Neurointerventional Procedures Research Articles

Iatrogenic retroperitoneal hematoma as an access-site complication of neurointervention.

To evaluate the clinical and imaging presentation, management, and outcome of iatrogenic retroperitoneal hematomas (IRPHs) during a series of neurointerventional procedures (NIPs). Six IRPH patients with complications, including five renal subcapsular hematomas (RSH) and one retroperitoneal hemorrhage, were observed among 2290 NIPs performed at our hospital from 2000 through 2020. The medical records, neurointerventional techniques, imaging data, and management of these six IRPH patients were retrospectively reviewed. All six patients received preprocedural dual antiplatelet medication and intraprocedural heparinization. All patients underwent right femoral access. The guidewires were not handled under full course fluoroscopy monitoring. The most common symptom of IRPH was periprocedural flank/abdominal pain (6/6, 100%), including five on the left side (83.3%). Hypotension or shock was observed in three patients (50%). Two patients (33%) were diagnosed intraoperatively by sonogram and received on-site treatment, whereas the other four were diagnosed by postprocedural abdominal computed tomography. Active extravasation from a renal artery was diagnosed by angiogram in the five patients with RSH and was successfully treated with embolization. Multiple bleeders in the branches of the renal artery were noted in three RSH patients (60%). The patient with retroperitoneal hematoma was treated conservatively. Unexplained periprocedural or postprocedural abdominal/flank pain, especially contralateral to the femoral access side of the NIPs, should raise the possibility of IRPH. To prevent IRPH, the authors suggest using full visual fluoroscopic monitoring for guidewire navigation during femoral catheterization of NIPs.

Treatment of posterior circulation stroke: Acute management and secondary prevention.

One-fifth of strokes occur in the territory of the posterior circulation, but their management, particularly acute reperfusion therapy and neurointervention procedures for secondary prevention, has received much less attention than similar interventions for the anterior circulation. In this review, we overview the treatment of posterior circulation stroke, including both interventions in the acute setting and secondary prevention. We focus on areas in which the management of posterior circulation stroke differs from that of stroke in general and highlight recent advances.Effectiveness of acute revascularization of posterior circulation strokes remains in large parts unproven. Thrombolysis seems to have similar benefits and lower hemorrhage risks than in the anterior circulation. The recent ATTENTION and BAOCHE trials have demonstrated that thrombectomy benefits strokes with basilar artery occlusion, but its effect on other posterior occlusion sites remains uncertain. Ischemic and hemorrhagic space-occupying cerebellar strokes can benefit from decompressive craniectomy.Secondary prevention of posterior circulation strokes includes aggressive treatment of cerebrovascular risk factors with both drugs and lifestyle interventions and short-term dual anti-platelet therapy. Randomized controlled trial (RCT) data suggest basilar artery stenosis is better treated with medical therapy than stenting, which has a high peri-procedural risk. Limited data from RCTs in stenting for vertebral stenosis suggest that intracranial stenosis is currently best treated with medical therapy alone; the situation for extracranial stenosis is less clear where stenting for symptomatic stenosis is an option, particularly for recurrent symptoms; larger RCTs are required in this area.

Reducing radiation exposure in neurointervention through dedicated training on the biplane angiographic system

To investigate whether the radiation dose in neurointerventional procedures is reduced if the interventionalist has a better working knowledge and skill to operate the biplane angiographic system (BAS). It is common practice in most centres in the UK for radiographers to drive many of the functions of the BAS under the instruction of the interventionalist who performs the procedure. The dose profile of a neurointerventionalist who was trained to perform procedures while operating the BAS independently was evaluated against that of a highly experienced neurointerventionalist when operating with a radiographer-assisted BAS. The dose-area product for 57 procedures was collected retrospectively. Working independently resulted in a statistically significant lower mean dose of 4,655 μGy·m2 compared to mean doses above 7,000 μGy·m2 with a radiographer-assisted BAS (p<0.05). Effectively this allowed for the mean dose to be reduced by as much as 38%. This study suggests that improved knowledge and skill in operating the BAS gives the neurointerventionalist the opportunity to minimise radiation dose. Therefore, this should be part of the skillset acquired by a qualified neurointerventionalist and be formally addressed in the interventional radiology curriculum.18.

