Absolute Ethanol Embolization of Arteriovenous Malformations in the Periorbital Region

Surgical treatment of small-sized S3 arterio-venous malformations with neo-adjuvant and adjuvant bleomycin

Arteriovenous Malformations are complex and challenging entities, and their treatment is often tailored on the patient. Interstitial sclerosing treatment with bleomycin is promising especially in cases where the aesthetical and/or functional burden of surgical intervention would be impactful as in the S3 AVM according to the SECg classification. We treated 15 patients presenting small (<10cm3) S3 arterio-venous malformations with 3 + 3 sessions of 15.000 IU of interstitial bleomycin. 9 patients presented moderate to good response to the first 3 sessions and thus surgical re-shaping was performed between the two cycles. US examination was done pre-treatment, before each session and every 3 months after the end of the protocol to assess the arterio-venous malformations. Fifteen of the seventeen patients concluded the protocol. 9 patients underwent surgical re-shaping while 6 skipped it because of their excellent response to the first 3 bleomycin injections. Major improvement in terms of appearance and symptoms (pulsations, ulcerations, bleeding or pain) were always achieved. There was a 20% of minor complications. The presented data are encouraging and seem to suggest that this may be a promising protocol to extend the use of bleomycin in arterio-venous malformations and reduce the impact of surgery.

Angiographic Types of Palpebral Arteriovenous Malformations and Relevant Therapeutic Options Based on Ethanol Embolization: A Multicenter Study

PURPOSE

The present work aimed to determine the different angio-architectural types of palpebral arteriovenous malformations (pAVMs) and appropriate ethanol embolotherapy for each type.

MATERIALS AND METHODS

This was a multi-center comparative effectiveness research retrospectively conducted from November 2012 to October 2021. A total of 70 patients with pAVMs were included, which was classified into cystic pAVMs (n=29) and diffuse pAVMs (n=41) based on the angio-architecture. Of the included patients, 17 with cystic pAVMs and 13 with diffuse pAVMs underwent ethanol embolization combined with coils (CE). The remaining participants underwent no-coil ethanol embolization (NCE). Participants had undergone 60 months of follow-up. Normality of data was tested by the D'Agostino and Pearson test. Correlation was tested by the Pearson χ2 test. Deterioration-free survival (DFS) rate was estimated using the Kaplan-Meier survival analysis. Multivariate Cox regression models included variables that were significant at a p value<0.05 in the univariate analysis to screen the prognostic factor.

RESULTS

The local symptoms of pAVMs, including pulsation, warmth, red plaque, blepharoptosis, bleeding, and visual blurring, along with the devascularizational grade of angiography were recorded before and after the respective procedures. Post-treatment complications were either evaluated at the 3-month routine follow-up or were self-reported by patients. Cystic pAVMs presented with significantly different clinical and angiographic features compared with diffuse pAVMs. With CE, patients with cystic pAVMs obtained a higher devascularizational grade (p<0.0001) and better clinical outcomes (p=0.0009) than those with diffuse pAVMs. Contrarily, with NCE, patients with diffuse pAVM had better outcomes than those with cystic pAVMs (p=0.0248). Moreover, the overall DFS rate was higher in patients with cystic pAVMs (p=0.0006). Finally, the angio-architecture of pAVMs was found to independently influence its prognosis (p=0.02).

CONCLUSIONS

In pAVMs, the angio-architectural type was associated with the relative prognostic status. Ethanol embolization combined with coils was an effective method to treat cystic pAVMs, whereas NCE was more suitable for the diffuse type, further emphasizing the importance of a type-based therapeutic strategy for pAVMs.

CLINICAL IMPACT

Palpebral arteriovenous malformations (pAVMs) are rare and tricky in clinical practices. The present study has divided the pAVMs into cystic and diffuse types according to their angiographic characteristics. Ethanol embolization with (CE) or without coils (NCE) was performed on both types. CE was suitable for cystic pAVMs; whereas NCE was a better choice for diffuse pAVMs. The five-year survival analyses provided evidence of the safety and efficacy of ethanol application in pAVMs. Finally, our work demonstrated that both the short- and long-term clinical outcomes of diffuse pAVMs were poor compared to those of cystic pAVM.

