Navigating radial artery loops in neurointerventions

The Zoom RDL radial access system for neurointervention: An early single-center experience

BACKGROUND

The transradial approach (TRA) for neurointerventional procedures is increasingly being used given its technical feasibility and safety. However, catheter trackability and device deliverability are reported barriers to TRA adoption.

METHODS

This is the first report describing the technical feasibility and performance of using the Zoom RDL Radial Access System (Imperative Care, Inc., Campbell, CA) in 29 patients who underwent neurointerventional procedures from October 2022 to January 2023 in a single-center institution.

RESULTS

Mean age of the study population was 61.9±17.2 years, 79.3% were male (23/29), and 62.1% were black (18/29). The most common procedures were stroke thrombectomy (31.0%, 9/29) and aneurysm embolization (27.6%, 8/29). All the stroke thrombectomy procedures were successfully performed; first-pass effect rate (mTICI≥2 c in one pass) was achieved in 66.7% (6/9) of cases. We used TRA in 86.2% of cases (25/29), including distal radial/snuffbox access in 31.0% (9/29) of cases. The radial diameter was >2 mm for all cases. An intermediate/aspiration catheter was used in 89.7% (26/29) of cases. Access success was achieved in 89.7% of cases (26/29); two cases required conversion from TRA to transfemoral approach (6.9%) and one case required conversion to a different guide catheter (3.4%). There were no access site complications or other Zoom RDL-related complications. One intracerebral hemorrhage, and one procedure-related thrombus were observed.

CONCLUSIONS

The use of Zoom RDL Radial Access System is technically feasible and effective for complex neurointerventional procedures with low complication rates.

Comparison of Transradial Access and Transfemoral Access for Diagnostic Cerebral Angiography in the Elderly Population

OBJECTIVE

Evaluate the efficacy, safety, and patient satisfaction of transradial access (TRA) compared with conventional transfemoral access (TFA) for diagnostic cerebral angiography in elderly patients (≥65 years of age).

METHODS

We performed a retrospective review of patients receiving cerebral angiography via TRA or TFA between October 2020 and December 2021 at 3 institutions. Basic patient characteristics, angiographic data, postoperative complications, and patient satisfaction were collected for analysis.

RESULTS

Of the 357 enrolled elderly patients, 175 were performed through TRA and 182 were performed through TFA. There was no significant difference in mean fluoroscopy time (8.6 ± 3.8 minutes vs. 9.1 ± 3.1 minutes; P = 0.103) and radiation exposure (47.7 ± 10.8 Gy-cm2 vs. 49.8 ± 11.3 Gy-cm2; P = 0.068) between the TRA and TFA groups. However, the TRA group had a shorter procedural time (54.7 ± 6.2 minutes vs. 61.1 ± 5.6 minutes; P < 0.001) and less contrast agent (83.2 ± 28.1 mL vs. 100.1 ± 26.2 mL; P < 0.001) than the TFA group. In terms of safety, the incidence of minor vascular access complications in the TRA group was lower than that in the TFA group (1.7% vs. 8.8%; P = 0.003). The incidence of serious complications and neurologic complications in the TRA group was also lower, although the difference was not statistically significant. Overall patient satisfaction was higher in the TRA group than that in the TFA group.

CONCLUSIONS

TRA was an efficient and safe alternative to conventional TFA in elderly patients who underwent diagnostic cerebral angiography and who underwent TRA were more satisfied. Findings supported the radial-first strategy for cerebral angiography in elderly populations.

Transradial or Transulnar Long Sheath Access to the Brachial Artery Allows for Neuroendovascular Procedures in Patients with Radial or Ulnar Artery Occlusion

BACKGROUND

Transradial access is an important tool for many neuroendovascular procedures. Occlusion of the radial or ulnar artery is not uncommon after transradial or transulnar access and can present a challenge for patients requiring repeat angiography.

