Efficacy and Safety of Venous Sac Embolization With or Without Feeding Artery Embolization Versus Feeding Artery Embolization Alone in the Management of Pulmonary Arteriovenous Malformations: A Systematic Review and Meta-analysis

PURPOSE

To evaluate by meta-analysis the safety and efficacy of venous sac embolization (VSE) with or without feeding artery embolization versus feeding artery embolization (FAE) alone in the management of pulmonary arteriovenous malformations (PAVMs).

METHODS

This systematic review and meta-analysis was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic literature search was performed in MEDLINE, Embase, and Scopus till August 31, 2021 to identify studies comparing the safety and efficacy of VSE with or without FAE versus FAE alone in PAVMs. The success of treatment was assessed by comparing the number of PAVMs with ≥70% decrease in the size of draining vein/sac between the 2 groups. The pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated using the random-effects inverse-variance model and were used to compare pooled therapeutic efficacy between the groups.

RESULTS

Three studies were found eligible for the meta-analysis. The included studies had a total of 169 patients (119 females and 50 males). The total number of PAVMs was 298, and hereditary hemorrhagic telangiectasia was present in 119 patients. The success of treatment was higher with VSE as compared to FAE (OR=3.54, 95% CI=1.66-7.56). The minor complications were similar in both groups, and one major complication occurred in the FAE group. More coils were used in the VSE group.

CONCLUSIONS

The present systematic review and meta-analysis has consolidated the evidence that VSE with or without FAE is more efficacious than FAE alone in the management of PAVMs without any increase in the associated risk of sac rupture or coil migration.

CLINICAL IMPACT

Until high-quality data from a prospective, multicentric, randomized controlled trial becomes available, the evidence consolidated by the present systematic review and meta-analysis showing the efficacy of venous sac embolization (with or without feeding artery embolization) over feeding artery embolization alone, can be used for clinical decision-making in the management of pulmonary arterio-venous malformations.

Ethanol embolization of arteriovenous malformations in the buttock: ten-year experiences in diagnoses and treatment options

BACKGROUND

Clinically, arteriovenous malformations in the buttocks (bAVMs) are extremely rare. Our study aimed to evaluate the efficacy and safety of ethanol embolotherapy in managing bAVMs.

RESULTS

A total of 32 patients with bAVMs (14 females and 18 males) from 2012 to 2021 were included in this study. All patients underwent complete clinical and imaging examinations. Further, the AVMs lesions were analyzed according to Schöbinger staging and Yakes classification. Each patient had undergone a multistage ethanol embolization. The amelioration of clinical symptoms and devascularization on angiography were evaluated at regular follow-ups. In the present cohort, the 11-20 age group had the most patients (15/32; 46.88%). A total of 124 embolization procedures were performed (average 3.88 procedures per patient), and the average dose of absolute ethanol was 18.96 mL per procedure. Thirteen patients with dominant draining veins underwent additional coil deployment before ethanol embolization (13/32; 40.63%). During follow-ups, clinical improvement was found in 23 of 27 who presented with a pulsating mass (85.19%), 17 of 20 with abnormal local skin temperature (85%), 5 of 6 with bleeding (83.33%), and 5 of 5 patients treated for pain (100%). More than 75% angiographic devascularization was achieved in 18 patients (18/32; 56.25%). Finally, 12 out of 13 patients (92.31%) reduced from Schöbinger Stage III to a lower grade, and ten patients exhibited a complete response (10/32; 31.23%). There was a single serious complication of local necrosis, while neither paranesthesia nor infection was observed postoperatively.

CONCLUSIONS

Ethanol embolization assisted with coils can treat bAVMs effectively and safely. The Yakes classification contributed to the optimal ethanol embolotherapy of bAVMs.

Coronary Artery Aneurysms, Arteriovenous Malformations, and Spontaneous Dissections-A Review of the Evidence

BACKGROUND

Coronary artery aneurysms (CAAs), coronary arteriovenous malformations (CAVMs), and spontaneous coronary artery dissections (SCADs) are rare clinical entities, and much is unknown about their natural history, prognosis, and management.

METHODS

A systematic search of MEDLINE, Embase, and Cochrane Library databases was performed in March 2023 to identify published papers related to CAAs, CAVMs, and SCADs.

RESULTS

CAAs are found in 0.3% to 12% of patients undergoing angiography and are often associated with coronary atherosclerosis. They are usually asymptomatic but can be complicated by thrombosis in up to 4.8% of patients and rarely by rupture (0.2%). CAAs can be managed medically, percutaneously with stents or coil embolization, and surgically. The most common surgical procedure is ligation of the aneurysm, followed by coronary artery bypass grafting. The incidence of CAVMs is 0.1% to 0.2% in patients undergoing angiography, and they are most likely associated with congenital abnormal development of the coronary vessels. The diagnosis of CAVMs is usually incidental. Surgical or percutaneous intervention is indicated for patients with large CAVMs, which carry a potential risk of myocardial infarction. SCADs represent 1% to 4% of all acute coronary syndromes and typically affect young women. SCADs are strongly correlated with pregnancy, suggesting the role of sex hormones in their pathogenesis. Conservative management of SCAD is preferred for stable patients without signs of ischemia as spontaneous resolution is frequently reported. Unstable patients should undergo revascularization either percutaneously or with coronary artery bypass grafting.

CONCLUSIONS

Further evidence regarding the management of these rare diseases is needed and can ideally be derived from multicenter collaborations.

Tumescent solution: a game changer in excising refractory arteriovenous malformation

Arteriovenous malformations of the head and neck are rare and inborn errors of vascular morphogenesis. They pose therapeutic challenges owing to their bleeding tendency and a high chance of recurrence. Treatment modalities include digital subtraction angiography with embolisation as a primary treatment or can be done preoperatively followed by surgical excision. We present a case of recurrent arteriovenous malformation of the postauricular region in an adolescent male who was taken up for upfront surgical excision with the help of a tumescent solution, thereby eliminating the need for embolisation and drastically reduced intraoperative blood loss.

Feasibility of Breath-Hold Zero TE Magnetic Resonance Imaging Sequence for Evaluation of Pulmonary Arteriovenous Malformations After Embolotherapy

ABSTRACT

We obtained breath-hold zero TE (ZTE) magnetic resonance imaging for the evaluation of pulmonary arteriovenous malformations before and after embolotherapy. To the best of our knowledge, there have been no reports of ZTE for the entire lung imaging in single breath-hold scan time such as 20 seconds. Breath-hold ZTE magnetic resonance imaging can be a useful technique for magnetic resonance-based follow-up of vascular lung diseases without using contrast media, reducing the undesired artifacts from metallic devices.

