Transvenous Embolization of Carotid Cavernous Fistula through Inferior Petrosal Sinus with Detachable Coils and Ethylene Vinyl Alcohol Copolymer

Summary

The purpose of the article is to present our experience in endovascular treatment via the inferior petrosal sinus of the carotid cavernous fistula with detachable coils and ethylene-vinyl alcohol copolymer.

Abstract

Carotid cavernous fistula (CCF) is a rare disease caused by abnormal communications between the internal carotid artery (direct fistula) or meningeal branches of the external carotid artery (indirect fistula) and the cavernous sinus (CS). Trauma is the most common cause of CCF. The clinical presentation of CCF is closely related to the venous drainage pattern. Orbital and neuro-ophthalmological symptoms are the most common clinical presentation of CCF with drainage through the superior ophthalmic vein (SOV). Endovascular embolization by arterial or venous approaches is the most common management of CCF. Transvenous embolization using detachable coils and ethylene-vinyl alcohol copolymer (EVOH) is an alternative method for the treatment of CCF. Endovascular embolization offers different options to treat CCF by minimally invasive approach decreasing morbidity and residual fistulas. The purpose of this article is to report our treatment experiences via the inferior petrosal sinus (IPS), and immediate-term outcomes of endovascular embolization of CCF by using detachable coils and EVOH.

Introduction

Carotid cavernous fistula (CCF) is defined as abnormal arteriovenous communications between the internal carotid artery or meningeal branches of the external carotid artery and the cavernous sinus¹. CCF can be classified based on the etiology (traumatic or spontaneous), flow rate (high or low flow), or the angiographic composition (direct or indirect)^1,2. The clinical presentation of CCF is closely related to the venous drainage pattern: orbital and neuro-ophthalmological symptoms associated with drainage via the SOV, whereas neurological symptoms or intracranial hemorrhage related to leptomeningeal drainage^3,4.

The main treatment for CCF includes observation, intermittent manual compression of the common carotid artery (CCA), stereotactic radiosurgery and endovascular embolization^2,3. Ethylene vinyl alcohol copolymer (EVOH) is a non-adhesive liquid embolic material that was firstly evaluated at UCLA Medical Center between January 1998 and May 1999⁵. The treatment has changed with the development of the transvenous approach in association with detachable coils and EVOH. CCF is treated by endovascular techniques evolved from unimodality (transarterial detachable balloon occlusion) to multimodality (transarterial/intravenous coils, detachable balloon, liquid embolic agents, endovascular stent, etc)^5,6,7. Recently, transvenous endovascular embolization has become a standard treatment for CCF because of its feasibility and safety^3,6,7. There are several venous approaches based on the type of venous drainage. If the CCF has a mainly posterior venous drainage, through the inferior petrosal sinus (IPS), this route is the simplest and shortest in most patients. Even if it cannot be shown on angiographical images or it is thrombosed, catheters can still be guided into the CS through it.

We report successful endovascular treatment of 7 CCF patients using detachable coils and EVOH via the inferior petrosal sinus. The technical details are described in this protocol. The final decision to treat with a transarterial or transvenous approach was made after the analysis of the clinical images, and angiographic findings in each case. Based on our prior experience of treating CCF procedures by transarterial or transvenous approaches, we have found that endovascular embolization via the inferior petrosal sinus is a very good option with good outcomes, also safer and more effective than that via arterial access^3,6.

Protocol

The protocol has been approved by the local medical and ethics committees. All patients provided written informed consent.

1. Preoperative Preparation

1. Ensure the patients are diagnosed with CCF: All patients undergo digital subtraction angiography (DSA), routine bilateral internal and external carotid angiography, vertebral arteriography for assessment of feeding arteries, sizes, venous drainage patterns of CCFs, and carotid artery compression test with three-dimensional rotational angiographic capability.
2. Ensure all the procedures are executed under general anesthesia.