METHODS

Between March 2022 and June 2023, patients undergoing transradial or transulnar angiography who were found to have a radial artery occlusion or ulnar artery occlusion were identified. Repeat catheterization of the occluded artery was attempted using a 21-gauge single wall puncture needle and a 0.021-inch wire to traverse the occlusion and insert a 23-cm sheath into the brachial artery.

RESULTS

A total of 25 patients undergoing 26 angiograms during the study period were found to have a radial artery occlusion or ulnar artery occlusion. Successful repeat catheterization of the occluded artery was achieved in 21 of 26 cases (80.7%). Outer diameter sheath size ranged from 5 Fr (0.0655 inch) to 8 Fr (0.1048 inch). No access complications were encountered. Number of prior angiograms, time since prior angiogram, and prior angiogram procedure time were associated with lower likelihood of successful access.

CONCLUSIONS

Transradial or transulnar neuroangiography through an occluded radial or ulnar artery is safe and feasible by traversing the occlusion into the brachial artery with a 23-cm sheath. Repeat catheterization is most successful in patients with an arterial occlusion <6 months old. This technique is important in patients who have limited options for arterial access, avoiding access site complications inherent in transfemoral access, and in patients who specifically require radial or ulnar artery access.

TRUST Technique for Neurointervention: A Promising Alternative for Complex Cases

BACKGROUND

Neurointervention via Transradial Access (TRA) is becoming increasingly popular as experience with this technique increases. However, approximately 8.6-10.3% of complex TRA cases are converted to femoral access due to a lack of support or radial artery spasm. This study aimed to assess the efficacy and safety of the TRUST (trans-radial coaxial catheter technique using a short sheath, Simmons catheter, and Tethys intermediate catheter) technique in interventional procedures via TRA.

METHODS

This was a single-center retrospective analysis of 16 patients admitted to our institute between January 2023 to May 2023 to undergo endovascular interventions with the TRUST technique via the TRA.

RESULTS

The mean age of the study population was 63.8 years, and 62.5% were male (10/16). The most common procedure was intracranial atherosclerotic stenosis (93.75%, 15/16). All procedures were performed successfully, and the most common procedures in our cohort were ballooning (50.0%, 8/16), stenting (18.75%, 3/16), and both procedures combined (31.25%, 1/16). All procedures were performed using the TRA, and the distal and proximal radial arteries were used for access in 31.35% (5/16) and 68.75% (11/16) of the cases, respectively. Technical success was achieved in all patients and most cases demonstrated mTICI ≥2b recanalization (93.75%, 15/16). In this case, no major access-site complications occurred.

CONCLUSION

The TRUST technique is technically safe and feasible and had a high technical success rate and low complication rate in our study. These results demonstrate that the TRUST technique is a promising alternative for patients undergoing complex neurointerventions.

Transradial versus transfemoral approach in cerebral angiography: A meta-analysis

BACKGROUND

Cerebral angiography has two common access sites: Transradial approach and transfemoral approach. However, there's no definitive answer to which one is superior.

OBJECTIVE

Compare transradial approach and transfemoral approach for a cerebral angiography procedure.

METHODS

A systematic review of the literature of studies reporting both transradial approach and transfemoral approach results was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. PubMed, Cochrane Library, and Embase were queried.

RESULTS

The meta-analysis examined 18 studies comprising 9388 patients undergoing cerebral angiography. Among the patients, 4598 underwent transradial approach (48.9%) and 4790 underwent transfemoral approach (51.1%). Our results revealed no statistical differences between the approaches regarding procedure success, crossover to transfemoral approach, procedure and fluoroscopy time between both approaches in cerebral angiography. Total, major, and minor complications comparisons were more favorable to transradial approach for this procedure.

CONCLUSION

These findings suggest, despite the ultimate decision regarding the choice of access method might be influenced by the physician's experience and personal preference, the data distinctly lean toward transradial approach as the preferable option for cerebral angiography. The advantages of transradial approach, highlighted by its lower complication rates, especially major complications, suggest that its adoption could contribute to enhanced patient safety and procedural outcomes.