Use of Polyurethane-Covered Stents for Exclusion of Pulmonary Arteriovenous Malformations

PURPOSE

To evaluate the safety, technical success and short-term effectiveness of polyurethane-covered stent (PK Papyrus, BioTronik, Berlin) in the treatment of pulmonary arteriovenous malformations (PAVMs) that are not amenable to embolotherapy.

MATERIALS AND METHODS

In this IRB-approved, retrospective study, data from patients who received polyurethane-covered stents for exclusion of PAVMs were analyzed. The study included 5 patients (all women) with a median age of 40 years (range 25-60). Patients presented with hypoxemia, TIAs, and/or epistaxis; 4 were confirmed to have HHT. All had multiple PAVMs diagnosed on chest CT and underwent embolization with other devices in addition to the polyurethane-covered stent. The indication for stent placement in all cases was a short and/or tortuous feeding artery. Safety was assessed by immediate or short-term complications, e.g., migration, stent thrombosis, and fracture. Technical success was defined as the ability to accurately place the stent at the intended location. Effectiveness was defined as successful exclusion of PAVM with no perfusion across the AVM.

RESULTS

Technical success of stent placement was 100%. AVM exclusion rate was 80% after single stent deployment; in the case of incomplete exclusion, success was achieved using an overlapping stent to completely cover a second feeding artery. During the median follow-up period of 5 months (range 2-10), all stents remained patent, and AVMs were excluded without other complications.

CONCLUSION

Exclusion of PAVMs with polyurethane-covered stents is technically feasible, safe, and shows short-term effectiveness for PAVMs with a short/tortuous feeding artery when traditional embolization techniques are not possible.

Prospective Study of Polytetrafluoroethylene-Covered Microplugs and Detachable Coils for Embolization of Pulmonary Arteriovenous Malformations: Technical Results, Procedure Times, and Costs

PURPOSE

To determine time to occlusion and procedure costs of embolization of pulmonary arteriovenous malformations (PAVMs) using a polytetrafluoroethylene-covered microplug compared with embolization using detachable coils.

MATERIALS AND METHODS

In this prospective study, 37 patients (mean age, 39.1 years [SD ± 17.6]) with 82 PAVMs underwent embolization with microplug or detachable coils between April 2019 and January 2023. Technical success, procedure time intervals, and costs were analyzed.

RESULTS

In 37 patients, 82 PAVMs and 101 feeding arteries were successfully treated (microplug, 64; microplug + another device, 5; detachable coils alone, 32). Time from embolic device inserted into the catheter to device deployed and time to occlusion differed significantly between microplug and detachable coil cohorts (P < .0001 for both). Embolization with ≥1 microplug had a significantly shorter occlusion time than embolization with detachable coils (median, 10.0 minutes saved per feeding artery) (P < .0001). Compared with detachable coil embolization, microplug embolization saved a median of 9.0 minutes per feeding artery (P < .0001) and reduced room cost by a median of $429 per feeding artery (P < .0001). Device costs per feeding artery did not differ significantly between microplug ($2,790) and detachable coil embolization ($3,147) (P = .87).

CONCLUSIONS

Compared with coils, microplugs had an equally high technical success rate but significant time to occlusion and room costs savings per feeding artery. Total room cost and device cost together did not differ significantly between microplugs and coils. Microplugs may be considered technically effective and at least cost-neutral for PAVM embolization where clinically appropriate.

Transarterial Embolization of Simple Pulmonary Arteriovenous Malformations: Long-Term Outcomes of 0.018-Inch Coils versus Vascular Plugs

PURPOSE

To compare the safety, effectiveness, and persistence rates of 0.018-inch coils with those of Amplatzer vascular plugs (AVPs; Abbott Vascular, Abbott Park, Illinois) for the treatment of pulmonary arteriovenous malformations (PAVMs) in response to a growing concern that 0.018-inch coil embolization would increase the long-term persistence rate.

MATERIALS AND METHODS

This is a retrospective, single-center study of a database (2002-2020) of 633 PAVM embolizations. Complex PAVMs and those not embolized with 0.018-inch coils or plugs were excluded. PAVM embolization material was classified into 4 groups: (a) 0.018-inch nonfibered coils (NFCs), (b) 0.018-inch fibered coils (FCs), (c) NFCs and FCs, or (d) plugs. Persistence was defined as flow through the PAVM on digital subtraction angiography (DSA) or as <30% diameter reduction of the aneurysmal sac on unenhanced computed tomography (CT). Kaplan-Meier analysis and Cox regression were used to assess PAVM's persistence-free survival.

RESULTS

A total of 312 PAVM embolizations with NFCs (43 PAVMs), FCs (127 PAVMs), NFCs and FCs (12 PAVMs), or plugs (130 PAVMs) in 109 patients (28% men; mean age = 49 years) were included. All PAVM embolizations were technically successful without any major adverse events. PAVM persistence-free survival rates at 10 years' follow-up were 40.8% versus 44.7% in the NFC and FC groups (P = .22) and 47.3% versus 81.0% in the 0.018-inch coil (NFC or FC) and plug groups (P < .0001), respectively. There were 0.43 (79/182) and 0.08 (10/130) re-embolization procedures per PAVM in the 0.018-inch coil and plug groups, respectively (P < .001).

CONCLUSIONS

PAVM embolization with 0.018-inch coils was safe, but persistence rate with PAVM embolization was significantly higher than that with plugs, with no significant differences between FCs and NFCs.

Management of congenital urogenital and perineal vascular malformations: correlation of clinical findings with diagnostic imaging for treatment decision

PURPOSE

 Analysis of clinical and diagnostic findings in rare urogenital and perineal vascular malformations only occurring in 2-3 % of vascular anomalies with regard to clinical symptoms and treatment decisions.

MATERIALS AND METHODS

 All 25 out of 537 patients presenting with congenital urogenital and perineal vascular malformations at our institution from 2014 to 2021 were included. Vascular anomaly classification, anatomical location, clinical symptoms at presentation, diagnostic imaging, and pain intensity were retrospectively assessed from the patient record and therapy management was evaluated.