Use of intravenous cangrelor in the treatment of ruptured and unruptured cerebral aneurysms: an updated single-center analysis and pooled analysis of current studies

BackgroundIntracranial stent placement for the treatment of cerebral aneurysms is increasingly utilized in both ruptured and unruptured scenarios. Intravenous (IV) cangrelor is a relatively new antiplatelet agent that was initially...

Evaluating the safety and efficacy of transradial approach for thrombectomy in posterior circulation stroke. A systematic literature review and meta-analysis.

Transradial access (TRA) is becoming more popular in neurointerventional radiology procedures and has been associated with reduced mortality, morbidity and access site complications. Guidelines state that TRA is a feasible option for posterior circulation thrombectomy however the evidence base is limited and no systematic literature review has yet been undertaken to evaluate its safety and efficacy. The Cochrane Library, PubMed, Web of Science, Scopus, TRIP and Embase databases were searched. Outcomes collected included TICI scores, puncture to recanalisation time, mRS scores at 90 days and access site complications. 291 records were identified and 31 full text articles were assessed for eligibility. Eight studies met the inclusion criteria and were meta-analysed. The rate of TICI 2b-3 was 94.7% (89.7-99.8% at 95% CI), TICI 3 was 67.9% (42.2-93.6% at 95% CI) and mRS 0-2 at 90 days was 49.8% (31.5-68.1% at 95% CI). Median puncture to reperfusion times were extracted from three studies as 24 (IQR 18-40), 24 (IQR 17.5-56.5) and 27 (IQR 24-33.5) minutes. No access site complications were reported. TICI 2b-3, TICI 3 and mRS scores were comparable to data for transfemoral access (TFA) from a large systematic review. Puncture to recanalisation times appeared lower than the TFA data but statistical comparison of this outcome was not possible. The use of TRA in posterior circulation thrombectomy is safe and effective with comparable results to TFA. Further research with a larger sample size is required to fully investigate the potential for shortened puncture to recanalisation times.

Feasibility of intraoperative MRI for endovascular coiling of intracranial aneurysms: A single centre experience.

Intraoperative magnetic resonance imaging system (iMRIS) surgical theatre is a highly integrated operating room with an intraoperative magnetic resonance imaging (iMRI) designed originally for brain tumour surgery. Its use in neurointerventional procedures, particularly in the setting of endovascular coiling of intracranial aneurysms, has not been discussed in the literature to date. We present our initial experience about the safety and feasibility of iMRI to assess post operative complications and provide baseline imaging post coiling of intracranial aneurysms. Consecutive patients who underwent iMRI between 2015 and 2018 were included in the study. Demographic, clinical details, endovascular technique and surgical outcomes were collected. Details of anesthesia during the procedure were also collected. Fifteen patients underwent iMRI with MRA to assess post coiling status of their elective endovascular coiling of intracranial aneurysms. The mean age in this cohort was 61 years and 46.7% were male. No immediate complications were seen either from the endovascular procedures or from the iMRI. All iMRI scans were performed as planned with no aborted or truncated scans. The image quality of the iMRI/MRA was adequate to detect the residual aneurysm, if present. There was no residual aneurysm on the angiogram that were not detected on the iMRIs. Of the 15 patients, 10 were safely discharged the following day and other 5 were discharged 2 days after their surgery. The iMRI is an advantageous tool which can be integrated into neurointerventional workflow resulting in early post peri-procedural feedback and potentially reduced post-operative hospital stay.

Visibility of liquid embolic agents in fluoroscopy: a systematic in vitro study

BackgroundEndovascular embolization using liquid embolic agents (LEAs) is frequently applied for the treatment of intracranial vascular malformations. Appropriate visibility of LEAs during embolization is essential for visual control and to...

Human “live cadaver” neurovascular model for proximal and distal mechanical thrombectomy in stroke

BackgroundPreclinical testing platforms that accurately replicate complex human cerebral vasculature are critical to advance neurointerventional knowledge, tools, and techniques. Here, we introduced and validated a human “live cadaveric” head-and-neck neurovascular...

Use of 1000fps High Speed X-ray Angiography (HSAngio) to quantify differences in flow diversion effects of three stents with different coverage densities in a cerebral aneurysm invitro model.