Selection of an Appropriate In Vitro Susceptibility Test for Assessing Anti-Pythium insidiosum Activity of Potassium Iodide, Triamcinolone Acetonide, Dimethyl Sulfoxide, and Ethanol

The orphan but highly virulent pathogen Pythium insidiosum causes pythiosis in humans and animals. Surgery is a primary treatment aiming to cure but trading off losing affected organs. Antimicrobial drugs show limited efficacy in treating pythiosis. Alternative drugs effective against the pathogen are needed. In-house drug susceptibility tests (i.e., broth dilution, disc diffusion, and radial growth assays) have been established, some of which adapted the standard protocols (i.e., CLSI M38-A2 and CLSI M51) designed for fungi. Hyphal plug, hyphal suspension, and zoospore are inocula commonly used in the drug susceptibility assessment for P. insidiosum. A side-by-side comparison demonstrated that each method had advantages and limitations. Minimum inhibitory and cidal concentrations of a drug varied depending on the selected method. Material availability, user experience, and organism and drug quantities determined which susceptibility assay should be used. We employed the hyphal plug and a combination of broth dilution and radial growth methods to screen and validate the anti-P. insidiosum activities of several previously reported chemicals, including potassium iodide, triamcinolone acetonide, dimethyl sulfoxide, and ethanol, in which data on their anti-P. insidiosum efficacy are limited. We tested each chemical against 29 genetically diverse isolates of P. insidiosum. These chemicals possessed direct antimicrobial effects on the growth of the pathogen in a dose- and time-dependent manner, suggesting their potential application in pythiosis treatment. Future attempts should focus on standardizing these drug susceptibility methods, such as determining susceptibility/resistant breakpoints, so healthcare workers can confidently interpret a result and select an effective drug against P. insidiosum.

Ethanol Embolization of Nasal Arteriovenous Malformations: A 10-Year, Single-Institution Experience

PURPOSE

To summarize a 10-year, single-institution experience with ethanol embolization of nasal arteriovenous malformations (NAVMs) in 52 patients.

PATIENTS AND METHODS

The present work was a retrospective study of 52 patients (aged between 1 and 67 years) with NAVMs who were treated with ethanol embolization between August 2009 and August 2019. The diagnosis of NAVMs was established based on clinical and imaging studies including ultrasound, computer tomography angiography, and digital subtract angiography. Embolization techniques used in the current study included transarterial, direct puncture, and a combination of both. The clinical and angiographic features, treatment methods, clinical outcomes, and complications were assessed within the mean period of 55.2 months (range, 1-119 months) after the last embolization.

RESULTS

The total number of embolization sessions (140 embolization procedures in 52 pts) included transarterial approach (1 pt), direct puncture (2 pt), and a combination of transarterial and direct puncture (49 pts). There was a positive correlation between nidus size and treatment sessions (r = 0.780, P = 0.0005) and the amount of ethanol injected (r = 0.840, P = 0.0004). Results of the current study showed that the therapeutic outcomes were complete response in two patients (3.8%) without recurrence throughout the follow-up period (range, 1-119 months; mean, 55.2 months), and partial response in 50 patients (96.2%). A total of seven patients (13.5%) experienced one or more complications, including skin necrosis in one patient (1.9%), transient hemoglobinuria in five patients (9.6%), and skin blister in five patients (9.6%).

CONCLUSION

The reported single-institution experience evidently indicated that ethanol embolotherapy has the potential to successfully devascularize NAVMs and also significantly improve symptoms and signs. Further, it was evident that the use of a combination of transarterial and direct puncture techniques has the potential to increase the rate of therapeutic response in patients with NAVMs.

Absolute Ethanol Embolization of Lip Arteriovenous Malformations: Observational Results from 10 Years of Experience

PURPOSE

To evaluate the safety and efficacy of ethanol embolization of lip arteriovenous malformations (AVMs).

MATERIALS AND METHODS

Seventy-six patients with lip AVMs were treated with 173 ethanol embolization procedures. Lip AVMs were treated with direct puncture alone in 21 patients (35 procedures, 20.2%), transarterial embolization alone in 13 patients (18 procedures, 10.4 %), and a combination of both in 60 patients (120 procedures, 69.3%). Adjunctive surgical resection was performed after embolization for cosmetic purposes based on the patient's request, including patient preference, functional impairment, and skin necrosis. The mean duration of follow-up was 30.9 months ± 27.6. The follow-up included clinic visits and telephonic questionnaires to evaluate the clinical signs and symptoms of AVMs as well as quality of life measures.

RESULTS

Of 76 patients, 51 showed 100% devascularization of AVMs, as determined using arteriography, followed by 23 with 76%-99% devascularization and 2 with 50%-75% devascularization. Of the 76 patients, 40 achieved complete symptom relief and 25 achieved major improvements in cosmetic deformity after embolization. Additionally, 54 patients achieved satisfactory function and aesthetic improvement with ethanol embolotherapy alone, whereas 22 achieved similar outcomes with a combination of ethanol embolotherapy and surgical intervention. Thirty-three adverse events (including 1 major) were documented.

