional outcome was evaluated by mRS score at 90 days post-operation. Score range: 0–6, with the higher score indicating greater disability; 0 indicating no symptoms at all, and 6 indicating death. mRS, modified Rankin scale.\u003c/p\u003e","description":"","filename":"figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4766966/v1/4f631e8e169c529fbf65023b.jpg"},{"id":70964775,"identity":"d34bf106-5c11-4d48-a68e-7c240ed62c70","added_by":"auto","created_at":"2024-12-09 16:15:43","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":708951,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4766966/v1/0352972d-c3eb-486c-9d21-700c071f57dd.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of Tortuosity of the V1-Segment Vertebral Artery on Mechanical Thrombectomy","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eCompared to acute anterior circulation occlusion, acute vertebrobasilar artery occlusion (AVBAO)-related ischemic stroke is associated with higher rates of disability and mortality.\u003csup\u003e1\u003c/sup\u003e Neither BEST\u003csup\u003e2\u003c/sup\u003e nor BASICS\u003csup\u003e3\u003c/sup\u003e demonstrated that patients with AVBAO would benefit from endovascular treatment (EVT). BASILAR\u003csup\u003e4\u003c/sup\u003e is a multicenter prospective registry study, suggesting that EVT improves clinical outcomes. Despite the lack of high-grade medicine-based evidence, EVT has been widely carried out in clinical practice to assess the disastrous consequences for patients with AVBAO.\u003csup\u003e1\u003c/sup\u003e Until May 2022, BAOCHE\u003csup\u003e5\u003c/sup\u003e study presented at the European Stroke Organization Conference (ESOC 2022) provided evidence-based proof for the posterior circulation EVT, showing that EVT significantly improved the 90-day clinical outcomes compared to the best medical treatment (46.4% \u003cem\u003evs\u003c/em\u003e. 24.3%). Although the technical success rate is about 85%, the benefit rate is only 32\u0026ndash;44%.\u003csup\u003e3, 4\u003c/sup\u003e Several studies have shown that prolonged time of reperfusion is a major factor affecting the outcomes of EVT\u003csup\u003e2, 6\u003c/sup\u003e; therefore, the recanalization of occluded vessels is the primary target of EVT.\u003c/p\u003e \u003cp\u003eTortuous vascular paths are the common causes of complications and even mechanical thrombectomy (MT) failure. The tortuous vascular anatomy hinders the smooth passage of microwires and microcatheters and prolongs the time of reperfusion.\u003csup\u003e7\u003c/sup\u003e In addition, during the pull-back process, the tortuous vessels may lead to the deformation and even collapse of the stent retrievers or aspiration catheters, which would reduce the combination power between the thrombectomy device and thrombosis and reduce the possibility of achieving the mTICI 2b/3 reperfusion.\u003csup\u003e8\u003c/sup\u003e Different from the MT of anterior circulation occlusion, bilateral vertebral arteries can be used as a path to the basilar artery for MT; however, up to 64% of patients with AVBAO have unilateral or bilateral extracranial vertebral artery (VA) stenosis or occlusion,\u003csup\u003e9\u003c/sup\u003e which greatly increases the difficulty of MT. Although the anatomic configuration of V1 segment of the VA has been classified previously,\u003csup\u003e10\u003c/sup\u003ethe impact of tortuosity of the V1-segment VA on MT has not yet been reported. This study retrospectively analyzed the patients with AVBAO undergoing MT in the Stroke Center of Xijing Hospital, aiming to investigate the association between the tortuosity of the V1-segment VA and outcomes of MT.\u003c/p\u003e"},{"header":"2 Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study subjects\u003c/h2\u003e \u003cp\u003ePatients with AVBAO undergoing MT in the Stroke Center of Xijing Hospital from November 2019\u0026ndash;March 2022 were consecutively enrolled in this study. The institutional review boards of Xijing Hospital approved the trials (KY20212150-C-1), and written informed consent was obtained from enrolled patients or their surrogates for endovascular treatment (EVT). All methods were performed in accordance with relevant guidelines and regulations. Written informed consent for registration was waived because the study was retrospective in nature and utilized anonymized data.\u003c/p\u003e \u003cp\u003eInclusion criteria: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;\u0026ge;\u0026thinsp;18-years-old; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) acute occlusion of the basilar artery or the intracranial VArtery resulting in no forward flow to the basilar artery confirmed by digital subtraction angiography; (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) MT was performed within 24 h after onset. Exclusion criteria were as follows: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) patients who underwent intracranial angioplasty or stenting at the same time; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) patients with spontaneous recanalization or no occlusion of the basilar artery by angiography; (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) patients who only underwent angiography without MT because of the difficulty of placing the microwire or microcatheter or for other reasons; (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) patients with tandem vertebrobasilar artery occlusion (extracranial VA recanalization or angioplasty must be performed before MT); (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e) incomplete baseline data.