BIAS technique in recanalization of symptomatic long-type chronic internal carotid artery occlusion

BIAS technique in recanalization of symptomatic long-type chronic internal carotid artery occlusion | 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 Research Article BIAS technique in recanalization of symptomatic long-type chronic internal carotid artery occlusion Xi Zhang, Guangxin Duan, He Zhang, Zhibin Chen, Tingzheng Zhang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6613960/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Due to the high risk and difficulty, endovascular treatment for symptomatic long-type chronic internal carotid artery occlusion still has not be recommended widely. Methods Patients underwent EVT with symptomatic long-type chronic internal carotid artery occlusion were enrolled, long-type occlusion was defined as the occlusion site from C1 to at least C4. Patients achieved recanalization were divided into 2 groups according to the strategy of operation. Recanalization based on balloon-catheter interaction was categorized as BIAS Group, and recanalization with other way was categorized as Control group. The rate of recanalization, peri-procedural complications, numbers of stent and time spent were evaluated. Results Among the 62 patients who received EVT, 54 (87.1%) achieved successful recanalization. The rate of peri-procedural complications was 19.3% (12/62), symptomatic complications rate was 6.5% (4/62), BIAS Group showed lower complications rate (P = 0.02). The BIAS showed fewer embolism (4.0% vs 13.8%, P = 0.36), but no significant difference. Rate of intracranial hemorrhage and reocclusion within 72h after recanalization showed no significant difference. Time of recanalization was greatly shortened by BIAS technique (58.9 ± 5.7 Vs 104.4 ± 11.3, P = 0.004), and the use of stents also reduced [1(1, 2) Vs 2 (1, 4), P = 0.03]. Conclusion BIAS technique could partly reduce the occurrence of peri-procedural complications. Moreover, it could greatly shorten the time of recanalization and reduced the use of stent. Trial registration Our study is a retrospective study, not a prospective study, we have not registered for the study. symptomatic chronic internal carotid artery occlusion recanalization endovascular treatment complication Figures Figure 1 Figure 2 Figure 3 What is already known on this topic Patients with symptomatic long-type chronic internal carotid artery occlusion suffer from frequent stroke recurrence. Due to the lack of standardized procedure, EVT for long-type CICAO showed low success rate and high complication risk. What this study adds: Technique named BIAS based on balloon-catheter interaction could shorten the time of recanalization for long-type CICAO, reduced the stent planted in internal carotid artery. Especially, BIAS could reduce the occurrence of perioperative complications. How this study might affect research, practice, or policy: BIAS could reduce radiation damage to doctors and patients and lighten economic burden on patients. Introduction Symptomatic chronic internal carotid artery occlusion (CICAO) usually defined as occlusion of internal carotid artery more than 24 hours, which is the main cause of ischemic stroke [ 1 – 2 ]. It has been reported that the stroke risk of symptomatic CICAO patients with long occlusive lesions (long-type CICAO) is as high as 14%~33% [ 3 ]. The traditional treatment of symptomatic CICAO mainly included statins and antiplatelet drugs [ 4 ]. However, even given the best medicine treatment (BMT), the symptomatic long-type CICAO patients still showed an annual stroke rate of 8%~14% [ 5 ]. Thus, more and more studies paid attention to surgical treatment. The efficacy of extracranial intracranial artery bypass has not been proved in large studies [ 6 – 7 ]. Endovascular therapy (balloon angioplasty / stenting) is also an inevitable choice for symptomatic CICAO, especially in long-type CICAO patients [ 8 ]. But endovascular treatment (EVT) is still in its infancy. Many single center, small sample studied reported that CICAO patients could benefit from EVT [ 9 – 10 ]. According to the operators’ operating habits and experience, there is a variety of EVT procedure. However, due to long occlusion time, long lesion, fresh thrombosis, revascularization of long-type CICAO presented technical challenges [ 11 ]. The complication rate of EVT in long-type CICAO was as high as 8–26%, mainly include intracranial hemorrhage, embolism, and acute stent thrombosis, the success rate was only 65–80% [ 12 – 15 ]. How to improve the recanalization rate and reduce complications in EVT for long-type CICAO patients is a common concern for all neuro-interventional physicians. In this article we defined a standardized surgical procedure, sequential balloon dilation, intermediate catheter aspiration, and stent implantation, which was named BIAS technique. We have preliminarily proved that BIAS technique had its advantage in some aspect. Method Patients Patients who underwent endovascular treatment from Mar 2019 and Mar 2024 with symptomatic long-type chronic internal carotid artery occlusion were enrolled. The norms or standards we based on for our research is the Helsinki Declaration, the institutional review board approved this study and IRB (Ethics Committee of Nanjing Drum Tower Hospital) number: 2021-399-02. Clinical trial number: not applicable. Selection criteria including: 1) internal carotid artery occlusion confirmed by digital subtraction angiography (DSA), occlusion was defined as no forward flow; 2) patients received standard medicine treatment still presented with occluded artery related ischemic stroke or TIA; 3) occlusion time exceeds 2 weeks; 4) decreased perfusion in occluded arterial supply area (measured by CT or MR perfusion); 5) the occlusion site from C 1 to at least C4; 6) a preoperative mRS score ≤ 3. The exclusion criteria were as follows: 1) Patients with AIS who performed mechanical thrombectomy were excluded in this study; 2) Common carotid artery occlusion; 3). Non atherosclerotic stenosis, including dissection, embolism, and moyamoya disease; Flow chat of the study was offered in Fig. 1 . For patients who meet the above conditions, the operator told them of the benefits and risks of EVT. Age, sex, risk factors, such as hypertension, diabetes, dyslipidemia, smoking, alcohol consumption were analyzed. Technical success and perioperative complications, mainly including distal embolism, SAH, intracranial hemorrhage and re-occlusion were observed. The time of recanalization which was defined as time spent from microwire pass through the occlusion section to satisfactory angioplasty, and the numbers of stent used was also analyzed. Endovascular Therapy General anesthesia was taken for EVT in patients with long-type CICAO. Recanalization with system strategy named BIAS based on balloon-catheter interaction was categorized as BIAS group. As shown in Fig. 2 , the BIAS technique mainly contains the following step: 1) B alloon dilatation (diameter = 2.0mm) from distal ICA to proximal ICA. 2) I ntracranial support