Middle Meningeal Artery Embolization with Liquid Embolic Agents for Chronic Subdural Hematoma: A Systematic Review and Meta-analysis

PurposeTo assess the efficacy and safety of middle meningeal artery (MMA) embolization with liquid embolic agents and the outcomes of patients following this procedure.Materials and MethodsA review of the literature was conducted to identify studies investigating the efficacy and safety of MMA embolization with liquid embolic agents in patients with chronic subdural hematoma (cSDH) in PubMed, Scopus, Embase, and Web of Science. The keywords “liquid embolic agent,” “middle meningeal artery,” “cSDH,” and “embolization” as well as their synonyms were used to build up the search strategy. The R statistical software and random-effects model were used for analysis. Heterogeneity was reported as I², and publication bias was calculated using the Egger test.ResultsOf 628 articles retrieved, 14 studies were eligible to be included in this study. Data of 276 patients were analyzed. n-Butyl cyanoacrylate and ethylene vinyl alcohol copolymer were the most commonly used embolic agents. This study revealed a pooled mortality rate of 0% (95% confidence interval [CI], 0.00%–100%), recurrence and failure rate of 3% (95% CI, 1%–10%), reoperation/reintervention rate of 4% (95% CI, 2%–12%), rate of size decrease of 94% (95% CI, 79%–98%), technical success rate of 100% (95% CI, 76%–100%), and adverse event rate of 1% (95% CI, 0.00%–4%).ConclusionsWith low mortality, recurrence, reoperation, and adverse event rates and a remarkable decrease in the size of hematomas, MMA embolization with liquid embolic agents may be considered a safe and effective treatment option in patients in whom surgical intervention has previously failed and as an alternative to conventional treatments.     

CTA-Based Patient-Tailored Femoral or Radial Frontline Access Reduces the Rate of Catheterization Failure in Chronic Subdural Hematoma Embolization

BACKGROUND AND PURPOSE:Chronic subdural hematoma embolization, an apparently simple procedure, can prove to be challenging because of the advanced age of the target population. The aim of this study was to compare 2 arterial-access strategies, femoral versus patient-tailored CTA-based frontline access selection, in chronic subdural hematoma embolization procedures.MATERIALS AND METHODS:This was a monocentric retrospective study. From the March 15, 2018, to the February 14, 2019 (period 1), frontline femoral access was used. Between February 15, 2019, and March 30, 2020 (period 2), the choice of the frontline access, femoral or radial, was based on the CTA recommended as part of the preoperative work-up during both above-mentioned periods. The primary end point was the rate of catheterization failure. The secondary end points were the rate of access site conversion and fluoroscopy duration.RESULTS:During the study period, 124 patients (with 143 chronic subdural hematomas) underwent an embolization procedure (mean age, 74 [SD, 13] years). Forty-eight chronic subdural hematomas (43 patients) were included during period 1 and were compared with 95 chronic subdural hematomas (81 patients) during period 2. During the first period, 5/48 (10%) chronic subdural hematoma embolizations were aborted due to failed catheterization, significantly more than during period 2 (1/95, 1%; P = .009). The rates of femoral-to-radial (P = .55) and total conversion (P = .86) did not differ between the 2 periods. No significant difference was found regarding the duration of fluoroscopy (P = .62).CONCLUSIONS:A CTA-based patient-tailored choice of frontline arterial access reduces the rate of catheterization failure in chronic subdural hematoma embolization procedures.

The annual incidence of chronic subdural hematomas (CSDHs), 14 to 20 per 100,000 individuals, means that the condition is one of the most frequently managed by neurosurgery departments.^1,2 CSDHs are thought to be sentinel health events, akin to hip fractures, with important reduction in life expectancy for patients compared with age-matched controls.³ The condition is, moreover, associated with far-from-negligible rates of morbidity and mortality, around 11% and 4%, respectively.⁴Standard management of symptomatic CSDHs includes surgical evacuation, mostly through twist drill or burr-hole craniostomy with closed-system drainage.^4-6 Recently, middle meningeal artery (MMA) embolization has emerged as a possible treatment of CSDHs.^7,8 The procedure is simple in appearance but can prove to be challenging in a subset of patients because of tortuous vasculature. Indeed, CSDH is mostly a disease of the elderly with two-thirds of cases accounted for in patients older than 65 years of age.¹ In the elderly, several factors, including peripheral vascular disease and vascular anatomy, can complicate or even preclude cervical vessel navigation by a traditional transfemoral approach.^9,10The transradial approach has recently emerged as an alternative to transfemoral access in interventional neuroradiology, with the stated aim of reducing access-related complications and patient discomfort.¹¹ It has also been envisioned that radial access may facilitate anterior circulation navigation in some patients.^10,11 The aim of this study was to compare 2 arterial-access strategies, frontline femoral versus patient-tailored frontline access selection (femoral or radial), based on a preoperative CTA, in CSDH embolization procedures.     

Imaging Artifacts of Liquid Embolic Agents on Conventional CT in an Experimental in Vitro Model

BACKGROUND AND PURPOSE:Endovascular embolization using liquid embolic agents is a safe and effective treatment option for AVMs and dural arteriovenous fistulas. The aim of this study was to assess the degree of artifact inducement by the most frequently used liquid embolic agents in conventional CT in an experimental in vitro model.MATERIALS AND METHODS:Dimethyl-sulfoxide–compatible tubes were filled with the following liquid embolic agents (n = 10, respectively): Onyx 18, all variants of Squid, PHIL 25%, PHIL LV, and n-BCA mixed with iodized oil. After inserting the tubes into a CT imaging phantom, we acquired images. Artifacts were graded quantitatively by the use of Hounsfield units in a donut-shaped ROI using a customized software application that was specifically designed for this study and were graded qualitatively using a 5-point scale.RESULTS:Quantitative and qualitative analyses revealed the most artifacts for Onyx 18 and the least artifacts for n-BCA, PHIL 25%, and PHIL LV. Squid caused more artifacts compared with PHIL, both for the low-viscosity and for the extra-low-viscosity versions (eg, quantitative analysis, Squid 18: mean ± SD, 30.3 ± 9.7 HU versus PHIL 25%: mean ± SD, 10.6 ± 0.8 HU; P < .001). Differences between the standard and low-density variants of Squid were observed only quantitatively for Squid 12. There were no statistical differences between the different concentrations of Squid and PHIL.CONCLUSIONS:In this systematic in vitro analysis investigating the most commonly used liquid embolic agents, relevant differences in CT imaging artifacts could be demonstrated. Ethylene-vinyl alcohol–based liquid embolic agents induced more artifacts compared with liquid embolic agents that use iodine as a radiopaque component.

