Tortuous Vascular Anatomy Research Articles

Abstract 144: Strategy for Managing Tandem Extracranial and Intracranial Occlusions: A Technical Note

Introduction Acute ischemic stroke (AIS) due to tandem extracranial and intracranial occlusions (TOs) occurs in 15‐30% of cases and poses significant challenges during acute stroke therapy, leading to worse outcomes compared to thrombectomies without tandem occlusions. Traditional approaches, including antegrade (intracranial revascularization first) and retrograde (extracranial revascularization first) strategies, have shown variable success. The retrograde approach, while potentially offering faster recanalization, often encounters difficulties in advancing the aspiration catheter through the extracranial occlusion site. This abstract outlines our technical algorithm for managing TOs in acute stroke therapy. Methods We conducted a retrospective review of patient records for those who underwent endovascular thrombectomy (EVT) for AIS from July 2021 to June 2024. Our recanalization algorithm for TOs involved: • Prioritizing stent‐retriever deployment across the occlusion site by crossing the extracranial occlusion with a microcatheter. This step aims to achieve early reperfusion via intracranial collaterals from the circle of Willis. Simultaneously, the stent retriever serves as an anchor which facilitates the passage of the aspiration catheter past the cervical occlusion, which is especially useful in case of tortuous vascular anatomy. • If the aspiration catheter successfully advanced through the extracranial occlusion, a retrograde approach was implemented using a combination of aspiration and stent retrieval. After successful intracranial thrombectomy, extracranial balloon angioplasty was performed if necessary. When performing balloon angioplasty, we redeployed the stent retriever in the supraclinoid internal carotid artery to serve as an anchor and distal protection device while using its wire for balloon advancement. • If passage through the cervical occlusion was unsuccessful, the microcatheter was removed while retaining the stent retriever. A 0.18 wire‐compatible PTA balloon was then advanced into the cervical internal carotid artery (ICA) for balloon angioplasty using the stent retriever's wire, thus implementing a modified antegrade approach while providing perfusion to the affected vascular territory. After angioplasty, the aspiration catheter was advanced into the intracranial occlusion site, and stent retrieval with contact aspiration was performed. We avoided extracranial stent angioplasty whenever feasible. Results Among 192 patients, 17 were identified with tandem extracranial and intracranial occlusions. The mean age was 72 years (range: 60‐83). Successful reperfusion on the final angiogram (TICI 2b/3) was achieved in all but one patient (TICI 1). Based on our proposed algorithm, 12 patients were treated with the retrograde approach, and 5 patients were treated with the modified antegrade approach. Six patients underwent thrombectomy only, without the need for angioplasty, while 10 patients required cervical ICA angioplasty. One patient required emergent carotid artery stent angioplasty due to recoiling and reocclusion of the cervical ICA. At three months, 9 patients (53%) had favorable clinical outcomes (mRS ≤3), 5 patients (29%) had unfavorable outcomes (mRS ≥4), and 3 patients were lost to follow‐up (18%). CONCLUSIONS Tandem occlusions represent a highly complex form of AIS. This retrospective review highlights our stepwise decision‐making approach to achieving satisfactory reperfusion. Further prospective studies with larger patient cohorts are needed to evaluate whether this strategy enhances the likelihood of successful reperfusion and improves clinical outcomes.

Enhancing precision in vascular embolization: evaluating the effectiveness of the intentional early detachment technique with detachable coils in complex cases

BackgroundThis study aimed to assess the effectiveness and versatility of an intentional early detachment technique with detachable coils in addressing challenging vascular embolization scenarios. This novel approach aims to provide an alternative method for achieving precise coil placement when standard methods of detachable coil placement are ineffective owing to vascular anatomy or limited available equipment.Materials and methodsThis retrospective study included 11 patients (nine males and two females; median age, 77 years) who underwent embolization procedures between October 2021 and December 2023 using the intentional early detachment technique through 1.6-Fr or 1.3-Fr microcatheters. In this technique, detachable coils were intentionally detached within the microcatheter and placed through saline flushing. The technique’s technical success, complications, and clinical success were evaluated.ResultsThe technique was applied in three distinct scenarios: tortuous vascular anatomy (four cases), inadequate system backup (three cases), and 1.3-Fr microcatheter use (four cases). The technical and clinical success rates were 100%. No complications were observed, and no cases of coil migration or malpositioning.ConclusionThe intentional early detachment technique is valuable for interventional radiologists and offers a solution for challenging vascular embolization scenarios. Its application is limited to specific circumstances; however, it can significantly enhance coil placement in complex cases, thereby contributing to improved patient care.Graphical

In Vitro Analysis of the Efficacy of Endovascular Thrombectomy Techniques according to the Vascular Tortuosity Using 3D Printed Models.