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Mechanical thrombectomy\u003c/h2\u003e \u003cp\u003eAll patients were treated with local anesthesia and conscious sedation. Angiographic catheters were used to identify the vascular pathways and vertebrobasilar artery occlusion, and carotid angiography was used to assess collateral compensation. The MT procedure consisted of stent retriever thrombectomy, thrombus aspiration, or a combination of the two approaches. The aspiration catheters include Sofia (MicroVention, USA) and Catlyst (Stryker, USA), and the stent retrievers include Solitaire (EV3 USA) and Trevo XP Provue (Stryker). Typically, MT is performed less than three times. All endovascular procedures were performed by an experienced neurointervention team. The head computed tomography (CT) scan was performed immediately after MT.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Baseline data collection\u003c/h2\u003e \u003cp\u003eThe following data were collected: age, sex, medical history (hypertension, diabetes, coronary heart disease, atrial fibrillation, and previous stroke), smoking, drinking, stroke etiologic classification, onset to groin puncture time, admission to groin puncture time, groin puncture to recanalization time, neurological deficits, and intravenous thrombolysis. The National Institution of Health Stroke Scale (NIHSS)\u003csup\u003e11\u003c/sup\u003e was used to assess the degree of neurological deficits. According to TOAST\u003csup\u003e12\u003c/sup\u003e classification, the etiologies of stroke were classified into large artery atherosclerosis, cardiogenic embolism, and other etiologies.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.4 V1-segment vertebral artery tortuosity\u003c/h2\u003e \u003cp\u003eClassification of the V1-segment VA tortuosity was conducted independently by two experienced neurointerventionists. In case of disputes, another neurointerventionist was invited to review the radiographs and determine the classification. All the experts were blinded to clinical data. According to the classification of extracranial internal carotid artery (ICA) tortuosity,\u003csup\u003e13\u003c/sup\u003e the V1-segment VA was classified as follows: straight, single-arc tortuosity (single curve), multi-arc tortuosity (\u0026ge;\u0026thinsp;2 arcs, S-shaped curve or wave-shaped curve), coiled (folded VA forming arterial loop), and kinked (folded VA forming acute [\u0026lt;\u0026thinsp;90\u0026deg;] angulation) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePrevious studies have shown that when the folded VA forms an arterial loop or acute angulation, the hemodynamics of VA are significantly disordered.\u003csup\u003e10\u003c/sup\u003e Therefore, in this study, patients were divided into two groups (tortuous and non-tortuous) according to the tortuous degree of V1-segment VA. The tortuous group included patients with coiled or kinked VA, while other patients were included in the non-tortuous group.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Outcomes\u003c/h2\u003e \u003cp\u003eThe outcomes included successful reperfusion, post-stroke neurological improvement at 7 days, favorable outcomes and poor outcomes, and symptomatic ICH within 24 h post-operation. The modified thrombolysis in cerebral infarction (mTICI) scale was used to evaluate the reperfusion after MT, and successful reperfusion was defined as the achievement of mTICI score 2b/3.\u003csup\u003e14\u003c/sup\u003e The neurological improvement was defined as a\u0026thinsp;\u0026ge;\u0026thinsp;10-point decrease of the NIHSS score from baseline or the score of 0 at 7 days from onset.\u003csup\u003e15\u003c/sup\u003e Head CT was used to evaluate the ICH within 24 h post-operation, including parenchymal hemorrhage and subarachnoid hemorrhage. Symptomatic ICH was defined as intracranial hemorrhage-associated neurological deterioration with \u0026ge;\u0026thinsp;4-point increase in the NIHSS score.\u003csup\u003e16\u003c/sup\u003e The functional prognosis was evaluated by modified Rankin scale (mRS).\u003csup\u003e17\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eAt 90 days post-operation, the mRS scores were assessed by experienced neurologists by telephone or outpatient follow-up to evaluate the functional prognosis of the patients. The mRS scores of 0\u0026ndash;2 and 5\u0026ndash;6 were defined as favorable and poor outcomes, respectively.