In addition to microneurosurgery and stereotactic radiation therapy, endovascular embolization using liquid embolic agents (LEAs) is an effective treatment mode for the therapy of cerebral AVMs or cranial dural AVFs. Depending on the type and extension of the vascular malformation, the endovascular treatment can be performed either alone or in combination with one of the other methods.¹For the treatment of such vascular malformations, several LEAs, each with different properties, are currently available on the market. The most commonly used nonadhesive material is Onyx (Medtronic), a LEA consisting of an ethylene-vinyl alcohol (EVOH) copolymer, dimethyl-sulfoxide, and tantalum powder. Numerous studies have demonstrated the effectiveness and safety of Onyx for the treatment of vascular malformations.^2,3 Another LEA, also based on EVOH and tantalum powder is Squid (Balt Extrusion), which has been commercially available since 2012, with its low-viscosity versions, Squid 18 and Squid 18 low density (LD), and its extra-low-viscosity versions, Squid 12 and Squid 12 LD. For adequate visibility during embolization, radiopacity for these 5 nonadhesive agents is induced by the admixed tantalum powder.^4,5 The difference between Onyx and Squid is that for Squid, the tantalum powder consists of a smaller “micronized” grain size, which is aimed at enhancing the homogeneity in radiopacity and improving the visibility during longer injections times.⁵ The aim of the LD variants of Squid is to reduce the radiopacity to improve the differentiation of the embolized and nonembolized parts of the malformation without influencing the embolic properties.A further commercially available LEA, which was introduced recently, is Precipitating Hydrophobic Injectable Liquid (PHIL; MicroVention) with its low-viscosity version PHIL 25% and its extra-low-viscosity version PHIL low viscosity (LV).^6,7 PHIL is a nonadhesive precipitating embolic agent that consists of 2 specific copolymers [poly(lactide-co-glycolide) and polyhydroxyethylmethacrylate] as its active ingredients and triiodophenol (an iodine compound), which is covalently bound to the copolymers, thus enabling the intrinsic radiopacity of PHIL.^8,9Before the introduction of these nonadhesive embolic agents, which are all based on the mechanism of precipitation, liquid embolization was predominantly performed with adhesive cyanoacrylates. The active component of cyanoacrylates is n-butyl cyanoacrylate (n-BCA), which is available in different chemical compositions and is normally mixed with iodized oil for adequate radiopacity. Even though the use of cyanoacrylates has decreased since the introduction of the above-mentioned nonadhesive LEAs,^10,11 n-BCA and its derivates are still used effectively in particular situations, for example, for the treatment of high-flow malformations and for specific techniques such as the pressure cooker technique.¹²A major drawback of LEAs is imaging artifacts, predominantly in CT.^13,14 Because intracranial vascular malformations are associated with an increased risk of peri- and postprocedural hemorrhage, embolization-related artifacts can represent a crucial obstacle in the detection of intracranial blood during or after embolization in CT.¹⁵ Furthermore, some vascular malformations, especially complex AVMs, cannot be completely occluded by endovascular means, requiring subsequent radiation therapy afterward.¹ The corresponding treatment-planning recordings are usually based on conventional CT imaging.¹⁶ Thus, embolization-related artifacts represent another substantial drawback for adequate and safe treatment planning of further radiation projects.^17-19Systematic data for imaging artifacts of LEAs is rare. To our knowledge, to date, only a few reports with low case numbers that investigated the imaging artifacts of the above-mentioned LEAs (Onyx versus PHIL and Onyx versus Squid) are available.^13,14 The differences in CT artifacts between Squid and PHIL, between nonadhesive LEAs and n-BCA, and imaging artifacts of the extra-low viscosity LEAs Squid 12 and PHIL LV were not the focus of research until now.The aim of the present study was the systematic assessment of artifacts of the most commonly used LEAs in conventional CT in an in vitro tube model.     

N-butyl Cyanoacrylate Glue Embolization of Arterial Networks to Facilitate Hepatic Arterial Skeletonization before Radioembolization

Purpose

Avoidance of nontarget microsphere deposition via hepatoenteric anastomoses is essential to the safety of yttrium-90 radioembolization (RE). The hepatic hilar arterial network may remain partially patent after coil embolization of major arteries, resulting in persistent risk. We retrospectively reviewed cases where n-butyl cyanoacrylate (n-BCA) glue embolization was used to facilitate endovascular hepatic arterial skeletonization before RE.

Methods

A total of 543 RE procedures performed between June 2004 and March 2012 were reviewed, and 10 were identified where n-BCA was used to embolize hepatoenteric anastomoses. Arterial anatomy, prior coil embolization, and technical details were recorded. Outcomes were reviewed to identify subsequent complications of n-BCA embolization or nontarget RE.

Results

The rate of complete technical success was 80 % and partial success 20 %, with one nontarget embolization complication resulting in a minor change in treatment plan. No evidence of gastrointestinal or biliary ischemia or infarction was identified, and no microsphere-related gastroduodenal ulcerations or other evidence of nontarget RE were seen. Median volume of n-BCA used was <0.1 ml.

