Abstract
BACKGROUND AND PURPOSE: We report our initial experience with ihtObtura, a novel nonadhesive liquid embolic agent (LEA) with progressive postembolization loss of radiopacity for curative embolization of brain AVMs (bAVMs).
MATERIALS AND METHODS: A post hoc analysis of the CLARIDAD trial, a single-center, first-in-human study, was performed. Collected data on consecutive patients with bAVMs treated with ihtObtura (between November 2021 and September 2022) were analyzed. Patient demographics, AVM characteristics, procedure details, and clinical treatment outcomes were collected. Imaging end points included complete occlusion rate at 6 months and loss of radiopacity at 4–6 weeks.
RESULTS: A total of 42 consecutive patients with bAVM who underwent 102 embolization procedures were included in the analysis. Most patients presented with intracranial hemorrhage (83%). The mean AVM classification was Spetzler-Martin (S-M) grade III–IV (90%), with a mean nidus size of 39 ± 14 mm. Complete occlusion was achieved in 26 of 28 patients (93%) who were able to complete all treatments during the study period. In the entire patient cohort, complete occlusion was observed in 62% (26/42 patients). Procedure-related disabling permanent neurologic deficit and procedure-related death were observed in 1 case each. Both events were related to postembolization intracranial hemorrhages. Progressive reduction of embolic material radiopacity was observed in all patients.
CONCLUSIONS: ihtObtura is a new LEA with similar properties as other currently available ethylene-vinyl alcohol copolymer (EVOH)–based liquid embolics with 1 major innovation—progressive reduction in embolic material radiopacity. This feature significantly improves anatomic understanding of residual AVM components during staged treatment of AVMs. This study provides initial evidence that the combination of EVOH-based diffusion properties with progressive loss of radiopacity allows for the potential improvement in rates of complete obliteration for bAVMs.
ABBREVIATIONS:
- bAVM
- brain AVM
- DMSO
- dimethyl-sulfoxide solvent
- EVOH
- ethylene-vinyl alcohol copolymer
- LEA
- liquid embolic agent
- S-M
- Spetzler-Martin scale
SUMMARY
PREVIOUS LITERATURE:
Treatment of high-grade brain AVMs (bAVMs) remains poor for all techniques. The cure rates by transarterial embolization rarely exceed 50% despite the use of current ethylene-vinyl alcohol copolymer (EVOH)–based liquid embolics. Technical and imaging advances, together with increasing operators’ experience, have enhanced the potential of curative embolizations, which is still limited by the high and permanent radiopacity of tantalum liquid embolic agent (LEA). Progressive darkening in high-grade lesions not only hinders complete cure but also increases the risk related with unnoticed premature venous obstruction. Therefore, next-generation EVOH-based LEA, characterized by progressive loss of radiopacity, may overcome these limitations and potentially improve the results of embolization from a curative perspective.
KEY FINDINGS:
A post hoc analysis of a consecutive group of bAVMs (90% Spetzler-Martin grade III–IV) enrolled in the CLARIDAD trial, a first-in-human clinical study to evaluate the safety and efficacy of the new LEA ihtObtura, revealed a complete occlusion rate of 93% in patients who were able to complete all treatments during the study period.
KNOWLEDGE ADVANCEMENT:
The present study suggests that the combination of modern endovascular techniques with ihtObtura allowed a high cure rate in a series of bAVMs with an important preponderance of high-grade lesions. The progressive loss of radiopacity, which allows visibility of residual AVM in staged treatments, may be a promising change in curative embolization.
Microsurgical resection remains an effective treatment for superficial Spetzler–Martin (S-M) grade I and II AVMs, while similar grade deep lesions are well treated with radiosurgery. Recent advancements in endovascular techniques such as ethylene-vinyl alcohol copolymer (EVOH)–based liquid embolics1⇓⇓-4 and pressure cooker techniques5⇓-7 with coils and cyanoacrylate embolics have significantly expanded the role of embolization in the treatment of brain AVMs (bAVMs).
Endovascular embolization in some recent studies has shown comparable results to microsurgery and radiosurgery for smaller grade lesions.1⇓⇓-4 The rapid development of the transvenous embolization approach is also changing treatment options because it allows immediate occlusion of AVMs.5,6
However, the safety and effectiveness of therapies in S-M grade III–V remain poor for all techniques including microsurgery, radiosurgery, and embolization. The reported cure rates by transarterial embolization rarely exceed 50% with the use of EVOH-based liquid embolics.7 Therefore, partial embolization followed by microsurgical resection or radiosurgery is often the treatment used for these lesions.8⇓-10 There remains divergence in opinion as to the additional benefit of embolization to microsurgery and radiosurgery in these lesions.