\u003csup\u003e15\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Statistical analysis\u003c/h2\u003e \u003cp\u003eHerein, we compared the baseline characteristics, treatment profiles, and outcomes between the tortuous and the non-tortuous groups. Means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviations (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\stackrel{-}{X}\\pm\\:S)\\)\u003c/span\u003e\u003c/span\u003e were calculated for continuous variables with normal distribution, and \u003cem\u003et\u003c/em\u003e-test was used for comparison between groups. Median and quartiles [\u003cem\u003eM\u003c/em\u003e (\u003cem\u003eP\u003c/em\u003e\u003csub\u003e25\u003c/sub\u003e, \u003cem\u003eP\u003c/em\u003e\u003csub\u003e75\u003c/sub\u003e)] were used for continuous skewed distribution, and Mann-Whitney \u003cem\u003eU\u003c/em\u003e test was used for comparison between groups. Categorical parameters were presented as numbers and percentages, and chi-square test or Fisher\u0026rsquo;s exact test was performed for comparison between groups. Binary logistic regression models were established to analyze the statistical association between the tortuosity of the V1 segment VA and each outcome, and the odds ratios (OR) with 95% confidence intervals (CIs) were calculated for the tortuous group using the non-tortuosity group as the reference. After adjustment for age, baseline NIHSS score, and groin puncture to reperfusion time, the impact of tortuosity of the V1-segment VA on each outcome was analyzed. Cohen\u0026rsquo;s kappa coefficient was used to analyze the consistency of VA classification between the two experts. Two-sided \u003cem\u003eP\u003c/em\u003e\u0026lt;0.05 was considered significant. Statistical analyses were carried out using the SPSS software package (version 25.0).\u003c/p\u003e \u003c/div\u003e"},{"header":"3 Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Patients\u0026rsquo; characteristics\u003c/h2\u003e \u003cp\u003eFrom November 2019\u0026ndash;March 2022, a total of 35 patients (21 men [60%]; median age, 65 [52, 70] years; median NIHSS score, 18.5 [6.75, 32.75]) were included in this study. A total of 12 patients (34.3%) underwent intravenous thrombolysis (IVT) prior to MT. Ten patients (28.6%) were treated by thrombus aspiration, and 25 patients were treated by stent retriever combined with aspiration thrombectomy. Of the 35 patients, 18 (51.4%) had large artery atherosclerosis, 14 (40%) presented cardiogenic embolism, and the remaining 3 (8.6%) showed other etiologies. Successful reperfusion (final mTICI score\u0026thinsp;\u0026ge;\u0026thinsp;2b) was achieved in 26 patients (74.3%); the median time from groin puncture to reperfusion was 135 min (95,210).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Comparison of baseline data between groups\u003c/h2\u003e \u003cp\u003eIn the present study, Cohen\u0026rsquo;s Kappa coefficient was used to analyze the consistency of two experts\u0026rsquo; evaluation of tortuosity of the V1-segment VA in 35 patients. Both experts agreed that 10 patients should be assigned to the tortuous group and 18 to the non-tortuous group. However, 3 patients were identified as a tortuous group by expert 1, but as non-tortuous group by expert 2; also, 4 patients were identified as a tortuous group by expert 2, but non-tortuous by expert 1. The overall Cohen\u0026rsquo;s kappa coefficient was 0.578 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001), showing moderate consistency. The discussion was required for 7 cases; 5 were classified as the tortuous group and 2 as the non-tortuous group.\u003c/p\u003e \u003cp\u003eFinally, 15 (42.9%) patients were included in the tortuous group, and the remaining 20 (57.1%) in the non-tortuous group. After stratification by group, the time from admission to groin puncture in the non-tortuous group was longer than that in the tortuous group (46 min \u003cem\u003evs\u003c/em\u003e. 32 min, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.039). Notably, compared to the non-tortuous group, the tortuous group had a higher median age (68 years \u003cem\u003evs\u003c/em\u003e. 63 years), higher baseline NIHSS score (24.5 \u003cem\u003evs\u003c/em\u003e. 18), and longer time from groin puncture to reperfusion (165 min \u003cem\u003evs\u003c/em\u003e. 125 min), although the differences were not statistically significant. Factors, such as medical history, classification of etiology, thrombectomy method, and intravenous thrombolysis, were similar between groups (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of baseline characteristics between groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll (n\u0026thinsp;=\u0026thinsp;35)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTortuous group (n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003enon-Tortuous group (n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e65.0 (52.0, 70.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68.0 (57.0, 74.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e63.0 (47.0, 67.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.067\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMen\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21 (60.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (46.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14 (70.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.163\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSmoking\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (37.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (40.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (35.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.762\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrinking\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (11.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (15.