Transvenous microguidewire looping technique for breach of ipsilateral inferior petrosal sinus occlusions en route to cavernous sinus dural arteriovenous fistulas

Abstract

Background and purpose

Transarterial access to dural arteriovenous fistulas (dAVFs) has been popularized by device improvements and novel embolic materials. However, this approach is limited in the cavernous sinus (CS) because of related complications and low cure rates. Although a transvenous approach, via ipsilateral inferior petrosal sinus (IPS), may be more suitable for CS-dAVFs, microcatheter delivery is occasionally impeded by ipsilateral IPS occlusion. Described herein is a microguidewire looping method to breach such occlusions, thus enabling access to CS lesions.

Methods

A microcatheter is initially advanced into the IPS orifice, and a microguidewire is passed into the occluded IPS. Looping is easily achieved through the resistance met. With greater support of the guiding catheter, the microguidewire (still looped) is then advanced into the CS. When nearing the CS, the microcatheter is further reinforced, and it is navigated along the microguidewire into the CS.

Results

This technique was applied in 10 instances of CS-dAVF with ipsilateral IPS occlusion, enabling ipsilateral access to the CS. In eight cases (80%), microdevice advancement was successful, culminating in effective transvenous coil embolization. Clinical and radiologic outcomes in all patients were excellent, with no delayed post-procedural cranial palsies.

Conclusion

This microguidewire looping technique enables safe and effective entry into the CS during transvenous coil embolization of CS-dAVFs with ipsilateral IPS occlusion.

Introduction

Cavernous sinus dural arteriovenous fistula (CS-dAVF) is more common in Asian countries compared with Western nations. CS-dAVF is defined as an abnormal arteriovenous communication involving dura mater within or near walls of the CS.¹ Apart from the few that spontaneously regress (10%), higher risk lesions (marked by cortical venous drainage, progressive visual loss, neurologic deficits, or hemorrhage) and those associated with intolerable diplopia, severe headache, and severe cosmetic disfigurement, require treatment to halt abnormal shunting.² A transvenous approach via the ipsilateral inferior petrosal sinus (IPS) is strategically critical in treating a variety of CS and sellar conditions.³ At times, practicing interventionists are likely to encounter ipsilateral IPS occlusion, which impedes microcatheter delivery to the CS. We recently devised a microguidewire looping technique to address the challenge of such situations. The feasibility and safety of this approach were explored in a limited group of patients, whose angiographic and clinical outcomes are presented herein.

Material and methods

Study population

A total of 38 patients with 40 CS-dAVFs were treated by transvenous coil embolization at our institution between January 2012 and June 2015. Of this population, 14 patients (35.0%) displayed ipsilateral IPS occlusion (IPS patent in 24), four of whom were treated through traditional microcatheter delivery (probing by gentle rotational advancement of a 0.014-inch microguidewire). In the other 10 patients (eight female; two male; mean age, 63.0 ± 5.7 years), in whom traditional maneuvers failed, our looping technique was applied.

General characteristics of the cohort are summarized in Table 1. All lesions (N = 10) were idiopathic in nature, lacking any association with trauma or surgery. The most common complaints were diplopia due to cranial nerve palsy (n = 8), followed by orbital symptoms (e.g. proptosis and conjunctival injection; n = 7), tinnitus (n = 2), and headache (n = 1). Diffuse lesions predominated (nine diffuse; one focal). Therapeutic alternatives were discussed both with neurologic/neurosurgical and neurointerventional teams in a multidisciplinary decision-making process, and informed consent was obtained from all patients after careful consultation. This retrospective study was approved by our institutional review board.

Table 1.

Summary of the patients’ data.

Number	Age	Sex	Etiology	Presentation	Fistula type/ Cognard class	Symptom duration (mo)	Main draining vein	Degree of occlusion	Procedural complication	Improvement of Sx	Miscellaneous
Successful access to CS using microguidewire looping
1	62	F	I	Diplopia/ proptosis	D/IIa	5	OV	Complete	No	Yes
2	62	F	I	Diplopia/ proptosis	D/IIa	5	OV	Complete	No	Yes
3	64	F	I	Proptosis/ tinnitus	D/IIa	2	OV	Complete	No	Yes
4	70	F	I	Diplopia/ proptosis	D/IIa	1	OV	Complete	No	Yes
5	74	F	I	Diplopia/ proptosis	D/IV	1	OV, SMCV	Complete	No	Yes
6	62	F	I	Headache/ tinnitus	Focal/IV	2	SMCV	Complete	No	Yes
7	53	M	I	Diplopia	D/IV	2	Contra. IPS	Complete	No	Yes
8	64	F	I	Diplopia/ proptosis	D/III	0.75	OV	Complete	No	Yes
Access failure by microguidewire looping											Further Tx
9	59	M	I	Diplopia/ proptosis	Focal/IIa	5	OV	Complete	No	Yes	TV app. through facial vein
10	65	F	I	Diplopia	D/IIa+b	5	Contra. IPS	Complete	No	Yes	TV app. through contra. IPS – delayed CNP

CNP: cranial nerve palsy; Contra.IPS: contralateral inferior petrosal sinus; D: diffuse; F: female; I: idiopathic; M: male; mo: month; OV: ophthalmic vein; SMCV: superficial middle cerebral vein; Sx: symptom; TV app.: transvenous approach; Tx: treatment.