CONCLUSIONS

Ethanol embolization of lip AVMs, as a mainstay, is efficacious in managing these lesions, with acceptable complications. Surgical resection after embolization may improve function and cosmesis in a subset of patients.

Progress and prospects of mechanotransducers in shear stress-sensitive signaling pathways in association with arteriovenous malformation

Arteriovenous malformations are congenital vascular lesions characterized by a direct and tangled connection between arteries and veins, which disrupts oxygen circulation and normal blood flow. Arteriovenous malformations often occur in the patient with hereditary hemorrhagic telangiectasia. The attempts to elucidate the causative factors and pathogenic mechanisms of arteriovenous malformations are now still in progress. Some studies reported that shear stress in blood flow is one of the factors involved in arteriovenous malformations manifestation. Through several mechanotransducers harboring the endothelial cells membrane, the signal from shear stress is transduced towards the responsible signaling pathways in endothelial cells to maintain cell homeostasis. Any disruption in this well-established communication will give rise to abnormal endothelial cells differentiation and specification, which will later promote arteriovenous malformations. In this review, we discuss the update of several mechanotransducers that have essential roles in shear stress-induced signaling pathways, such as activin receptor-like kinase 1, Endoglin, Notch, vascular endothelial growth factor receptor 2, Caveolin-1, Connexin37, and Connexin40. Any disruption of these signaling potentially causes arteriovenous malformations. We also present some recent insights into the fundamental analysis, which attempts to determine potential and alternative solutions to battle arteriovenous malformations, especially in a less invasive and risky way, such as gene treatments.

Comprehensive Treatment and Vascular Architecture Characteristic of High-Flow Vascular Malformations in Periorbital Regions

OBJECTIVE

This study analyzed the vascular architecture characteristics of high-flow vascular malformations (VMs) in periorbital regions, as well as the treatment and imaging prognosis of occlusion degree of the outflow veins.

METHOD

The clinical data of 24 patients with high-flow VMs in periorbital regions treated in our center from 2012 to 2019 were analyzed retrospectively, and the vascular architecture characteristics, treatment methods, and follow-up results were recorded.

RESULTS

The vascular architecture of high-flow VMs in periorbital regions which usually contained the intracranial feeding arteries (24/24,100.0%) and intracranial outflow veins (18/24, 75.0%). The average age of first diagnosis was 23 ± 16 years; the average age of treatment was 37 ± 10 years; the median follow-up time was 42.5 months. Twenty-four patients with high-flow VMs in periorbital regions had 58 treatments in all. The imaging cure was achieved in 6 patients by complete occlusion of outflow veins, and no recurrence was found by DSA. Eighteen patients who get incomplete occlusion of outflow veins were given 49 treatments, and 8 patients had imaging recurrence. Seven patients (7/24, 29.2%) had treatment-related complications in all.

CONCLUSIONS

Patients with high-flow VMs in periorbital regions are the most complex cases. The prognosis of patients whose outflow veins can be completely occluded is relatively good. The stepwise embolization while preserving organ function is advisable. Nevertheless, the incidence of treatment complications is still high.

Treatment Outcomes of Embolization for Peripheral Arteriovenous Malformations

PURPOSE

To evaluate treatment outcomes of embolization for peripheral arteriovenous malformations (AVMs) in a tertiary referral center where ethanol is the primary agent of choice.

METHODS

A retrospective study was performed of 93 patients (median age, 31 years; range, 2-66 years) with peripheral AVMs treated with embolization (n = 442; median, 2 per patient; range, 1-82) between January 2010 and July 2016. Ethanol was used in most cases (n = 428; 97%). AVMs were classified as type I (n = 3), type II (n = 57), type IIIa (n = 5), type IIIb (n = 15), and type IV (n = 13) according to the Yakes classification system. Effectiveness of embolization was based on AVM devascularization on angiography: 100% (total), 90%-99% (near-total), 70%-90% (substantial), 30%-70% (partial), and 0%-30% (failure). Complications were graded according to the Society of Interventional Radiology classification.

RESULTS

In 69% of patients, 70%-100% devascularization was achieved. Total and near-total occlusion of the nidus were more often achieved in AVMs of types I and IIIa (both 100%) than in AVMs of types II, IIIb, and IV (56%, 67%, and 39%, respectively; P = .019). A total of 109 complications were identified: 101 minor (22.9%) and 8 major (1.8%). Major complications included wounds (n = 5), false aneurysm (n = 1), finger contracture (n = 1), and severe pain (n = 1) requiring therapy. The patient complication risk was significantly affected by the number of procedures (relative risk = 2.0; P < .001). Age, AVM location, and angioarchitecture type did not significantly affect complication risk.