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.619\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17 (48.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (40.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11 (55.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.380\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiabetes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (28.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (33.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (25.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.712\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoronary heart disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (8.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (10.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAtrial fibrillation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (14.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (10.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.631\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious stroke\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (20.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (20.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEtiology of stroke\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.771\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLarge artery atherosclerotic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (51.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (46.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11 (55.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiac embolism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (40.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (46.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (35.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOther or unknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (8.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (10.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMT strategy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.276\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAspiration\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (28.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (40.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (20.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAspiration\u0026thinsp;+\u0026thinsp;stent retriever\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (71.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (60.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16 (80.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntravenous thrombolysis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (34.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (26.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8 (42.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.350\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime from onset to puncture\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e330.0 (271.3, 454.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e330.0 (255.0, 437.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e330.0 (275.0, 505.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.837\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime from door to puncture\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e42.0 (26.0, 53.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32.0 (22.0, 44.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e46.0 (32.0, 80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.039\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime from puncture to reperfusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e135.0 (95.0. 210.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e165.0 (100.0, 205.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e125.0 (65.0, 210.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.151\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBaseline NIHSS score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.5 (6.8, 32.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24.5 (6.5, 32.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18.0 (8.0, 35.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.821\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNIHSS score at 24 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.0 (3.5, 25.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.0 (2.0, 33.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17.0 (7.0, 24.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.957\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eData are n (%) or median (P25, P75); NIHSS, National Institutes of Health Stroke Scale.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Comparison of outcomes between groups\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the rate of favorable outcomes in the tortuous group was significantly lower than that in the non-tortuous group (20% \u003cem\u003evs\u003c/em\u003e. 57.9%), and the difference was statistically significant after adjustment for age, baseline NIHSS score, and the time from groin puncture to reperfusion (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.034). The rates of successful recanalization, poor outcomes, and neurological improvement at 7 days did not reach statistical significance. The rate of symptomatic ICH was higher in the tortuous group than in the non-tortuous group (26.7% \u003cem\u003evs\u003c/em\u003e. 15.8%), although not significantly. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the overall distribution of the mRS scores at 90 days in the tortuous and non-tortuous groups.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of outcomes between groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTortuous group (n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003enon-Tortuous group (n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eUnadjusted\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003eAdjusted\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eOR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003emTICI score 2b/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (73.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.429 (0.281\u0026ndash;7.261)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.667\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.014 (0.166\u0026ndash;6.202)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.988\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFavorable outcome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (57.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.182 (0.038\u0026ndash;0.864)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.106 (0.013\u0026ndash;0.846)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.034\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePoor outcome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (53.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (31.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.476 (0.610\u0026ndash;10.058)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.205\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.461 (0.489\u0026ndash;12.392)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.275\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeurological improvement at 7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7(36.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.167 (0.282\u0026ndash;4.835)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.832\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.603 (0.094\u0026ndash;3.854)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.593\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSymptomatic ICH within 24 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (26.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (15.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.939 (0.361\u0026ndash;10.430)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.440\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.344 (0.187\u0026ndash;9.678)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.769\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"8\" nameend=\"c8\" namest=\"c1\"\u003e \u003cp\u003emTICI, modified thrombolysis in cerebral infarction scale; NIHSS, National Institutes of Health Stroke Scale; ICH, intracranial hemorrhage; Adjusted for age, baseline NIHSS score, and time from puncture to reperfusion.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eHitherto, only a few studies have reported data on the impact of tortuosity of the V1-segment VA on MT outcomes in patients with AVBAO. The main finding of this study was that the rate of favorable outcome at 90 days was significantly lower in patients with than without coiled or kinked V1-segment VA (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.034). The tortuous group had a higher incidence of symptomatic ICH than the non-tortuous group (26.7% \u003cem\u003evs\u003c/em\u003e. 15.8%). The rate of successful reperfusion did not differ between the groups.\u003c/p\u003e \u003cp\u003eIn the present study, none of the baseline characteristics showed statistical differences, except for the time from admission to groin puncture. Notably, the age and female proportion of patients in the tortuous group were higher than those in the non-tortuous group, which is consistent with previous studies.\u003csup\u003e18\u003c/sup\u003e Also, the stroke severity was higher in the tortuous group than in the non-tortuous group (baseline NIHSS score of 24.5 \u003cem\u003evs\u003c/em\u003e. 18), which might be due to the older age and multiple comorbidities. The groin puncture to reperfusion time was longer in the tortuous group than in the non-tortuous group (165 min \u003cem\u003evs\u003c/em\u003e. 125 min), which was considered to be one of the factors leading to poor outcomes.\u003csup\u003e15\u003c/sup\u003e In addition, the shorter time from admission to groin puncture (32 min \u003cem\u003evs\u003c/em\u003e. 46 min) in the tortuous group might reduce the difference in the clinical outcomes between the groups. The difference in clinical outcomes between groups may be the result of the combined effect of clinical characteristics. In the present study, a large difference was detected quantitatively in some baseline parameters between groups, but it did not reach statistical significance, which was related to the small sample size.