catheter (6F-115cm, ID = 0.071 inch) moved forward gradually with the help of balloon dilatation (diameter = 3.0mm) from proximal ICA to distal ICA. 3) A spiration through intracranial support catheter drawn back from distal ICA to proximal ICA gradually with microguidewire hold. 4) S tenting or further balloon angioplasty or successfully ended the operation. A representative case was shown in Fig. 3 . The details of the techniques for endovascular recanalization: Intracranial support catheter (Wallaby Medical, China or Medtronic, USA). Patients in Control group achieved recanalization with other way without the balloon-catheter interaction. Outcome Measures Modified Thrombolysis in Cerebral Ischemia scale (mTICI) was taken to assessed reperfusion status, and mTICI score of 3 was considered as successful recanalization. Patients underwent EVT were taken care in NICU for at least 24 hours after surgery. Doctors measured the condition of patients, once the patients showed stroke like performance, head CTA and perfusion was taken. Once re-occlusion in stent occurred, patients would undergo EVT after measurement. Head CT was taken to evaluate the cerebral hemorrhage 4 hours to 7 days after endovascular therapy. Early re-occlusion was defined as the discrete discontinuation of the arterial contrast column within the treated artery on follow-up CTA. Symptomatic hemorrhage was defined as hemorrhage associated with neurological deterioration (> 3 points increase in NIHSS). Number of stents used, and time of recanalization were analyzed. The primary outcome was the time of recanalization; secondary outcomes was number of stents used. The safety outcome of the study was peri-procedural complication rate. Statistical Analysis Continuous variables were described by median and interquartile range. The count (n) and percentage (%) were used to describe categorical variables. Baseline and procedural characteristics and treatment outcomes were compared among different groups. The categorical and binary variables were analyzed by χ2 test, and continuous variables were analyzed by Mann-Whitney U test. All statistical analyses were completed by SPSS software (version 25.0; IBM SPSS, Chicago, IL), and P value < 0.05 was considered significant. Results Baseline Characteristics Our study included 62 patients. 8 patients failed to recanalization since the microwire failed to pass through occlusion site, 25 patients used BIAS technique, 29 patients achieved recanalization in Control group. The baseline characteristics were presented in Table 1 . Overall, the age, and risk factors of ischemic stroke, such as hypertension, diabetes, smoking and alcohol, showed no differences among the 2 groups. Table 1 Comparison of relative risk factors Variable BIAS (n = 25) Control (n = 29) P Male (%) 100.0 (25/25) 96.6 (28/29) 0.99 Age (years) 65.4 ± 1.7 62.9 ± 1.7 0.18 Hypertension (%) 68.0(17/25) 62.1(18/29) 0.78 Diabetes (%) 48.0(12/25) 37.9(11/29) 0.58 Dyslipidemia 24(6/25) 24.1(7/29) 0.99 Postprocedural oral antiplatelet medication 25(100%) 29(100%) 0.99 Smoking (%) 72.0(18/25) 51.7(15/29) 0.17 Alcohol (%) 24.0(6/25) 31.0(9/29) 0.76 Baseline NIHSS score 4(2-6.25) 4(2–6) 0.61 Baseline mRS score 2(1–2) 2(1–2) 0.34 Location of the occlusion 0.92 C1-C4 14 17 C1-C5 4 6 C1-C6 5 4 C1-C7 2 2 Perioperative Outcome Perioperative outcome was showed in Table 2 . 87.1% patients (54/62) achieved successful reperfusion after endovascular therapy (mTICI > 2b). The rate of complication rate within 72 hours was 19.4% (12/62), but the symptomatic complication rate was only 6.5%, including 2 case of symptomatic ICH and 2 case of stent thrombosis. In BIAS Group, 1 patient presented early re-occlusion and 1 patient showed branch embolization. 10 patients in Control group showed perioperative complication, including 4 patients occurred distal embolism, 2 patients occurred SAH, 3 patient occurred intracranial hemorrhage and 1 patient showed early re-occlusion. Table 2 Perioperative Outcome of patients received EVT. EVT(n = 62) Successful reperfusion 54(87.1) Postprocedural Perfusion TICI = 3 49(79.0) TICI = 2b 5(8.1) Complication rate 12(19.4) Symptomatic Complication rate 4(6.5) Symptomatic ICH 2(3.2) Stent thrombosis 2(3.2) Asymptomatic Complication rate 8(12.9) Distal embolism 5(8.1) Asymptomatic ICH 3(4.8) Death 0(0) And we compared the technic indicators between BIAS and Control group in Table 3 . We found that BIAS technique could greatly shorten the time spent on recanalization (58.9 ± 5.7 Vs 104.4 ± 11.3, P = 0.004). In addition, patients in BIAS Group used fewer stents (P = 0.03), which greatly reduced the economic burden on patients. When it came to the perioperative complications, we found that complications within 72h in BIAS Group (2/25) was lower than Control group (10/29), P = 0.02. In BIAS Group, 1 patient showed distal embolism, 1 patient showed early re-occlusion after recanalization. In Control group, 4 patient presented distal embolism, 5 patients showed intracranial hemorrhage including 2 ICH, 1 patient presented early re-occlusion after recanalization. 1 patient in BIAS Group and 3 patients in Control group showed symptomatic complications within 72h, which presented no statistical difference. 3 patients in Control group showed persistent Symptom over 72h, including 1 case of distal embolism and 2 cases of SAH. Table 3 Technic indicators of recanalization between the 2 groups Variable BIAS (n = 25) Control (n = 29) P Time of recanalization 58.9 ± 5.7 104.4 ± 11.3 0.004 Number of stents 1(1,2) 2 (1,4) 0.03 Complications within 72h (%) 8.0(2/25) 34.5(10/29) 0.02 Distal embolism (%) 4.0(1/25) 13.8(4/29) 0.36 Intracranial hemorrhage (%) 0 (0/12) 17.2(5/29) 0.05 Re-occlusion (%) 4.0(1/25) 3.4(1/29) 0.99 Symptomatic complications within 72h (%) 4.0(1/25) 10.3 (3/29) 0.61 Distal embolism (%) 4.0(1/25) 3.4(1/29) 0.99 Intracranial hemorrhage (%) (0/25) 6.9(2/29) 0.49 Persistent Symptom over 72h (%) 0(0/25) 10.3(3/29) 0.24 Distal embolism (%) 0 (0/12) 3.4(1/29) 0.99 Intracranial hemorrhage (%) 0 (0/12) 6.9(2/29) 0.49 Discussion As reported in most studies, the difficulty of recanalization for long-type CICAO patients is the ceiling of neurovascular intervention surgery, featured by low success rate and high complication rate [ 16 – 17 ]. In this article we proposed a new surgical procedure, named BIAS, which could ensure the success rate while reduce the risk of complications. Also, application of BIAS technique in the EVT for long-type CICAO patients could shorten the time of recanalization. And BIAS reduced the use of stent, which might lead to expand on the economic implications, such as cost savings and resource utilization, would be beneficial for healthcare providers and policymakers. After proximal stenosis and occlusion, the vascular lumen collapses, accompanied by intravascular thrombosis [ 1 ]. It is difficult for CEA to open the long segment occlusion of intracranial artery [ 2 ]. Although endovascular treatment provides the possibility for treating intracranial occlusion, the load of thrombus in long segment occlusion is large, and the