Therapeutic strategy

Microguidewire looping was undertaken as follows: (1) microcatheter advancement into the IPS orifice; (2) looping of the microguidewire tip; (3) reinforcement of guiding system support; (4) advancement of the looped microguidewire to the CS, passing through the occluded IPS; and (5) microcatheter passage into the CS under microguidewire guidance. A schematic of the technique is shown in Figure 1.

Figure 1.

Schematic of microguidewire looping technique to breach occluded ipsilateral inferior petrosal sinus (IPS) (left side, anteroposterior (AP) view; right side, lateral view).

(a) Anteromedial placement of guiding catheter in jugular vein to locate caudal orifice of occluded IPS; (b) microdevice selection of IPS orifice; (c) microguidewire loop shaped by resistance of occluded caudal IPS; (d) advancement of guiding catheter into the IPS orifice to enhance support; (e) looped microguidewire tip advanced to the cavernous sinus (CS) lesion through occluded IPS; and (f) passage of microcatheter into CS under guidance of microguidewire.

To locate the IPS orifice, biplane imaging is mandatory. Typically, IPS arises from the anteromedial jugular vein, running anterior, medial, and cephalad with respect to the CS (see Figure 1(a)). A curved guiding catheter tip in the anteromedial position is directed into the IPS orifice, and once properly selected, microguidewire passage through the occluded IPS proceeds. If traditional torque is insufficient to breach the occlusion, the resistance encountered easily allows the microguidewire to loop. By reinforcing the guiding system support (to counter resistance met), the looped microguidewire is then forced through the occluded IPS. There are two ways to boost support: The guiding catheter may be inserted as deeply as possible within the IPS orifice (see Figure 1(c)); or a coaxial system, engaging a 4F or 5F angiography catheter, may be implemented to anchor the catheter deeply. Once the looped microguidewire is passed, it must be advanced to a draining vein or delivered well into the CS, allowing the microcatheter to follow and pass through the occluded IPS (supplemental video file 1). After microcatheter entry into the CS, control injection of contrast through the microcatheter is performed to confirm placement in the correct compartment of the sinus that is involved by the fistula. Microdevice selection of the fistula or mural channel is then possible, and coil embolization is performed. At our institution, size 18 microcatheters (Excelsior 1018; Stryker, Cork, Ireland), as the minimum caliber accommodating pushable coil, and 0.014-inch microguidewires with polymeric jackets (Transcend; Stryker) are primarily used. Larger-sized microcatheters are more difficult to navigate through IPS occlusions.

Endovascular procedures

Endovascular procedures were largely performed under general anesthesia (n = 8), with two patients undergoing local anesthesia. Prior to treatment, angioarchitectural explorations were conducted via Integris V (Philips Medical Systems, Best, The Netherlands) or Innova IGS 630 (GE Healthcare, Wauwatosa, WI, USA) biplane system to assess feeding arteries, location/extent of fistulous sites, and venous parameters. All lesions were categorized as focal or diffuse type, depending on whether these fistulas (mural channels) were limited in scope or involved areas of CS diffusely. In addition, Cognard classifications were assigned. Antiplatelet preparations were not routinely prescribed in advance of procedures, but after femoral sheath placement, systemic heparinization was customary, using single 2000-IU injections.

Angiographic outcome and follow-up states

Immediate angiographic results after endovascular embolization were classified by degree of shunt as follows: complete occlusion, near-complete occlusion, and partial occlusion.²

Clinical follow-up at one and three months post-treatment was advised for completely occluded fistulas. Further imaging studies, such as digital subtraction angiography (DSA) or magnetic resonance angiography (MRA), were recommended only in patients with aggravated clinical symptoms. In those lesions showing near-complete or partial occlusion post-treatment, DSA was recommended at one month.

Results

The looping technique described was attempted in 10 CS-dAVFs with IPS occlusion, all of which were refractory to traditional maneuvers. Successful passage was achieved in eight of these lesions (80%), and subsequent transvenous embolization was curative in all fistulas accessible by microdevices (Figure 2). There were no procedure-related complications, and post-procedural symptom improvement was consistently observed. In the two instances in which microguidewire looping failed, alternate venous routes were used (one contralateral IPS, one ipsilateral facial vein), also enabling curative treatments, but one patient suffered transient cranial nerve palsy in the aftermath.