\u003c/p\u003e \u003cp\u003eFurthermore, the rates of successful reperfusion were similar between groups (80% \u003cem\u003evs\u003c/em\u003e. 73.3%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.998), but the rate of favorable outcomes of the tortuous group was significantly lower than that of the non-tortuous group, which may be related to futile recanalization after MT. Futile recanalization refers to the failure of patients to achieve functional independence at 90 days after MT (mRS score\u0026thinsp;\u0026gt;\u0026thinsp;2) despite successful recanalization of occluded vessels on imaging (mTICI 2b/3).\u003csup\u003e19\u003c/sup\u003e RESCUE-RE\u003csup\u003e6\u003c/sup\u003e showed that the rate of futile recanalization after MT in patients with acute ischemic stroke was up to 49%. BEST\u003csup\u003e2\u003c/sup\u003e showed that 46% of patients with AVBAO, who received EVT within 8 h after symptom onset, underwent futile recanalization. ANGEL-ACT\u003csup\u003e20\u003c/sup\u003e is a real-world study comparing the safety and efficacy of MT \u003cem\u003evs\u003c/em\u003e. combined IVT and MT, suggesting that futile recanalization after MT was associated with advanced age, high baseline NIHSS score, and prolonged recanalization time. In this study, the overall rate of futile recanalization was 57.7% (15/26): 66.7% (8/12) in the tortuous group and 50% (7/14) in the non-tortuous group. The high rate of futile recanalization in the tortuous group may be related to older age, high baseline NIHSS scores, and prolonged recanalization time.\u003c/p\u003e \u003cp\u003eWith the improvement in devices, we might be able to successfully navigate tortuous vessels and establish a stable thrombectomy path in most cases, potentially at the expense of prolonged recanalization time. Another previous study has shown that extracranial internal carotid artery (ICA) tortuosity is not correlated to the number of thrombectomies and successful recanalization but is correlated with neurological improvement.\u003csup\u003e21\u003c/sup\u003e Similar conclusions were reached in this study, the rates of successful recanalization were similar between groups, but the rate of favorable outcomes at 90 days in the tortuous group was significantly lower than that in the non-tortuous group. This phenomenon indicated that further shortening the time from onset to recanalization may be crucial to improving the outcomes of patients with AVBAO.\u003c/p\u003e \u003cp\u003ePrevious studies have shown that aspiration catheters and stent retrievers damage the intima and artery walls.\u003csup\u003e22\u003c/sup\u003e Excessive tortuous vessels increase the difficulty of the intravascular operation and passage times, as well as the risk of vascular injury. In addition, excessive tortuous vessels prolong the operation time and the recovery time of cerebral blood perfusion, which further aggravates the damage to the blood-brain-barrier. It is prone to reperfusion injury following successful recanalization, which increases the risk of symptomatic ICH.\u003csup\u003e23\u003c/sup\u003e The present study showed that there was no significant difference in the incidence of symptomatic ICH between groups. A recent study from Japan demonstrated that although ICA tortuosity was associated with ICH after MT, it was not associated with symptomatic ICH.\u003csup\u003e15\u003c/sup\u003e This negative result could be attributed to the small sample size of symptomatic ICH. Currently, only 7 cases of symptomatic ICH have been reported in the present study, and only 14 were included in the Japanese study.\u003c/p\u003e \u003cp\u003eHow to improve the favorable outcomes of patients with VA tortuosity after MT is challenging in clinical practice, and only a few studies have addressed this concern. When the aspiration catheter or stent retriever is pulled back, excessive tortuous vessels lead to the deformation or even collapse of the thrombectomy device, thus weakening the combination power between the device and thrombus, resulting in the rupture and escape of thrombus and even failure of MT.\u003csup\u003e15\u003c/sup\u003e In the future, how to overcome the adverse effects of vascular tortuosity on MT might become an effective means to improve the outcomes of patients. Notably, the vascular tortuosity can be straightened out by stenting or surgery;\u003csup\u003e24\u003c/sup\u003e on the other hand, the design of thrombectomy devices should be updated to improve the performance to adapt to different vascular anatomy.\u003csup\u003e25\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eNevertheless, the present study has several limitations. First, this was a single-center retrospective study, and the inherent bias could not be avoided. Second, to avoid the influence of device updates on the results, the time span of the cases included in this study was short; hence, the sample size was small, which may lead to the instability of the results. Third, tortuosity in other relevant vessels, especially V3-segment VA was not assessed. The unevaluated confounding factors may affect the results. Thus, large-scale clinical trials are needed to study the effect of VA tortuosity on MT in the future.