High temporal resolution images acquired using 1000fps HSAngio can be used to visualize blood flow patterns and derive flow velocities during neurointerventional procedures. In this work we use this technology to quantify the changes in the blood flow velocities inside a cerebral aneurysm after treatment with three different stents with varying degrees of metal coverage density; stent A : <2%, stent B: 23% and stent C: 40%. A 3D printed in-vitro model of internal carotid artery aneurysm was connected to a flow loop (60% water, 40% glycerol solution used as circulation fluid, circulation flow rate 8 L/s). An automatic programmable injector (KD Scientific Legato 110) was used to inject iodine contrast agent at a rate of 88 mL/min in 3secs. 1000 fps HSAngio sequences of the contrast injection were acquired using an Aries single photon counting detector (Direct Conversion Inc., Stockholm). From these images blood flow velocities were calculated using an optical flow algorithm. As expected the biggest reduction in blood flow velocity inside the aneurysm was 32.4% after deployment of stent C. However, the velocity profile distribution indicated there was still a significant inflow jet into the aneurysm which could be caused by a endoluminal leak between the stent and the vessel wall. The average reduction was only 14% after placement of stent B and 3% after placement of stent A. Blood velocity distribution maps derived using 1000fps HSAngiography technology can be used to evaluate the quality of flow diversion within the aneurysm after placement of stent. Critical information such as endo luminal leakage which can cause treatment failure can also be detected.

Real-time Detection of Patient Head Position and Cephalometric Landmarks from Neuro-Interventional Procedure Images Using Machine Learning for Patient Eye-Lens Dose Prediction.

A deep learning (DL) model has been developed to estimate patient-lens dose in real-time for given exposure and geometric conditions during fluoroscopically-guided neuro-interventional procedures. Parameters input into the DL model for dose prediction include the patient head shift from isocenter and cephalometric landmark locations as a surrogate for head size. Machine learning (ML) models were investigated to automatically detect these parameters from the in-procedure fluoroscopic image. Fluoroscopic images of a Kyoto Kagaku anthropomorphic head phantom were taken at various known X (transverse) and Y (longitudinal) shifts, as well as different magnification modes, to create an image database. For each image, anatomical landmark coordinate locations were obtained manually using ImageJ and are used as ground-truth labels for training. This database was then used to train the two separate ML models. One ML model predicts the patient head shift in both the X and Y directions and the other model predicts the coordinates of the anatomical landmarks. From the coordinates, the distance between these anatomical landmarks is calculated, and input into the DL dose-prediction model. Model performance was evaluated using mean absolute error (MAE) and mean absolute percentage error (MAPE) for the head-shift and landmark-coordinate models, respectively. The goal is to implement these two separate models into the Dose Tracking System (DTS) developed by our group. This would allow the DTS to automatically detect the patient head size and position for eye-lens dose prediction and eliminate the need for manual input by the clinical staff.

Simultaneous Biplane High Speed 1000 fps X-ray Angiography (HSAngio).

High-speed 1000-fps x-ray Angiography (HSAngio) images can be used to visualize blood-flow patterns and derive flow velocities during neurointerventional procedures. In this work, we present for the very first-time, orthogonal views of contrast injection in an aneurysm model acquired simultaneously using biplane HSAngio imaging. 3-D printed in-vitro models A and B of two different internal carotid-artery aneurysms were connected to a flow loop (circulation fluid: 60% water, 40% glycerol solution, circulation flow rate: 8 L/s). An automatic programmable injector (KD Scientific Legato 110) injected iodine contrast agent at a rate of 88 mL/min for a duration of 3 sec. With an RQA5 spectrum, 1000 fps HSAngio sequences of the contrast injection were acquired simultaneously on the frontal plane using the Actaeon detector (Direct Conversion, Stockholm) and on the lateral plane using the Aries (Direct Conversion, Stockholm) detector. The start of contrast injection and simultaneous biplane x-ray exposures and detector image acquisitions were manually synchronized to capture the initial inflow of contrast into the aneurysm region. For model A the frontal plane images gave a better visualization of the flow streamlines in the parent artery in the inflow (average velocity 28 cm/s) and outflow (average velocity 24 cm/s) region of the aneurysm. The vortices within the aneurysm region especially within the aneurysm dome were better visualized in the lateral plane images (average velocity 27 cm/s). Biplane HSAngio imaging techniques can give more accurate representations of 3-D blood flow within the complex vascular pathology of the human brain, compared to single-plane imaging.

The resolute Onyx drug eluting stent for neurointervention: A technical series.