Achieving complete recanalization with the front-line endovascular thrombectomy device improves the outcome of acute stroke. The aim of this study was to evaluate whether various thrombectomy techniques including contact aspiration, stent retriever thrombectomy, and combination therapy differ in first-pass effect and distal emboli in acute large-vessel occlusion simulated using 3D printed nontortuous and tortuous cerebrovascular anatomy models. 3D printed flow models were manufactured using angiographic data of nontortuous and acutely angulated tortuous vascular anatomy from real patients. Three thrombectomy techniques, contact aspiration, stent retriever, and combined methods, were tested under proximal protection with the balloon-guiding catheter. The first-pass effect and distal emboli rates were analyzed in addition to the thrombectomy-failure mechanisms of the respective techniques. A total of 30 thrombectomy experiments were performed. The overall incidence of first-pass effect in the nontortuous and tortuous anatomy was 80.0% versus 46.7%. The overall incidence of distal emboli in the nontortuous and tortuous anatomy was 26.7% versus 46.7%. The contact aspiration technique showed better first-pass effect (80.0%) and distal emboli rates (20%) in the tortuous model compared with other techniques. The combined technique did not show remarkable superiority of the first-pass effect and distal emboli in either the nontortuous or tortuous anatomy. Shearing off of the thrombus was the main mechanism of thrombectomy failure in the combined group. The tortuous vascular anatomy may worsen the first-pass effect and distal emboli rates. The combined techniques failed to show improvement in outcome due to the shearing-off phenomenon of the thrombus during retrieval.

Utility of the novel guide catheter in mechanical thrombectomy for emergent large vessel occlusion stroke.

A number of large bore guide catheters are currently available for use in neuroendovascular surgery. This study represents a multi-institutional retrospective series of patients undergoing mechanical thrombectomy with the use of a TracStar Large Distal Platform (LDP) guide catheter and assessed its performance in vivo in 107 patients. To review a multi-institutional initial experience with the TracStar LDP guide catheter during mechanical thrombectomy for emergent large vessel occlusion (ELVO). A retrospective review was performed at two level one stroke centres to include all patients who underwent mechanical thrombectomy and had the TracStar LDP guide catheter used during the intervention. The TracStar LDP guide catheter was successfully used in 107 mechanical thrombectomies. In anterior circulation ELVO, the guide catheter advanced into the cavernous segment of the internal carotid artery in 62.6% (62/99) of cases. In posterior circulation cases, the guide catheter advanced to the basilar artery in 87.5% (7/8) of cases. A thrombolysis in cerebral infarction 2b or greater reperfusion was obtained in 90.7% (97/107). No complications occurred related to the TracStar LDP guide catheter. Three complications occurred with aspiration catheters including a small dissection that did not require further intervention and fracturing of the AXS Catalyst 6 catheter tip in two cases. No thromboembolic events occurred. The TracStar LDP large bore guide catheter is safe and effective at navigating the tortuous vascular anatomy often encountered during mechanical thrombectomy for stroke. The flexible distal and stiffer proximal components provide a good combination of navigability and support for use in neuroendovascular interventions.

Simplified classification of cavernous internal carotid artery tortuosity: a predictor of procedural complexity and clinical outcomes in mechanical thrombectomy