\u003c/p\u003e"},{"header":"5 Conclusions","content":"\u003cp\u003eThe tortuosity of V1-segment VA was independently associated with a lower rate of favorable outcome at 90 days following MT. The tortuosity of V1-segment VA had no significant effect on successful reperfusion and symptomatic ICH. Improving device performance to accommodate the tortuous vessels or straightening out the tortuous vascular anatomy may be an effective tool to improve the outcomes of MT.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare no conflicts of interest.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003ePatient consent for publication\u003c/h2\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis study was funded by the Xijing Hospital\u0026rsquo;s Discipline Booster Program (XJZT19Z24).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eZhou-cheng Kang, Hang-hang Zhao: Conception and design of the study. Data Curation. Data and statistical analysis. Writing- Original Draft. Writing - Review \u0026amp; Editing. Rui Shi: The operation assistant. Conception and design of the study. Data Curation. Supervision. Writing - Review \u0026amp;Editing. Dong Wei: Primary operator. Yang Li and Li Li: The operation assistant.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eWe gratefully thank Dr. Shuai Kang of department of Stomatology, the 989th Hospital for his contribution to the statistical support.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData are available upon reasonable request. Data related to the analysis are available to researchers on request to reproduce the results or replicate the procedure by directly contacting the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBuchman SL, Merkler AE. Basilar Artery Occlusion: Diagnosis and Acute Treatment. Current treatment options in neurology 2019;21:45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu X, Dai Q, Ye R, et al. Endovascular treatment versus standard medical treatment for vertebrobasilar artery occlusion (BEST): an open-label, randomised controlled trial. The Lancet Neurology 2020;19:115\u0026ndash;122.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLangezaal LCM, van der Hoeven E, Mont'Alverne FJA, et al. Endovascular Therapy for Stroke Due to Basilar-Artery Occlusion. The New England journal of medicine 2021;384:1910\u0026ndash;1920.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZi W, Qiu Z, Wu D, et al. Assessment of Endovascular Treatment for Acute Basilar Artery Occlusion via a Nationwide Prospective Registry. JAMA neurology 2020;77:561\u0026ndash;573.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi C, Wu C, Wu L, et al. Basilar Artery Occlusion Chinese Endovascular Trial: Protocol for a prospective randomized controlled study. 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Stroke 2022:101161strokeaha121037904.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHacke W, Kaste M, Bluhmki E, et al. Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke. The New England journal of medicine 2008;359:1317\u0026ndash;1329.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBamford JM, Sandercock PA, Warlow CP, Slattery J. Interobserver agreement for the assessment of handicap in stroke patients. Stroke 1989;20:828.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoskas F, Kieffer E, Kieffer A, Bahnini A. Loops and folds of the carotid and vertebral arteries: indications for surgery. Journal des maladies vasculaires 1994;19 Suppl A:51\u0026ndash;54.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHussein HM, Saleem MA, Qureshi AI. Rates and predictors of futile recanalization in patients undergoing endovascular treatment in a multicenter clinical trial. Neuroradiology 2018;60:557\u0026ndash;563.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTong X, Wang Y, Fiehler J, et al. Thrombectomy Versus Combined Thrombolysis and Thrombectomy in Patients With Acute Stroke: A Matched-Control Study. Stroke 2021;52:1589\u0026ndash;1600.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenson JC, Brinjikji W, Messina SA, Lanzino G, Kallmes DF. Cervical internal carotid artery tortuosity: A morphologic analysis of patients with acute ischemic stroke. Interventional neuroradiology: journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences 2020;26:216\u0026ndash;221.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePeschillo S, Diana F, Berge J, Missori P. A comparison of acute vascular damage caused by ADAPT versus a stent retriever device after thrombectomy in acute ischemic stroke: a histological and ultrastructural study in an animal model. Journal of neurointerventional surgery 2017;9:743\u0026ndash;749.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDesai SM, Tonetti DA, Morrison AA, et al. Relationship between reperfusion and intracranial hemorrhage after thrombectomy. Journal of neurointerventional surgery 2020;12:448\u0026ndash;453.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenes V, Netuka D. Surgical correction of symptomatic vertebral artery kinking. British journal of neurosurgery 2003;17:174\u0026ndash;178.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKaneko N, Komuro Y, Yokota H, Tateshima S. Stent retrievers with segmented design improve the efficacy of thrombectomy in tortuous vessels. Journal of neurointerventional surgery 2019;11:119\u0026ndash;122.