The VEBAS score: a practical scoring system for intracranial dural arteriovenous fistula obliteration.

BACKGROUND: Tools predicting intracranial dural arteriovenous fistulas (dAVFs) treatment outcomes remain scarce. This study aimed to use a multicenter database comprising more than 1000 dAVFs to develop a practical scoring system that predicts treatment outcomes. METHODS: Patients with angiographically confirmed dAVFs who underwent treatment within the Consortium for Dural Arteriovenous Fistula Outcomes Research-participating institutions were retrospectively reviewed. A subset comprising 80% of patients was randomly selected as training dataset, and the remaining 20% was used for validation. Univariable predictors of complete dAVF obliteration were entered into a stepwise multivariable regression model. The components of the proposed score (VEBAS) were weighted based on their ORs. Model performance was assessed using receiver operating curves (ROC) and areas under the ROC. RESULTS: A total of 880 dAVF patients were included. Venous stenosis (presence vs absence), elderly age (<75 vs ≥75 years), Borden classification (I vs II-III), arterial feeders (single vs multiple), and past cranial surgery (presence vs absence) were independent predictors of obliteration and used to derive the VEBAS score. A significant increase in the likelihood of complete obliteration (OR=1.37 (1.27-1.48)) with each additional point in the overall patient score (range 0-12) was demonstrated. Within the validation dataset, the predicted probability of complete dAVF obliteration increased from 0% with a 0-3 score to 72-89% for patients scoring ≥8. CONCLUSION: The VEBAS score is a practical grading system that can guide patient counseling when considering dAVF intervention by predicting the likelihood of treatment success, with higher scores portending a greater likelihood of complete obliteration.

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.

Aromatic Yeasts: Interactions and Implications in Coffee Fermentation Aroma Profiles.

Nontraditional yeasts prevalent in tropical agricultural fermentations such as coffee and cocoa are known to contribute to aroma profiles, yet the functional roles and interactions between the associated microbial consortia in a farm fermentation are unclear. Here, boiled green bean extract (GBE) from green coffee beans was developed as a rich screening medium to deconstruct the microbial consortia and their interactions during the fermentation of dried green coffee beans. When cultivated in coculture with S. cerevisiae on GBE, strain-specific groupings with distinct volatile organic profiles were observed for nontraditional yeasts (e.g., Hanseniaspora spp., Pichia kudriavzevii). Further changes are evident when constructed consortia composed of nontraditional yeast, S. cerevisiae, and Lactococcus lactis var. cremoris were cultured in GBE, and a comparison with abiotically acidified GBE suggests that pH plays a major role in the influence of lactic acid bacteria (LAB) on fermentation aromas. This approach represents a tool for the development of starter culture formulations to create different flavor profiles in coffee fermentation.

Deuterated buprenorphine retains pharmacodynamic properties of buprenorphine and resists metabolism to the active metabolite norbuprenorphine in rats.

Introduction: An active metabolite of buprenorphine (BUP), called norbuprenorphine (NorBUP), is implicated in neonatal opioid withdrawal syndrome when BUP is taken during pregnancy. Therefore, reducing or eliminating metabolism of BUP to NorBUP is a novel strategy that will likely lower total fetal exposure to opioids and thus improve offspring outcomes. Precision deuteration alters pharmacokinetics of drugs without altering pharmacodynamics. Here, we report the synthesis and testing of deuterated buprenorphine (BUP-D2). Methods: We determined opioid receptor affinities of BUP-D2 relative to BUP with radioligand competition receptor binding assays, and the potency and efficacy of BUP-D2 relative to BUP to activate G-proteins via opioid receptors with [35S]GTPγS binding assays in homogenates containing the human mu, delta, or kappa opioid receptors. The antinociceptive effects of BUP-D2 and BUP were compared using the warm-water tail withdrawal assay in rats. Blood concentration versus time profiles of BUP, BUP-D2, and NorBUP were measured in rats following intravenous BUP-D2 or BUP injection. Results: The synthesis provided a 48% yield and the product was ≥99% deuterated. Like BUP, BUP-D2 had sub-nanomolar affinity for opioid receptors. BUP-D2 also activated opioid receptors and induced antinociception with equal potency and efficacy as BUP. The maximum concentration and the area under the curve of NorBUP in the blood of rats that received BUP-D2 were over 19- and 10-fold lower, respectively, than in rats that received BUP. Discussion: These results indicate that BUP-D2 retains key pharmacodynamic properties of BUP and resists metabolism to NorBUP and therefore holds promise as an alternative to BUP.