The modest results obtained with the embolization alone are probably multifactorial. These are related to the limited diffusion properties (based on viscosity) of currently available embolic agents where nidal penetration is desired but premature venous obstruction is not. Another major issue is the tantalum-based radiopacity in current EVOH agents that results in significant metal artifacts that preclude proper estimation of residual AVMs on postprocedure MRI, CT scan, and angiography. This is particularly true for staged transarterial embolization where previous embolic material obscures smaller components of residual nidal filling.
This limitation not only hinders complete cure but also increases the risk of the procedure because of premature venous obstruction with residual nidal patency. ihtObtura represents the next generation of EVOH-based liquid embolic agents (LEAs), characterized by increased options for diffusion (based on available viscosities) and by progressive postembolization loss of radiopacity. Our aim was to perform a post hoc analysis to evaluate the safety and efficacy of ihtObtura in a consecutive group of AVMs enrolled in the CLARIDAD trial, with a particular focus on the obliteration rates.
MATERIALS AND METHODS
We obtained institutional review board approval, specifically to perform a post hoc analysis on consecutive patients with bAVMs who underwent treatment with ihtObtura (Iberhospitex, S.A.) during enrollment in the single-arm, open-label CLARIDAD trial.11 This trial enrolled patients requiring liquid embolics for any neurovascular indication between November 2021 and September 2022 at a single institution.
Collected data included baseline demographic data, clinical presentation, and mRS scores before procedure and at 30 days, 3 months, 6 months, 12 months, and 24 months after embolization for all indications. Additionally, for AVMs specifically we collected size (measured in millimeters), volume, location, side, and S-M grade. Radiographic analysis was assigned to an independent core laboratory (Neuroangiografía Terapéutica S.L.). Collected procedural details included the type of injection technique used, the number of feeders embolized, the volume of ihtObtura injected, and the radiation dose administered. We also documented the occurrences of microcatheter occlusion and extravasation of the LEA during injection. Each embolization session aimed to target a specific compartment within the nidus, and any additional cyanoacrylate glue injections through alternate feeders to achieve complete embolization of the targeted compartment or for the pressure cooker technique along with coils to enhance nidal penetration of ihtObtura were also documented. To assess the progression of radiopacity loss, skull x-rays were performed at 4–8 weeks, 3 months, 6 months, 12 months, and 24 months postembolization and analyzed by an independent core laboratory (Neuroangiografía Terapéutica S.L.). A STROBE checklist was utilized during the construction of this manuscript.
Treatment Strategy and Endovascular Procedure
The patients with AVMs were evaluated by an interdisciplinary team consisting of neuroradiologists, neurologists, and neurosurgeons for assessment of therapeutic options. We did not intend adjunctive embolization before microsurgery or radiosurgery. Therefore, when endovascular treatment was selected, all patients were treated with the goal of obtaining a cure by embolization alone, typically by using a staged approach.
The principal treatment strategy for curative embolization was to progressively occlude the AVM from the smaller peripheral nidal components, eventually working toward the largest in a staged approach. We initiated embolization targeting the anastomoses from indirect feeders. This was followed by embolization of the smallest feeders and then progressively attacking larger pedicles. We eventually targeted the main feeders including their primary draining veins to finally close the main outflow vein.7 If this strategy did not result in a cure through a transarterial approach alone, further transvenous embolization was performed with curative intent.
A conebeam head CT scan was obtained before and after each embolization procedure inside the angiographic suite. All procedures were performed under general anesthesia on a single-plane (Philips Allura FD20, Philips Healthcare) angiographic unit. Heparin was administered in the arterial flushes at 1.000 IU/L. A 7F sheath was placed the right femoral artery. A 4-vessel cerebral angiogram was performed, and subsequently a 7F guiding catheter was inserted in either the internal carotid or the dominant vertebral artery to attack the targeted arterial supply. Angiographic 3D and multiplanar reconstructions were performed in each territory, and 3D fusion was applied when 2 territories were involved in the AVM. Superselective microcatheterization of all the feeders was carried out to evaluate the AVM architecture and determine the order of embolization of the various pedicles in each targeted territory. Whenever possible, the feeders were embolized using the pressure cooker technique12 with 2 microcatheters, a Magic1.2 (Balt) to create the plug with cyanoacrylate glue with or without coils, and a detachable tip dimethyl-sulfoxide solvent (DMSO)–compatible microcatheter (Sonic 1.2, Balt) to inject ihtObtura. In vessels below 0.6 mm, or when the angioarchitecture of the targeted feeder showed multiple distal in passage feeders, a single microcatheter was used in combination with the plug and push technique.