manipulation of the guide wire will decrease when it passes through long thrombus [ 18 ]. In addition, longer thrombi may require more stents to repair the vascular wall, increasing the risk of thrombosis during and after surgery [ 19 ]. In addition to relieving stenosis, the surgeon should also pay attention to preventing thrombus escape. Therefore, there are still significant limitations in endovascular treatment. As all EVT in intracranial and extracranial arterial occlusion, microwires passed the occluded segment and reached the distal vascular lumen was the first step to successful recanalization [ 20 ]. However, the subsequent processing steps vary greatly depending on the surgeons’ habits. A meta-analysis enrolled 528 CICAO patients received EVT, found that, the total complication rate was 8–20%, symptomatic cerebral infarction was 9%, hyper perfusion was 0.8%, and symptomatic cerebral hemorrhage was 5% [ 21 – 22 ]. The similar conclusion was drawn by a retrospective study of EVT in long-type CICAO. Adequate research has shown that due to the lack of standardized surgical procedures, EVT in long-type CICAO presented low success rate and high complication rate [ 23 ]. In our BIAS Group, 1 patient presented re-occlusion and 1 patient showed branch embolization, patient presented re-occlusion caused by acute stent thrombosis, and achieved revascularization after second endovascular treatment. We reviewed this patient, fond that he had resistance to antiplatelet drugs, and we immediately adjusted the antiplatelet treatment. Acute stent thrombosis is a common complication in EVT, which related to multiple factors, such as antiplatelet drug resistance, stent malposition, et al [ 24 ]. Another patient in BIAS group showed branch embolization, his vascular wall magnetic resonance imaging showed large amount of thrombus in the lumen, although we aspirate some thrombus, still thrombus escape occurred. We found that it might be safe to delay the surgery time for long-type CICAO with high load thrombosis. In BIAS technique, we first chose small diameter balloon dilation from the distal to proximal ICA, which could reduce the risk of distal embolism, since the retrograde flow due to occlusion. The second step was put the intracranial support catheter in ICA by the help with balloon dilatation (diameter = 3.0mm), which not only prepared for the next aspiration step, but also played a role in reshaping the occluded ICA. The third step was aspiration with intracranial support catheter, which was the key step to reduce thrombus burden and decrease the risk of distal embolism. These were the core skills of BIAS technique. Given the complexity of managing long-type CICAO, interdisciplinary teams, including neurologists, radiologists, and vascular surgeons, is essential. Performing recanalization surgery on CICAO patient needs stricter intraoperative anesthesia [ 25 ]. Maintaining stable blood pressure and professional neurological anesthesia may reduce the incidence of low perfusion infarction related to general anesthesia surgery [ 26 ]. Hybrid surgery combining carotid artery incision, distal thrombectomy, and intracranial stenting may be a feasible approach for long segment occlusion [ 27 ]. At present, hybrid surgery for CICAO is still in the exploratory stage. Patients need to be observed in neurological intensive care for at least 24 hours after EVT, paying close attention to the patient's vital signs and whether there are any new symptoms, which puts higher demands on quality of nursing and medical care [ 28 ]. Still, our studies had several limitations. First, the distal embolism rate was lower in BIAS group, but without statistical differences. Second, the sample size is small. Third, further subgroup analysis has not been completed. Fourth, this study is a retrospective study, prospective registration research is urgent in the future to provide more sufficient evidence in BIAS technique for EVT in long-type CICAO patients. Conclusion Successful recanalization of long-type non-acute internal carotid artery occlusion increased the peri-procedural complications, BIAS technique might partly reduce it happening. Moreover, it could greatly shorten the time of recanalization and reduce the use of stent. Abbreviations BMT Best medicine treatment DSA digital subtraction angiography EVT Endovascular Treatment ICH Intracranial hemorrhage NAICAO Non-acute internal carotid artery occlusion TIA Transient ischemic attack Declarations Research ethics approval The institutional review board approved this study and IRB (Ethics Committee of Nanjing Drum Tower Hospital) number was 2016-169-01. Ethics approval and consent to participate Our study adhered to the Declaration of Helsinki. The institutional review board approved this study and IRB (Ethics Committee of Nanjing Drum Tower Hospital) number: 2021-399-02. Informed consent to participate was obtained from all of the participants in the study. Consent for publication Not Applicable. Competing interests The authors declare no conflict of interest. Funding: This research was supported by the National Natural Science Foundation of China (82101396). Author Contribution Xi Zhang designed the experiments and wrote the main manuscript text, Guangxin Duan and Zhibin Chen prepared figures 1-3, He Zhang , Tingzheng Zhang , Zhengjuan Lu and Jingwei Li analyzed and interpreted the data. Yun Luo conceived and designed the experiments. All authors reviewed the manuscript. Acknowledgements None. Data Availability Data is provided within the manuscript or supplementary information files References Saini H, Cerejo R, Williamson R, et al. Internal Carotid Artery Occlusion: Management[J]. 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Luo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuklEQVRIiWNgGAWjYBACPghlw8DYwNxAnBY2CJUG1MJImpbDQEy0FonkY9K8O87nMfcvbJPmYbCT0yWkk00iLU2a98ztYsYZD0Fako3NDhDUkmMmzdt2O7FxxkGQlgOJ24jUco50LQcSG/sbidXC8yzZcm5bMtAWxmbLOQZE+IWfPfngjbdtdokb+w8fvPGmwk6OoBYgYJEAkYYzElikeAwIKwcB5g8gUp7/APPHH8TpGAWjYBSMghEGAFCTP6UTGIB2AAAAAElFTkSuQmCC","orcid":"","institution":"Nanjing University Medical School Affiliated Nanjing Drum Tower Hospital","correspondingAuthor":true,"prefix":"","firstName":"Yun","middleName":"","lastName":"Luo","suffix":""}],"badges":[],"createdAt":"2025-05-07 16:53:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6613960/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6613960/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":84281523,"identity":"bcfc44f0-d1bf-480a-8c72-6035ddd26ec4","added_by":"auto","created_at":"2025-06-10 06:51:22","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":39450,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFlow chat of the study\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6613960/v1/2444e1944e27ba546d970e68.jpg"},{"id":84281522,"identity":"ae1d8d09-6c5d-43e0-a302-ccf28cd33e80","added_by":"auto","created_at":"2025-06-10 06:51:22","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":40534,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe main step of the BIAS technique\u003c/strong\u003e. \u003cstrong\u003eA\u003c/strong\u003e Microwires passed the occluded segment and reached the distal vascular lumen. \u003cstrong\u003eB \u003c/strong\u003eBalloon dilatation (diameter=2.0mm) from distal ICA to proximal ICA. \u003cstrong\u003eC-D \u003c/strong\u003eIntracranial support catheter moved forward gradually with the help of balloon dilatation (diameter=3.0mm) from proximal ICA to distal ICA. \u003cstrong\u003eE\u003c/strong\u003e Aspiration through intracranial support catheter drawn back from distal ICA to proximal ICA gradually with the help of \u003ca href=\"http://www.baidu.com/link?url=rkBC6uhlyd2dIMwUo7a75qvrZYYWAv0ESVGHd2G1cy7m9rLm83kRddAK3OOa78YyEL9P009ts3aHp2kG8MrgW5oz-ZDz3HJK5K5BRfVz1I7p7DNPj2_91ci2fn1RwGaF\" target=\"_blank\"\u003emicroguidewire\u003c/a\u003e. \u003cstrong\u003eF \u003c/strong\u003eStenting or further balloon angioplasty or successfully ended the operation.