Recurrent Osteomyelitis Caused by Mycobacterium abscessus Necessitating Surgical Decompression and Revision Surgery With Interbody Fusion.

Epidural abscesses can be caused by a number of different organisms, including atypical Mycobacterium. This is a rare case report of an atypical Mycobacterium epidural abscess requiring surgical decompression. Here, we present Mycobacterium abscessus causing a nonpurulent epidural collection surgically treated with laminectomy and washout and discuss clinical clues and radiologic characteristics associated with this condition. A 51-year-old male with a past medical history of chronic intravenous (IV) drug use presented with a three-day history of falls and three-month history of progressively worsening bilateral lower extremity radiculopathy, paresthesias, and numbness. MRI demonstrated an enhancing collection at L2-3 ventral and to the left of the spinal canal causing severe compression of the thecal sac, along with heterogenous contrast enhancement of the L2-3 vertebral bodies and intervertebral disc. The patient was taken for an L2-3 laminectomy and left medial facetectomy, where a fibrous, nonpurulent mass was discovered. Cultures ultimately demonstrated Mycobacterium abscessus subspecies massiliense, and the patient was discharged on IV levofloxacin, azithromycin, and linezolid with complete symptomatic relief. Unfortunately, despite surgical washout and antibiotic coverage, the patient presented twice more, the first time with a recurrent epidural collection requiring repeat drainage and the second time with a recurrent epidural collection with discitis and osteomyelitis with pars fractures requiring repeat epidural drainage and interbody fusion. It is important to recognize that atypical Mycobacterium abscessus can cause a nonpurulent epidural collection, especially in high-risk patients such as those with a history of chronic IV drug use. Additionally, our initial intraoperative findings of a fibrous, adherent mass suggest that in cases where this entity is suspected, surgical decompression should be carefully considered. To this end, the radiologic findings associated with this condition, namely, an enhancing ventral epidural mass involving the disc space, should also be recognized. The notable postoperative course consisting of recurrent collections and osteomyelitis with a pars fracture suggests that early fusion should be considered as an option in these patients. This case report presents clinical and radiologic findings associated with an atypical Mycobacterium discitis and osteomyelitis. The clinical course described herein suggests that early fusion in these patients may provide superior results to decompression alone.

Cohort study on the differential expression of inflammatory and angiogenic factors in thrombi, cerebral and peripheral plasma following acute large vessel occlusion stroke.

Inflammation plays an important role in the pathogenesis of stroke. The differential expression of inflammatory and angiogenic factors in thrombi and plasma remain undefined. In this observational cohort study, we evaluated angiogenic factors and inflammatory cytokines, in cerebral thrombi, local cerebral plasma (CP), and peripheral plasma (PP) in patients with acute ischemic stroke. Protein analysis of thrombi, CP and PP were used to measure angiogenic and inflammatory proteins using electrochemiluminescence. Our data indicate that VEGF-A, VEGF-C, bFGF, IL-4, IL-13, IL-1ß, IL-2, IL-8, IL-16, IL-6 and IL-12p70 were higher in the thrombi of acute ischemic stroke patients than in the CP and PP of stroke patients. Moreover, the protein levels of GM-CSF were lower in the PP than in the CP and the clot. Moreover, VEGF-D, Flt-1, PIGF, TIE-2, IL-5, TNF-ß, IL-15, IL-12/IL-23p40, IFN-γ and IL-17A were higher in PP and CP than in thrombi. Our results show that cytokines mediating the inflammatory response and proteins involved in angiogenesis are differentially expressed in thrombi within the cerebral and peripheral circulations. These data highlight the importance of identifying new biomarkers in different compartments of the circulatory system and in thrombi that may be used for the diagnosis and treatment of stroke patients.