Current methods for angioplasty and stenting of the intracranial vasculature for neurointervention are limited. The Wingspan Stent System is Food and Drug Administration (FDA) approved with human device exemption for a limited patient group and despite numerous prospective registries and trials demonstrating reasonable safety, still carries warnings from the FDA for its use. Given these limitations, we present the technical nuances and outcomes of the off-label use of the Resolute Onyx drug-eluting stent (DES) for neurointerventional purposes. Retrospective chart review of all patients undergoing a neurointerventional procedure with the Resolute Onyx DES was done from January 2017-2021. The Resolute Onyx is a coronary balloon-mounted drug-eluting (zotarolimus) single wire laser cut stent. Technical details and procedural outcomes were collected. In total 40 patients had attempted placement of the Resolute Onyx DES with procedural success in 95% of patients. The most common vessel stented was the basilar artery, 30% (12/40). The most common indication was intracranial atherosclerotic disease in 62.5% (25/40) patients, followed by acute stroke in 17.5% (7/40) of patients. The technical and procedural outcomes were excellent with only one technical complication (2.5%). This series describes the initial technical safety and utility of utilizing a new generation balloon-mounted drug-eluting stent for neurointerventional purposes. This stent offers the potential for improved navigability, delivery, and outcomes compared to current neurointerventional options and warrants further study.

Feasibility of robot-assisted neuroendovascular procedures.

Geographic factors prevent equitable access to urgent advanced neuroendovascular treatments. Robotic technologies may enable remote endovascular procedures in the future. The authors performed a translational, benchtop-to-clinical study to evaluate the in vitro and clinical feasibility of the CorPath GRX Robotic System for robot-assisted endovascular neurointerventional procedures. A series of bench studies was conducted using patient-specific 3D-printed models to test the system's compatibility with standard neurointerventional devices, including microcatheters, microwires, coils, intrasaccular devices, and stents. Optimal baseline setups for various procedures were determined. The models were further used to rehearse clinical cases. Subsequent to these investigations, a prospective series of 6 patients was treated using robotic assistance for complex, wide-necked intracranial saccular aneurysms between November 2019 and February 2020. The technical success, incidence of periprocedural complications, and need for conversion to manual procedures were evaluated. The ideal robotic setup for treatment of both anterior and posterior circulation aneurysms was determined to consist of an 80-cm guide catheter with a 115-cm-long intermediate catheter, a microcatheter between 150 and 170 cm in length, and a microwire with a minimum length of 300 cm. All coils, intrasaccular devices, and stents tested were compatible with the system and could be advanced or retracted safely and placed accurately. All 6 clinical procedures were technically successful, with all intracranial steps being performed robotically with no conversions to manual intervention or failures of the robotic system. There were no procedure-related complications or adverse clinical outcomes. This study demonstrates the feasibility of robot-assisted neurointerventional procedures. The authors' results represent an important step toward enabling remote neuroendovascular care and geographic equalization of advanced endovascular treatments through so-called telestroke intervention.

Antithrombotic therapies for neurointerventional surgery: a 2021 French comprehensive national survey

BackgroundNeurointerventionists lack guidelines for the use of antithrombotic therapies in their clinical practice; consequently, there is likely to be significant heterogeneity in antithrombotic use between centers. Through a nationwide survey,...

Duplication and Fenestration of the Inferior Petrosal Sinus: Cadaveric Study with Application to Imaging, Skull Base Surgery, and Neurointerventional Procedures

Reports of a duplicated or fenestrated inferior petrosal sinus (IPS) are scarce or not found in the literature, respectively. To our knowledge, there are no cadaveric reports of the latter. This study used 20 adult cadaveric heads (40 sides). After removal of the brain, the IPS was dissected using a surgical microscope. Specimens with duplication or fenestration of the IPS anywhere along its course were photographed and measured. On 2 (5%) left sides, a fenestration was identified in the IPS. One of these was found to have 2 fenestrations. The mean length and width of the 3 fenestrations were 2.3 mm and 0.95 mm, respectively. The 3 fenestrations were located at the middle to terminal parts of the IPS. On 2 (5%) left sides and 1 (2.5%) right side, the IPS was duplicated over a part of its course. The mean length and width of the duplicated parts of the IPS were 25.9 mm and 3.1 mm, respectively. No statistical significance was found for fenestrations or duplications comparing males versus females, but fenestrations were statistically significant (P < 0.05) for occurring on left sides. Unfamiliarity with a duplicated or fenestrated IPS could increase risk of iatrogenic injury and misinterpretation of imaging. Further radiological imaging studies are required to substantiate more accurately the mechanisms by which a duplicated or fenestrated IPS affects clinical outcomes. Nonetheless, anatomical awareness of such lesser known variations of the IPS is crucial for promoting safe and effective interventional approaches at the skull base.

