Endovascular Management of Cerebral Pial Arteriovenous Fistula: A Technical Experience
Year: 2025
Type: article
Study design: Case Report
Abstract: Key Message: Endovascular treatment stands as a cornerstone in the management of PAVF, providing patients with a safe and effective means of achieving flow disconnection and improving clinical outcomes.Pial arteriovenous fistulae (PAVF) are rare intracranial vascular lesions, predominantly seen in children, and are distinct from arteriovenous malformations (AVMs) and dural arteriovenous fistulae (DAVF). PAVF often leads to high morbidity and mortality. PAVF, also known as nongalenic pial arteriovenous fistula, is characterized by direct communication between pial arteries and cortical veins without an intervening nidus. The direct arteriovenous shunting results in high venous flow and subsequent development of venous aneurysmal dilatations and varicosities. The exact incidence and prevalence of PAVF in the general population is unknown, but it accounts for approximately 1.6% of all intracranial vascular malformations.[1,2] PAVF differs from brain AVMs, which involve abnormal connections via a cluster of vessels called a nidus within brain parenchyma. PAVF, on the other hand, consists of direct shunting between pial arteries and veins without a nidus. In a dural AVF, there is abnormal shunting between dural vessels that normally would not supply the brain tissue and veins that normally drain the brain.[3] PAVF can present with a wide range of neurological symptoms, including headache, seizures, focal neurological deficits, or even life-threatening intracranial hemorrhage. Some cases may be asymptomatic and discovered incidentally.[4] Owing to the association of PAVF with significant morbidity and mortality, treatment is usually necessary. Flow disconnection, either by microsurgery or endovascular techniques, is the mainstay of management. Surgery can be challenging for PAVF, especially when lesions are deep-seated or located in eloquent brain areas. Endovascular embolization, using liquid embolic agents and coils, is advantageous due to its noninvasiveness and relatively straightforward access. The aim of treatment is to occlude the abnormal arteriovenous shunt and prevent further neurological complications.[2,5] Through this video, we demonstrate a case of a pial arterio-venous fistula (PAVF) in a 13-year-old female successfully treated by transarterial embolization using detachable coils. A 13-year-old female presented to us with headache for 6 months which got aggravated since last 3 days. On physical examination, she was conscious and oriented to time, place, and person with a GCS (Glasgow Coma Scale) score of 15. Her neurological examination was unremarkable. Plain CT (computed tomography) head revealed hyperdensity in the left sylvian region suggestive of acute subarachnoid hemorrhage. DSA brain showed a PAVF fed by a branch from M2 segment of left middle cerebral artery (MCA) and draining into the left sylvian vein. Large aneurysmal venous varices were seen distal to the fistulous connection with varicose dilation of the Sylvian vein. After thorough assessment of all the treatment options available, we planned the endovascular trans-arterial embolization of fistulous connection. Under general anesthesia, right femoral artery was punctured and accessed using 8 French femoral sheath (Cook Medical, Bloomington IN, USA). Then a 6 Fr 100 centimeters Envoy guiding catheter (Codman Neuro, Raynham, MA, USA) was advanced to the left ICA. After taking a roadmap of the left ICA injection, an 8 Fr Neuron max long sheath (Penumbra Inc., Alameda, CA, USA) with a Catalyst-5 intermediate catheter (Stryker Neurovascular, Fremont, CA, USA) was exchanged and advanced into the distal part of the left ICA. An angiogram was taken, fistula site was identified and cannulated with Echelon-10 microcatheter (Medtronic, Dublin, Ireland) under roadmap guidance. After cannulating the fistula, selective angiogram was taken to confirm arteriovenous fistula. Then we started deploying the detachable coils into the dilated venous aneurysmal channel. An angiogram was taken to look for the status of occlusion of the fistula. The angiogram taken showed incomplete occlusion of the fistula and but filling of the draining veins slowed down. Then, large filling coils were deployed to densely pack the dilated venous channel and angiogram performed thereafter, showed complete occlusion of the arteriovenous fistula. The procedure was uneventful and the post-operative CT head done showed no evidence of any infarct or fresh bleed. The patient was discharged on POD-3 days with significant improvement in headache and no added neurological deficits. Video Timeline with Audio Transcript 0:00-0:13- This video shows a stepwise technique of trans-arterial coil embolization of a rare case of pial arteriovenous fistula. 0:14-0:21- A 13-year-old female presented to us with chief complaint of headache for 6 months which got aggravated since last 3 days. 0:22-0:29- On physical examination she was conscious and oriented to time, place, and person with a GCS (Glasgow Coma Scale) score of 15/15. 