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6613960/v1/bb11c94392d26a2386e53cc8.jpg"},{"id":84281528,"identity":"4326c197-61d6-457a-8ee9-8120d163b4a5","added_by":"auto","created_at":"2025-06-10 06:51:23","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":80782,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRepresentative case.\u003c/strong\u003e \u003cstrong\u003eA-D\u003c/strong\u003e Digital subtraction angiography showed occlusion of the right internal carotid artery with an occlusion length from C1 to C6.\u003cstrong\u003eE-F\u003c/strong\u003e Samll balloon dilatation from C6 to C1.\u003cstrong\u003eG-H \u003c/strong\u003eIntracranial support catheter moved forward gradually with the help of balloon dilatation (diameter=3.0mm) from C1 to C6.\u003cstrong\u003e I \u003c/strong\u003eAspiration through intracranial support catheter drawn back from C6 to C1 gradually with the help of \u003ca href=\"http://www.baidu.com/link?url=rkBC6uhlyd2dIMwUo7a75qvrZYYWAv0ESVGHd2G1cy7m9rLm83kRddAK3OOa78YyEL9P009ts3aHp2kG8MrgW5oz-ZDz3HJK5K5BRfVz1I7p7DNPj2_91ci2fn1RwGaF\" target=\"_blank\"\u003emicroguidewire\u003c/a\u003e. \u003cstrong\u003eJ \u003c/strong\u003eStent implantation.\u003cstrong\u003e K-L \u003c/strong\u003eThe right ICA was successfully recanalized, achieving a Thrombolysis in Cerebral Infarction (TICI) grade of 3.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6613960/v1/15b41f485c6789430de895ad.jpg"},{"id":89283458,"identity":"c8c59dc4-1fbd-44c6-b27f-7e1766c251c7","added_by":"auto","created_at":"2025-08-18 10:53:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1395261,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6613960/v1/78e24767-7f5b-435a-b689-5b26df65be62.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"BIAS technique in recanalization of symptomatic long-type chronic internal carotid artery occlusion","fulltext":[{"header":"What is already known on this topic","content":"\u003cp\u003ePatients with symptomatic long-type chronic internal carotid artery occlusion suffer from frequent stroke recurrence. Due to the lack of standardized procedure, EVT for long-type CICAO showed low success rate and high complication risk.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat this study adds:\u003c/strong\u003e Technique named BIAS based on balloon-catheter interaction could shorten the time of recanalization for long-type CICAO, reduced the stent planted in internal carotid artery. Especially, BIAS could reduce the occurrence of perioperative complications.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow this study might affect research, practice, or policy:\u003c/strong\u003e BIAS could reduce radiation damage to doctors and patients and lighten economic burden on patients.\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eSymptomatic chronic internal carotid artery occlusion (CICAO) usually defined as occlusion of internal carotid artery more than 24 hours, which is the main cause of ischemic stroke [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. It has been reported that the stroke risk of symptomatic CICAO patients with long occlusive lesions (long-type CICAO) is as high as 14%~33% [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The traditional treatment of symptomatic CICAO mainly included statins and antiplatelet drugs [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, even given the best medicine treatment (BMT), the symptomatic long-type CICAO patients still showed an annual stroke rate of 8%~14% [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Thus, more and more studies paid attention to surgical treatment. The efficacy of extracranial intracranial artery bypass has not been proved in large studies [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Endovascular therapy (balloon angioplasty / stenting) is also an inevitable choice for symptomatic CICAO, especially in long-type CICAO patients [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. But endovascular treatment (EVT) is still in its infancy. Many single center, small sample studied reported that CICAO patients could benefit from EVT [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAccording to the operators\u0026rsquo; operating habits and experience, there is a variety of EVT procedure. However, due to long occlusion time, long lesion, fresh thrombosis, revascularization of long-type CICAO presented technical challenges [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The complication rate of EVT in long-type CICAO was as high as 8\u0026ndash;26%, mainly include intracranial hemorrhage, embolism, and acute stent thrombosis, the success rate was only 65\u0026ndash;80% [\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHow to improve the recanalization rate and reduce complications in EVT for long-type CICAO patients is a common concern for all neuro-interventional physicians. In this article we defined a standardized surgical procedure, sequential balloon dilation, intermediate catheter aspiration, and stent implantation, which was named BIAS technique. We have preliminarily proved that BIAS technique had its advantage in some aspect.\u003c/p\u003e"},{"header":"Method","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients\u003c/h2\u003e \u003cp\u003ePatients who underwent endovascular treatment from Mar 2019 and Mar 2024 with symptomatic long-type chronic internal carotid artery occlusion were enrolled. The norms or standards we based on for our research is the Helsinki Declaration, the institutional review board approved this study and IRB (Ethics Committee of Nanjing Drum Tower Hospital) number: 2021-399-02. Clinical trial number: not applicable.