ihtObtura and Embolization Technique
ihtObtura is a new LEA based on EVOH. Opacification is achieved by a copolymer-bound iodinated compound obviating the need for shaking before use (as required for use before Onyx [Medtronic] to mix the settled tantalum1). The solvent, DMSO, remains similar to other EVOHs. ihtObtura is available in 3 different viscosities—15, 20, and 35 centipoise (the 100th of a poise, 1 poise dynes/cm2 or 1 mPa·s) quoted as low, medium, and high viscosity of ihtObtura, which represents an improvement on the 2 viscosities available for Onyx (18 and 34).
Injection of ihtObtura is preceded by flushing of the microcatheter with adequate volume to replace the deadspace, which is 0.4 mL of DMSO for Sonic1.2. Injections of ihtObtura were performed under continuous blank roadmap fluoroscopy. High-viscosity ihtObtura was used in high-flow shunts, while medium and low viscosity are used for small and indirect feeders as well as with pressure cooker technique and in transvenous embolization.
Each staged embolization was discontinued when the angiographic controls demonstrated complete obliteration of the targeted compartment and the microcatheter was retrieved leaving the distal detachable tip in place. In case of incomplete occlusion of the selected compartment, other feeders were embolized with ihtObtura whenever possible. Cyanoacrylate glue was used in feeders that could only be accessed with a Magic 1.2 microcatheter (because this catheter is not DMSO compatible). Compartments were defined to keep the maximal amount of embolic agent at no more than 4 mL per staged session.
After the procedure, a conebeam CT was obtained to confirm location of deposited embolic material as well as exclude iatrogenic bleeding. The patients were extubated and transferred to the intensive care unit, where blood pressure was monitored and maintained at a level to reduce mean arterial pressure by 30 mm Hg from baseline for 24 hours. Dexamethasone was administered parenterally during embolization and for the following 5 days either parenterally or orally.
Follow-Up
Each staged embolization session was scheduled 4–6 weeks after the prior procedure until complete angiographic occlusion was achieved. The delayed complete obliteration of the AVM was assessed on follow-up DSA performed at 6 months after the last embolization procedure.
Clinical follow-up was based on neurologic examination as well as patient- and family-reported mRS. A clinical examination was performed before admission, at hospital discharge, and at 1, 3, 6, 12, and 24 months after the final embolization procedure. Treatment-related complications were classified into 5 categories from least to worst: technical complications without clinical sequelae transient neurologic deficits, nondisabling permanent neurologic deficits (mRS 0–2), disabling permanent neurologic deficits (mRS 3–5), and death.
RESULTS
A total of 42 consecutive patients (19 women) with a mean age of 37 years (range 13–69 years) were enrolled in the study. The most common clinical presentation was intracerebral hemorrhage in 35 (83%) patients. The AVMs were graded S-M II, III, and IV in 4 (9%), 13 (31%), and 25 (59%) patients, respectively (Supplemental Data). The location was supratentorial in 37 (88%) and infratentorial in 5 (12%) patients. There were 5 deep-located AVMs (12%). The mean size was of 39 ± 14 mm. Eloquent cortex was involved in 30 patients (71%).
A total of 160 injections of ihtObtura were performed in 102 procedures. The pressure cooker technique was used in 87 feeders, the push and plug technique in 66, and the retrograde venous pressure cooker in 7. In most sessions, except for 2, the targeted compartment of the AVM was completely embolized with ihtObtura. Additional injection of diluted glue was needed in these 2 cases to achieve complete occlusion of the targeted compartment.