Conclusion

n-BCA glue embolization is useful to eliminate hepatoenteric networks that may result in nontarget RE, especially in those that persist after coil embolization of major vessels such as the gastroduodenal and right gastric arteries.     

Dual-Lumen Balloon Catheters May Improve Liquid Embolization of Vascular Malformations: An Experimental Study in Swine

BACKGROUND AND PURPOSE:Liquid embolic agents are increasingly used to treat vascular malformations. We sought to assess embolization with these agents by using a dual-lumen balloon catheter in an experimental setting.MATERIALS AND METHODS:Eighteen injections of liquid embolic agents were performed in the rete mirabile of swine. We used 3 methods to control liquid embolic agent reflux: 1) dual-lumen balloon-catheter (group A, n = 8); 2) injection of liquid embolic agent after proximal n-BCA plug formation through a second microcatheter (group B, n = 4); and 3) standard liquid embolic agent injection (group C, controls, n = 6). The following outcomes were graded by using ordinal scales by angiography, macrophotography, and radiography of retia after euthanasia: 1) angiographic and pathologic extent of liquid embolic agent embolization of the rete, 2) reflux of liquid embolic agents in the parent artery, and 3) density of liquid embolic agents in the proximal rete. Technical complications were also recorded. A successful injection was defined as an embolization that reached the contralateral rete without reflux into proximal external branches. Exact logistic regression analyses were performed to compare groups.RESULTS:There were significant differences among groups for reflux (P = .029) and liquid embolic agent density in the proximal rete (P = .014), while extension to the contralateral rete did not reach statistical significance (P = .07). Injections differed among groups (P = .004), with dual-lumen balloon-catheter injections more frequently successful compared with control injections (P = .019).CONCLUSIONS:Dual-lumen balloon catheters allowed better liquid embolic agent injections than standard injections.

Ethylene-vinyl alcohol copolymer liquid embolic agents (LEAs) have changed the management of vascular malformations such as arteriovenous malformations and dural arteriovenous fistulas.^1–4 LEAs such as Onyx (Covidien, Irvine, California) can be injected through small microcatheters, and on injection, they precipitate out of the dimethyl-sulfoxide solvent and slowly harden after coming in contact with blood. These agents are cohesive rather than adhesive and perhaps better controlled than other agents such as n-BCA. In many cases, these features (of LEAs such as Onyx/Phil) may permit longer injections and possibly more complete embolizations than other LEAs.¹The standard method used to control injections is to slowly inject the LEA, allowing some reflux for a short plug proximal to the catheter tip to form and harden, and to wait for the LEA to preferentially move in an antegrade direction deep into the nidus of the malformation. One factor potentially limiting the efficacy of the injection is excessive reflux of LEA back along the catheter, which can enter and occlude unwanted vessels.⁵ Additionally, if a segment of microcatheter that is too long is left in contact with the LEA for too long, the proximal plug may entrap the catheter tip in place. Removal of entrapped catheters has led to intracranial hemorrhages, leading to an FDA warning regarding this aspect of treatment with Onyx.⁶Several potential solutions to these problems have been proposed. One option is to use 2 microcatheters together: One microcatheter with a detachable tip is used for the injection of the LEA, while the other microcatheter is used to deliver n-BCA quickly, intentionally gluing the detachable portion of the first catheter, forming the proximal plug that will prevent reflux of LEA, and ensuring antegrade embolization of the nidus.^7–9 Another option is to use a dimethyl-sulfoxide–compatible dual-lumen balloon catheter, in which 1 lumen is used to inflate a balloon and prevent reflux, while the second lumen delivers the embolic agent (Scepter; MicroVention, Tustin, California).^5,10Animal models may be useful to inform clinical applications of embolic agents.^11–14 We sought to explore whether using a dual-lumen balloon catheter could improve embolization of the swine rete (a model often used for experimental AVM embolization)^12,15,16 and prevent excessive reflux compared with more traditional techniques. We hypothesized that the use of the balloon would promote more complete nidus filling with less reflux and fewer complications than other methods.     

Combined Treatment of Brain AVMs with Use of Onyx Embolization followed by Radiosurgery

BACKGROUND AND PURPOSE:The treatment of cerebral AVMs is complex, reliant on interventions such as embolization, surgery, and radiosurgery, or a combination of these modalities. To date, treatment with the embolic agent Onyx, followed by radiosurgery, has not been evaluated. The goal of this study was to evaluate the safety and efficacy of this combination in a homogeneous, monocentric series.MATERIALS AND METHODS:From April 2003 to June 2008, a total of 20 patients (11 women and 9 men; age range, 10–55 years) were treated for AVMs with Onyx embolization followed by radiosurgery. AVM sizes were <3 cm in 7 patients and ≥3 cm in 13 patients. Modalities and complications of the procedure were analyzed as well as the long-term clinical and anatomic outcomes (2–5 years after treatment).RESULTS:Of 17 patients evaluated by DSA after radiosurgery, 10 (58.8%) were observed to have complete occlusion of the AVM nidus. Complete occlusion was observed in 5 (71.4%) of 7 Spetzler-Martin grade I–II AVMs and in 5 (50.0%) of 10 Spetzler-Martin grade III–IV AVMs. Complete occlusion was observed in 4 (80.0%) of 5 AVMs of <3 cm and 6 (50.0%) of 12 AVMs of >3 cm. One of 20 patients had significant worsening of clinical status (mRS ≥2) at long-term follow-up.CONCLUSIONS:In this preliminary series, the safety and efficacy of combined treatment by Onyx embolization followed by radiosurgery are quite satisfactory, with a low rate of clinical complications (5.0%) and a 58.8% rate of complete obliteration of the AVM.