\u003c/p\u003e \u003cp\u003eSelection criteria including: 1) internal carotid artery occlusion confirmed by digital subtraction angiography (DSA), occlusion was defined as no forward flow; 2) patients received standard medicine treatment still presented with occluded artery related ischemic stroke or TIA; 3) occlusion time exceeds 2 weeks; 4) decreased perfusion in occluded arterial supply area (measured by CT or MR perfusion); 5) the occlusion site from C 1 to at least C4; 6) a preoperative mRS score\u0026thinsp;\u0026le;\u0026thinsp;3. The exclusion criteria were as follows: 1) Patients with AIS who performed mechanical thrombectomy were excluded in this study; 2) Common carotid artery occlusion; 3). Non atherosclerotic stenosis, including dissection, embolism, and moyamoya disease; Flow chat of the study was offered in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. For patients who meet the above conditions, the operator told them of the benefits and risks of EVT. Age, sex, risk factors, such as hypertension, diabetes, dyslipidemia, smoking, alcohol consumption were analyzed. Technical success and perioperative complications, mainly including distal embolism, SAH, intracranial hemorrhage and re-occlusion were observed. The time of recanalization which was defined as time spent from microwire pass through the occlusion section to satisfactory angioplasty, and the numbers of stent used was also analyzed.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEndovascular Therapy\u003c/h3\u003e\n\u003cp\u003eGeneral anesthesia was taken for EVT in patients with long-type CICAO. Recanalization with system strategy named BIAS based on balloon-catheter interaction was categorized as BIAS group. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the BIAS technique mainly contains the following step:\u003c/p\u003e \u003cp\u003e \u003cb\u003e1) B\u003c/b\u003ealloon dilatation (diameter\u0026thinsp;=\u0026thinsp;2.0mm) from distal ICA to proximal ICA.\u003c/p\u003e \u003cp\u003e \u003cb\u003e2) I\u003c/b\u003entracranial support catheter (6F-115cm, ID\u0026thinsp;=\u0026thinsp;0.071 inch) moved forward gradually with the help of balloon dilatation (diameter\u0026thinsp;=\u0026thinsp;3.0mm) from proximal ICA to distal ICA.\u003c/p\u003e \u003cp\u003e \u003cb\u003e3) A\u003c/b\u003espiration through intracranial support catheter drawn back from distal ICA to proximal ICA gradually with microguidewire hold.\u003c/p\u003e \u003cp\u003e \u003cb\u003e4) S\u003c/b\u003etenting or further balloon angioplasty or successfully ended the operation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA representative case was shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The details of the techniques for endovascular recanalization: Intracranial support catheter (Wallaby Medical, China or Medtronic, USA).\u003c/p\u003e \u003cp\u003ePatients in Control group achieved recanalization with other way without the balloon-catheter interaction.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eOutcome Measures\u003c/h3\u003e\n\u003cp\u003eModified Thrombolysis in Cerebral Ischemia scale (mTICI) was taken to assessed reperfusion status, and mTICI score of 3 was considered as successful recanalization. Patients underwent EVT were taken care in NICU for at least 24 hours after surgery. Doctors measured the condition of patients, once the patients showed stroke like performance, head CTA and perfusion was taken. Once re-occlusion in stent occurred, patients would undergo EVT after measurement. Head CT was taken to evaluate the cerebral hemorrhage 4 hours to 7 days after endovascular therapy. Early re-occlusion was defined as the discrete discontinuation of the arterial contrast column within the treated artery on follow-up CTA. Symptomatic hemorrhage was defined as hemorrhage associated with neurological deterioration (\u0026gt;\u0026thinsp;3 points increase in NIHSS). Number of stents used, and time of recanalization were analyzed. The primary outcome was the time of recanalization; secondary outcomes was number of stents used. The safety outcome of the study was peri-procedural complication rate.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eContinuous variables were described by median and interquartile range. The count (n) and percentage (%) were used to describe categorical variables. Baseline and procedural characteristics and treatment outcomes were compared among different groups. The categorical and binary variables were analyzed by χ2 test, and continuous variables were analyzed by Mann-Whitney U test. All statistical analyses were completed by SPSS software (version 25.0; IBM SPSS, Chicago, IL), and P value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBaseline Characteristics\u003c/h2\u003e \u003cp\u003eOur study included 62 patients. 8 patients failed to recanalization since the microwire failed to pass through occlusion site, 25 patients used BIAS technique, 29 patients achieved recanalization in Control group. The baseline characteristics were presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Overall, the age, and risk factors of ischemic stroke, such as hypertension, diabetes, smoking and alcohol, showed no differences among the 2 groups.\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 relative risk factors\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBIAS (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl (n\u0026thinsp;=\u0026thinsp;29)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100.0 (25/25)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e96.6 (28/29)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e65.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e62.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.18\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHypertension (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e68.0(17/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e62.1(18/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.78\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDiabetes (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e48.0(12/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e37.9(11/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.58\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDyslipidemia\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e24(6/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e24.1(7/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.99\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePostprocedural oral antiplatelet medication\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e25(100%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e29(100%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.99\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSmoking (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e72.0(18/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e51.7(15/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.17\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAlcohol (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e24.0(6/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e31.0(9/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.76\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBaseline NIHSS score\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e4(2-6.25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e4(2\u0026ndash;6)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.61\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBaseline mRS score\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e2(1\u0026ndash;2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e2(1\u0026ndash;2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.34\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLocation of the occlusion\u003c/b\u003e\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=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.92\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC1-C4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e14\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e17\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC1-C5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e6\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC1-C6\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC1-C7\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePerioperative Outcome\u003c/h3\u003e\n\u003cp\u003ePerioperative outcome was showed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. 