RESULTS

 In total, 25 patients (10 females (40 %), 15 males (60 %)), aged 6 to 77 years were included. Diagnoses were: 10 (40 %) venous malformations (VMs), 5 (20 %) lymphatic malformations (LMs) and 10 (40 %) arteriovenous malformations (AVMs). Malformation manifestations were: 12 (32 %) lesser pelvis, 12 (32 %) external genitalia, and 13 (34 %) perineal/gluteal region. One AVM was located in the kidney. The leading clinical symptom was pain. The mean intensity was 6.0/10 for LM, 5.7/10 for VM, and 4.5/10 for AVM. Further major symptoms included physical impairment, local swelling, and skin discoloration. Bleeding complications or sexual dysfunction were rare findings. Patients with VM reported significantly more symptoms than patients with AVM (p = 0.0129). In 13 patients (52 %) minimally invasive therapy was indicated: 10 (77 %) sclerotherapies and 3 (23 %) transcatheter embolization procedures. Complete symptomatic remission was achieved in 9 (69 %) patients, partial response in 3 (23 %) patients, and 1 patient showed no clinical response to therapy. Follow-up appointments without the need for immediate minimally invasive therapy were significantly more common in patients with AVMs than in patients with VMs (p = 0.0198).

CONCLUSION

 To create a higher awareness of congenital urogenital and perineal vascular malformations. Awareness of this rare condition avoids misdiagnosis. Therapy decisions should be symptom-oriented. Emergency intervention is rarely required, even in fast-flow vascular malformations.

KEY POINTS

  · Venous malformations cause more symptoms with higher pain intensity than arteriovenous malformations.. · Diagnosis and adequate treatment can be hampered by a lack of awareness of the clinical presentation.. · Bleeding complications are rare, even in high-flow vascular malformations.. · Pain and physical impairment are the most commonly observed symptoms in these patients..

Fetal choroid plexus arteriovenous malformation, masquerading as a neoplastic lesion

A woman in her 20s, who was pregnant, underwent a routine antenatal ultrasound revealing organised intraventricular haemorrhage and a vascular area in the left thalamic region. Fetal MRI raised suspicion of arteriovenous malformation (AVM). The baby was delivered at 36 weeks via C-section, and initial brain MRI suggested a possible neoplastic lesion.Cerebral angiography confirmed a large AVM involving the left choroid plexus with arterial feeders from the left anterior and posterior choroidal arteries and a large venous varix draining into the vein of Galen. Both arterial feeders were successfully embolised with Onyx and glue, achieving complete occlusion.Choroid plexus AVMs are rare and often lead to intraventricular or intraparenchymal haemorrhage. Surgical treatment has shown success, but endovascular management is effective, especially for small, deep-seated AVMs, offering a better prognosis.

Preliminary Experience with a Low-Profile High-Density Braid Occluder for Transcatheter Embolization of Pulmonary Arteriovenous Malformations

This brief report describes safety, technical feasibility, and early treatment effectiveness of the low-profile braided occluder (LOBO; Okami Medical, San Diego, Caliornia) for embolization of 9 pulmonary arteriovenous malformations (PAVMs) in 4 patients (3 female and 1 male; age range: 33 to 63 years; 3 patients showed positive results for hereditary hemorrhagic telangiectasia genes). A total of 10 occluders were deployed in 10 vessels (median treated vessel diameters, 3 and 4 mm for LOBO-3 and LOBO-5 groups, respectively). All devices were successfully deployed into the feeder pulmonary arteries, achieving complete cessation of flow. There were no severe adverse events or device migrations. Available short-term follow-up computed tomography (6 PAVMs: median, 7 months; range, 1.5-7 months) demonstrated complete occlusion without persistence or recanalization. The early experience of embolization of PAVMs using a low-profile braided occluder showed it to be safe and effective. Further studies with larger cohorts and longer follow-up periods are warranted.

Adnexal arteriovenous malformation presenting with spontaneous massive haemoperitoneum

Arteriovenous malformations (AVMs) are vascular anomalies composed of a tangle of abnormal vessels in which one or more feeding arteries are directly connected to one or more draining veins via a nidus with no intervening capillary bed. The adnexa are particularly rare sites for the formation of such malformations. Here, we present the case of a middle-aged woman who presented with spontaneous massive haemoperitoneum occurring as a result of a ruptured adnexal AVM. The diagnosis was suspected on transabdominal sonography and confirmed on CT angiography. The patient was shifted to the interventional radiology suite for an urgent angioembolisation following which she improved haemodynamically and her symptoms resolved. The case highlights the fact that although exceedingly rare, gonadal AVMs are an important cause of spontaneous intraperitoneal bleeding. Diagnostic and interventional radiology play an important role in the early and accurate diagnosis of this entity, and angioembolisation can be lifesaving in such patients.

Balloon Pressure Technique with the Scepter Mini Balloon as Part of the Endovascular Strategy for Brain Arteriovenous Malformations Embolization : Preliminary Multicenter Experience

BACKGROUND

The balloon pressure technique (BPT) is an alternative to the pressure cooker technique. A dual lumen balloon (DLB) is used to inject the liquid embolic agent through the working lumen while the balloon is inflated. The purpose of our study was to report our early experience using the Scepter Mini dual lumen balloons for BPT in brain arteriovenous malformation (bAVM) embolization.

MATERIAL AND METHODS

Consecutive patients treated from July 2020 to July 2021 in 3 tertiary centers using the BPT with low-profile dual lumen balloons (Scepter Mini, Microvention, Tustin, CA, USA) by endovascular means for bAVMs were retrospectively reviewed. Patient demographics and bAVM angio-architectural features were collected. The feasibility of Scepter Mini balloon navigation close to the nidus was evaluated. Technical as well as clinical (ischemic and/or hemorrhagic) complications were also systematically assessed. The occlusion rate was evaluated on follow-up DSA.

RESULTS

A total of 19 patients (10 females; mean age = 38.2 years) consecutively treated for a bAVM (8 ruptured/11 unruptured) using the BPT with a Scepter Mini through 23 embolization sessions were included in our series. Navigation of the Scepter Mini was feasible in all cases. Of the patients 3 (16%) had procedure-related ischemic stroke and 2 patients (10.5%) had late hemorrhages. None of these complications led to severe permanent sequela. Complete occlusion of bAVM embolized with intention to cure was recorded in 11/13 cases (84.6%).

CONCLUSION

The BPT using low-profile dual lumen balloons is feasible and seems safe for embolization of bAVMs. It may help to reach high occlusion rates, especially when performed in the intent to cure by embolization only.

Abnormal uterine bleeding due to uterine arteriovenous malformation in an early adolescent with intrauterine contraceptive device in situ

We report a case of uterine arteriovenous malformation in an early adolescent who presented with heavy vaginal bleeding 2 months after termination of pregnancy with copper intrauterine contraceptive device (IUCD) insertion. The patient was admitted and had medical treatment, including blood transfusion and subsequently transcatheter embolisation of the arteriovenous malformation to control her bleeding. The IUCD was left in situ. Her symptoms completely resolved by 4 months post-procedure.