Retained radial catheters associated with variant radial anatomy in neurointerventional procedures

BACKGROUND

Transradial artery access (TRA) for neurointerventional procedures is gaining widespread acceptance. However, complications that were previously rare may arise as TRA procedures increase. Here we report a series of retained catheter cases with a literature review.

METHODS

All patients who underwent a neurointerventional procedure during a 23-month period at a single institution were retrospectively reviewed for a retained catheter in TRA cases. In cases of retained catheters, imaging was reviewed for anatomical variances in the radial artery, and clinical and demographic case details were analyzed.

RESULTS

A total of 1386 nondiagnostic neurointerventional procedures were performed during the study period, 631 (46%) initially via TRA. The 631 TRA cases were performed for aneurysm embolization (n=221, 35%), mechanical thrombectomy (n=116, 18%), carotid stent/angioplasty (n=40, 6%), arteriovenous malformation embolization (n=38, 6%), and other reasons (n=216, 34%). Thirty-nine (6%) TRA procedures crossed over to femoral access, most commonly because the artery of interest could not be catheterized (26/39, 67%). A retained catheter was identified in five cases (1%), and one (0.2%) patient had an entrapped catheter that was recovered. All six patients with a retained or entrapped catheter had aberrant radial anatomy.

CONCLUSION

Retained catheters for neurointerventional procedures performed via TRA are rare. However, this complication may be associated with variant radial anatomy. With the increased use of TRA for neurointerventional procedures, awareness of anatomical abnormalities that may lead to a retained catheter is necessary. We propose a simple protocol to avoid catheter entrapment, including in emergent situations such as TRA for stroke thrombectomy.

Transradial Access Failures During Neuroangiography for Patients With Moyamoya

BACKGROUND

Despite studies continuing to demonstrate the utility of transradial access (TRA) in neuroangiography, minimal data exist regarding predictors of TRA failure. Furthermore, although many patients with moyamoya disease/syndrome will require life-long angiographic evaluation, even less has been reported on the usage of TRA in this population.

OBJECTIVE

To perform a matched analysis at our high-volume moyamoya center to determine predictors of TRA failure in these patients.

METHODS

A total of 636 patients undergoing TRA for neuroangiography were identified from 2018 to 2020. Demographic and angiographic characteristics including radial artery spasm (RAS), radial anomalies, and access site conversion were compared between patients with moyamoya and the rest of the cohort. A 4:1 matched analysis, based on age and sex, was also performed to eliminate confounding variables.

RESULTS

Patients with moyamoya were younger (40 vs 57 years, P < .0001), had smaller radial diameters (1.9 vs 2.6 mm, P < .0001), more commonly had a high brachial bifurcation (25.9% vs 8.5%, P = .008), more frequently experienced clinically significant RAS (40% vs 8.4%, P < .0001), and more often required access site conversion (26.7% vs 7.8%, P = .002). Increasing age was associated with less TRA failures in patients with moyamoya (odds ratio = 0.918) but more failures in the rest of the cohort (odds ratio = 1.034). In the matched analysis, patients with moyamoya continued to experience more radial anomalies, RAS, and access site conversions.

CONCLUSION

Patients with moyamoya, when controlling for age and sex, have higher rates of TRA failure during neuroangiography. Increasing age in Moyamoya is inversely correlated with TRA failures suggesting that younger patients with moyamoya are at higher risk of extracranial arteriopathy.

Emergency Department Visits for Chronic Subdural Hematomas within 30 Days after Surgical Evacuation with and without Middle Meningeal Artery Embolization

BACKGROUND AND PURPOSE

Middle meningeal artery embolization after surgical evacuation of a chronic subdural hematomas is associated with fewer treatment failures than surgical evacuation. We compared emergency department visits within 30 days for patients with chronic subdural hematomas with and without adjunctive middle meningeal artery embolization.