87.1% patients (54/62) achieved successful reperfusion after endovascular therapy (mTICI\u0026thinsp;\u0026gt;\u0026thinsp;2b). The rate of complication rate within 72 hours was 19.4% (12/62), but the symptomatic complication rate was only 6.5%, including 2 case of symptomatic ICH and 2 case of stent thrombosis. In BIAS Group, 1 patient presented early re-occlusion and 1 patient showed branch embolization. 10 patients in Control group showed perioperative complication, including 4 patients occurred distal embolism, 2 patients occurred SAH, 3 patient occurred intracranial hemorrhage and 1 patient showed early re-occlusion.\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\u003ePerioperative Outcome of patients received EVT.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEVT(n\u0026thinsp;=\u0026thinsp;62)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuccessful reperfusion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54(87.1)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostprocedural Perfusion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTICI\u0026thinsp;=\u0026thinsp;3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e49(79.0)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTICI\u0026thinsp;=\u0026thinsp;2b\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e5(8.1)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eComplication rate\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e12(19.4)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSymptomatic Complication rate\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e4(6.5)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSymptomatic ICH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e2(3.2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStent thrombosis\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e2(3.2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAsymptomatic Complication rate\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e8(12.9)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDistal embolism\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e5(8.1)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAsymptomatic ICH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e3(4.8)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDeath\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0(0)\u003c/b\u003e\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\u003eAnd we compared the technic indicators between BIAS and Control group in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. We found that BIAS technique could greatly shorten the time spent on recanalization (58.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.7 Vs 104.4\u0026thinsp;\u0026plusmn;\u0026thinsp;11.3, P\u0026thinsp;=\u0026thinsp;0.004). In addition, patients in BIAS Group used fewer stents (P\u0026thinsp;=\u0026thinsp;0.03), which greatly reduced the economic burden on patients. When it came to the perioperative complications, we found that complications within 72h in BIAS Group (2/25) was lower than Control group (10/29), P\u0026thinsp;=\u0026thinsp;0.02. In BIAS Group, 1 patient showed distal embolism, 1 patient showed early re-occlusion after recanalization. In Control group, 4 patient presented distal embolism, 5 patients showed intracranial hemorrhage including 2 ICH, 1 patient presented early re-occlusion after recanalization. 1 patient in BIAS Group and 3 patients in Control group showed symptomatic complications within 72h, which presented no statistical difference. 3 patients in Control group showed persistent Symptom over 72h, including 1 case of distal embolism and 2 cases of SAH.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTechnic indicators of recanalization between the 2 groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBIAS (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl (n\u0026thinsp;=\u0026thinsp;29)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime of recanalization\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.7\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e104.4\u0026thinsp;\u0026plusmn;\u0026thinsp;11.3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.004\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNumber of stents\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e1(1,2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e2 (1,4)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.03\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eComplications within 72h (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e8.0(2/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e34.5(10/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.02\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDistal embolism (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e4.0(1/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e13.8(4/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.36\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eIntracranial hemorrhage (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0 (0/12)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e17.2(5/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.05\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRe-occlusion (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e4.0(1/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e3.4(1/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.99\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSymptomatic complications within 72h (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e4.0(1/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e10.3 (3/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.61\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDistal embolism (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e4.0(1/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e3.4(1/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.99\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eIntracranial hemorrhage (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e(0/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e6.9(2/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.49\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePersistent Symptom over 72h (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0(0/25)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e10.3(3/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.24\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDistal embolism (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0 (0/12)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e3.4(1/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.99\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eIntracranial hemorrhage (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0 (0/12)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e6.9(2/29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.49\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAs reported in most studies, the difficulty of recanalization for long-type CICAO patients is the ceiling of neurovascular intervention surgery, featured by low success rate and high complication rate [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In this article we proposed a new surgical procedure, named BIAS, which could ensure the success rate while reduce the risk of complications. Also, application of BIAS technique in the EVT for long-type CICAO patients could shorten the time of recanalization. And BIAS reduced the use of stent, which might lead to expand on the economic implications, such as cost savings and resource utilization, would be beneficial for healthcare providers and policymakers.\u003c/p\u003e \u003cp\u003eAfter proximal stenosis and occlusion, the vascular lumen collapses, accompanied by intravascular thrombosis [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. It is difficult for CEA to open the long segment occlusion of intracranial artery [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Although endovascular treatment provides the possibility for treating intracranial occlusion, the load of thrombus in long segment occlusion is large, and the manipulation of the guide wire will decrease when it passes through long thrombus [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In addition, longer thrombi may require more stents to repair the vascular wall, increasing the risk of thrombosis during and after surgery [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In addition to relieving stenosis, the surgeon should also pay attention to preventing thrombus escape. Therefore, there are still significant limitations in endovascular treatment.\u003c/p\u003e \u003cp\u003eAs all EVT in intracranial and extracranial arterial occlusion, microwires passed the occluded segment and reached the distal vascular lumen was the first step to successful recanalization [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, the subsequent processing steps vary greatly depending on the surgeons\u0026rsquo; habits. A meta-analysis enrolled 528 CICAO patients received EVT, found that, the total complication rate was 8\u0026ndash;20%, symptomatic cerebral infarction was 9%, hyper perfusion was 0.8%, and symptomatic cerebral hemorrhage was 5% [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The similar conclusion was drawn by a retrospective study of EVT in long-type CICAO. Adequate research has shown that due to the lack of standardized surgical procedures, EVT in long-type CICAO presented low success rate and high complication rate [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our BIAS Group, 1 patient presented re-occlusion and 1 patient showed branch embolization, patient presented re-occlusion caused by acute stent thrombosis, and achieved revascularization after second endovascular treatment. We reviewed this patient, fond that he had resistance to antiplatelet drugs, and we immediately adjusted the antiplatelet treatment. Acute stent thrombosis is a common complication in EVT, which related to multiple factors, such as antiplatelet drug resistance, stent malposition, et al [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Another patient in BIAS group showed branch embolization, his vascular wall magnetic resonance imaging showed large amount of thrombus in the lumen, although we aspirate some thrombus, still thrombus escape occurred. We found that it might be safe to delay the surgery time for long-type CICAO with high load thrombosis.\u003c/p\u003e \u003cp\u003eIn BIAS technique, we first chose small diameter balloon dilation from the distal to proximal ICA, which could reduce the risk of distal embolism, since the retrograde flow due to occlusion. The second step was put the intracranial support catheter in ICA by the help with balloon dilatation (diameter\u0026thinsp;=\u0026thinsp;3.0mm), which not only prepared for the next aspiration step, but also played a role in reshaping the occluded ICA. The third step was aspiration with intracranial support catheter, which was the key step to reduce thrombus burden and decrease the risk of distal embolism. These were the core skills of BIAS technique.\u003c/p\u003e \u003cp\u003eGiven the complexity of managing long-type CICAO, interdisciplinary teams, including neurologists, radiologists, and vascular surgeons, is essential. Performing recanalization surgery on CICAO patient needs stricter intraoperative anesthesia [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Maintaining stable blood pressure and professional neurological anesthesia may reduce the incidence of low perfusion infarction related to general anesthesia surgery [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Hybrid surgery combining carotid artery incision, distal thrombectomy, and intracranial stenting may be a feasible approach for long segment occlusion [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. At present, hybrid surgery for CICAO is still in the exploratory stage. Patients need to be observed in neurological intensive care for at least 24 hours after EVT, paying close attention to the patient's vital signs and whether there are any new symptoms, which puts higher demands on quality of nursing and medical care [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eStill, our studies had several limitations. First, the distal embolism rate was lower in BIAS group, but without statistical differences. Second, the sample size is small. Third, further subgroup analysis has not been completed. Fourth, this study is a retrospective study, prospective registration research is urgent in the future to provide more sufficient evidence in BIAS technique for EVT in long-type CICAO patients.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eSuccessful recanalization of long-type non-acute internal carotid artery occlusion increased the peri-procedural complications, BIAS technique might partly reduce it happening. Moreover, it could greatly shorten the time of recanalization and reduce the use of stent.