Coil-assisted ethanol embolotherapy for refractory head and neck arteriovenous malformations with Onyx recrudescence: 10-Year experiences

OBJECTIVE

This study aimed to evaluate the outcomes of coil-assisted ethanol embolotherapy in recanalized head and neck arteriovenous malformations (HNAVMs) with dilated outflowing veins after Onyx treatment.

METHODS

Thirty-six patients with HNAVMs (18 females and 18 males with a mean age of 26.83 years) who experienced recurrence after Onyx embolization from October 2007 to October 2017 were included in this study. All patients underwent complete clinical and angiographic examinations. Further, each patient was classified based on the Schobinger stage before undergoing staged ethanol embolization. All patients were followed up for 5 years in-person at an interval of 3 months after discharge. The Kaplan-Meier method was used to perform the recurrence-free survival analysis.

RESULTS

Sixteen patients (44.4%) had Schobinger stage II HNAVMs, and the remaining patients had Schobinger stage III or IV (20/36 patients [55.6%]) HNAVMs. A total of 116 embolization procedures were performed, coils were applied in 107 procedures (92.2%) among patients with dilated outflowing veins. The dose of absolute ethanol was 16.39 mL per procedure in patients with Schobinger II HNAVMs, and 22.45 mL per procedure in patients with Schobinger III and IV HNAVMs (P = .024, 95% confidence interval, 1.128-5.009). During the 3-month evaluation, complete response was observed in 13 of 36 patients (36.1%), and partial response was observed in 23 of 36 patients (63.9%). The 5-year recurrence-free survival rate for patients who underwent Onyx treatment had improved 58.3% after ethanol embolization (95% confidence interval, 2.853-9.595; P < .0001).

CONCLUSIONS

Coil-assisted ethanol embolotherapy could treat refractory HNAVMs with Onyx recrudescence effectively.

Targeted embolisation for coexisting conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas with a varix on a shared drainer†

BACKGROUND

The coexistence of vascular malformations in the conus medullaris and cauda equina has been rarely reported, and the complex angioarchitecture in multiple arteriovenous lesions remains poorly understood.

CASE DESCRIPTION

A 17-year-old woman presented with a sudden-onset, stepwise worsening of weakness and pain in the bilateral legs. Angiography revealed conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas. One of the drainers was shared between the coexisting lesions and harboured a varix. Targeted embolisation of a fistulous point in the conus lesion was performed with precaution to prevent occluding the common drainage route, which led to symptom improvement with angiographical diminishment of the varix.

CONCLUSIONS

Recognising that communications between drainers can be observed in multiple spinal arteriovenous lesions is important in facilitating a safe embolisation. Cautious assessment of angiogram with fusion images of cone-beam computed tomography and volumetric T2 magnetic resonance imaging can help in establishing the diagnosis and treatment strategy.

Genetic Profile of Arteriovenous Anomalies of the Head and Neck: Implications in Progression and Therapeutic Approaches

BACKGROUND

Arteriovenous Malformations (AVMs) are complex vascular anomalies that are usually sporadic and can have a variable clinical course. Treatment of AVMs can lead to severe sequeale and require thorough decision-making. There is a lack of standardized treatment protocols showing a growing need for pharmacological targeted therapies, specially in the most severe cases where surgery may not be feasible. Current knowledge in molecular pathways and genetic diagnosis have shed light in the pathophysiology of AVMs, opening possibilities for personalized treatment strategies.

METHODS

We performed a retrospective review of patients with head and neck AVMs treated in our department between 2003 and 2021 and performed a complete physical examination and imaging with ultrasound and angio-CT or MRI. Patients underwent genetic testing on AVMs' tissue samples and/or peripheral blood samples. Patients were grouped according to the genetic variant and a correlation between phenotype and genotype was studied.

RESULTS

22 patients with head and neck AVMs were included. We found eight patients with varians in MAP2K1, four patients with pathogenic variants in KRAS, six patients with pathogenic variants in RASA1, one patient with a pathogenic variant in BRAF, one patient with a pathogenic variant in NF1, another patient with a pathogenic variant in CELSR1 and one patient with pathogenic variants in PIK3CA and GNA14. Patients with MAP2K1 variants were the biggest group, with a moderate clinical course. Patients with KRAS mutations showed the most aggressive clinical course and a high rate of recurrence and osteolysis. Patients with RASA1 variants showed a characteristic phenotype with an ipsilateral capillary malformation in the neck.

CONCLUSION

We found a correlation between genotype and phenotype in this group of patients. The genetic diagnosis of AVMs is recommended in order to stablish a personalized treatment strategy. Targeted therapies are currently being investigated with promising results and may be recommended in addition to conventional surgical or embolization procedures, specially in the most complex cases.

LEVEL OF EVIDENCE

Level IV.

Clinical phenotype of adolescent and adult patients with extracranial vascular malformation

OBJECTIVE

In recent years, genotypic characterization of congenital vascular malformations (CVMs) has gained attention; however, the spectrum of clinical phenotype remains difficult to attribute to a genetic cause and is rarely described in the adult population. The aim of this study is to describe a consecutive series of adolescent and adult patients in a tertiary center, where a multimodal phenotypic approach was used for diagnosis.

METHODS

We analyzed clinical findings, imaging, and laboratory results at initial presentation, and set a diagnosis according to the International Society for the Study of Vascular Anomalies (ISSVA) classification for all consecutively registered patients older than 14 years of age who were referred to the Center for Vascular Malformations at the University Hospital of Bern between 2008 and 2021.

RESULTS

A total of 457 patients were included for analysis (mean age, 35 years; females, 56%). Simple CVMs were the most common (n = 361; 79%), followed by CVMs associated with other anomalies (n = 70; 15%), and combined CVMs (n = 26; 6%). Venous malformations (n = 238) were the most common CVMs overall (52%), and the most common simple CVMs (66%). Pain was the most frequently reported symptom in all patients (simple, combined, and vascular malformation with other anomalies). Pain intensity was more pronounced in simple venous and arteriovenous malformations. Clinical problems were related to the type of CVM diagnosed, with bleeding and skin ulceration in arteriovenous malformations, localized intravascular coagulopathy in venous malformations, and infectious complications in lymphatic malformations. Limb length difference occurred more often in patients with CVMs associated with other anomalies as compared with simple or combined CVM (22.9 vs 2.3%; P < .001). Soft tissue overgrowth was seen in one-quarter of all patients independent of the ISSVA group.