0:30-0:35- On neurological examination, she did not have any cranial nerve deficits or weakness in either of her limbs. 0:36-0:42- Plain CT head revealed a hyperdense region near left sylvian fissure, suggestive of hemorrhage. 0:43-0:55- Hence, we planned a DSA brain which showed, a pial arteriovenous fistula fed by a branch from M2 segment of left middle cerebral artery and draining into the left sylvian vein, then into the cavernous sinus. 0:56-1:03- This is the 3-dimesnional reconstructed image showing the arterial feeder, aneurysmal venous dilatations and the draining vein as marked with the arrows. Large aneurysmal venous varices were seen distal to the fistulous connection with continuous dilation of the Sylvian vein. 1:04-1:13- MANAGEMENT STRATEGY: The main aim of treating the pial arteriovenous fistulas is to occlude the abnormal arterio-veinous shunting. 1:14-1:35- Flow disconnection can be done either by microsurgery or by endovascular techniques which includes simple coiling using detachable coils or by embolization using the liquid embolic agents such as nBCA, ONYX, SQUID, MENOX Or PHIL. 1:36-1:53- After evaluating all the available treatment options, we chose the endovascular approach that involves deploying the detachable coils to occlude the abnormal fistulous connection and venous drainage and thus disconnection of the fistulous link. 1:54-2:16- These were the hardware required during the procedure. Femoral Sheath 8 FR (Cook Medical, Bloomington IN, USA) Envoy Guiding Catheter 6 FR (Codman Neuro, Raynham, MA, USA) Neuron Max 8 FR Long Sheath (Penumbra Inc., Alameda, CA, USA) Catalyst-5 Intermediate Supporting catheter 5 FR (Stryker Neurovascular, Fremont, CA, USA) Eschelon10 Microcatheter (Medtronic, Dublin, Ireland) Guidewires (Teremo 150 And 250 Centimeters) Microwire (Synchro 14) Target 360 Detachables Coils (Stryker Neurovascular, Fremont, CA, USA). 2:17-2:43- PROCEDURE: After explaining the procedure and taking well informed and written consent, the patient was shifted to DSA suit. The patient was laid down supine and general anaesthesia was given. Then right inguinal region was prepared for femoral assess. Right femoral artery was punctured and assessed using 8 French femoral sheath. A 6 Fr 100 centimetres Envoy guiding catheter was advanced to the aortic arch and subsequent DSA of bilateral ICA, bilateral ECA and VA were taken. 2:44-2:56- This is the angiogram of left ICA, anteroposterior and lateral views, showing a pial arterio-veinous fistula fed by a branch of the M2 segment of the left middle cerebral artery and draining into the left sylvian vein, which is draining into the cavernous sinus. 2:57-3:08- This is the 3-dimensional reconstructed image of the left ICA angiogram showing the pial arteriovenous fistula with the arterial feeders, venous drainage and the associated venous aneurysm as shown by the arrows. 3:09-3:26- Then a road map of left ICA angiogram was taken and Envoy catheter was exchanged with 8 Fr long sheath NEURON MAX and advanced till proximal part of left ICA. Then an intermediate catheter, Catalyst-5 was taken and advanced till the distal part of left ICA as marked with arrows. 3:27-3:42- Then, using the 3-dimensional reconstruction, a working angle was created and an angiogram was taken at this working angle, the fistulous site was identified and cannulated with an Echelon-10 microcatheter under roadmap guidance. 3:43-4:05- After cannulating the fistula, selective angiogram was taken to confirm arteriovenous fistula. Then we started deploying the detachable coils into the dilated venous aneurysmal channel. 4:06-4:17- An angiogram was taken to look for the status of occlusion of the fistula. The angiogram taken showed incomplete occlusion of the fistula and but filling of the draining veins slowed down. 4:18-4:32- Then, large filling coils were deployed to pack the dilated venous aneurysmal channel densely and angiogram performed thereafter showed complete occlusion of the fistulous connection. 4:33-4:39- Here, we can see that there is complete obliteration the fistulous connection and there is no abnormal venous drainage seen. 4:40-4:49- Postembolization angiogram revealed complete occlusion of the PAVF with contrast stasis in dilated aneurysmal sac as shown by the arrows. 4:53-5:00- This is the biplanar angiogram of the left ICA taken after completion of procedure showing complete occlusion of the fistula and normal venous drainage. 5:01-5:16- The procedure was uneventful and post operative CT head done showed no evidence of any infarct or fresh hemorrhage. The coil artifacts can be seen as marked with the arrow. 