2. Vascular catheterization

1. Catheter and sheath preparation
   1. Prepare a 5F vascular sheath and a 6F vascular sheath, a 100-cm length of 4F H1 catheter and a 90-cm length of 6F or 5F guiding catheter, two 150-cm length of microcatheters with the inner diameter of 0.017'.
   2. Prepare a 150-cm guidewire with the diameter of 0.035' and a 200-cm length of microwire with the diameter of 0.014'.
2. Confirm the pulse of the femoral artery below the middle segment of the inguinal ligament, which is the site of puncture.
3. Puncture the left femoral artery via percutaneous approach and put a 5F vascular sheath into it with modified Seldinger technique. Position a 4F H1 catheter into the common carotid artery related to the CCF through the sheath with continuous heparinized saline solution (1000 U heparin diluted per 500 mL) perfusion for angiography during the procedure.
4. Puncture the right femoral vein via percutaneous approach and put a 6F vascular sheath into it with modified Seldinger technique. Position a 6F or 5F guiding catheter through the sheath with continuous heparinized saline solution (1000 U heparin diluted per 500 mL) perfusion in the internal jugular vein nearby the IPS.
5. Confirm the IPS by delayed arterial roadmap with three-dimensional rotational angiographic capability. The IPS is a main draining vein of CS, which flows into the internal jugular vein.
6. Coaxially navigate two microcatheters with a microwire into the CS through the IPS progressively step by step under the road mapping, and then gently inject the contrast medium (2 mL at 150 pounds per square inch) with the high-pressure injector from the microcatheter (selective venography) to confirm the position.
   1. To do this, position one microcatheter into the proximal side of the superior ophthalmic vein (SOV) through the IPS and another into the middle capacity of the CS.
   2. In cases of occluded IPS, use another stiffer microwire to pass through the sinus. Inject 2000 U heparin after the femoral artery puncture.

3. Embolization of CCF with detachable coils and EVOH

1. Detach several coils into the proximal SOV and the anterior position of the CS through the microcatheters. However, identify the residual fistulas on the control angiogram after coil detachment. Place the tips of the microcatheters among the detached coils.
2. Flush the microcatheter with 10 mL normal saline, followed by 0.25 mL dimethyl sulfoxide (DMSO) to fill the microcatheter dead space. Slowly inject 0.25 mL EVOH by hand into the dead space of the microcatheter and then start the embolization with the persistent injection of EVOH. The procedure is shown on angiography.
   NOTE: The EVOH is initially injected into the coil mesh and proximal position of the SOV. It penetrates the anterior compartment followed by the posterior compartment of the CS through two microcatheters with manually persistent injection.
3. Ensure preserving the blood flow of the ICA by digital subtraction angiography.

4. Estimation of treatment

1. Immediately perform angiography after the procedure to check for the occlusion of the CCF^6,7.
   NOTE: The immediate angiographic result is defined as complete disappearance, minor residual fistula, and significant residual fistula^6,7.

5. Postoperative Care

1. Let the patient recover from general anesthesia.
2. Check the patient on the following days for any discomfort, and for the improvement of symptoms in the hospital.
3. Follow up the patients admitted to hospital accordingly for the digital subtraction angiography at 3-month, 1-year and 2-year after treatment to confirm further improvement or recurrence.

Results

In our study, all 7 patients underwent angiographic evaluation and successful endovascular embolization. All patients presented with more than one symptom, conjunctival congestion and chemosis were the most common symptoms. No patient presented with seizures or hemorrhagic/ischemic stroke.

Table 1 clinical and angiographic baseline characteristics with the technique of transvenous embolization. A transvenous approach via the IPS was successful in 7 patients.

Discussion

Recently, endovascular treatment has become the most common therapy for CCFs. Successful treatment of CCFs is to occlude the abnormal shunts between the ICA or meningeal branches of the external carotid artery and the CS while keeping the ICA unobstructed. The treatment can be achieved with transarterial or transvenous approach to obliterate the affected side CS with coils or other embolic materials. Some patients with direct CCFs can be cured with the deployment of a covered stent across the fistula through ICA. The dis...

Materials

Name	Company	Catalog Number	Comments
EV3 coil	Medtronic, Irvine, California, USA	material for endovascular treatment
MicroPlex coil	MicroVention, California, USA	material for endovascular treatment
EVOH	Medtronic, Irvine, California, USA	material for endovascular treatment
Echelon/microcatheter	Medtronic, Irvine, California, USA	interventional material
Envoy/guiding catheter	Johnson & Johnson Company,USA	interventional material
vascular sheath	Terumo Corporation, Tokyo, Japan	interventional material