Pharmacokinetics of bleomycin sclerotherapy in patients with vascular malformations.

Bleomycin, a chemotherapy agent that inhibits synthesis of DNA, has been increasingly utilized in sclerotherapy for patients with vascular malformations. A serious long-term risk of intravenous bleomycin is dose-dependent interstitial pneumonitis. Little is known about absorption and circulating levels of bleomycin when used in sclerotherapy for patients with vascular malformations. This is an Institutional Review Board (IRB)-approved prospective study on patients receiving bleomycin sclerotherapy in the management of vascular malformations. Depending on the type of vascular malformation, bleomycin was administered either in the lumen or interstitial space of the involved lesion. A bleomycin assay measured serum bleomycin plasma concentrations versus time at seven intervals following treatment. Pharmacokinetic parameters were obtained for each participant and included peak plasma concentration (Cmax ), time to reach peak plasma concentration (Tmax ), volume of distribution (Vd ), elimination half-life (t1/2 ), the volume of plasma cleared of the drug per unit time (CL), and total systemic exposure area under the curve (AUC). Fifteen patients were enrolled (5: lymphatic, 4: venous, 6: arteriovenous malformations). Bleomycin was administered interstitially (IS) in 11 patients and intraluminal (IL) in four; median age of 13 years (range: 2-67). Pharmacokinetic analysis revealed terminal elimination half-life (t1/2λz ) of 88.51 (±23.09) and 111.61 (±37.75) minutes for the IS and IL groups, respectively. Vd was 4.86 L (±6.74) and 1.55 L (±0.54) for the IS and IL groups, respectively. AUC was 53.9 (±23.45) and 129.17 (±93.57) mg min/L for the IS and IL groups, respectively. There were no statistically significant differences in t1/2λz , Vd , or AUC parameters between groups. Bleomycin is absorbed systemically when used as a sclerosant for vascular malformations when injected either IS or IL.

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.

Short-Term Safety of Repeated Acetaminophen Use in Patients With Compensated Cirrhosis.

Current guidelines recommend restricting acetaminophen (APAP) use in patients with cirrhosis, but evidence to support that recommendation is lacking. Prior studies focused on pharmacokinetics (PK) of APAP in cirrhosis but did not rigorously examine clinical outcomes, sensitive biomarkers of liver damage, or serum APAP-protein adducts, which are a specific marker of toxic bioactivation. Hence, the goal of this pilot study was to test the effects of regularly scheduled APAP dosing in a well-defined compensated cirrhosis group compared to control subjects without cirrhosis, using the abovementioned outcomes. After a 2-week washout, 12 subjects with and 12 subjects without cirrhosis received 650 mg APAP twice per day (1.3 g/day) for 4 days, followed by 650 mg on the morning of day 5. Patients were assessed in-person at study initiation (day 1) and on days 3 and 5. APAP-protein adducts and both conventional (alanine aminotransferase) and sensitive (glutamate dehydrogenase [GLDH], full-length keratin 18 [K18], and total high-mobility group box 1 protein) biomarkers of liver injury were measured in serum on the mornings of days 1, 3, and 5, with detailed PK analysis of APAP, metabolites, and APAP-protein adducts throughout day 5. No subject experienced adverse clinical outcomes. GLDH and K18 were significantly different at baseline but did not change in either group during APAP administration. In contrast, clearance of APAP-protein adducts was dramatically delayed in the cirrhosis group. Minor differences for other APAP metabolites were also detected. Conclusion: Short-term administration of low-dose APAP (650 mg twice per day, <1 week) is likely safe in patients with compensated cirrhosis. These data provide a foundation for future studies to test higher doses, longer treatment, and subjects who are decompensated, especially in light of the remarkably delayed adduct clearance in subjects with cirrhosis.