Cerebral AVMs are associated with significant morbidity and mortality related to intracerebral hemorrhage, seizures, and progressive neurologic decline.¹ The treatment of cerebral AVMs can be quite complicated, and indication for treatment in some clinical situations is controversial (eg, for asymptomatic AVMs). Moreover, several modalities of treatment are available (surgery, radiosurgery, and embolization), and these modalities can be used in combination for some AVMs.Several techniques are available for embolization, dependent on the embolization agent used and technique of microcatheterization. For many years, embolization with n-BCA has been standard clinical practice for the treatment of brain AVMs. In the last 10 years, n-BCA has been progressively replaced by Onyx (ev3, Irvine, California), a copolymer that precipitates when coming into contact with blood.^2–5 The progression of Onyx when injected into a brain AVM follows a lavalike flow pattern and is not associated with the risks of gluing the distal portion of the microcatheter as when using n-BCA. Onyx injections can be more prolonged and controlled compared with n-BCA, making it possible to occlude larger portions of the nidus during each injection.The combination of embolization and radiosurgery is often used in the treatment of brain AVMs; however, the effectiveness of this combination remains controversial. Some series have suggested that embolization before radiosurgery was associated with lower obliteration rates and worse outcomes.^6,7 Several mechanisms have been suggested to explain lower obliteration rates, including recanalization of the nidus after embolization, enhanced angiogenesis after embolization (as demonstrated in animal models), difficulty in delineation of the nidus after embolization, and beam attenuation by the liquid embolization material.In most studies dedicated to the combination therapy of embolization followed by radiosurgery for the treatment of brain AVMs, particles or glue were used as the embolization agent.^6,8,9 To our knowledge, no study to date has evaluated embolization with Onyx followed by radiosurgery. To very precisely evaluate the combined therapy of Onyx embolization and radiosurgery, we conducted a monocentric, retrospective study, with all patients having very homogeneous modalities of treatment with embolization and radiosurgery.     

Liquid Embolic Agents for Endovascular Embolization: Evaluation of an Established (Onyx) and a Novel (PHIL) Embolic Agent in an In Vitro AVM Model

BACKGROUND AND PURPOSE:Embolization plays a key role in the treatment of arteriovenous malformations. The aim of this study was to evaluate an established (Onyx) and a novel (precipitating hydrophobic injectable liquid [PHIL]) liquid embolic agent in an in vitro AVM model.MATERIALS AND METHODS:An AVM model was integrated into a circuit system. The artificial nidus (subdivided into 28 honeycomb-like sections) was embolized with Onyx 18 (group Onyx; n = 8) or PHIL 25 (group PHIL; n = 8) with different pause times between the injections (30 and 60 seconds, n = 4 per study group) by using a 1.3F microcatheter. Procedure times, number of injections, embolization success (defined as the number of filled sections of the artificial nidus), volume of embolic agent, and frequency and extent of reflux and draining vein embolization were assessed.RESULTS:Embolization success was comparable between Onyx and PHIL. Shorter pause times resulted in a significantly higher embolization success for PHIL (median embolization score, 28 versus 18; P = .011). Compared with Onyx, lower volumes of PHIL were required for the same extent of embolization (median volume per section of the artificial nidus, 15.5 versus 3.6 μL; P < .001).CONCLUSIONS:While the embolization success was comparable for Onyx and PHIL, pause time had a considerable effect on the embolization success in an in vitro AVM model. Compared with Onyx, lower volumes of PHIL were required for the same extent of embolization.

Arteriovenous malformations are complex vascular structures composed of feeding arteries, an intervening network of small pathologic blood vessels (the so-called nidus), and draining veins. The lack of an intervening capillary bed allows high-flow arteriovenous shunting of blood. While AVMs can occur throughout the entire body, cerebral AVMs are of particular relevance due to their ability to cause impairing neurologic symptoms and their considerable risk of hemorrhage.¹Alone or in combination with microneurosurgery and stereotactic radiation therapy, embolization plays an important role in the management of cerebral AVMs.² The aim of AVM embolization is complete filling of the nidus, while unwanted reflux into the feeding arteries should be minimized and premature embolization of the draining veins should be avoided.³A wide variety of embolic agents has been and is currently used for embolization of AVMs. At present, the liquid embolic agents (LEAs) ethylene-vinyl alcohol copolymer (EVOH) and n-butyl cyanoacrylate are used most frequently.⁴ Although the embolization results have improved since the introduction of EVOH-based LEAs with rates of complete obliteration ranging from 16% to 100%, the success rate of AVM embolization, especially for complex AVMs, is not yet satisfying.^2,3 Currently, new LEAs are being introduced to improve embolization features, such as embolization efficacy, intraprocedural handling, and control. Furthermore, their use should improve fluoroscopic visibility and reduce artifacts in postinterventional imaging.The aim of this study was to evaluate an established EVOH-based embolic agent and a novel copolymer-based embolic agent in an in vitro AVM model.     

Comparison of Feeding-Artery-Only versus Nidus-Plus-Feeding-Artery Embolization of Pulmonary Arteriovenous Malformations

PurposeTo compare coil embolotherapy outcomes of feeding-artery-only versus nidus-plus-feeding-artery technique for treating pulmonary arteriovenous malformations (PAVMs).Materials and MethodsA total of 219 treatment-naïve PAVMs embolized in 90 patients at a single center from 2008 to 2018 met inclusion criteria for retrospective evaluation. Of the patients, 87% had a diagnosis of hereditary hemorrhagic telangiectasia (HHT). Feeding artery (FA) diameters ≥2 mm were treated. Coil embolization techniques were classified on the basis of embolic deployment zone: (i) distal feeding artery (DFA) technique (coil-to-nidus distance ≤ 1 cm) or (ii) nidus plus feeding artery (NiFA) technique. Successful embolization predictors were assessed using a multivariate linear regression model with input from patient- and PAVM-specific variables.ResultsTreatment success was achieved in 192 of 219 PAVMs (87.7%) over a mean follow-up period of 19 months. Statistically significant predictors of success in the linear regression model included simple angioarchitecture, NiFA embolization technique, and shorter follow-up duration. Stratified by technique, success rates were 99 of 105 (94.3%) and 93 of 114 (81.6%) PAVMs for NiFA and DFA, respectively (P = .007). On average, NiFA-embolized PAVMs had a larger FA diameter (3.6 mm vs 2.7 mm, P < .001) and comprised more complex PAVMs (48% vs 22%, P < .001) than DFA. Treatment success was not significantly associated with sac size or FA diameter.ConclusionsCoil embolization of both the nidus and FA was associated with a higher persistent occlusion rate than FA embolization alone.     