Efficacy of the MRA-Based Road Mapping of the Para-Aortic Access Route before Mechanical Thrombectomy in Patients with Acute Ischemic Stroke

Introduction: The aim of this study was to clarify whether magnetic resonance angiography (MRA)-based road mapping of the para-aortic transfemoral access route can reduce the procedural time of mechanical thrombectomy in patients with acute ischemic stroke. We further investigated the role of pre-procedural MRA-based road mapping in optimal initial catheter selection for rapid mechanical thrombectomy. Materials and Methods: We retrospectively reviewed 57 consecutive patients with acute ischemic stroke who underwent mechanical thrombectomy at our hospital between April 2018 and May 2021. Twenty-nine patients underwent MRA-based road mapping to visualize the para-aortic access route, whereas 28 patients only underwent routine head magnetic resonance imaging/angiography without MRA-based road mapping before neuro-interventional procedures. We then compared the basic procedural times required for mechanical thrombectomy, such as the time from femoral artery puncture to recanalization (“puncture to recanalization time”) and the time from the admission to recanalization (“door to recanalization time”), between the groups. Results: MRA-based road mapping significantly reduced the “puncture to recanalization time” (52.0 min vs. 70.0 min; p = 0.019) and the “door to recanalization time” (146 min vs. 183 min; p = 0.013). Conclusion: MRA-based road mapping of the para-aortic access route is useful to reduce the procedural time of mechanical thrombectomy in acute stroke patients, possibly by enabling optimal initial catheter selection during the procedure.

Establishing a New Neurointerventional Facility in a Remote Area of a Low-Middle Income Country (LMIC): Initial Experience.

Background Timely performed Neurointervention procedures in patients with neurovascular disorders save them from mortality and lifelong morbidity, in addition to relieving the immense economic and social burden associated with these diseases. Materials and Methods We retrospectively reviewed data of neurointerventions performed in our hospital from November 2019 till March 2021. Patient age, sex, diagnosis, preoperative, and postoperative imaging findings were collected and analyzed. Types of procedures, success/failure, procedure-related and procedure-unrelated complications were noted and described. Results Total 161 procedures were done (diagnostic n = 89, therapeutic n = 72). Among the 72 cases of therapeutic procedures, angiographic success was noted in 60 cases, partial success was noted in 5 cases (RR grade 3 occlusion) and failure was noted in 7 cases [mechanical thrombectomy (n = 2), coiling (n = 1), flow diverter (n = 1), Caroticocavernous fistula (n = 1), cerebral Arteriovenous malformation (n = 2)]. Among therapeutic cases (n = 72), patient outcome was categorized as improved (with mRS 0-2 at discharge) in 64 cases (60 neurointerventions, 4 converted to surgery), morbidity in form of weakness was noted in 2 cases, mortality was noted in 8 cases. There were no hemorrhagic complications due to rupture or dissection. Ischemic complications were noted in form of thromboembolic complications in three cases and vessel occlusion (delayed MCA occlusion) in one case. Conclusion With recent efforts by medical associations and governments to provide access to these lifesaving, disability averting neuro-interventions, it’s important to recognize and define challenges in implementation of neuro-intervention services. In this article, we share our early experience in establishing a neurointervention facility in a backward region of a low–middle income country.

Abstract TP167: Unanticipated Platelet Function Fluctuations Occur During The First 8 Hours After Neurointerventional Procedures In Patients Receiving Dual Anti-platelet Therapy

