Elsevier

World Neurosurgery

Volume 80, Issue 5, November 2013, Pages 538-548
World Neurosurgery

Peer-Review Report
The Evolution of Endovascular Treatment of Carotid Cavernous Fistulas: A Single-Center Experience

https://doi.org/10.1016/j.wneu.2013.02.033Get rights and content

Objective

Carotid-cavernous fistulas (CCFs) are pathologic arteriovenous shunts between the carotid artery and cavernous sinus. The resulting venous congestion within the cavernous sinus accounts for the classic ocular symptoms associated with these lesions. Endovascular treatment of CCFs has evolved over time to include a variety of transarterial and transvenous embolization techniques. The present series comprises our institutional experience with the endovascular treatment of CCF.

Methods

We reviewed our prospectively maintained clinical database for patients with CCF who were evaluated between December 1995 and August 2012. Clinical and demographic data were extracted from medical records, operative notes, and radiographic reports. Cerebral angiograms were reviewed.

Results

The study included 100 (42 direct CCF [dCCF], 58 indirect [iCCF]) patients. Of the 42 patients with dCCF, endovascular treatment was possible in 40 (95%), with an overall 8% morbidity and 2% mortality. Before March 2004, dCCFs were primarily treated with the use of detachable balloons. After the withdrawal of detachable balloons from the market, coil embolization emerged as the first-line treatment. It was accomplished either transarterially or transvenously and often incorporated balloon or stent protection of the parent vessel. After initial treatment, 33 patients (82%) exhibited complete obliteration of their fistula, whereas an additional four (10%) patients demonstrated fistula thrombosis on follow-up angiography. Endovascular access was achieved in 48 (83%) of the 58 patients with iCCF. In this cohort, the morbidity rate was 8%, and there were no deaths. Transvenous approaches were used to treat 88% of these patients and included both transfemoral venous access to the cavernous sinus and direct access through the ophthalmic veins. Immediate fistula occlusion was observed in 37 (77%) patients, and 1 of the 11 patients with a residual fistula progressed to thrombosis on follow-up. Transarterial embolization alone was used in six cases, and five required combined transvenous/transarterial approaches.

Conclusions

For dCCF, the lack of availability of detachable balloons led to the adoption of both transarterial and transvenous coil embolization with adjunctive techniques of parent vessel protection. For iCCF, advances in techniques of venous access have facilitated treatment of lesions with restricted venous outflow. Treatment strategies for CCF continue to evolve with advances in endovascular techniques.

Introduction

Carotid-cavernous fistulas (CCFs) are pathologic connections between the carotid artery and cavernous sinus. There are two primary subtypes of these lesions. Direct CCFs (dCCFs) represent a defect in the wall of the cavernous segment of the internal carotid artery. Most dCCFs occur in young men after a blunt or penetrating trauma (10). However, dCCFs also occur spontaneously, related to a ruptured cavernous-carotid aneurysm or in the setting of a collagen vascular disorder. Indirect CCFs (iCCFs) are more appropriately regarded as dural arteriovenous fistulas. These lesions are located in the walls of the cavernous sinus and exhibit multiple connections between the cavernous sinus and meningeal branches of the cavernous carotid artery, the external carotid artery, or both. Indirect fistulas may develop after resolution of cavernous sinus thrombosis (2) and occur most commonly in postmenopausal women (10).

Both classes of CCFs produce increased blood flow into the cavernous sinus, which overwhelms existing means of venous egress. This fistulous flow is typically shunted through the ophthalmic veins, producing the classic symptoms of proptosis, chemosis, conjunctival injection, and diplopia. The resultant increased intraocular pressure may ultimately result in visual compromise. In both classes of fistula, intracranial hemorrhage may occur if significant retrograde venous drainage is present (26).

The various strategies used to treat direct and indirect CCFs relate to differences in the size and anatomic location of the pathologic shunt as well as to variations in arterial inflow dynamics and patterns of venous outflow. Low-flow iCCFs that present with mild symptomatology often are best managed conservatively by manual compression of the ipsilateral carotid artery and jugular vein, in conjunction with close follow-up of intraocular pressure and visual acuity (15). For patients with severe or progressive symptoms and for those who do not respond to conservative management, treatment is warranted. Historically, endovascular treatment strategies have included both transarterial and transvenous routes of access for embolization via the use of detachable balloons, coils, and liquid embolic agents. Some cases require placement of an intravascular stent and may require parent artery occlusion to achieve successful fistula obliteration. These techniques have evolved over time, and safe and effective endovascular strategies are now available for even the most complex CCF.

In the present study, we analyzed our center's experience in managing 100 consecutive patients with CCF and in this work emphasize evolving treatment strategies that incorporate advances in endovascular materials and techniques. We also present several representative cases depicting the various avenues of endovascular treatment to illustrate technical nuances associated with the treatment of these lesions.

Section snippets

Methods

We retrospectively reviewed our prospectively maintained clinical database and identified 100 patients with CCF who underwent evaluation for endovascular treatment between December 1995 and September 2012 at Barrow Neurological Institute of St. Joseph's Hospital and Medical Center in Phoenix, Arizona, USA. Relevant clinical and demographic data were extracted after a review of outpatient clinic and inpatient hospital medical records, operative notes, radiologic reports, and cerebral angiograms.

Direct Fistula

Of the 42 cases of dCCFs, 40 were treated with endovascular techniques (95%). Multiple embolization sessions were performed in 15 of 40 (37.5%) treated patients (mean 1.7 ± 1.1 sessions), ranging from a single session to a maximum of five sessions. In one patient, an inability to catheterize the fistula prompted craniotomy for surgical trapping. In the second patient, no adequate venous access could be accomplished to a very small dCCF that was not amenable to transarterial embolization. The

Endovascular Techniques for Direct Fistulae

Transarterial approaches have historically represented first-line treatment for dCCF. In the United States, detachable silicone balloons were widely and successfully used to treat dCCF. In 2004, however, these devices were withdrawn from market, and neurointerventionalists began to use detachable coils to close fistula. In cases in which the site of the fistula is clear, such as fistulas related to a ruptured cavernous aneurysm with a well-defined neck, coil embolization may be effective in

Conclusions

Treatment strategies for CCF will continue to evolve as endovascular devices and techniques advance. Reconstructive techniques for direct fistulas using both covered stents 18, 25, 29 and flow-diverting stents (20) to facilitate parent vessel preservation will likely gain prominence in the coming years. Increasing experience with the use of EVOH to treat many types of arteriovenous fistulas is likely to expand the treatment armamentarium for CCF. As with other rare cerebrovascular lesions,

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    Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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