Results are detailed in the Supplemental Data, while Figs 1 and 2 present 2 illustrative cases. The Supplemental Data show the 3 different radiopacity loss patterns found in the skull x-rays analysis of ihtObtura casts. At the end of the study period, planned staged embolizations were completed in 28 patients with further staged endovascular treatment planned in the remaining 14 patients. In patients who had concluded all planned stages, complete AVM angiographic occlusion rate was 93% (26/28 patients). If the entire cohort were considered the final complete obliteration rate would be 62% (26/42) including AVMs about to undergo further embolization. Among the 24 high-grade AVM cases that completed the treatment cycle, 22 (92%) experienced complete occlusion. The remaining 2 patients experienced postembolization intracranial hemorrhage resulting in an mRS score of 4 and 6.
Left frontal ruptured high-grade AVM. Left ICA DSA in (A) lateral and (B) frontal views. C, Substracted lateral view after the first session of treatment, where the pressure cooker technique was performed (white arrow) to inject 3.5 mL of ihtObtura. Reduced radiopacity allows visualization of the different structures of the nidus (arrowheads). D, Same unsubstracted projection 1 month later, just before the second session of treatment. Radiopacity of ihtObtura almost disappeared. E–F, Last session of treatment 5 months after the first session. E, Left ICA DSA in lateral view, showing a small nidus remnant after 5 sessions (black arrows). F, Supraselective DSA of the remaining feeder, including the nidus remnant (white arrow) and the early draining vein (black arrow) in AP view. G–H, Angiographic control 6 months later. G, Unsubstracted lateral view. The tips indicate the detachable microcatheters previously used (white arrows) and complete disappearance of the radiopacity of ihtObtura. H, DSA in AP view showing complete occlusion. I, Conebeam CT at follow-up showing the tips of the microcatheters (white arrows) due to the lack of artifacts. AP = anterior to posterior.
Staged treatment of a right parieto-occipital ruptured high-grade AVM using ihtObtura. A, Right internal carotid angiogram showing the original AVM. B, The previous microcatheter tips (white arrows) show the significant loss of radiopacity in the unsubstracted lateral view. C, DSA in lateral view from right ICA showing a nidus remnant (arrowheads) (D), which is better visualized in the supraselective run (arrowheads). E, Final ihtObtura cast after complete embolization of the remnant nidus, including the draining vein (black arrows). F, Final DSA from the right ICA.
A total of 102 endovascular embolization procedures were performed, with a mean of 2.4 sessions (range 1–7) per patient. Nineteen patients were treated in 1–2 sessions, 18 in 3–4 sessions, and 5 in 5–7 sessions. On average, 3.7 (range 1–14) feeders were embolized per patient. Additionally, an average of 7.2 mL (range 0.8–20) of ihtObtura was used per patient, with 2.9 mL (range 0.4–14) used for each embolization session. An average of 81% (18–100) ± 29 (mean ± standard deviation) core lab–adjudicated volume reduction was obtained at the end of the endovascular procedures in the entire cohort.
No systemic or local side effects attributable to the injection of ihtObtura were observed. During injections, there were no cases of microcatheter occlusion. Trapping of the tip of a microcatheter occurred after injection of n-BCA requiring leaving the microcatheter in place.
Additional surgical excision was achieved in 1 patient 1 month after angiographic occlusion during the cranioplasty procedure (Supplemental Data).
A reduction in the appearance of the cast of ihtObtura on x-rays was observed in all patients. This reduction appeared to be progressive starting at 2 weeks and further reducing at 4 and 6 weeks. Most initial radiopacity had disappeared in 100 of 102 procedures at 6 weeks. In 2 cases loss of radiopacity was less robust and these both were transvenous approaches for last-session treatments, with an extensive injection of ihtObtura to occlude the AVM.
Follow-up DSA at 6 months confirmed complete obliteration in all 26 patients for whom angiographic curative embolization was achieved. No recanalization was found in relation to the loss of radiopacity of the injected embolic agent.
Postembolization Clinical Morbidity and Mortality
Postoperative intracranial hemorrhage occurred in 4 patients among 102 procedures, which translates to 4% risk per procedure and 9% risk per patient. The first was a patient with a left frontal grade IV AVM that had bled 3 times in the previous few months before the first embolization session. One day after the second procedure, the patient deteriorated clinically with reduced consciousness, right-side hemiplegia, and aphasia. An emergent CT scan revealed a left frontal hematoma with midline shift. Immediate decompressive craniectomy and hematoma evacuation were performed, but the patient’s condition did not improve and they were discharged with significant weakness and speech difficulties (mRS 4). The second patient had intracerebral hemorrhage 48 hours after the second staged embolization session for a grade IV left frontal AVM. Conservative treatment was chosen due to the hematoma size and location. Unfortunately, the condition worsened 12 hours later, resulting in death. Two other hemorrhages without mass effect were managed conservatively. Both patients developed postprocedural neurologic deficits but rapidly improved and remained at their preprocedural baseline of mRS 1 at 6-month follow-up.