Antiplatelet agents are administered before and after neuroendovascular surgery to minimize implant-associated thromboembolic events. Dual antiplatelet therapy (DAPT) uses aspirin plus P2Y12 receptor inhibitors: clopidogrel, ticagrelor, or prasugrel. Effects are quantified in P2Y12 reactivity units (PRU) and aspirin reactivity units (ARU) by the point-of-care assay, Accumetrics VerifyNow. We hypothesized that intraoperative events such as anesthesia may affect platelet inhibition, increasing the risk of unanticipated ischemic events in the early postoperative period. This retrospective study was approved by the institutional review board. 50 patients who underwent Verify Now testing preoperatively and within 12 hours postoperatively after placement of cervical or intracranial stents at a single institution (January 1, 2018 - May 25, 2021) were included. PRU values &gt; 194 and ARU values &gt; 550 were considered subtherapeutic. Anesthetic agents, heparin dosage, clopidogrel responsiveness, platelet count, liver function, procedure type and length, NIH stroke scale scores, and demographics were compared to perioperative platelet inhibition values. Our results indicate that P2Y12 inhibition is likely affected by intraoperative events. Approximately 25% of patients exhibited marginal (170-193) or subtherapeutic (&gt; 194) PRU values during the first 8 hours following neuroendovascular procedures. The greatest variation occurred in the ticagrelor group (PRU median change 84) and was more likely to occur with reduced doses of both ticagrelor and clopidogrel. A single prasugrel patient (clopidogrel non-responder) exhibited the greatest absolute change (PRU 156 -&gt; 316). ARU variations were less pronounced suggesting that perioperative aspirin platelet inhibition is more resilient. In conclusion, patients undergoing elective neuroendovascular procedures may be at risk for thromboembolic ischemic complications during the first 8 hours postoperatively due to shifts in P2Y12 mediated platelet inhibition. ARU values were less effected, supporting the use of DAPT as an ongoing clinical standard of care.

Abstract 78: A Single Center Comparison Of Transradial And Transfemoral Approaches For Carotid Angioplasty And Stent Placement

Context: Transradial access has been increasingly utilized for neurointerventional procedures including carotid angioplasty and stent placement (CAS) over the past decade. At our center, we adopted transradial approach as the preferred approach in 2020. Objective: To compare the results of transradial approach with transfemoral approach for CAS as part of a quality assurance initiative. Methods: We analyzed data collected for all non-urgent CAS procedures performed at our institute in the last 24 months by same interventionalists to minimize inter-operator variability. We looked at the rates of technical failure; hemorrhagic complications classified as major (hemoglobin decrease &gt;5 g/dL or intracranial hemorrhage with deficits), minor (hemoglobin decreases 3-5 g/dL or intracranial hemorrhage without residual deficits), or insignificant; and any stroke and/or death within 1-month post procedure. Results: A total of 182 non-urgent CAS procedures were performed at our institution; 116 (64%) were initiated using transfemoral approach and 66 (36%) were initiated using transradial approach. The median age was similar between the two group (66.5 years versus 66.7 years). There were 6 (3%) CAS procedures initiated using transradial approach but later converted to transfemoral due to anatomical and/or technical difficulties. One (0.6%) CAS procedure initiated using transfemoral approach was converted to transradial approach due to severe iliofemoral atherosclerosis. The rates of any stroke and/or death were 1.6% (n=1) and 3.3%% (n-=4) in patients undergoing CAS using transradial and transfemoral approaches, respectively. The rate of major hemorrhagic complications were 1.6% (n=1) and 5.7% (n-=7) in patients undergoing CAS using transradial and transfemoral approaches, respectively. Conclusions: The rates of major hemorrhagic complications were lower among patients who underwent CAS via transradial approach compared with CAS using transfemoral approach although the rates of technical failure remain relatively high with transradial approach.

Rist Guide Catheter for Endovascular Procedures: Initial Case Series from a Single Center.

The transradial approach (TRA) for endovascular procedures has become a frequent practice in neurointervention. Advantages of the TRA include less access-site complications, early ambulation, and less postprocedural pain. The Rist 079 radial access guide catheter (Medtronic) is the first device designed specifically for neurointerventions performed through the TRA. In this study, we report our initial experience with the Rist catheter in a variety of neurointerventional procedures, aiming to evaluate the performance of this device and discuss its limitations. A prospectively maintained database was retrospectively searched to identify patients who underwent procedures using the Rist catheter. Information on demographics, procedural details, and complications was recorded. Seventy-eight patients were included in the study, with a mean age of 60.3 years (range, 25-92 years); 45 (57.7%) were men. The interventional or diagnostic procedure was successfully completed in 77 patients (98.7%). The radial artery was the primary access-site choice in 71 patients (91%). The most frequent type of procedures performed were coiling or stent-assisted coiling (16.7%) and angioplasty and stenting (16.7%), followed by middle meningeal artery embolization (14.1%). Crossover to femoral artery access while maintaining use of the Rist was done in 5 cases (6.4%). Reasons for access or procedural failure included anatomical anomaly of the target vessel, unfavorable geometry of the great vessels, and proximal tortuosity of the supra-aortic vessels. We demonstrated a high success rate with use of the Rist catheter system for a variety of procedures.