Onyx embolization for dural arteriovenous fistulas: a multi-institutional study.

BACKGROUND: Although the liquid embolic agent, Onyx, is often the preferred embolic treatment for cerebral dural arteriovenous fistulas (DAVFs), there have only been a limited number of single-center studies to evaluate its performance. OBJECTIVE: To carry out a multicenter study to determine the predictors of complications, obliteration, and functional outcomes associated with primary Onyx embolization of DAVFs. METHODS: From the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database, we identified patients who were treated for DAVF with Onyx-only embolization as the primary treatment between 2000 and 2013. Obliteration rate after initial embolization was determined based on the final angiographic run. Factors predictive of complete obliteration, complications, and functional independence were evaluated with multivariate logistic regression models. RESULTS: A total 146 patients with DAVFs were primarily embolized with Onyx. Mean follow-up was 29 months (range 0-129 months). Complete obliteration was achieved in 80 (55%) patients after initial embolization. Major cerebral complications occurred in six patients (4.1%). At last follow-up, 84% patients were functionally independent. Presence of flow symptoms, age over 65, presence of an occipital artery feeder, and preprocedural home anticoagulation use were predictive of non-obliteration. The transverse-sigmoid sinus junction location was associated with fewer complications, whereas the tentorial location was predictive of poor functional outcomes. CONCLUSIONS: In this multicenter study, we report satisfactory performance of Onyx as a primary DAVF embolic agent. The tentorium remains a more challenging location for DAVF embolization, whereas DAVFs located at the transverse-sigmoid sinus junction are associated with fewer complications.

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.

Effect of Hispanic Status in Mechanical Thrombectomy Outcomes After Ischemic Stroke: Insights From STAR.

Background and Purpose: Epidemiological studies have shown racial and ethnic minorities to have higher stroke risk and worse outcomes than non-Hispanic Whites. In this cohort study, we analyzed the STAR (Stroke Thrombectomy and Aneurysm Registry) database, a multi-institutional database of patients who underwent mechanical thrombectomy for acute large vessel occlusion stroke to determine the relationship between mechanical thrombectomy outcomes and race. Methods: Patients who underwent mechanical thrombectomy between January 2017 and May 2020 were analyzed. Data included baseline characteristics, vascular risk factors, complications, and long-term outcomes. Functional outcomes were assessed with respect to Hispanic status delineated as non-Hispanic White (NHW), non-Hispanic Black (NHB), or Hispanic patients. Multivariate analysis was performed to identify variables associated with unfavorable outcome or modified Rankin Scale ≥3 at 90 days. Results: Records of 2115 patients from the registry were analyzed. Median age of Hispanic patients undergoing mechanical thrombectomy was 60 years (72­84), compared with 63 years (54­74) for NHB, and 71 years (60­80) for NHW patients (P<0.001). Hispanic patients had a higher incidence of diabetes (41%; P<0.001) and hypertension (82%; P<0.001) compared with NHW and NHB patients. Median procedure time was shorter in Hispanics (36 minutes) compared to NHB (39 minutes) and NHW (44 minutes) patients (P<0.001). In multivariate analysis, Hispanic patients were less likely to have favorable outcome (odds ratio, 0.502 [95% CI, 0.263­0.959]), controlling for other significant predictors (age, admission National Institutes Health Stroke Scale, onset to groin time, number of attempts, procedure time). Conclusions: Hispanic patients are less likely to have favorable outcome at 90 days following mechanical thrombectomy compared to NHW or NHB patients. Further prospective studies are required to validate our findings.

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.

Challenges in Diagnosis and Management of Previously Embolized Spinal Dural Arteriovenous Fistulae.