Intra-arterial ampicillin and gentamicin and the incidence of splenic abscesses following splenic artery embolization: A 20-year case control study

PurposeSplenic abscesses represent a major complication following splenic artery embolization. The purpose of this study was to assess the effectiveness of intra-arterial antibiotics administered during splenic artery embolization in reducing splenic abscess formation.Materials and methods406 patients were screened. 313 (77.1%) patients who underwent splenic artery embolization and were >18 years old were included. Mean age of the cohort was 58 ± 15 years (range: 18–88 years). There were 205 (65.5%) male patients and 108 (34.5%) female patients. 197 (62.9%) patients underwent embolization without intra-arterial antibiotics and 116 (37.1%) patients underwent embolization with 1 g ampicillin and 80 mg gentamicin administered in an intra-arterial fashion. Primary outcome was splenic abscess formation. Secondary outcomes included type of splenic artery embolization, embolic agent, and technical success.ResultsPartial splenic embolization was performed in 229 (73.1%) patients. Total splenic embolization was performed in 84 (26.8%) patients. Platinum coils were the most commonly used embolic agent overall (n = 178; 56.9%) followed by particulates (n = 114; 36.4%). Embolization technical success was achieved in 312 (99.7%) patients. 7 (3.6%) splenic abscesses were detected in the non-intra-arterial antibiotic group and 1 (0.9%) in the intra-arterial antibiotic cohort (P = 0.27). Coils were found to be statistically more likely to result in splenic abscesses than any other embolic agent (P = 0.03). Mean time to abscess identification was 74 days ±120 days (range: 9–1353 days).ConclusionSplenic abscesses occurred more frequently in patients who did not receive intra-arterial antibiotics during splenic embolization; however, this did not reach statistical significance.     

Meta-analysis of Intraprocedural Comparative Effectiveness of Vascular Plugs Vs Coils in Proximal Splenic Artery Embolization and Associated Patient Radiation Exposure

PurposeTo compare vascular plugs to coil embolization of the proximal splenic artery and evaluate differences in radiation exposure to the patients.MethodsAn electronic literature search was performed for relevant studies from January 2000 to July 2018 that compared the efficacy of vascular plugs vs coils in splenic artery embolization. Only studies that investigated coil or vascular plug use, without combination with other embolic agents, were included. Meta-analysis was performed using a fixed effects model approach with the inverse variance-weighted average method to determine pooled differences in time to vessel occlusion, procedure time, fluoroscopy time, total number of devices used, and radiation exposure. Heterogeneity was assessed using the I square statistic. Pooled outcomes were compared, and quality assessments were evaluated using the Newcastle Ottawa Scale.ResultsEight studies met inclusion criteria. 81 patients were embolized with vascular plugs and 52 patients with coils only. The most common indication for splenic artery embolization was trauma. Time to vessel occlusion was shorter in the vascular plug group by 7.11 minutes (P = 0.003). Fluoroscopy time was shorter by 13.82 minutes in the vascular plug cohort, and these patients received less radiation (?439 mGy) compared to the coil group (P = 0.006 and P = 0.02, respectively). The number of devices was significantly fewer in the vascular plug group (?3.54; P < 0.001). Procedure time was not statistically significant.ConclusionOur data supports the vascular plug is superior to coils for embolization of the proximal splenic artery with respect to occlusion time, fluoroscopy time, patient radiation exposure, and number occlusive devices used.     

Safety and Efficacy of Peripheral Embolization with EASYX Liquid Embolic Agent: A Multicenter Prospective Study

PurposeTo evaluate the clinical safety and efficacy of EASYX, a new nonadhesive precipitating liquid embolic agent based on a polyvinyl alcohol ether polymer labeled with iodine molecules, for peripheral embolization.Materials and MethodsThis open-label prospective multicenter study was conducted on 50 consecutive patients treated with embolization using EASYX in 3 academic hospitals from April 2018 to July 2019. Indications for embolization were symptomatic varicocele (n = 15), type II endoleak (n = 8), acute hemorrhage (n = 16), portal vein embolization (PVE; n = 9), or angiomyolipoma (AML; n = 2). Patient characteristics, technical and clinical success rates, pain at injection, and satisfaction of the interventional radiologists were assessed. Follow-up imaging was performed using ultrasound for varicoceles (at 1 month) and computed tomography (CT) for the other indications (at 3 or 6 months).ResultsThe immediate technical success rate was 98%. The clinical success rates were 100% for acute hemorrhage and type II endoleaks, 89% for PVE, 86% for varicoceles, and 50% for AMLs. Patients who underwent PVE showed significant hypertrophy of the future liver remnant at follow-up (P < .001), and 55.6% of patients proceeded to hepatectomy. The absence of artifacts on imaging allowed improved monitoring of the aneurysmal sac in patients with type II endoleaks. The satisfaction rate of the interventional radiologists was >90% for 5 of 7 items.ConclusionsEASYX as a novel copolymer liquid embolic agent was safe and efficient for peripheral embolization. The absence of tantalum allowed reduced CT artifacts on imaging follow-up, which was especially useful in patients with type II endoleaks.     