CONCLUSIONS

In our adult and adolescent population with peripheral vascular malformations, simple venous malformations predominated, with pain as the most common clinical symptom. In one-quarter of cases, patients with vascular malformations presented with associated anomalies on tissue growth. The differentiation of clinical presentation with or without accompanying growth abnormalities need to be added to the ISSVA classification. Phenotypic characterization considering vascular and non-vascular features remains the cornerstone of diagnosis in adult as well as pediatric patients.

Sclerotherapy for congenital vascular malformations with mixing foam of polidocanol and liquid of bleomycin

OBJECTIVE

To evaluate the efficacy of sclerotherapy for congenital vascular malformation (CVM) using a combination of polidocanol foam and bleomycin liquid.

METHODS

A retrospective review of a prospectively collected data on patients who had sclerotherapy for CVM from May 2015 to July 2022 was performed.

RESULTS

A total of 210 patients with a mean age of 24.8 ± 2.0 years were included. Venous malformation (VM) was the most common type of CVM, accounting for 81.9% (172/210) of all patients. At 6 months follow-up, the overall clinical effective rate was 93.3% (196/210), and 50% (105/210) of patients were clinically cured. The clinical effective rates in VM, lymphatic, and arteriovenous malformation group were 94.2%, 100%, and 100%.

CONCLUSION

Sclerotherapy using a combination of polidocanol foam and bleomycin liquid is an effective and safe treatment for venous and lymphatic malformations. It is a promising treatment option with satisfactory clinical outcome in arteriovenous malformations.

Eradication of the nidus in arteriovenous malformations with a dominant outflow vein in the lower extremities using coils and absolute ethanol

OBJECTIVE

In the present study, we summarize our experience in locating the nidus of arteriovenous malformations (AVMs) with a dominant outflow vein (DOV) in the lower extremities and eradicating the nidus with ethanol and coils.

METHODS

Twelve patients with lower extremity AVMs who underwent ethanol embolization combined with DOV occlusion from January 2017 to May 2018 were enrolled in the present study. Selective angiography was used to locate the nidus of the AVMs, which was eradicated using ethanol and coils via the direct puncture pathway. All treated patients underwent postoperative follow-up (mean, 25.5 months; range, 14-37 months).

RESULTS

The 12 patients underwent a total of 29 procedures (mean, 2.4; range, 1-4) with 27 detachable coils and 169 Nester coils (Cook Medical Inc, Bloomington, IN). Of the 12 patients, 7 (58.3%) had a complete response and 5 (41.7%) a partial response. Three patients (25%) had minor complications such as blister and superficial skin ulcers during follow-up. However, they recovered spontaneously and completely. No major complications were recorded.

CONCLUSIONS

Ethanol embolization combined with coil-assisted DOV occlusion has the potential to eradicate the nidus of lower extremity AVMs with acceptable complication rates.

[Clinical analysis of interventional embolization for 9 cases with frontal arteriovenous malformation]

PURPOSE

To investigate the efficacy and safety of interventional embolization in the treatment of frontal arteriovenous malformation (AVM).

METHODS

A retrospective study was used to analyze 9 patients with frontal AVM who were treated in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The patients were treated with interventional embolization under the guidance of DSA. The scope of lesions was observed through DSA, and the injection dose of sclerosing agent was predicted so that the drug could be injected into the lesion cavity. The efficacy, adverse reactions and complications of all patients were observed and analyzed.

RESULTS

Among the 9 patients, there were 7 males(77.8%) and 2 females(22.2%), aged from 1.5-20 years old. Local swelling or mass was the main reported symptom(66.7%). The blood supply arteries of the cases involved in this study included superficial temporal artery and ophthalmic artery. All patients received interventional embolization treatment under general anesthesia, a total of 19 times (each patient received 1-6 times, average 2.1 times/person), and the average single dose of absolute ethanol was 9.0 mL. A total of 80 coils (4.2 coils/time on average) were used for 5 times (80 coils/19 times) with absolute ethanol embolization. In addition, bleomycin was used 3 times, pingyangmycin was used 2 times, and 3% polydocanol was used 1 time to assist embolization. Among the 9 cases included in this study, 4 cases were cured, 3 cases were basically cured, 2 cases were improved, and the effective rate of treatment was 100%. No local or systemic complications were reported in all patients.

CONCLUSIONS

In the treatment of frontal arteriovenous malformation, correct diagnosis according to clinical and imaging manifestations, and interventional embolization with anhydrous ethanol according to DSA angiography results can reduce trauma, improve symptoms, control lesions, and obtain relatively satisfactory treatment results. This scheme is safe and effective.

CT chest-cerebral angiography for basilar artery occlusion caused by pulmonary arteriovenous malformation

Early diagnosis of basilar artery occlusion (BAO) based only on clinical findings is challenging. We present a fully recovered case of BAO caused by pulmonary arteriovenous malformation (PAVM) that was diagnosed early using a protocol for CT angiography (CTA) and promptly treated with endovascular therapy (EVT). A woman in her 50s complained of vertigo with normal level of consciousness (LOC). On arrival, her LOC decreased to a Grass Coma Scale score of 12, and we performed a CT chest-cerebral angiography protocol. Head CTA showed BAO, and an intravenous tissue plasminogen activator was administered, followed by EVT. Chest contrast-enhanced CT showed PAVM in segment 10 of the left lung, which was treated with coil embolisation. For patients with a complaint of vertigo, BAO should be suspected, even if they have an initially normal LOC. A CT chest-cerebral angiography protocol is useful for prompt diagnosis and treatment of BAO and can reveal undetermined causes.

Diagnosis and Management of Persistent Pulmonary Arterio-venous Malformations following Embolotherapy

Embolotherapy is the primary treatment for pulmonary arterio-venous malformations (PAVMs). Approximately, 2-25% of PAVMs demonstrate persistence following embolization. Early identification and treatment of persistent PAVMs are critical to mitigating life threatening complications. The presence of prior embolic devices and complex angioarchitecture of persistent PAVMs pose technical challenges during repeat embolotherapy. In this article, we review patterns of persistence, factors affecting the persistence, endovascular treatment techniques, and outcomes.