MATERIALS AND METHODS

All cases of chronic subdural hematoma treated from January 1, 2018, through December 31, 2020, were retrospectively reviewed. Treatment was classified as surgery only or surgery combined with middle meningeal artery embolization. The primary outcome was 30-day emergency department presentation and readmission.

RESULTS

Of 137 patients who met the study criteria, 28 (20%) underwent surgery combined with middle meningeal artery embolization. Of these 28 patients, 15 (54%) underwent planned middle meningeal artery embolization and 13 (46%) underwent embolization after surgical failure. The mean chronic subdural hematoma size at presentation in the group with surgery only (n = 109, 20.5 [SD, 6.9] mm) was comparable with that in the combined group (n = 28, 18.7 [SD, 4.5] mm; P = .16). A significantly higher percentage of the surgery-only group presented to the emergency department within 30 days compared with the combined group (32 of 109 [29%] versus 2 of 28 [7%] patients; P = .02). No significant difference was found with respect to readmission (16 [15%] versus 1 [4%] patient; P = .11). Nine patients (8%) in the surgery-only group were readmitted for significant reaccumulation or residual subdural hematoma compared with only 1 patient (4%) in the combined group (P = .40).

CONCLUSIONS

Surgical evacuation combined with middle meningeal artery embolization in patients with chronic subdural hematoma is associated with fewer 30-day emergency department visits compared with surgery alone.

Intracranial aneurysms in the infant population: an institutional case series and individual participant data meta-analysis

OBJECTIVE

Infantile intracranial aneurysms are exceedingly rare. The goal of this study was to evaluate an institutional case series of infantile intracranial aneurysms, as well as those reported in the contemporary literature, to determine their demographics, presentation, management, and long-term outcome.

METHODS

A comprehensive literature review from 1980 to 2020 was performed to identify individual cases of intracranial aneurysms in the infantile population ≤ 2 years of age. Additional cases from the authors' institution were identified during the same time period. An individual participant data meta-analysis (IPDMA) was performed, abiding by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Patient demographic, radiographic, and clinical information was obtained. Descriptive statistical data were recorded, and multivariate logistic regression analyses were performed.

RESULTS

Patient data were obtained for 133 patients from 87 articles in the literature. Ten additional patients at the authors' institution were also identified, for a total of 143 patients included in the IPDMA. The majority (72.7%) of this cohort consisted of idiopathic aneurysms, while 13.3% were posttraumatic pseudoaneurysms, 9.8% were infectious mycotic aneurysms, and 4.2% were aneurysms associated with a systemic connective tissue disorder or vasculitis. The mean age at presentation was 6.6 months. The majority of infants (97.9%) harbored only 1 aneurysm, and hemorrhage was the most common presenting feature (78.3%). The mean aneurysm size was 14.4 mm, and giant aneurysms ≥ 25 mm comprised 12.9% of the cohort. Most aneurysms occurred in the anterior circulation (80.9%), with the middle cerebral artery (MCA) being the most commonly affected vessel (51.8%). Management strategies included open surgical aneurysm ligation (54.0%), endovascular treatment (35.0%), surgical decompression without aneurysm treatment (4.4%), and medical supportive management only (13.9%). Surgical aneurysm ligation was more commonly performed for MCA and anterior cerebral artery aneurysms (p = 0.004 and p = 0.015, respectively), while endovascular techniques were favored for basilar artery aneurysms (p = 0.042). The mean follow-up period was 29.9 months; 12.4% of the cohort died, and 67.0% had a favorable outcome (Glasgow Outcome Scale score of 5).

CONCLUSIONS

This study is, to the authors' knowledge, the largest analysis of infantile intracranial aneurysms to date. The majority were idiopathic aneurysms involving the anterior circulation. Surgical and endovascular techniques yielded equally favorable outcomes in this cohort. Long-term outcomes in the infantile population compared favorably to outcomes in adults.