Endovascular Treatment of Ophthalmic Artery Aneurysms: Assessing Balloon Test Occlusion and Preservation of Vision in Coil Embolization

BACKGROUND AND PURPOSE:ICA–ophthalmic artery aneurysms have unique configurations corresponding to relative risks of ophthalmologic morbidities. Presented herein are clinical and radiologic outcomes of coil embolization in ophthalmic artery aneurysms.MATERIALS AND METHODS:From January 2003 to September 2013, endovascular coiling was performed in 43 consecutive patients with ophthalmic artery aneurysms, each classified by the degree to which the ophthalmic artery was incorporated by the aneurysm and the contiguity between the ophthalmic artery entry and parent ICA. Clinical and radiologic outcomes of this approach were investigated, including the technical aspects of treatment and the efficacy of balloon test occlusion.RESULTS:Among 14 patients (32.6%, all ophthalmic artery types) undergoing balloon test occlusion before endovascular coiling, patent collaterals between the external carotid artery and ophthalmic artery were demonstrated in 12 (85.7%) and complete compromise of the ophthalmic artery (without affecting vision) occurred in 4 patients during coiling. Steam-shaped S-configured (67.9%) or straight microcatheters (17.8%) facilitated aneurysm selection in most of the superiorly directed ophthalmic artery aneurysms (n = 28), and steam-shaped pigtail microcatheters (85.7%) were useful in medially directed aneurysms (n = 14). Balloon protection (n = 22) was generally used to facilitate coiling, or a stent (n = 9) was alternatively deployed. Satisfactory aneurysmal occlusion was achieved through coil embolization in 37 lesions (86.1%). During follow-up of 35 patients (mean interval, 12.9 ± 9.4 months), only 1 instance (2.9%) of major recanalization was observed.CONCLUSIONS:If one tailors technical strategies, ophthalmic artery aneurysms are amenable to safe and effective endovascular coil embolization, which tends to be stable in follow-up. Balloon test occlusion may be helpful in devising treatment strategies to preserve vision when coiling ophthalmic artery aneurysms (especially those incorporating an ophthalmic artery origin) is done.

Despite considerable progress in microsurgical techniques, surgical treatment of ICA–ophthalmic artery aneurysms (OAs) is challenging, given their proximity to the optic apparatus, anterior clinoid process, and cavernous sinus. The recently developed neurointerventional arm enables an endovascular approach in this setting as an alternative to surgical clipping and the relatively high morbidity it entails. Nevertheless, the risk of impaired vision due to unexpected thromboembolism or occlusion of the OA after coiling is still a major concern.^1–3 Earlier investigations of endovascular treatment generally have considered OA lesions a subset of paraclinoid aneurysms.^4–7 Furthermore, such reviews have not fully addressed vision as an outcome, including angiographic assessment of collateral circulation before treatment. In this study, only aneurysms originating at the orifice of the OA are presented; we focused on angiographic and clinical aspects of vision as a measure of therapeutic outcome.     

Tratamiento combinado,mediante embolización y cirugía,de los aneurismas cerebrales rotos con hematoma cerebral e hipertensión intracraneal: Análisis retrospectivo y revisión de la bibliografía

Objective

To determine whether the urgent embolization of a cerebral aneurysms and posterior surgery on cerebral hematomas is safe and efficacious in patients with hematomas and signs of intracranial hypertension due to the rupture of cerebral aneurysms.

Predictors of Prostatic Artery Embolization Technical Outcomes: Patient and Procedural Factors

Purpose

To identify technical factors that significantly change prostatic artery embolization (PAE) technical outcomes and to derive and test technical outcome predictive models.

Mechanical rotational thrombectomy in long femoropopliteal artery and bypass occlusions: risk factors for periprocedural peripheral embolization

PURPOSEWe aimed to examine lesion characteristics influencing technical outcome and periprocedural peripheral embolization (PPE) during percutaneous mechanical rotational thrombectomy (PMT) of long femoropopliteal artery and bypass occlusions.METHODSRetrospectively, 65 consecutive patients (43 male patients, mean age 70±12 years; Rutherford category I–III), undergoing PMT (Rotarex^®, Straub Medical AG) with acutely/subacutely occluded femoropopliteal arteries/bypasses were included. Occlusions (mean length, 217±98 mm) were treated by PMT followed by percutaneous transluminal angioplasty (PTA) plus drug-coated balloon or PTA plus stenting/stentgrafting. Technical success was defined as residual stenosis <30%. Follow-up included duplex ultrasound and ankle-brachial index (ABI) after 12 months. Endpoints were technical success, complications, improvement of Rutherford category, ABI, and patency (re-stenosis <50%). The influence of lesion length, duration, and thrombus density (measured in preinterventional computed tomography angiography) on technical success and PPE was analyzed.RESULTSTechnical success was 18% (12/65) after PMT alone, 92% (60/65) after additional means. Four patients (6%) underwent bypass surgery and one patient (2%) amputation. PPE occurred in 11% (7/65). During the 12-month follow-up, three patients (5%) were lost to follow-up. ABI increased from baseline 0.5±0.12 to 0.81±0.14 (p = 0.001) and Rutherford category increased by at least one level in 57 patients at 12-month follow-up (clinical success, 88%). At 12 months, primary patency was 57.4% (95% CI, 45.8%–68.9%) and secondary patency was 75.0% (95% CI, 59.8%–72.3%). As risk factors for PPE, we identified lesion length >200 mm (15%; 6/39; OR 4.5; 95% CI, 0.5–40; p = 0.014) and thrombus density ≤45 HU (20%; 2/10; OR 3.0; 95% CI, 0.2–38.9; p = 0.05). No significant relation between risk factors and technical success was found.CONCLUSIONPMT followed by PTA or implantation of stent (grafts) appears to be effective and safe for revascularization of acute/subacute long occlusions. Thrombus density <45 HU and lesion length above 20 cm represent risk factors for PPE during PMT.

