February 2, 2022

Transvenous Embolization of Cerebrospinal Fluid Venous Fistulas Appears Promising in Large Case Series

February 3, 2022—In a study published online in Journal of NeuroInterventional Surgery, Brinjikji et al demonstrated that transvenous embolization of cerebrospinal fluid venous fistulas (CSFVFs) resulted in significant improvement in headache and overall clinical outcomes in a majority of patients.

Key Findings

Transvenous embolization of CSFVFs was highly effective, with 90% of patients achieving substantial symptom improvement.
More than 90% of patients showed improvement in brain MRI findings, as measured by Bern score.
Transvenous embolization of CSFVFs was safe, with no major hemorrhagic or spinal ischemic complications.

The investigators performed a retrospective review of a prospectively collected database of patients with spontaneous intracranial hypotension (SIH) caused by CSFVFs, as confirmed by digital subtraction myelography, who underwent transvenous embolization at Mayo Clinic in Rochester, Minnesota.

All patients were evaluated by a neurologist with expertise in CSF dynamics disorders and underwent baseline and 3-month follow-up brain MRI with and without contrast. Brain MRIs were analyzed using the Bern score and classified as low (≤ 2 points), intermediate (3-4 points), or high (≥ 5 points) probability of finding a spinal CSF leak (scale of 9 points). Patients also completed the 6-item Headache Impact Test (6-HIT) at baseline and 3-month follow-up, in which score severities were divided into little or no impact (36-49), some impact (50-55), substantial impact (56-59), and severe impact (≥ 60). The patient’s overall sense of postintervention improvement was also collected using Patient Global Impression of Change (PGIC) scores.

Paired t-test was used to report changes in Bern and HIT-6 scores at follow-up.

A total of 40 patients (29 female, 11 male) with 50 CSFVFs were included (mean age, 57.4 ± 10.3 years). Mean Bern score improved from 5.7 ± 3.0 at baseline to 1.3 ± 2.0 at 3-month follow-up (P < .0001). Mean baseline HIT-6 score was 67.2 ± 11.1 and improved to 41.5 ± 10.1 at follow-up (P < .0001). Median PGIC score was 1, with 90% (36 patients) reporting at least minimal improvement and 82.5% (33 patients) reporting much or very much improvement.

Seven (17.5%) patients experienced rebound intracranial hypertension severe enough to require temporary medical management, and 30% of patients reported some local pain at the site of embolization 3 months postprocedure. In three (7.5%) patients, small amounts of Onyx (Medtronic) were seen in the pulmonary arteries on postoperative CT, but these were asymptomatic.

As noted by the authors, limitations included the short follow-up and inconsistent pretreatment MRI protocols because patients were referred from multiple centers.

Based on the study results, transvenous embolization should be considered for the treatment of CSFVFs in patients with SIH, noted the investigators.

ENDOVASCULAR TODAY ASKS…

Lead author Waleed Brinjikji, MD, with Mayo Clinic in Rochester, Minnesota, was asked to provide some additional insights into the study’s findings and what comes next.

How did you determine what would be the most meaningful endpoints for this unique study, addressing clinical findings and patient-reported effects?

In order to identify the most meaningful endpoints, we surveyed the headache and SIH literature. We found that 6-HIT was a good indicator of headache severity. However, it was not a perfect outcome to study because many SIH patients do not present with headache but with other neurologic symptoms. Furthermore, in some patients, headache is not even the most severe symptom (many patients have hearing loss, tinnitus, cognitive dysfunction, or ataxia). That is why we also included the PGIC.

Including the complications noted, what possible unintended effects must be considered and further studied?

When sealing these leaks, whether with surgery or endovascular techniques, we need to be mindful about the risk of rebound intracranial hypertension. This can be debilitating in its own right and can even result in the formation of new leaks. In the end, we need better protocols to identify patients who are at risk for rebound intracranial hypertension so we can properly prophylactically treat them.

You concluded that further studies are needed to confirm the technique and assess the durability of the treatment effect. What are the most significant questions to be addressed?

In all honesty, I would love to conduct a proper clinical trial in this space. This disease is much more prevalent than we realize, and we do not have proper clinical trials examining treatment outcomes for these patients. Also, it is important that others performing this intervention publish their results as well. The treatment needs to be shown to be generalizable to all interventionalists interested in treating this disease. I know of at least 20 physicians in the United States and Europe who have been treating these patients, and I am looking forward to seeing their excellent results.

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