Figure 2.

Patient illustration: 62-year-old female suffering diplopia for two months.

(a) and (b) Right cavernous sinus dural arteriovenous fistulas (CS-dAVFs) shown by both external carotid artery (ECA) angiographies. Note ipsilateral inferior petrosal sinus (IPS) occlusion and main venous drainage of superficial middle cerebral vein. The fistula was supplied by multiple dural branches of both internal and ECAs, including accessory meningeal artery, internal maxillary artery and middle meningeal artery, etc.; (c) with 6F guiding catheter (coaxial system using 4F angiocatheter) positioned in the right jugular vein, IPS orifice selected using 0.014-inch microguidewire and microcatheter: loop formed at occluded caudal IPS; (d) microguidewire breach of IPS, with guiding catheter and coaxial angiocatheter anchored in IPS orifice; (e) microguidewire advanced well within CS (note further looping of the microguidewire within CS for proper rigidity); (f) microcatheter follows microguidewire path; (g) transvenous embolization performed; and (h) No shunting of blood by fistula on completion angiography.

Discussion

Although a transarterial approach to dAVF has been popularized by device advancements, novel embolic materials, and the improved treatment outcomes achieved, use of this strategy for CS-dAVF is still controversial, given the complications (i.e. cranial nerve palsy and cerebral infarction in high-risk lesions) and low cure rates of such procedures. Typically, transvenous embolization confers better outcomes. A transvenous route through an ipsilateral IPS is generally preferred, providing a relatively straight course and the shortest route to CS. However, occlusion of ipsilateral IPS, thus impeding microcatheter delivery to the CS, is not uncommon in instances of CS-dAVF. Thrombotic venous or sinus occlusion is a well-known and frequent accompaniment of dAVF. Rhim et al.² confirmed ipsilateral IPS occlusion in 34.5% of CS-dAVFs at time of treatment. Such occlusions must be breached by the microdevices deployed in order for coil embolization to succeed. Once there is access to CS, successful embolization is achievable in nearly all instances of CS-dAVF.

Our microguidewire looping method appears viable and effective as an alternative approach, should customary measures fail. At present it is not advocated for first-line use. In this limited series, microguidewire looping allowed access to the CS in 80% (8/10) of lesions refractory to traditional maneuvers, compared with 28.6% (4/14) for first-line traditional attempts. Study of a much larger population is still needed to validate these positive provisional findings. Lekkhong et al.⁴ recently described a method that probes and accesses the CS through occluded IPS using a 0.035- or 0.038-inch guidewire

Based on a relatively higher success rate (54.3%), Rhim et al.² favored first-line ipsilateral IPS access in instances of CS-dAVF with IPS occlusion. However, blind navigation through an occluded IPS may bring unwanted complications. For example, sinus or venous injury may result from traditional probing of an IPS occlusion with a sharp microguidewire tip. This looping technique creates a rounded distal terminus to help avoid venous injury and easily explore the occluded pathway. Other venous routes, including contralateral IPS, superior petrosal sinus, or ophthalmic vein (via facial vein or by direct puncture), likewise may serve as reasonable alternatives.^5–8 As in two patients in this series for whom microguidewire looping failed, alternative routes are logically dictated by angioanatomic configurations.

To navigate an occluded IPS, the caudal end of the IPS must first be located. Several publications have described anatomic variations of IPS, including six types detailed by Mitsuhashi et al.⁹ Based on anatomy and with some experience, the caudal end of the IPS should be accessible by microdevice; but there are other challenges in approaching fistulas within/near the CS. Support for the guiding catheter is a critical element. The guiding catheter is subject to kick-back and should be firmly anchored within the caudal end of the IPS before any microdevices are passed to breach an occlusion. A coaxial system, embedding an angiocatheter in the occluded IPS via guiding catheter, may also enhance guiding system support. If support is maximized, the looping technique enables excellent outcomes.

Another critical step is advancing the microcatheter into the CS once the microguidewire has gained CS entry. The challenge is created by differences in catheter caliber. Again, microguidewire support must be reinforced, allowing the microcatheter to follow the microguidewire. The microguidewire must also be advanced far enough to a draining vein or well into the CS for microcatheter advancement. Occasionally, it may be necessary to further loop the microguidewire within the CS for proper rigidity (see Figure 2(e)).

Conclusion

This microguidewire looping technique may have merit in instances of CS-dAVF where traditional maneuvers prove difficult or fail because of ipsilateral IPS occlusion. Long-term study of a larger patient series is needed to confirm the preliminary safety and efficacy observed.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.