BACKGROUND: Given the growing prevalence of initial endovascular treatment for type 1 spinal dural arteriovenous fistulae (dAVF), there are an increasing number of patients presenting with progressive symptoms related to recurrent previously embolized spinal dAVF. This study's goal was to identify demographic, clinical, and radiographic variables among patients who have failed embolization of type I spinal dAVF. METHODS: A retrospective review of 24 consecutive surgeries for type I spinal dAVF performed by the senior author (A.D.L.) identified 5 patients who underwent open surgery for failed embolization. These 5 cases were reviewed for location of fistula, time from embolization to recurrence, preoperative functional status, fistulous point encountered at surgery, and clinical outcome of the patient at 3-month follow-up. A representative example case is reviewed in detail. RESULTS: The median age at time of recurrence was 63 years (range 51-73 years). The median timing of embolization to recurrence of neurologic symptoms was 5 months (range 1-54) and to surgery 7 months (range 2-60 months). The level of the spinal dAVF was most frequently at T12-L1 (n = 3). Spinal magnetic resonance arteriography led to localization of the spinal dAVF in 2 patients and spinal catheter angiogram in 3 cases. All patients had definitive radiographic cure of the dAVF at last clinical follow-up. CONCLUSIONS: The increased use of endovascular treatment of spinal dAVF has led to the treatment of refractory cases with a greater degree of surgical complexity. Open surgical ligation continues to provide the most definitive treatment outcomes for this complex spinal vascular entity.

PTMViz: a tool for analyzing and visualizing histone post translational modification data.

BACKGROUND: Histone post-translational modifications (PTMs) play an important role in our system by regulating the structure of chromatin and therefore contribute to the regulation of gene and protein expression. Irregularities in histone PTMs can lead to a variety of different diseases including various forms of cancer. Histone modifications are analyzed using high resolution mass spectrometry, which generate large amounts of data that requires sophisticated bioinformatics tools for analysis and visualization. PTMViz is designed for downstream differential abundance analysis and visualization of both protein and/or histone modifications. RESULTS: PTMViz provides users with data tables and visualization plots of significantly differentiated proteins and histone PTMs between two sample groups. All the data is packaged into interactive data tables and graphs using the Shiny platform to help the user explore the results in a fast and efficient manner to assess if changes in the system are due to protein abundance changes or epigenetic changes. In the example data provided, we identified several proteins differentially regulated in the dopaminergic pathway between mice treated with methamphetamine compared to a saline control. We also identified histone post-translational modifications including histone H3K9me, H3K27me3, H4K16ac, and that were regulated due to drug exposure. CONCLUSIONS: Histone modifications play an integral role in the regulation of gene expression. PTMViz provides an interactive platform for analyzing proteins and histone post-translational modifications from mass spectrometry data in order to quickly identify differentially expressed proteins and PTMs.

Radial Artery Access for Cerebral Angiography: 2-Dimensional Operative Video.

A number of studies have demonstrated that the radial artery is a safer access site than the femoral artery for endovascular procedures.1-4 In the prospective randomized studies comparing transradial and transfemoral approaches for cardiac procedures, there was a 60% reduction in access site complications as well as significant decreases in all-cause mortality with the transradial approach as compared to transfemoral, which has led to the adoption of a radial first strategy.5-7 Neurointerventional studies have demonstrated similar safety benefits as well as improved patient preference.8-14 In this video, a patient presented with an unruptured anterior communicating artery aneurysm and consented to a transradial artery diagnostic cerebral angiogram. This technical video demonstrates the key preprocedural preparation, room setup, patient positioning, steps for radial artery, and distal radial artery puncture and sheath placement. Distal transradial artery access is our preferred approach for diagnostic cerebral angiography because of an improved safety profile and procedural ergonomics. In cases in which a larger radial artery is advantageous such as for neurointerventions requiring larger systems, a standard transradial approach may be performed.9 In this video, a full 6-vessel cerebral angiogram is performed, followed by our arteriotomy closure technique using our standard equipment including a 10-cm 5 French Glidesheath Slender (Terumo, Japan), 100-cm hydrophilic coated 5 French Simmons 1 catheter (Merit OEM), 0.035 hydrophilic coated guidewire, and SafeGuard closure device (Merit, Salt Lake City, Utah).