5:17-5:26- The patient was discharged on post-operative day 3 with significant improvement in the headache and no added neurological deficit. The patient is in follow up and is doing fine. 5:26-5:36- These are the references. Video Link: https://drive.google.com/file/d/1ev8Ibwz1dibBkbZQIhBo_JicoI_aNkn8/view?usp=sharing QR Code: Video timeline with audio transcript Discussion Pial arteriovenous fistulae (PAVF) are rare intracranial vascular lesions, predominantly seen in children and are distinct from arteriovenous malformations (AVMs) and dural arteriovenous fistulae (DAVF). The precise prevalence of pial arteriovenous fistulas (PAVF) remains uncertain due to its rarity, with estimated rates ranging between 0.1/100,000 and 1/100,000 individuals, showing no gender predilection. PAVF accounts for approximately 1.6% of all brain vascular malformations, and in pediatric cases, it constitutes around 4% of cerebral vascular malformations. These fistulas form as a result of a direct connection between an arterial feeder and a solitary draining vein, without an intervening network of vessels, leading to turbulent high-flow conditions and the development of venous varices and aneurysmal dilatations.[2,6-8] While primarily congenital, PAVF can also arise from traumatic or iatrogenic causes. Clinical presentation varies and may include intracerebral hemorrhage, seizures, headache, focal neurological deficits, or signs of raised intracranial pressure. In neonates and infants, symptoms may manifest as high output cardiac failure, increased head circumference, and the presence of a bruit.[9] Treatment of PAVF aims to close the shunt, typically through endovascular or surgical methods. Conventional surgical techniques involve clipping or cauterization of the fistula vessels, which can be effective but carry a high risk of neurological morbidity, especially for deep-seated or eloquently located lesions. Abrupt disconnection may also lead to hyperemia due to the perfusion pressure breakthrough phenomenon.[10,11] In endovascular treatment, the primary goal is to occlude the fistula. Liquid embolic materials such as Onyx or glue, along with coils alone or in combination, are used to achieve this goal. Coils alone have been shown to provide immediate complete obliteration of fistulas in some cases. Meanwhile, glue injection, particularly with N-butyl cyanoacrylate (NBCA), can achieve occlusion of the feeding vessel close to the fistula site, with penetration into the proximal vein. We used coiling alone as an embolic material in our patients with immediate complete obliteration of fistulas. Lv et al.[12] treated seven patients with detachable coils alone and complete obliteration was obtained in 4 patients. Alurkar et al.[13] treated two patients with coils alone with complete obliteration. Limaye et al. reported a series of five cases treated with NBCA glue as an embolic material. It gives fluidity to fill the vascular spaces, control during injection and provides a permanent occlusion. With glue injection, it is desirable that the feeding artery is occluded close to the fistula along with glue penetration into the proximal part of the vein. However, because of rapid flow at the fistula, significant risk exists for embolization of normal distal draining vein and possible pulmonary embolization.[9] Also, embolization of a normal vein draining into the venous channel of the pial AVF may result in venous infarction. Strategies such as balloon occlusion at the feeding artery or partial coil embolization in the proximal vein can help slow down flow within the fistula, reducing the risk of embolic material migration. Nonetheless, the lumen balloon catheter technique may present maneuverability challenges and an increased risk of catheter retention or rupture.[14] In our case, we chose endovascular trans-arterial embolization using detachable coils thus avoiding the aforementioned risks of using the liquid embolic agents. Endovascular techniques offer advantages of noninvasiveness and relatively straightforward access compared to surgical interventions. However, careful consideration of the risks and benefits of each approach is essential to ensure optimal patient outcomes. The most common procedure-related complication reported in the literature is new intracranial hemorrhage (12.6%), followed by the development of new neurological deficit (7.4%).[15] Glue migration, thalamic infarcts, and pulmonary embolism occurred in patients following deflation of balloon. Conclusion Pial arteriovenous fistulas (PAVF) represent a rare but serious vascular anomaly associated with significant morbidity and mortality. Effective treatment, particularly through endovascular means, plays a crucial role in achieving favorable clinical outcomes. Utilizing endovascular techniques such as liquid embolic agents, coils, or their combination has emerged as a safe, feasible, and efficient approach. Endovascular treatment stands as a cornerstone in the management of PAVF, providing patients with a safe and effective means of achieving flow disconnection and improving clinical outcomes. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Source: Neurology India
Institution: Dr. Ram Manohar Lohia Institute of Medical Sciences
Language: English
Subfield: Clinical Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
OpenAlex ID: W4407252243