ABSTRACT Objectives Thromboaspiration catheters are increasingly used for the endovascular treatment of large vessel stroke (LVS), while tortuous vascular anatomy still remains one major challenge in mechanical thrombectomy. Prompt assessing and understanding cavernous internal carotid artery (cICA) tortuosity may help to predict procedural complexities of mechanical thrombectomy and thus improve the clinical outcomes. Methods A retrospective review was performed on a cohort of LVS patients with thromboaspiration catheter. Simplified classification of cICA tortuosity was applied by measurement of the angle of the posterior genus (P) and the height from the peak of the posterior genu to the trough of the anterior genu (D). Statistical analyses were performed to analyze differences among the obtained types of cICA tortuosity regarding procedural characteristics and clinical outcomes. Results A total of 150 patients with LVS proximal to the internal ICA terminus and middle cerebral artery (MCA) were included in this study, and three types of cICA tortuosity were defined by the simplified classification. The index, such as patients ages and hypertension, procedural fluoroscopy time, the degree of cICA tortuosity, first-pass success, final reperfusion, and 90-day mortality showed significant differences among the three types (P < 0.05), while 90-day good outcome (mRS 0–2) only presented significant difference between Type I and Type III (P < 0.05). Conclusions The study indicated that the grading of cICA tortuosity is highly correlated with procedural complexity and clinical outcome in mechanical thrombectomy. The proposed classification system may be helpful in pre-procedure prognostication complexity and clinical outcomes. Abbreviations:LVS: large vessel stroke; cICA: cavernous internal carotid artery; mRS: modified Rankin Scale; AIS: acute ischemic stroke; MCA: middle cerebral artery; M1: first division of middle cerebral artery; M2: second division of middle cerebral artery; M3: third division of middle cerebral artery; TICI: Thrombolysis In Cerebral Infarction; TICI 2b: two-thirds of occluded territory reperfusion; DSA: digital subtraction angiography; FT: fluoroscopy time.

Iatrogenic Portal Venous Circulatory Injuries in the IR Suite.

Advanced portal venous interventions including transjugular intrahepatic portosystemic shunts, variceal sclerotherapy, and portal venous recanalization are more widely performed, as more aggressive approaches to manage portal hypertension increase patient candidacy for liver transplantation and other therapies. Initial percutaneous portal access may be achieved through transjugular, transsplenic, and transhepatic accesses. Although rare, a potentially life-threatening complication from these approaches is hemorrhage from venous perforation.[1] [2] Patients with portal hypertension often have tortuous vascular anatomy, weakened vessel walls, and high portal venous pressures, predisposing them to potentially devastating outcomes if this complication is encountered. As such, interventional radiologists must take extra precaution to avoid venous injuries during advanced portal venous interventions.[3] [4] Herein we present two patients who experienced rapid, dramatic decompensation from intraperitoneal hemorrhage after initial access was achieved. These cases provide an overview of the clinical course and management strategies for this rare complication in the hopes of improving patient outcomes.

A neurovascular high-frequency optical coherence tomography system enables in situ cerebrovascular volumetric microscopy

Intravascular imaging has emerged as a valuable tool for the treatment of coronary and peripheral artery disease; however, no solution is available for safe and reliable use in the tortuous vascular anatomy of the brain. Endovascular treatment of stroke is delivered under image guidance with insufficient resolution to adequately assess underlying arterial pathology and therapeutic devices. High-resolution imaging, enabling surgeons to visualize cerebral arteries' microstructure and micron-level features of neurovascular devices, would have a profound impact in the research, diagnosis, and treatment of cerebrovascular diseases. Here, we present a neurovascular high-frequency optical coherence tomography (HF-OCT) system, including an imaging console and an endoscopic probe designed to rapidly acquire volumetric microscopy data at a resolution approaching 10 microns in tortuous cerebrovascular anatomies. Using a combination of in vitro, ex vivo, and in vivo models, the feasibility of HF-OCT for cerebrovascular imaging was demonstrated.

Design, Modeling, and Control of a Coaxially Aligned Steerable (COAST) Guidewire Robot.

Manual navigation of a guidewire is the first step in endovascular interventions. However, this procedure is time consuming with uncertain results due to tortuous vascular anatomy. This paper introduces the design of a novel COaxially Aligned STeerable (COAST) guidewire robot that is 0.40 mm in diameter demonstrating variable curvature and independently controlled bending length of the distal end. The COAST design involves three coaxially aligned tubes with a single tendon running centrally through the length of robot. The outer tubes are made from micromachined nitinol allowing for tendon-driven bending of the robot at various segments of the robot, thereby enabling variable bending curvatures, while an inner stainless steel tube controls the bending length of the robot. By varying relative positions of the tubes and the tendon by insertion and retraction in the entire assembly, various joint lengths and curvatures can be achieved, which enables a follow-the-leader motion. We model the kinematics, statics, as well as the coupling within tubes of the COAST robot and develop a simple controller to control the distal tip of the robot. Finally, we experimentally demonstrate the ability of COAST guidewire to accurately navigate through phantom anatomical bifurcations and tortuous anatomy.