CONCLUSIONS

AVM embolization resulted in 70%-100% devascularization in 69% of patients, with few major complications. This study indicates that the type of AVM angioarchitecture affects the number of procedures needed and the achievability of AVM devascularization.

Absolute Ethanol Embolization Combined with Surgical Resection of Scalp Arteriovenous Malformations: Interim Results

PURPOSE

To assess treatment methods, interim results, and complications of absolute ethanol embolization combined with surgical resection of scalp arteriovenous malformations (AVMs).

MATERIALS AND METHODS

From September 2012 to January 2015, 15 consecutive patients (8 male and 7 female) with scalp AVMs underwent staged ethanol embolizations. Ethanol embolization was performed using transcatheter and/or direct puncture techniques. Ten patients with scalp AVMs with a dominant outflow vein (DOV) also underwent coil deployment before ethanol embolization. Two patients underwent surgical resection after ethanol embolization was achieved. Follow-up evaluations included clinical outcome of symptoms and signs and imaging at 1.5 months, 6 months, and annually thereafter.

RESULTS

In 15 patients, 33 ethanol embolizations were performed; 16 coil deployments were performed in 10 patients who had scalp AVMs with a DOV. Of 15 patients, 8 (53.3%) were cured, 2 of whom underwent surgical resection. All 8 patients showed no recurrence in the follow-up period (range, 12-48 months; mean, 25 months). Seven patients (46.7%) had partial remission and will need further treatment sessions for residual AVMs (range, 1-12 months; mean, 7 months). In 3 of 15 patients (20%), 7 minor complications (skin blisters and necrosis) occurred. All minor complications healed with wound dressing and observation. There were no major complications.

CONCLUSIONS

Ethanol embolization has the potential for cure in management of scalp AVMs, with an acceptable risk of minor and major complications. Once AVMs are devascularized, surgical resection can be performed to improve cosmetic results.

Treatment of Early-stage Extracranial Arteriovenous Malformations with Intralesional Interstitial Bleomycin Injection: A Pilot Study

Purpose To assess the efficacy and safety of intralesional interstitial bleomycin injection in the treatment of early-stage (Schobinger stage I or II) extracranial arteriovenous malformations (AVMs). Materials and Methods This prospective study involved 34 patients with early-stage AVMs, as defined by the Schobinger staging system. The patients received intralesional interstitial bleomycin injected at a maximum dose of 15 000 IU or 1000 IU per kilogram of body weight for children who weighed less than 15 kg per procedure for a total of 6 months (once every month). Therapeutic outcome was evaluated by the degree of devascularization at angiography and the clinical outcome 3 months after the last treatment. Further follow-up was evaluated based on further clinical outcome. Adverse events were recorded according to the Society of Interventional Radiology classification. Results Of the 34 patients with early-stage AVM, 32 (mean age, 20.5 years; 24 female [75%]) completed the study. The results showed that 27 (84.4%, 95% confidence interval [CI]: 71.1, 97.7) patients were responsive to bleomycin injection, including nine (28.1%) with a complete response. Four (12.5%) patients showed no response, and one (3.1%) patient experienced worsening 3 months after the last treatment. During further follow-up (mean follow-up time, 20.7 months; range, 5-28 months), the outcome remained stable in 31 (96.9%) of the 32 patients. A major complication, anaphylactic shock, was observed in one (3.1%, 95% CI: 0, 9.5) patient. Common minor complications included hyperpigmentation, nausea, pruritus, and bullae. Conclusion Intralesional interstitial bleomycin injection is a feasible approach for early-stage AVMs and yields safe and effective outcomes. ^© RSNA, 2017.

Embolization of palpebral and orbito-frontal fistulas: technical and anatomical considerations in treating high-flow superficial skin lesions with liquid embolics

The treatment of palpebral and periorbital fistulas may be challenging due to the presence of multiple anastomosis with eloquent ophthalmic and intracranial vascular territories. Moreover, cosmetic and functional characteristics of this area pose unique challenges to open surgical approaches and endovascular therapy. We review the advantages and disadvantages of different liquid embolics in treating palpebral and periorbital fistulas as we describe three successfully treated cases. Moreover, we describe important anatomical landmarks that should be considered at the time of treatment of these lesions.