Iatrogenic radial arteriovenous fistula closure via intraluminal compression in a patient with fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is an arteriopathy of medium-sized vessels causing pathological arterial wall fragility. However, only minimal data exist on evaluating the risk of transradial access (TRA) in these patients. We describe the case of a woman in her 70s who underwent left middle meningeal artery embolisation for an acute-on-chronic subdural haematoma via right TRA. Radial angiography demonstrated significant FMD throughout the entire right upper extremity. To prevent radial spasm, a 23 cm sheath was placed without difficulty. However, follow-up angiography demonstrated the presence of a new radial arteriovenous fistula (AVF) just distal to the brachial bifurcation. Since no forearm haematoma or limb ischaemia developed, the procedure was continued transradially. After embolisation, the guide catheter was removed and follow-up angiography demonstrated resolution of the fistula. This case illustrates that, in the absence of concerning clinical signs, compression from the guide catheter alone may facilitate thrombosis of an acutely identified iatrogenic radial AVF.

Radial Long Sheath Angioplasty for Proximal Severe Flow Limiting Radial Artery Spasm Utilizing the Dotter Technique

BACKGROUND

Although studies continue to demonstrate the advantages of transradial access (TRA) for neurointerventions, radial artery spasm (RAS) remains a frequent cause of TRA failure. Dotter initially described a technique to dilate areas of peripheral vascular stenosis by advancing sequentially larger catheters across the lesion over a wire. We present our institutional experience performing a modified Dotter technique utilizing long radial sheaths to dilate areas of proximal flow limiting RAS.

OBJECTIVE

To review the use of the Dotter technique for alleviating RAS in patients undergoing TRA for neurointerventions.

METHODS

A retrospective review of all patients undergoing TRA for neurointerventions at our institution from 2018-2020 was performed to identify patients with proximal flow limiting RAS. In identified patients, a modified Dotter technique was employed to dilate the stenosis. Demographic and periprocedural data were assessed to identify any adverse outcomes.

RESULTS

Four patients with severe proximal flow limiting RAS were identified. In each case, a hydrophilic long radial sheath and vascular dilator were sequentially advanced through the stenosis. In all cases, repeat angiography demonstrated improvement of the spasm and final radial angiograms demonstrated persistent improvement in caliber and regularity of the vessel. Each procedure was also completed via TRA with no periprocedural complications.

CONCLUSIONS

Our modified Dotter technique is effective in bypassing areas of severe proximal flow limiting RAS thus obviating the need for access site conversion. Additional studies are warranted to understand the implication of the angioplasty-like effects seen within the radial artery following removal of the long radial sheaths.

Radiographic clearance of chronic subdural hematomas after middle meningeal artery embolization

BACKGROUND

Few reports discuss variables associated with improved outcomes after middle meningeal artery (MMA) embolization for chronic subdural hematomas (cSDHs). We analyzed radiographic evidence of cSDH clearance after MMA embolization to elucidate optimal techniques, hematoma clearance rates, and suitable length of follow-up.

METHODS

Patients who underwent MMA embolization for cSDH from January 1, 2018 through December 31, 2020 were analyzed. Patient characteristics, demographics, and technical procedural details were examined. Outcomes for cSDHs analyzed included complete or near-complete resolution at 30, 90, and 180 days following embolization. A multivariable logistic regression analysis identified variables predictive of rapid clearance and resolution of hematomas at 90 days.

RESULTS

The study cohort comprised 66 patients with 84 treated cSDHs. The mean (SD) cSDH size differed significantly at 30-day (8.8 (4.3) mm), 90-day (3.4 (3.0) mm), and 180-day (1.0 (1.7) mm) follow-up (p<0.001). More cSDHs had complete or near-complete resolution at 180 days (92%, 67/73) than at 90 (63%, 45/72) and 30 days (18%, 15/84) post-embolization (p<0.001). Only distal embolysate penetration was independently associated with rapid clearance (OR 3.9, 95% CI 1.4 to 11.1; p=0.01) and resolution of cSDHs at 90 days (OR 5.0, 95% CI 1.7 to 14.6; p=0.003).