Ophthalmic artery occlusion following n-butyl cyanoacrylate embolization of an orbital arteriovenous malformation

A 33-year-old pregnant woman presented with six months of right-sided proptosis. Neuroimaging revealed a right orbital arteriovenous malformation arising from the second segment of the ophthalmic artery. As she was 9 weeks pregnant, the decision was made to monitor her closely. Over the following six months, her proptosis progressed, accompanied by decreased visual acuity, afferent pupillary defect, and red desaturation concerning for compressive optic neuropathy. After planned c-section, she underwent embolization with n-butyl cyanoacrylate. Upon awakening after embolization, she had no light perception vision from her right eye and was found to have ophthalmic artery obstruction. She ultimately developed a blind painful right eye and underwent enucleation with histopathology demonstrating glue in the central retinal artery, posterior ciliary arteries, and choroid. This case highlights ophthalmic artery occlusion as a rare complication of orbital arteriovenous malformation embolization and demonstrates correlating histopathological findings, which have not previously been reported.

Successful WEBectomy during embolization of temporal arteriovenous malformation-associated flow-related basilar aneurysms

OBJECTIVE

Intra-procedural WEB device migration is a scarcely reported complication that necessitates prompt intervention.

CASE PRESENTATION

Endovascular treatment of two broad necked flow-related aneurysms was planned aided by WEB-SL (Woven EndoBridge-single layer) devices in a 71-year-old female with known left temporal arteriovenous malformation. Inadvertent distal migration occurred while performing a control angiogram with an automated iodine injector. Immediate retrieval was successfully performed using a Solitaire stent-retriever.

CONCLUSION

To our knowledge, we report for the first time the successful retrieval of a distally migrated WEB using a stent-retriever device.

Endovascular management of pulmonary arteriovenous malformations presenting as multiple brain abscesses

Pulmonary arteriovenous malformations (PAVMs) are rare vascular lesions characterised by abnormal connections between the pulmonary artery and vein bypassing the pulmonary capillary bed and causing right-to-left shunt. Paradoxical embolism is known to occur in these cases, leading to inoculation of septic focus in the systemic circulation. We report a case of multiple PAVMs who presented clinically with seizures and altered sensorium. On radiological work-up, multiple brain abscesses and large PAVMs were evident. The patient was successfully treated by endovascular embolisation of the PAVMs using a vascular plug and multiple coils. The patient showed complete clinical recovery and resolution of brain abscesses on follow-up.

Recurrent pulmonary arteriovenous malformation in a patient with Sjögren syndrome: A case report

RATIONALE

Pulmonary manifestations of Sjögren syndrome (SS) are variable and may involve the airway or lung parenchyma and increase the risk of vascular and malignant disease. However, to date, only one case of pulmonary arteriovenous malformation (AVM) has been reported in a patient with SS. Here, we report a rare case of recurrent pulmonary AVMs with aggravating multiple cysts in a patient with SS during a period of 14 years.

PATIENT CONCERNS

A 45-year-old woman was diagnosed with SS and pulmonary AVM in the right lung. Her AVMs were embolized successfully and she was followed up annually for 14 years. Eleven years after the initial treatment, her chest computed tomography showed new pulmonary AVMs in the left lung with aggravating multiple cysts.

DIAGNOSIS

We diagnosed her with SS according to the American-European consensus group criteria of 2010. Chest computed tomography and angiographic findings confirmed the recurrence of pulmonary AVMs.

INTERVENTIONS

The patient's recurrent pulmonary AVMs were successfully treated by embolization.

OUTCOMES

Although her multiple cystic lung lesions had been aggravating during 14 years, she received embolization for the pulmonary AVMs twice and developed no complication related to these procedures. Currently, the patient is 56 years old and still alive with good performance state.

LESSONS

To date, only one case of pulmonary AVM has been reported in a patient with SS. The patient died 2.5 years after the diagnosis without recurrence of AVM. Here, we present a rare case of recurrent pulmonary AVMs associated with aggravating multiple cysts in both lungs, which were observed during long-term follow-up, in a patient with SS.

Management of intra-osseous arteriovenous malformations of the mandible

Intra-mandibular arteriovenous malformations (IM-AVM) are rare congenital lesions sadly known by the appearance of cataclysmic haemorrhages. It represents a therapeutic challenge which requires a multidisciplinary approach. This paper aims to evaluate the characteristics and management of IM-AVM through the illustration of six case reports, the largest serie in the literature to our knowledge. This retrospective study included all patients with IM-AVM treated in the hospital of Lyon and Saint-Etienne between 1982 and 2021, in France. The management of mandibular AVMs should be individualized and permanently adjusted according to their stage of development, which makes their management difficult. Furthermore, long-term follow-up is essential to detect and manage the subclinical progression of the lesion. Based on these results and a systematic review of the literature, an algorithm has been developed to guide the treatment strategy for this are pathology.

The Importance of a Multidisciplinary Approach in a Patient with Long-term Multisystemic Manifestations of Unrecognized Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), also called Rendu-Osler-Weber syndrome, is a rare autosomal dominant multisystemic vascular disorder, characterized by widespread mucocutaneous teleangiectasias, frequent visceral arteriovenous malformations (AVM) and a tendency for bleeding. This diagnosis should be suspected in all dermatological patients with generalized mucocutaneous vascular lesions at sites of predilection, associated frequent epistaxis and a positive family history. The aim of this paper is to emphasize the importance of a multidisciplinary approach, the role and timely cooperation of dermatologists and otorhinolaryngologists in the early clinical recognition and diagnosis of the disease. We present a family case of a 63-year - old patient with typical clinical features of HHT and long-standing multisystemic complications of unrecognized disease.

[Treatment effects of sandwich-shaped resection and cheiloplasty applied in macrocheilia secondary to arteriovenous malformations]

To summarize the clinical experience of sandwich-shaped resection and cheiloplasty in the treatment of macrocheilia secondary to arteriovenous malformation, and to observe its clinical efficacy and complications. The clinical data of 27 patients with macrocheilia secondary to arteriovenous malformation who received surgical treatment from January 2018 to October 2020 in Linyi Cancer Hospital were retrospectively analyzed. There were 14 males and 13 females. The median age was 4.5 years (ranged from 2 to 57 years). There were 18 cases of upper lip and 9 cases of lower lip. All patients had received interventional embolization sclerotherapy for 5 to 10 times before surgery with unsatisfied effect. There was no obvious improvement in the appearance,whereas 3 cases progressed presenting as abnormal enlargement. Sandwich-shaped resection and cheiloplasty was performed in all the patients. Histopathological examinations confirmed arteriovenous malformations in all 27 cases. Twenty-six patients received one course of operation and one received two courses. Partial mucosal necrosis occurred in 1 case and healed after dressing change, while the rest healed by first intention. Local recurrence occurred in 2 cases within 6 months after operation. A four-level standard was used for long-term evaluation, and 24 cases got grade Ⅲ (good), three cases got grade Ⅱ (moderate) after 1 to 3 years of follow-up. Sandwich-shaped resection and cheiloplasty can achieve good long-term efficacy with excellent appearance and function. Due to its advantages of hidden incision and three-dimensional resection and reservation, it is worthy of further clinical promotion.