The Rotarex^® percutaneous mechanical rotational thrombectomy (PMT) device (Straub Medical AG) has been used for almost two decades and has been proven to be safe and effective in several studies analyzing endovascular revascularization of acute and subacute iliac and femoropopliteal arteries (1–5) as well as venous and synthetic bypass graft occlusions (4, 6, 7). The combination of PMT and additional devices such as drug-coated balloons, stents, or stentgrafts has shown satisfactory long-term patency rates (3, 8, 9). Therefore, PMT has evolved to an effective endovascular alternative to vascular surgery and other minimal invasive techniques such as thrombolysis and thrombus aspiration. However, in studies with larger patient populations technical success rates vary between 90% and 97% (3–5), and the most common complication, acute periprocedural peripheral embolization (PPE), has been reported between 0% and 24% (1–3, 5). Several factors may pose risks for technical failure or acute PPE such as lesion length or duration of the lesion. Studies investigating the correlation between potential risk factors influencing technical success and the risk for occurrence of PPE during PMT interventions do not exist to the best of our knowledge. Therefore, the objectives of this analysis were to evaluate technical success, effectiveness, and safety of the Rotarex percutaneous mechanical rotational thrombectomy device, as well as to analyze the influence of lesion length, duration of the occlusion, and thrombus density on technical success and the occurrence of PPE.     

Transcatheter Arterial Embolization for Secondary Postpartum Hemorrhage: Outcome in 52 Patients at a Single Tertiary Referral Center

PurposeTo assess the safety and efficacy of transcatheter arterial embolization (TAE) for the management of secondary postpartum hemorrhage (PPH) and to determine the factors associated with the clinical outcomes.Materials and MethodsA retrospective analysis of 52 patients (mean age, 31.6 y; range, 25–40 y) undergoing TAE for secondary PPH was performed. Clinical data, including maternal characteristics, delivery details, embolization details, and transfusion requirements, were obtained. Univariate analyses were performed to determine the factors related to clinical outcomes.ResultsThe major cause of bleeding was retained placental tissue (44.2%; 23 of 52). Actively bleeding foci were observed in 25 (48.1%) patients. Technical and clinical successes were achieved in 100% and 90.4% (47 of 52) of patients, respectively. Gelatin sponge particles with (n = 10) or without (n = 38) permanent embolic materials, such as microcoils or N-butyl cyanoacrylate, were most commonly used (92.3%; 48 of 52), whereas permanent embolic materials alone were used in 7.7% (4 of 52) of patients. In five patients, embolization failed, and these patients were managed by hysterectomy (n = 3), repeat TAE (n = 1), or conservative management (n = 1). Bleeding control was eventually achieved in all five patients. No maternal risk factors were related to clinical results. The median and mean follow-up periods were 3 months and 12.6 months (range, 1–62 mo). Regular menstruation resumed in all 44 patients with available follow-up, and 5 of the patients became pregnant.ConclusionsTAE for secondary PPH is safe and effective and showed technical and clinical success in 100% and 90.4% of patients, respectively. Approximately half of these patients showed a positive bleeding focus, and the use of permanent embolic materials was also common.     

Coil Embolization of the Splenic Artery: Impact on Splenic Volume

PurposeTo determine the impact of coil embolization of the splenic artery on splenic volume based on computed tomography (CT) imaging.Materials and MethodsSplenic artery embolization (SAE) was performed in 148 consecutive patients over an 8-year period in an institutional review board–approved retrospective study. Of these, 60 patients (36 men; mean age, 49 y) had undergone contrast-enhanced CT before and after SAE with a mean time interval of 355 days. Pre- and postembolization splenic volumes were calculated with volume-rendering software. Presence of Howell–Jolly bodies was ascertained on laboratory tests. A trauma control group consisted of 39 patients with splenic laceration and follow-up CT but no splenic intervention.ResultsSAE in trauma patients resulted in an insignificant decrease in mean spleen size from 224 cm³ to 190 cm³ (P = .222). However, postembolization splenic volume was significantly smaller than follow-up volume in the trauma control group (353 cm³; P < .001). In nontrauma patients, the mean splenic volume decreased from 474 cm³ to 399 cm³ after SAE (P = .068). Multivariable analysis revealed that coil pack location was the only factor significantly affecting resultant splenic volume (P = .016). For trauma and nontrauma patients, distal embolization resulted in significant splenic volume loss (P = .034 and P = .013), whereas proximal embolization did not. No patients had persistent circulating Howell–Jolly bodies after SAE. No patients required repeat embolization or splenectomy.ConclusionsCoil embolization of the splenic artery resulted in a modest but significant decrease in splenic volume when performed distally; proximal embolization resulted in an insignificant volume change.     

Safety and Efficacy of Transcatheter Arterial Embolization for Lower Gastrointestinal Bleeding: A Single-center Experience with 112 Patients

PurposeTo assess the safety and efficacy of transcatheter arterial embolization for lower gastrointestinal bleeding (LGIB) and to determine the prognostic factors that affect clinical outcome.Materials and MethodsAll patients diagnosed with LGIB by angiography at a single institution from April 2006 to January 2013 were included in a retrospective study. The rates of technical success, early recurrent bleeding, major complications, clinical success, and in-hospital mortality for transcatheter arterial embolization were determined. The influence of possible prognostic factors on the outcome was analyzed.ResultsA total of 112 patients were included (36 with small-bowel LGIB, 36 with colon LGIB, and 40 with rectal LGIB). N-butyl cyanoacrylate (NBCA) was the embolic agent for 84 patients (75.0%), whereas gelatin sponge pledgets (n = 20), microcoils (n = 2), polyvinyl alcohol particles with adjunctive gelatin sponge pledgets (n = 1), and blood clots (n = 1) were used in the other patients. The technical success rate was 96.4%. For the entire group, the rates of early recurrent bleeding, major complications, clinical success, and in-hospital mortality were 17.4%, 4.6%, 74.5%, and 25.0%, respectively. These were 15.2%, 4.8%, 75.3%, and 26.2%, respectively, in the NBCA group. Hematologic malignancy, immobilization status, and coagulopathy were significant prognostic factors for clinical outcomes.ConclusionsTranscatheter arterial embolization is a safe and effective treatment for LGIB. NBCA could be used as a primary embolic agent for this procedure.     