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"ischemic stroke, acute vertebrobasilar artery occlusion, mechanical thrombectomy, vertebral artery tortuosity","lastPublishedDoi":"10.21203/rs.3.rs-4766966/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4766966/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground and Objective\u003c/h2\u003e \u003cp\u003eTortuosity of the vasculature poses challenges to mechanical thrombectomy (MT); however, only a few studies have reported the impact of vertebral artery (VA) tortuosity on MT. The present study aimed to investigate the impact of tortuosity of the V1-segment VA on MT in patients with acute vertebrobasilar artery occlusion (AVBAO).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThe patients diagnosed with AVBAO and treated with MT in the Stroke Center of Xijing Hospital from November 2019 to March 2022 were analyzed retrospectively. According to the tortuosity of V1-segment VA, patients were divided into tortuous (coiling and kinking) and non-tortuous groups (straight, single-arc, and multi-arc). A binary logistic regression model was established to analyze the association between the tortuosity of V1-segment VA and successful reperfusion (mTICI\u0026thinsp;\u0026ge;\u0026thinsp;2b), neurological improvement at 7 days, favorable and poor outcome at 90 days, and symptomatic intracranial hemorrhage (ICH) within 24 h. After adjustment for age, baseline National Institute of health stroke scale (NIHSS) score and puncture-to-recanalization time, the impact of tortuosity of the V1-segment VA on outcomes was analyzed.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAfter screening, 35 patients were enrolled in this study. The overall rate of successful reperfusion was 74.3% (26/35), and 40% (14/34) patients achieved favorable outcomes at 90 days. Subsequently, 15/35 (42.9%) patients were included in the tortuous group, and the remaining 20 patients comprised the non-tortuous group. After adjustment for age, baseline NIHSS score, and puncture-to-recanalization time, the rate of 90-day favorable outcome in the tortuous group was significantly lower than that of the non-tortuous group (20% \u003cem\u003evs\u003c/em\u003e. 57.9%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.034), while the rates of reperfusion (80% \u003cem\u003evs\u003c/em\u003e. 73.7%) and 7-day neurological improvement (33.3% \u003cem\u003evs\u003c/em\u003e. 36.8%) were similar between the two groups. The incidence of 24-h symptomatic ICH in the tortuous group was higher than that in the non-tortuous group (26.7% \u003cem\u003evs\u003c/em\u003e. 15.8%), albeit not significantly.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eIn patients with AVBAO, tortuosity of the V1-segment VA was negatively associated with favorable outcomes 90 days after MT.\u003c/p\u003e","manuscriptTitle":"Impact of Tortuosity of the V1-Segment Vertebral Artery on Mechanical Thrombectomy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-26 12:49:11","doi":"10.21203/rs.3.rs-4766966/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-10-03T10:37:53+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-10-01T17:11:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-10-01T06:06:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"287178511537500476952588182498328971435","date":"2024-09-21T15:29:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"40212837817810471828451460315315346339","date":"2024-09-21T07:51:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"314408396054934546213990947536354542668","date":"2024-09-18T07:02:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"328748278868944497548940126849734576145","date":"2024-09-18T06:12:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"253817125845293983974006586617755211181","date":"2024-09-17T17:52:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"334502426352363387810582964020404943334","date":"2024-09-17T14:40:12+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-17T08:53:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"79503155799260235446863562597909587061","date":"2024-09-12T06:47:03+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-09-10T06:38:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-09-10T06:36:24+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-07-24T04:29:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-07-23T06:05:11+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-07-19T08:18:30+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5ec463af-15f0-4eb4-bb3c-434577333bd4","owner":[],"postedDate":"August 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":36208374,"name":"Biological sciences/Neuroscience/Diseases of the nervous system"},{"id":36208375,"name":"Biological sciences/Neuroscience"},{"id":36208376,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2024-12-09T16:03:38+00:00","versionOfRecord":{"articleIdentity":"rs-4766966","link":"https://doi.org/10.1038/s41598-024-80396-0","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-12-02 15:57:43","publishedOnDateReadable":"December 2nd, 2024"},"versionCreatedAt":"2024-08-26 12:49:11","video":"","vorDoi":"10.1038/s41598-024-80396-0","vorDoiUrl":"https://doi.org/10.1038/s41598-024-80396-0","workflowStages":[]},"version":"v1","identity":"rs-4766966","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4766966","identity":"rs-4766966","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}