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBMT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eBest medicine treatment\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eDSA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003edigital subtraction angiography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eEVT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eEndovascular Treatment\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eICH\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eIntracranial hemorrhage\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNAICAO\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eNon-acute internal carotid artery occlusion\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTIA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eTransient ischemic attack\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":" \u003cp\u003e \u003cstrong\u003eResearch ethics approval\u003c/strong\u003e \u003cp\u003e The institutional review board approved this study and IRB (Ethics Committee of Nanjing Drum Tower Hospital) number was 2016-169-01.\u003c/p\u003e\u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e \u003cp\u003e Our study adhered to the Declaration of Helsinki. The institutional review board approved this study and IRB (Ethics Committee of Nanjing Drum Tower Hospital) number: 2021-399-02. Informed consent to participate was obtained from all of the participants in the study.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003eNot Applicable.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e \u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThis research was supported by the National Natural Science Foundation of China (82101396).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eXi Zhang designed the experiments and wrote the main manuscript text, Guangxin Duan and Zhibin Chen prepared figures 1-3, He Zhang , Tingzheng Zhang , Zhengjuan Lu and Jingwei Li analyzed and interpreted the data. Yun Luo conceived and designed the experiments. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eNone.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData is provided within the manuscript or supplementary information files\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSaini H, Cerejo R, Williamson R, et al. Internal Carotid Artery Occlusion: Management[J]. Curr Neurol Neurosci Rep, 2022, 22: 383-388.\u003c/li\u003e\n\u003cli\u003eLall A, Yavagal D, Bornak A. Chronic total occlusion and spontaneous recanalization of the internal carotid artery: Natural history and management strategy[J]. Vascular, 2021, 29: 733-741.\u003c/li\u003e\n\u003cli\u003eCao G, Hu J, Tian Q, et al. Surgical therapy for chronic internal carotid artery occlusion: a systematic review and meta-analysis[J]. Updates Surg, 2021, 73: 2065-2078.\u003c/li\u003e\n\u003cli\u003eLi S, Zhao W, Liu G, et al. 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Stroke, 2011, 42: 2850-4.\u003c/li\u003e\n\u003cli\u003eShojima M, Nemoto S, Morita A, et al. Protected endovascular revascularization of subacute and chronic total occlusion of the internal carotid artery[J]. AJNR Am J Neuroradiol, 2010, 31: 481-6.\u003c/li\u003e\n\u003cli\u003eGiuseppe T, Alessandro M, Filippo D, et al. Acute Stent Thrombosis: Severe In-Stent Malapposition and Insufficient Platelet Inhibition as Partners in Crime[J]. J Invasive Cardiol, 2021, 33: 0.\u003c/li\u003e\n\u003cli\u003eWang A, Apolonia E, Abramowicz. Role of anesthesia in endovascular stroke therapy[J]. Curr Opin Anaesthesiol, 2017, 30: 0.\u003c/li\u003e\n\u003cli\u003eGrubb RL Jr, Powers WJ, Clarke WR, et al. Surgical results of the Carotid Occlusion Surgery Study [J]. J Neurosurg, 2013, 118(1): 25-33.\u003c/li\u003e\n\u003cli\u003eShih YT, Chen WH, Lee WL, et al. Hybrid surgery for symptomatic chronic total occlusion of carotid artery: a technical note [J]. Neurosurgery, 2013, 73(1 Suppl Operative): onsE117-123.\u003c/li\u003e\n\u003cli\u003eChen YH, Leong WS, Lin MS, et al. Predictors for successful endovascular intervention in chronic carotid artery total occlusion[J]. JACC Cardiovasc Interv, 2016, 9(17):1825-1832.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"symptomatic chronic internal carotid artery occlusion, recanalization, endovascular treatment, complication","lastPublishedDoi":"10.21203/rs.3.rs-6613960/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6613960/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e \u003cp\u003eDue to the high risk and difficulty, endovascular treatment for symptomatic long-type chronic internal carotid artery occlusion still has not be recommended widely.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003ePatients underwent EVT with symptomatic long-type chronic internal carotid artery occlusion were enrolled, long-type occlusion was defined as the occlusion site from C1 to at least C4. Patients achieved recanalization were divided into 2 groups according to the strategy of operation. Recanalization based on balloon-catheter interaction was categorized as BIAS Group, and recanalization with other way was categorized as Control group. The rate of recanalization, peri-procedural complications, numbers of stent and time spent were evaluated.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eAmong the 62 patients who received EVT, 54 (87.1%) achieved successful recanalization. The rate of peri-procedural complications was 19.3% (12/62), symptomatic complications rate was 6.5% (4/62), BIAS Group showed lower complications rate (P\u0026thinsp;=\u0026thinsp;0.02). The BIAS showed fewer embolism (4.0% vs 13.8%, P\u0026thinsp;=\u0026thinsp;0.36), but no significant difference. Rate of intracranial hemorrhage and reocclusion within 72h after recanalization showed no significant difference. Time of recanalization was greatly shortened by BIAS technique (58.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.7 Vs 104.4\u0026thinsp;\u0026plusmn;\u0026thinsp;11.3, P\u0026thinsp;=\u0026thinsp;0.004), and the use of stents also reduced [1(1, 2) Vs 2 (1, 4), P\u0026thinsp;=\u0026thinsp;0.03].\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e \u003cp\u003eBIAS technique could partly reduce the occurrence of peri-procedural complications. Moreover, it could greatly shorten the time of recanalization and reduced the use of stent.\u003c/p\u003e\u003cp\u003e\u003cb\u003eTrial registration\u003c/b\u003e\u003c/p\u003e \u003cp\u003eOur study is a retrospective study, not a prospective study, we have not registered for the study.\u003c/p\u003e","manuscriptTitle":"BIAS technique in recanalization of symptomatic long-type chronic internal carotid artery occlusion","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-10 06:51:17","doi":"10.21203/rs.3.rs-6613960/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8ce0e49b-e737-44d9-b179-46e7c3a92c88","owner":[],"postedDate":"June 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-18T10:53:17+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-10 06:51:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6613960","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6613960","identity":"rs-6613960","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}