Bariatric Arterial Embolization with Calibrated Radiopaque Microspheres and an Antireflux Catheter Suppresses Weight Gain and Appetite-Stimulating Hormones in Swine

PurposeTo examine safety and efficacy of bariatric arterial embolization (BAE) with x-ray–visible embolic microspheres (XEMs) and an antireflux catheter in swine.Material and MethodsBAE with selective infusion of XEMs (n = 6) or saline (n = 4, control) into gastric fundal arteries was performed under x-ray guidance. Weight and plasma hormone levels were measured at baseline and weekly for 4 weeks after embolization. Cone-beam CT images were acquired immediately after embolization and weekly for 4 weeks. Hormone-expressing cells in the stomach were assessed by immunohistochemical staining.ResultsBAE pigs lost weight 1 week after embolization followed by significantly impaired weight gain relative to control animals (14.3% vs 20.9% at 4 weeks, P = .03). Plasma ghrelin levels were significantly lower in BAE pigs than in control animals (1,221.6 pg/mL vs 1,706.2 pg/mL at 4 weeks, P < .01). XEMs were visible on x-ray and cone-beam CT during embolization, and radiopacity persisted over 4 weeks (165.5 HU at week 1 vs 158.5 HU at week 4, P = .9). Superficial mucosal ulcerations were noted in 1 of 6 BAE animals. Ghrelin-expressing cell counts were significantly lower in the gastric fundus (17.7 vs 36.8, P < .00001) and antrum (24.2 vs 46.3, P < .0001) of BAE pigs compared with control animals. Gastrin-expressing cell counts were markedly reduced in BAE pigs relative to control animals (98.5 vs 127.0, P < .02). Trichrome staining demonstrated significantly more fibrosis in BAE animals compared with control animals (13.8% vs 8.7%, P < .0001).ConclusionsXEMs enabled direct visualization of embolic material during and after embolization. BAE with XEMs and antireflux microcatheters was safe and effective.     

Transarterial Onyx Embolization of Cranial Dural Arteriovenous Fistulas: Long-Term Follow-Up

BACKGROUND AND PURPOSE:Endovascular therapy with liquid embolic agents is a common treatment strategy for cranial dural arteriovenous fistulas. This study evaluated the long-term effectiveness of transarterial Onyx as the single embolic agent for curative embolization of noncavernous cranial dural arteriovenous fistulas.MATERIALS AND METHODS:We performed a retrospective review of 40 consecutive patients with 41 cranial dural arteriovenous fistulas treated between March 2006 and June 2012 by using transarterial Onyx embolization with intent to cure. The mean age was 57 years; one-third presented with intracranial hemorrhage. Most (85%) had cortical venous drainage. Once angiographic cure was achieved, long-term treatment effectiveness was assessed with DSA and clinical follow-up.RESULTS:Forty-nine embolization sessions were performed; 85% of cranial dural arteriovenous fistulas were treated in a single session. The immediate angiographic cure rate was 95%. The permanent neurologic complication rate was 2% (mild facial palsy). Thirty-five of the 38 patients with initial cure underwent short-term follow-up DSA (median, 4 months). The short-term recurrence rate was only 6% (2/35). All patients with occlusion at short-term DSA undergoing long-term DSA (median, 28 months) had durable occlusion. No patient with long-term clinical follow-up (total, 117 patient-years; median, 45 months) experienced hemorrhage.CONCLUSIONS:Transarterial embolization with Onyx as the single embolic agent results in durable long-term cure of noncavernous cranial dural arteriovenous fistulas. Recurrence rates are low on short-term follow-up, and all patients with angiographic occlusion on short-term DSA follow-up have experienced a durable long-term cure. Thus, angiographic cure should be defined at short-term follow-up angiography instead of at the end of the final embolization session. Finally, long-term DSA follow-up may not be necessary if occlusion is demonstrated on short-term angiographic follow-up.

Endovascular therapy is commonly used for the treatment of noncavernous cranial dural arteriovenous fistulas (cDAVFs). Cyanoacrylates, ethyl alcohol, coils, and particles can be used alone or in combination via transarterial, transvenous, or occasionally direct percutaneous treatment routes. There is no US Food and Drug Administration–approved liquid embolic agent for the treatment of cDAVFs. The ethylene-vinyl alcohol copolymer liquid embolic system (Onyx; Covidien, Irvine, California) is FDA-approved for the presurgical embolization of brain arteriovenous malformations. Since Onyx has become available, transarterial embolization of cDAVFs by using Onyx as the sole endovascular embolic agent has become our preferred treatment strategy. This endovascular treatment approach represents an “off-label” use of the Onyx liquid embolic system.The immediate occlusion rate in large cohort studies of patients treated with transarterial Onyx embolization ranges from 62% to 92%, and short-term durable occlusion has been demonstrated.^1–4 We have previously reported our short-term experience using Onyx in these patients⁵ and have compared the success of this technique with embolization using n-butyl cyanoacrylate.⁶ However, there currently remain no published data on the long-term effectiveness for embolization of cDAVFs by using Onyx, to our knowledge. Here we report our long-term angiographic occlusion rate and clinical follow-up in a cohort of noncavernous cranial DAVFs that were treated by using transarterial Onyx embolization with the intention of complete cure.