CONCLUSION

Although 63% of cSDHs with MMA embolization had complete or near-complete resolution by 90 days post-procedure, 92% reached this stage by 180 days. Therefore, 90-day follow-up may be insufficient to determine the effectiveness of MMA embolization for cSDHs, particularly compared with surgical evacuation alone. Also, distal MMA penetration may be associated with more rapid hematoma clearance.

Republished: Manual reduction of a radial artery loop under direct fluoroscopic visualization

Transradial access has become increasingly used in neurointerventions because it reduces access site complications. However, radial artery anomalies can be difficult to navigate, often necessitating conversion to femoral access. We describe the case of a female patient in her early 70 s who underwent preoperative embolization of a carotid body tumor via right transradial access. Her radial angiogram demonstrated the presence of a radial artery loop which was successfully navigated with a triaxial system but would not spontaneously reduce even after the guide catheter was advanced into the subclavian artery. However, manual manipulation of the catheters in the antecubital fossa under direct fluoroscopic visualization reduced the loop allowing the procedure to continue transradially. Although a majority of radial loops can be traversed and reduced using standard techniques, this case demonstrates that manual reduction can be successful when other measures fail. We recommend attempting this method before converting the access site.

Manual reduction of a radial artery loop under direct fluoroscopic visualization

Transradial access (TRA) has become increasingly utilized in neurointerventions because it reduces access site complications. However, radial artery anomalies can be difficult to navigate, often necessitating conversion to femoral access. We describe the case of a female patient in her early 70s who underwent preoperative embolization of a carotid body tumor via right TRA. Her radial angiogram demonstrated the presence of a radial artery loop which was successfully navigated with a triaxial system but would not spontaneously reduce, even after the guide catheter was advanced into the subclavian artery. However, manual manipulation of the catheters in the antecubital fossa under direct fluoroscopic visualization reduced the loop, allowing the procedure to continue transradially. Although most radial loops can be traversed and reduced using standard techniques, this case demonstrates that manual reduction can be successful when other measures fail. We recommend attempting this method prior to converting the access site.

Radial artery access anatomy: considerations for neuroendovascular procedures

Although enthusiasm for transradial access for neurointerventional procedures has grown, a unique set of considerations bear emphasis to preserve safety and minimize complications. In the first part of this review series, we will review important anatomical considerations for safe and easy neuroendovascular procedures from a transradial approach. These include normal and variant radial artery anatomy, the anatomic snuffbox, as well as axillary, brachial, and great vessel arterial anatomy that is imperative for the neuroendovascular surgeon to be intimately familiar prior to pursuing transradial access procedures. In the next part of the review series, we will focus on safety and complications specific to a transradial approach.

The Rist radial access system: a multicenter study of 152 patients

BACKGROUND

Transradial access (TRA) for neurointervention is becoming increasingly popular as experience with the technique grows. Despite reasonable efficacy using femoral catheters off-label, conversion to femoral access occurs in approximately 8.6-10.3% of TRA cases, due to an inability of the catheter to track into the vessel of interest, lack of support, or radial artery spasm.

METHODS

This is a multicenter, retrospective case series of patients undergoing neurointerventions using the Rist Radial Access System. We also present our institutional protocol for using the system.

RESULTS

152 patients were included in the cohort. The most common procedure was flow diversion (28.3%). The smallest radial diameter utilized was 1.9 mm, and 44.1% were performed without an intermediate catheter. A majority of cases (96.1%) were completed successfully; 3 (1.9%) required conversion to a different radial catheter, 2 (1.3%) required conversion to femoral access, and 1 (0.7%) was aborted. There was 1 (0.7%) minor access site complication and 4 (2.6%) neurological complications.

CONCLUSIONS

The Rist catheter is a safe and effective tool for a wide range of complex neurointerventions, with lower conversion rates than classically reported.