TCT-128 Diamondback 360 Coronary Orbital Atherectomy System for Treating De Novo, Severely Calcified Coronary Lesions in Elderly Patients: 1-Year Results from the ORBIT II Trial

Percutaneous coronary intervention (PCI) in elderly patients is associated with higher rates of complications and worse short term prognosis. This may be due to increased co-morbidities including renal disease, tortuous vascular anatomy, and calcified arteries. For these reasons, elderly patients

E-050 Navigation of a Distal Cerebral Embolic Protection Device through Significant Vascular Tortuosity with a Novel Rapid Exchange Catheter System during Carotid Artery Stenting

IntroductionCarotid stenosis is a prevalent cause of ischemic cerebrovascular disease. Carotid endarterectomy and carotid artery stenting (CAS) have both been shown to provide effective and durable reductions in the risk...

Iliac Artery Occlusion With “Oxbow Lake” Formation Following Stent Deployment in a Tortuous External Iliac Artery During EVAR

In this case report, we describe a complication that we term the "oxbow lake" deformity. This phenomenon occurs when a tortuous elongated external iliac artery segment is artificially straightened by an iliac stent resulting in kinking and compression of a redundant loop with lumen compromise. We describe the anatomy, corrective treatment, and outcome. This occurrence is potentially foreseeable with tortuous vascular anatomy and recognition can allow appropriate management planning avoiding complications for the patient.

Distal intracranial catheterization of patients with tortuous vascular anatomy using a new hybrid guide catheter

Background A hybrid guide catheter mates the traditional strong guide catheter with a thin, soft distal tip, allowing placement further into the distal cervical or proximal cranial circulation. Case Description We present 5 cases in which traditional guide catheters were unable to successfully navigate tortuous anatomy or provide stable support for intervention. Conclusion Hybrid guide catheters provided safe, stable support for successful treatment. Hybrid guide catheters allow for treatment for patients who previously were not candidates for neuroendovascular surgery.

Utility of the “buddy” wire in intracranial procedures

Patients undergoing neurointerventional procedures with excessively tortuous vascular anatomy often have limited treatment options. The ability to pass and maintain the stability of micro-guidewires, catheters, and interventional devices is often a product of guide catheter steadiness. A companion wire passed through the lumen of the guide catheter to increase the guide catheter's stiffness can overcome the challenges associated with tortuous anatomy; this companion wire is referred to as a "buddy" wire. We demonstrate the technical success of this system by presenting a patient whose endovascular treatment would have otherwise been impossible without a "buddy" wire.

Intracranial Percutaneous Transluminal Angioplasty for Arteriosclerotic Stenosis

Patients with intracranial arteriosclerotic disease have significant morbidity and mortality rates, and some are unresponsive to medical treatment and have unacceptable surgical risks. Percutaneous transluminal angioplasty of the intracranial vessels is a possible alternative to surgery. To present our experience with percutaneous transluminal angioplasty and to summarize our data. Sixteen patients underwent intracranial percutaneous transluminal angioplasty for high-grade arteriosclerotic stenosis based on strict inclusion and exclusion criteria. All patients had symptoms referable to the stenosis except one. Angioplasty was performed in 6 intracranial vertebral arteries, 3 basilar arteries, 5 middle cerebral arteries, and 3 distal internal carotid arteries. One patient had concomitant stent placement. There was 1 treatment failure secondary to tortuous vascular anatomy. Vessel caliber was increased to more than 80% of normal in 6 patients and to 50% to 70% of normal in 6 patients, with a reduction of symptoms. Three intimal dissections occurred during angioplasty; one of these, in a precavernous segment of the internal carotid artery, was stented. One patient restenosed within 1 month of treatment. The remaining treated arteries remained patent during follow-up of 3 months to 2 years. Stroke as a complication occurred in 2 patients, 1 mild and 1 severe. There was no mortality. Occlusive arteriosclerotic disease involving the intracranial cerebral vessels can be managed medically with antiplatelet and anticoagulant drug therapy or surgically. However, in patients who are unresponsive to medical therapy or who have unacceptable surgical risks, percutaneous transluminal angioplasty is an attractive alternative that can be performed in selected patients with relatively low risk and good clinical outcome.