Before treatment, all patients had mRS scores ranging between 0 and 2. After treatment, 40 patients (95%) maintained an independent functional outcome (mRS 0–2) at both 30 days and 6 months. Among them, 28 patients showed no change in neurologic status at 30 days compared with pretreatment. Twelve patients experienced at least 1-point mRS worsening at 30 days, but by 6 months, 6 had improved and regained their pretreatment condition (Fig 3).
Distribution of mRS scores before treatment and at 30 days, 6 months, 12 months, and 24 months after embolization using ihtObtura. 0 = no symptoms; 1 = no clinically significant disability; 2 = slight disability (patient is able to look after own affairs without assistance but is unable to carry out all previous activities); 3 = moderate disability (patient requires some help but is able to walk unassisted); 4 = moderately severe disability (patient is unable to attend to bodily needs without assistance and unable to walk unassisted); 5 = severe disability (patient requires constant nursing care and attention); 6 = death.
Finally, nondisabling permanent neurologic deficits were encountered in 6 patients (14%) and disabling treatment-related complications in 1 patient with mRS 4 (2%). There was 1 treatment-related death (2%). Three patients experienced transient neurologic deficits (7%).
DISCUSSION
In the present study, we report the first experience with ihtObtura, an innovative EVOH-based liquid embolic agent, with an iodinated component for fluoroscopic visualization which progressively loses radiopacity with time11 for the treatment of 42 consecutive patients with bAVMs.
The radiopacity of ihtObtura allows for visualization of all vascular structures during embolization. The radiopacity is lower than tantalum-based EVOH (Onyx [Medtronic Neurovascular, Irvine, California], Squid [Balt Extrusion, Montmorency, France], Menox [Meril Life Sciences, Vapi, India]) and similar to Precipitating Hydrophobic Injectable Liquid (PHIL; MicroVention, Aliso Viejo, California), which is also iodine-based. We did not find any situation where this reduced opacity was inadequate for visualization or led to unintended occlusion of vessels. The increased resolution of current angiographic systems favorably allows a reduction in radiopacity of the embolic agent without compromising visualization as compared with Onyx, which was developed 30 years ago. The conjugation of iodine to EVOH polymer in ihtObtura as compared with a simple suspension of tantalum with Onyx avoids the need for preprocedural shaking and mixing and instead provides homogeneous diffusion of the opacifying agent. This feature grants excellent visualization of ihtObtura throughout the procedures as compared with other LEAs, where tantalum can precipitate in protracted injections, leading to blocked catheters that were not encountered with ihtObtura.
An important property for the safety of EVOH-based liquid embolics has been the concentric centripetal deposition of the liquid polymer inside blood vessels that allows for patency of vessels until later stages when the entire lumen is filled. This is in sharp contrast to Phil or cyanoacrylates that begin by precipitating in the middle of the vessels first.
Another advantage derived from the use of iodine in ihtObtura is the reduction of beam hardening or metal artifacts, with subsequent improved analysis of the brain parenchyma on CT and MR imaging.
In our initial experience ihtObtura allowed a high rate of complete obliteration of planned segments of high-grade AVMs by transarterial embolization alone (153/160 pedicles). This was related to both high level of nidal diffusion as well as use of the pressure cooker technique in 87 of 160 feeders.13 The low rate of observed hemorrhage (4 in 102 embolization procedures)14⇓-16 may be related to improved penetration of low-viscosity ihtObtura to smaller remaining feeding arteries within each nidal compartment. We did not observe low-viscosity ihtObtura inadvertently penetrate collateralized normal arteries. Importantly, we did not detect any microcatheter occlusion, including prolonged injections through 1.2F detachable tip microcatheters.