Image-Guided Embolotherapy of Arteriovenous Malformations of the Face

Purpose

To evaluate the safety and outcome of image-guided embolotherapy of extracranial arteriovenous malformations (AVMs) primarily affecting the face.

Materials and Methods

A multicenter cohort of 28 patients presenting with AVMs primarily affecting the face was retrospectively investigated. Fifty image-guided embolotherapies were performed, mostly using ethylene–vinyl alcohol copolymer-based embolic agents. Clinical and imaging findings were assessed to evaluate response during follow-up (symptom-free, partial relief of symptoms, no improvement, and progression despite embolization), lesion devascularization (total, 100%; substantial, 76–99%; partial, 51–75%; failure, < 50%; and progression), and complication rates (classified according to the CIRSE guidelines). Sub-analyses regarding clinical outcome (n = 24) were performed comparing patients with (n = 12) or without (n = 12) subsequent surgical resection after embolotherapy.

Results

The median number of embolotherapy sessions was 2.0 (range, 1–4). Clinical outcome after a mean follow-up of 12.4 months (± 13.3; n = 24) revealed a therapy response in 21/24 patients (87.5%). Imaging showed total devascularization in 14/24 patients (58.3%), including the 12 patients with subsequent surgery and 2 additional patients with embolotherapy only. Substantial devascularization (76–99%) was assessed in 7/24 patients (29.2%), and partial devascularization (51–75%) in 3/24 patients (12.5%). Complications occurred during/after 12/50 procedures (24.0%), including 18.0% major complications. Patients with subsequent surgical resections were more often symptom-free at the last follow-up compared to the group having undergone embolotherapy only (p = 0.006).

Conclusion

Image-guided embolotherapy is safe and effective for treating extracranial AVMs of the face. Subsequent surgical resections after embolization may substantially improve patients’ clinical outcome, emphasizing the need for multimodal therapeutic concepts.

Level of Evidence

Level 4, Retrospective study.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00270-022-03169-0.

A Computational Framework for Pre-Interventional Planning of Peripheral Arteriovenous Malformations

PURPOSE

Peripheral arteriovenous malformations (pAVMs) are congenital lesions characterised by abnormal high-flow, low-resistance vascular connections-the so-called nidus-between arteries and veins. The mainstay treatment typically involves the embolisation of the nidus, however the complexity of pAVMs often leads to uncertain outcomes. This study aims at developing a simple, yet effective computational framework to aid the clinical decision making around the treatment of pAVMs using routinely acquired clinical data.

METHODS

A computational model was developed to simulate the pre-, intra-, and post-intervention haemodynamics of a patient-specific pAVM. A porous medium of varying permeability was employed to simulate the sclerosant effect on the nidus haemodynamics. Results were compared against clinical data (digital subtraction angiography, DSA, images) and experimental flow-visualization results in a 3D-printed phantom of the same pAVM.

RESULTS

The computational model allowed the simulation of the pAVM haemodynamics and the sclerotherapy-induced changes at different interventional stages. The predicted inlet flow rates closely matched the DSA-derived data, although the post-intervention one was overestimated, probably due to vascular system adaptations not accounted for numerically. The nidus embolization was successfully captured by varying the nidus permeability and increasing its hydraulic resistance from 0.330 to 3970 mmHg s ml-1. The nidus flow rate decreased from 71% of the inlet flow rate pre-intervention to 1%: the flow completely bypassed the nidus post-intervention confirming the success of the procedure.

CONCLUSION

The study demonstrates that the haemodynamic effects of the embolisation procedure can be simulated from routinely acquired clinical data via a porous medium with varying permeability as evidenced by the good qualitative agreement between numerical predictions and both in vivo and in vitro data. It provides a fundamental building block towards a computational treatment-planning framework for AVM embolisation.

Pulmonary arteriovenous malformations: A case of missed diagnosis in a neonate

Pulmonary arteriovenous malformation (PAVM) is a congenital vascular abnormality that can cause persistent cyanosis in children. PAVMs can go undetected till adulthood; however, there have been several neonatal cases reported over the years. This case report describes a classical manifestation of a child with isolated PAVM whose diagnosis was likely missed during the neonatal period. A high level of clinical awareness of this condition is crucial as early diagnosis and appropriate treatment can prevent lifethreatening complications and mortality. Diagnosis was confirmed by computed tomography pulmonary angiography and percutaneous transcatheter embolotherapy resulted in complete resolution of symptoms.

Venous thrombosis via pulmonary arteriovenous malformation causing acute myocardial infarction in a relatively young female patient

Pulmonary arteriovenous malformation (PAVM) is a probable cause of thromboembolic diseases such as acute myocardial infarction (MI); however, few cases have been reported. A woman in her early 40s developed acute-onset chest pain; an ECG showed ST-elevated MI. Emergency catheter angiography showed that the culprit lesion was a thrombus that was treated successfully with aspiration. She had a history of deep venous thrombosis and CT revealed PAVM. It was likely that the venous thrombus had moved into the coronary artery through the PAVM. Catheter embolisation of the PAVM was performed and she did not experience any other cardiac event until 6 months after embolisation.

Selective Arterial Embolisation of Uterine Arteriovenous Malformation in an Infertile Patient, subsequent Term Pregnancy and Postpartum Recurrence

Uterine arteriovenous malformation (AVM) is a rare entity. This report describes selective catheterisation and embolisation of a uterine AVM in an infertile woman, subsequent spontaneous pregnancy and postpartum recurrence of the AVM treated with a second embolisation procedure. A 22-year woman presented with menometrorrhagia and failure to conceive. Pelvic magnetic resonance imaging showed a large uterine AVM. Selective catheterisation and embolisation of the AVM was performed. The patient conceived spontaneously two months later and delivered vaginally. A second embolisation was performed due to recurrence of uterine AVM at six months postpartum. This is the first case reporting postpartum recurrence of a pre-conceptionally treated uterine AVM. Selective catheterisation and embolisation is a minimally-invasive, fertility-preserving procedure that successfully treats uterine AVM and should be the treatment of choice when the patient desires pregnancy. Successful pregnancy and vaginal delivery following embolisation is possible; however, an increased awareness of postpartum AVM recurrence is required. Key Words: Fertility, Pregnancy, Therapeutic embolisation, Uterus, Arteriovenous malformation.