Upper extremity transvenous access for neuroendovascular procedures: an international multicenter case series.

BACKGROUND: Radial artery access for transarterial procedures has gained recent traction in neurointerventional due to decreased patient morbidity, technical feasibility, and improved patient satisfaction. Upper extremity transvenous access (UETV) has recently emerged as an alternative strategy for the neurointerventionalist, but data are limited. Our objective was to quantify the use of UETV access in neurointerventions and to measure failure and complication rates. METHODS: An international multicenter retrospective review of medical records for patients undergoing UETV neurointerventions or diagnostic procedures was performed. We also present our institutional protocol for obtaining UETV and review the existing literature. RESULTS: One hundred and thirteen patients underwent a total of 147 attempted UETV procedures at 13 centers. The most common site of entry was the right basilic vein. There were 21 repeat puncture events into the same vein following the primary diagnostic procedure for secondary interventional procedures without difficulty. There were two minor complications (1.4%) and five failures (ie, conversion to femoral vein access) (3.4%). CONCLUSIONS: UETV is safe and technically feasible for diagnostic and neurointerventional procedures. Further studies are needed to determine the benefit over alternative venous access sites and the effect on patient satisfaction.

Navigating radial artery loops in neurointerventions.

BACKGROUND: Although studies continue to demonstrate lower complications in neurointerventions using transradial access (TRA) compared with transfemoral approaches, anatomic radial variants can be difficult to navigate and remain one of the frequent causes of access site conversion. OBJECTIVE: To evaluate predictors of TRA failure in neuroendovascular patients with radial loops and suggest a protocol for managing these anomalies. METHODS: A prospective collection of patients undergoing TRA at participating institutions from July 2018 to September 2020 was reviewed. Patients with a radial loop were identified. Patient demographics and procedural characteristics were evaluated to determine predictors of both TRA failure and successful reduction of the radial loop. RESULTS: We identified 32 transradial neurointerventions in which patients had radial loops. Twenty-two (68.8%) were identified by diagnostic angiography, and the majority were performed for evaluation or treatment of an aneurysm (56.3%). TRA failure occurred in 13 (40.6%) of the cohort and happened more frequently in patients over 60 years of age (p=0.01) and those with recurrent radial artery diameters ≤2 mm (p=0.02). Of the 19 patients who had successful TRA, 12 (63.2%) procedures were performed through the recurrent radial artery. CONCLUSION: Although radial loops are associated with high transradial failure rates, our results suggest that the presence of a loop is not an absolute contraindication to TRA. Therefore, we recommend attempting loop navigation using our protocol. Patient age, vascular tortuosity, and recurrent radial artery size should help dictate when to convert to an alternative access site.

Predicting the degree of difficulty of the trans-radial approach in cerebral angiography.

BACKGROUND: To evaluate anatomical and clinical factors that make trans-radial cerebral angiography more difficult. METHODS: A total of 52 trans-radial diagnostic angiograms were evaluated in a tertiary care stroke center from December 2019 until March 2020. We analyzed a number of anatomical variables to evaluate for correlation to outcome measures of angiography difficulty. RESULTS: The presence of a proximal radial loop had a higher conversion to femoral access (p<0.03). The presence of a large diameter aortic arch (p<0.01), double subclavian innominate curve (p<0.01), left proximal common carotid artery (CCA) loop (p<0.001), acute subclavian vertebral angle (p<0.01), and absence of bovine aortic arch anatomy (p=0.03) were associated with more difficult trans-radial cerebral angiography and increased fluoroscopy time-per-vessel. CONCLUSION: The presence of a proximal radial loop, large diameter aortic arch, double subclavian innominate curve, proximal left CCA loop, acute subclavian vertebral angle, and absence of bovine aortic arch anatomy were associated with more difficult trans-radial cerebral angiography. We also introduce a novel grading scale for diagnostic trans-radial angiography.