Radiographic analysis of skull x-rays at 2, 4, 6, and 12 weeks demonstrated progressive loss of radiopacity in all patients. The loss of radiopacity correlated with time postembolization, while the correlation was inverse with volume of injected ihtObtura and diameter of embolized vessels. Overall, most of the initial radiopacity had disappeared at 6 weeks. Our staging strategy uses repeat embolization typically 4 to 8 weeks apart. The disappearance of radiopacity was near complete at each stage because EVOH is itself radiolucent and the iodine-based component progressively diffuses out of the AVM postembolization. This critical novel value allowed optimal angiographic assessment of residual AVM without obscuration from deposited tantalum-based EVOH materials. This singular feature may significantly improve ability to curatively embolize high-grade AVMs.
We addressed the smallest indirect feeders and the critical anastomoses first. This was followed by the main feeders and their individual primary draining veins. Finally, transarterial embolization was continued until occlusion of the main outflow vein to achieve an endovascular cure. In our experience, the quality of new imaging technologies plays a key role, including 3D, 4D, or 6D imaging by conebeam CT–based multiplanar reconstructions after fusion of volumetric imaging of different vascular territories each with a different color code. This has led to better understanding of critical collaterals, direct feeders as well as segmentation of the venous outflow, which is crucial for endovascular cure without increasing risk.5,6,17,18 These imaging paradigms are transformationally improved with loss of radiopacity.
Curative embolization in a single session is a reasonable goal for small lesions (<2–3 cm), but larger AVMs are best managed in a staged fashion.15,19,20 Several publications have shown high rates of occlusion with endovascular treatment in low-grade AVMs1⇓⇓-4 with low morbimortality; nevertheless, these results have not been replicated for high-grade AVMs treated with staged embolization. Reported endovascular cure in the literature, including series with high-grade AVMs, rarely exceeds 50%, while reported complication rates remain significant (Supplemental Data).2,21⇓⇓⇓-25
Patients who had completed all stages of planned embolization with ihtObtura showed a complete occlusion rate of 93% (26/28). These anatomic results suggest an improvement in the overall occlusion rates for high-grade S-M AVMs (92% in current series, with mean nidus size 39 ± 14 mm).
Similar results were published by Abud et al,26 with a 94% occlusion rate in a series of 17 AVMs, with no mortality and a permanent morbidity of 6%. However, this series was limited because they included only AVMs that were considered potentially curable by endovascular treatment (mean nidus size 26.2 mm). Only 9 cases were high-grade AVMs.
De Castro-Afonso et al27 presented a series of 23 pediatric AVMs, with 16 S-M grade III or IV, in which complete angiographic occlusion was achieved in 91% (21/23 patients) and there were no complications resulting in permanent functional disability or death. Longer follow-up is mandatory in a pediatric population given the potential for recurrence.
Our series shows an overall permanent neurologic complication rate of 14%. However, most were nondisabling complications. At 24-month follow-up, most of the patients improved their clinical status, with a final mRS 0 in 29 patients, mRS 1 in 10, mRS 2 in 1, and mRS 6 in another 1 (Fig 3).
Our rate of major hemorrhagic complications (4%) is less than the reported 8%–11% rate associated with transarterial Onyx embolization.14⇓-16 Permanent disabling neurologic deficit (mRS 4) in 1 patient and death in another 1 were related to postoperative bleeding (Fig 3). As a result, 1 treatment-related permanent disabling neurologic complication (2%, 1/42) and 1 treatment-related death (2%, 1/42) were observed in our series.
Our study has several limitations. The lack of a control group remains a major limitation of the study. We, however, had our imaging results adjudicated by an independent imaging core laboratory. Furthermore, no quantitative analysis was feasible for radiopacity loss. It should be noted that we did not complete all planned staged embolizations in 14 patients (33%) during the study period, which reduced the rate of angiographic cure for the entire cohort. Another potential limitation was the use of a monoplane angiographic suite during the study as compared with biplane angiography.
CONCLUSIONS
A high rate of curative embolization despite the preponderance of high-grade AVMs was observed in this initial experience with ihtObtura. The nidal penetration of ihtObtura and the progressive radiopacity loss, which allows excellent visibility of residual AVM after 6 weeks, are key procedural assets and improve staged embolization and probably contribute to eventual cure. Additional controlled studies are needed to validate the capacity of curative embolization for high-grade AVMs using ihtObtura.
Footnotes
This research has been partially supported by Iberhospitex, S.A.
Disclosure forms provided by the authors are available with the full text and PDF of this article at www.ajnr.org.
Indicates open access to non-subscribers at www.ajnr.org
References
- Received November 8, 2024.
- Accepted after revision April 23, 2025.
- © 2025 by American Journal of Neuroradiology
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