Management of acquired uterine arteriovenous malformation associated with retained products of conception

PURPOSE

To evaluate the efficacy and safety of different treatments for acquired uterine arteriovenous malformation associated with retained products of conception (UAVM-RPOC) and investigate the role of uterine artery embolization (UAE) in acquired UAVM-RPOC.

MATERIALS AND METHODS

This was a retrospective study of consecutive patients who presented with UAVM by ultrasound after recent termination pregnancy. 48 patients were included in this study, divided into two groups (massive and minor bleeding groups) according to vaginal bleeding. The treatments were analyzed between groups. Technical and clinical success of UAE was analyzed.

RESULTS

Of the 48 patients, 11 patients were in the massive bleeding group, and 37 were in the minor bleeding group. 5 patients were referred for UAE in each group, and UAE was a priority for patients with unstable hemodynamics (chi-square value=5.524, p=0.022). Conservative management, dilation and curettage (D&C), operative hysteroscopy, and UAE were performed in 16 (33%), 18 (38%), 7 (15%) and 13 (27%) patients, respectively. Two patients following ectopic pregnancy suffered uncontrollable bleeding during D&C and required UAE. Three patients underwent UAE before surgery to prevent hemorrhage. The technical and clinical success rate of UAE was 100%. No complications or recurrence occurred.

CONCLUSION

UAE is a safe and effective treatment for UAVM-RPOC and a priority for patients with unstable hemodynamics. Conservative management, D&C and hysteroscopy are safe and effective for UAVM-RPOC patients with stable hemodynamics. However, UAVM-RPOC following ectopic pregnancy may have high risks of massive hemorrhage during procedures.

What do Cochrane systematic reviews say about congenital vascular anomalies and hemangiomas? A narrative review

BACKGROUND

Congenital vascular anomalies and hemangiomas (CVAH) such as infantile hemangiomas, port-wine stains and brain arteriovenous malformations (AVMs) impair patients' lives and may require treatment if complications occur. However, a great variety of treatments for those conditions exist and the best interventions remain under discussion.

OBJECTIVE

To summarize Cochrane systematic review (SR) evidence on treatments for CVAH.

DESIGN AND SETTING

Review of SRs conducted in the Division of Vascular and Endovascular Surgery of Universidade Federal de São Paulo, Brazil.

METHODS

A broad search was conducted on March 9, 2021, in the Cochrane Database of Systematic Reviews to retrieve any Cochrane SRs that assessed treatments for CVAH. The key characteristics and results of all SRs included were summarized and discussed.

RESULTS

A total of three SRs fulfilled the inclusion criteria and were presented as a qualitative synthesis. One SR reported a significant clinical reduction of skin redness by at least 20%, with more pain, among 103 participants with port-wine stains. One SR reported that propranolol improved the likelihood of clearance 13 to 16-fold among 312 children with hemangiomas. One SR reported that the relative risk of death or dependence was 2.53 times greater in the intervention arm than with conservative management, among 218 participants with brain AVMs.

CONCLUSION

Cochrane reviews suggest that treatment of port-wine stains with pulsed-dye laser improves redness; propranolol remains the best option for infantile hemangiomas; and conservative management seems to be superior to surgical intervention for treating brain AVMs.

Congenital Renal Arteriovenous Malformation: Diagnostic Clues and Methods

Background and objectives: Renal arteriovenous malformation (AVM) is a rare disease and is difficult to be diagnosed by conventional methods because of its rarity. In this study, we investigated the diagnostic clues, and made an algorithm for the better diagnosis of renal AVM. Materials and Methods: We reviewed 13 patients who were diagnosed with AVM by using renal angiography from 1986 to 2020 at our institutes. We evaluated clinical features, diagnostic tools, treatment modalities, and outcomes after the treatment of patients. Results: All patients were female, and the mean age was 36.9 years (range 19 to 54 years). Twelve (92.3%) patients complained of gross hematuria. Four (30.8%) patients showed symptoms in relation with pregnancy and delivery. Angiographic findings demonstrated cirsoid type in 10 patients and aneurysmal type in 3 patients. Among the 11 patients who underwent computed tomography, AVMs were detected in 3 (27.3%) patients. Renal duplex Doppler was performed in 6 patients, and all of these patients were diagnosed with AVM, demonstrating a vascular turbulence or blood-rich area. Twelve patients were initially treated with transarterial embolization. Nephrectomy was performed in two patients due to persistent bleeding with hypovolemic shock. Conclusions: We should consider possible AVMs in patients who were not detected by conventional work up for hematuria, especially in mid-aged, pregnant, or recently delivered women. Renal duplex Doppler might be the optimal diagnostic modality in these patients. Our diagnostic algorithm could be aid to diagnosis and treatment for renal AVM patients.

Arteriovenous Malformations-Current Understanding of the Pathogenesis with Implications for Treatment

Arteriovenous malformations are a vascular anomaly typically present at birth, characterized by an abnormal connection between an artery and a vein (bypassing the capillaries). These high flow lesions can vary in size and location. Therapeutic approaches are limited, and AVMs can cause significant morbidity and mortality. Here, we describe our current understanding of the pathogenesis of arteriovenous malformations based on preclinical and clinical findings. We discuss past and present accomplishments and challenges in the field and identify research gaps that need to be filled for the successful development of therapeutic strategies in the future.

Successful retrograde transvenous embolization under balloon occlusion for rectal arteriovenous malformation

A 57-year-old man was admitted to our hospital because of frequent hematochezia. Colonoscopy exhibited a submucosal tumor-like lesion in the lower rectum. Abdominal contrast-enhanced computed tomography showed a rectal arteriovenous malformation (AVM) on the right side wall of the lower rectum. The feeder was the superior rectal artery, with early venous return. Embolization of the draining vein and feeding artery of the AVM with N-butyl-2-cyanoacrylate under balloon occlusion was planned. Angiography of the superior rectal artery showed the nidus in the rectum with early venous return of contrast material. The portal vein was punctured percutaneously under ultrasound guidance, and a balloon catheter advanced to the distal part of the superior rectal vein. Venography under balloon occlusion showed the outflow vein and nidus. Transvenous and transarterial nidus embolization with N-butyl-2-cyanoacrylate under balloon occlusion was then performed. Since the embolization, there have been no further episodes of bleeding. There is no established treatment for AVMs. Successful treatment requires targeting and eradication of the nidus. We successfully performed embolization therapy for a rectal AVM via a retrograde transvenous approach. This technique may be suitable for completely eradicating the nidus without the risk of embolism.