Pial arteriovenous fistula: A clinical and neuro-interventional experience of outcomes in a rare entity

Spontaneous occlusion of a pial arteriovenous fistula after angiography: The role of iodinated contrast media

Intracranial non-galenic pial arteriovenous fistula (PAVF) is an extremely rare vascular malformation, where one or more pial arteries feeds directly into a cortical vein without any intervening nidus. Though occasionally they can be asymptomatic, neurological symptoms such as headache, seizure, or focal neurological deficit are more common presenting features. Life threatening or fatal hemorrhage is not uncommon, hence needed to be treated more often than not. Spontaneous occlusion of PAVF is reported only four times before. We report a 49-year-old gentleman, who was diagnosed to have a PAVF, possibly secondary to trauma. He presented 5 months and 22 days from initial digital subtraction angiography (DSA) for treatment, and follow-up angiogram showed complete obliteration. He denied any significant event, medication or alternate treatment during this period. His clinical symptoms were stable as well. We postulate iodinated contrast medium induced vasculopathy as a possible cause, which has been described for other vascular pathologies, but never for PAVF.

Curative transvenous embolization for congenital multi-hole pial arteriovenous fistula

OBJECTIVE

Congenital intracranial pial arteriovenous fistula (PAVF) is a rare cerebral vascular pathology characterized by a direct shunt between one or more pial feeding arteries and a cortical draining vein. Transarterial endovascular embolization (TAE) is widely considered first line therapy. Curative TAE may not be achievable in the multihole variant due to the potential to harbor innumerable small feeding arteries. Transvenous embolization (TVE) may be considered to target the final common outlet of the lesion. Here, we present a series of four patients with complex multi-hole congenital PAVF treated with staged TAE followed by TVE.

METHODS

A retrospective review was conducted on patients who underwent treatment for congenital, multi-hole PAVFs treated by a combined TAE/TVE approach at our institution since 2013.

RESULTS

We identified four patients with multi-hole PAVF treated by a combined TAE/TVE. Median age was 5.2 (0-14.7) years. Median follow-up of 8 (1-15) months by catheter angiography and 38 (23-53) months by MRI/MRA was obtained. TVE achieved complete occlusion in three patients that proved durable on radiographic follow-up and demonstrated excellent clinical outcomes with a modified Rankin Score (mRS) of 0 or 1. Complete occlusion of the draining vein was not achieved by TVE in one case. This patient is graded as pediatric mRS=5 three years post-procedure.

CONCLUSIONS

With thorough technical considerations, our series indicates that TVE of multi-hole PAVF that are refractory to TAE is feasible and effective in arresting the consequences of chronic, high-flow AV shunting produced by this pathology.

Pial arteriovenous fistula associated with vein of Galen dilatation in adult: A case report and MRI findings

Pial arteriovenous fistula (PAVF) is a rare intracranial vascular lesion where direct communication exists between one or more pial arteries and a cerebral vein, without an intervening nidus and located in the subpial meningeal space. When the drainage of PAVF involves a dilated, but already formed vein of Galen (VOG), it should be distinguished from other vascular lesions located in this area, because their angio-architecture, natural history and treatment options are different. A 33-year-old female was admitted to our hospital with a history of new-onset generalized tonic-clonic seizures. Clinical examination showed no neurological deficit. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) depicted an arteriovenous fistula that was fed by the pial branches from left posterior cerebral artery and drained into the medial atrial vein before joining the VOG confluence and causing VOG dilatation. No nidus between the feeding arteries and draining vein, dural feeding arteries, or anatomical variations commonly seen with true vein of Galen aneurysmal malformations (VOGM) were found. These finding suggested a diagnosis of a PAVF associated with vein of Galen dilatation, which was confirmed by digital subtraction angiography. The patient was treated with transarterial glue embolization in 1 section, resulting in nearly complete occlusion of the fistula. Conventional MRI and MRA are noninvasive modalities that can provide valuable information regarding the anatomic localization of the fistula point, the feeding arteries, the venous sac, and their relationship with surrounding structures. These techniques are helpful for accurate diagnosis and treatment planning.

Direct arteriovenous fistula due to a blister-like aneurysm of the supraclinoid internal carotid artery hijacking its adjacent vein

BACKGROUND

This is the first report of a direct acquired arteriovenous fistula (AVF) between an intracranial aneurysm and its adjacent pial vein.

CASE DESCRIPTION

A 33-year-old male suffered subarachnoid hemorrhage. Computed tomography angiography revealed an aneurysm of the supraclinoid internal carotid artery (ICA). Digital subtraction angiography (DSA) showed that the aneurysm of the supraclinoid ICA was blister-like and that one large vessel crossing the aneurysm provided two draining paths into the bilateral cavernous sinuses and superior sagittal sinus. Microsurgery confirmed the presence of a blister-like aneurysm and proved the vessel crossing and connected to the aneurysm to be a pial vein, resulting in a direct AVF between the aneurysm and its adjacent vein. The blister-like aneurysm together with some of the ICA wall was clipped to reconstruct the ICA and preserve the anterior choroidal artery (AchA). Postoperative DSA showed the following: the blister-like aneurysm had been completely clipped; the ICA was narrow, but the blood flow was sufficient; and the AchA was intact. After discharge, the patient recovered uneventfully without neurological deficits.

CONCLUSIONS

Exceptionally, an intracranial ruptured aneurysm can hijack its adjacent pial vein as its draining path, forming a direct AVF. Microsurgery can be used to confirm the angioarchitecture of the AVF, and clipping is a good treatment choice.

A Systematic Review of Non-Galenic Pial Arteriovenous Fistulas

OBJECTIVE

Non-galenic pial arteriovenous fistulas (NGPAVFs) are rare cerebrovascular pathologies accounting for only 1.6%-4.8% of all brain vascular malformations. We performed a comprehensive review of NGPAVF cases reported in the literature to further characterize their clinical patterns of presentation, angiographic features, management, clinical outcomes, and complications.

METHODS

We searched PubMed, Google Scholar, and Embase from each database's earliest records to April 2022 for all relevant English language articles. A total of 3280 articles were screened to identify those that met prespecified inclusion criteria. Differences in clinical outcomes between children (≤18 years old) and adults (>18 years old) and those articles in which NGPAVFs were associated with the presence of a varix or a hemorrhage were statistically examined.

RESULTS

A total of 242 patients in 86 articles were included. The mean patient age was 18.51 ± 18.80 years. The male-to-female ratio was 1.44:1. Headache was the most common initial presentation (42.6%) in the study cohort. Hemorrhage occurred at a significantly higher frequency in adults (P = 0.004), whereas more children presented with congestive heart failure (P < 0.001). Surgical, endovascular, and combination therapy led to comparable rates of complete NGPAVF obliteration (86.8%, 85.2%, and 88.5%, respectively). Fifty-nine patients (24.4%) experienced a complication, ranging from minor neurological deficit to severe hemorrhage. The mortality rate for the overall cohort was 3.3%, and all deceased patients had a varix associated with their fistulas.

CONCLUSIONS

To our knowledge, we report the largest literature review describing the clinical course and characteristics of NGPAVFs. All treatment approaches resulted in favorable obliteration rates and overall patient outcomes.