Endovascular management of internal carotid artery pseudoaneurysms: A single-centre experience of 20 patients
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.236958
Source of Support: None, Conflict of Interest: None
Keywords: Coiling, internal carotid artery, parent artery occlusion, pseudoaneurysms, stenting
Pseudoaneurysms (PSAs) of the internal carotid artery (ICA) are uncommon lesions. Common etiologies include trauma, infections, iatrogenic causes, and malignancies. Their prompt diagnosis is essential as they may have a potentially lethal course. Fatal rupture into the airway may lead to torrential hemorrhage due to lack of tamponade effect. There is also a high risk of recurrent cerebral embolism. Commonly, these lesions present as a pulsatile neck mass with aero-digestive tract compressive symptoms. Both surgical and endovascular techniques are available for their management. Lately, endovascular management has proven to be advantageous over surgical management. It is less invasive and is helpful especially when surgery is contraindicated due to various reasons. Vascular surgeries always have a risk of intraoperative fatal hemorrhage and/or major vessel occlusion. There are neither randomised trial data nor specific guidelines regarding the management of ICA PSAs. We describe our experience in the endovascular treatment of ICA PSAs secondary to various etiological factors. We also present the management algorithm for ICA PSAs followed at our institute.
We retrospectively reviewed the clinical, digital subtraction angiography (DSA), and computed tomography angiography (CTA) data from our department from 2004 to 2016 after approval from the departmental ethics committee. A total of 20 patients with ICA PSAs were identified. Clinical details, as well as the DSA (Philips AlluraXper FD20/10 Biplane), CTA, and ultrasound data were retrieved and evaluated [Table 1].
All our cases were managed on an emergency basis under general anaesthesia. Tracheostomy was chosen over intubation for the PSAs presenting with a significant bulge into the oro-nasopharynx causing dysphagia, respiratory distress, and/or stridor.
Parent artery occlusion (PAO) was performed in 10 patients (50%), stenting in 7 patients (35%), and PSA coiling in 3 patients (15%). Balloon occlusion test was performed prior to PAO in all cases. For PAO, the artery was occluded both proximal and distal to the aneurysm, with trapping of the neck of PSA using coils to prevent recanalization and immediate or delayed distal embolism. This was performed either by a single or double catheter technique. A single catheter was used whenever there were some distal holding spaces, i.e., the presence of a narrowing within the vessel lumen or a genu of the artery. Vessels with a larger calibre and a straighter course required the double catheter technique. It was performed by keeping one catheter tip distal to the aneurysmal neck with another placed proximally. Initially, about 60% to 70% of a longer detachable coil was placed undetached in the distal part of the vessel. Rest of the multiple required detachable/pushable coils (Hilal, Cook Inc., Bloomington, IN 47404, USA) were deployed proximally for complete occlusion and trapping. The first coil was then deployed completely and detached at the end after ensuring stability of the coil mass.
Patients who were candidates for stenting, received 300 mg of clopidogril and asprin just prior to the procedure and were subsequently kept on dual antiplatelet agents (75 mg clopidogrel and 150 mg aspirin) for 6 months to one year. A total of 7 patients underwent stenting; 4 stent grafts were used for cervical ICA PSAs (Fluency plus; Angiomed GmBh and Company, Karlsrhue, Germany; Viabahn; W. L. Gore and Associates, Inc., Flagstaff, AZ, USA), 2 stent grafts for cavernous ICA PSAs (Aneugraft; PCS, ITGI Medical, Or Akiva, Israel), and 1 bare stent (Absolute pro; Abbot Vascular, Santa Clara, CA 95054, USA) was used for a patient of cervical ICA PSA with dissection.
In intracranial PSAs, where the dome of the aneurysm was supported either by significant partial thrombosis or bony structures, coiling was preferred over PAO and stent graft. Embolization of the PSAs was performed using detachable micro coils from different vendors. (Axium; Micro Therapeautics, Inc, Ev3, Irvine, CA 92618, USA; Microplex 10 Hypersoft; MicroVentionInc, Tustin CA 92780 USA).
Outcome and follow-up
Adequacy of immediate outcome was assessed by evaluating the post-procedural DSA images and the clinical profile of the patients. The patients were also evaluated for any acute neurological deficit in the post-operative period. Long-term clinical and imaging (ultrasound/CTA/MR) follow up was carried out at 3 months, 6 months and at one year.
There were 15 (75%) male and 5 (25%) female patients with their age ranging from 11 months to 60 years. The PSAs were involving the cervical ICA in 12 (60%) patients, and the intracranial ICA in 8 (40%) patients. The common causes of PSA formation in our series were iatrogenic (n = 8; fine needle aspiration cytology [FNAC]/biopsy for an underlying infection = 7, surgery = 1) followed by trauma (n = 7) and a spontaneous PSA formation secondary to infection (n = 5). All the post-FNAC or biopsy cases were referred from peripheral hospitals.
The most common clinical complaint for the presence of an extracranial PSA was a pulsatile neck mass. Other additional symptoms included dysphagia (n = 1), respiratory distress (n = 3), stridor (n = 1), ear bleed (n = 1), and middle cerebral artery (MCA) stroke (n = 1). Intracranial PSAs presented with epistaxis (n = 5), diplopia/orbital chemosis (n = 2), or subarachnoid hemorrage (SAH) [n = 1]. PAO with trapping of the aneurysm was performed in 10 patients (extracranial = 7, intracranial = 3). Stent graft was used in 6 patients (extracranial = 4, intracranial = 2). Bare stenting was performed in one patient with dissecting extracranial PSA. The coiling of intracranial PSAs was performed in 3 patients. None of the patients had immediate or delayed neurological deficit. Patient 4 required recoiling and trapping for recurrence of the PSA at a follow up of 2 years [Table 1]. The protocol in the representative patients, representing the various management strategies, is being described.
Patient 3, a 39-year old male, presented with a rapidly increasing pulsatile neck swelling on the right side. History revealed that the patient had undergone a tonsillar biopsy at a peripheral clinic. The Doppler ultrasound study and CTA showed a defect in the medial wall of the right proximal ICA with a large broad neck PSA, which was measuring about 25 × 30 × 35 mm. Fluency stent graft (Angiomed GmBh and Company, Karlsrhue, Germany) was placed across the neck of the PSA as the balloon occlusion test was found to be negative for establishment of collateral circulation. Post-stenting check DSA revealed complete non-opacification of the PSA with a patent right ICA. There was an immediate decrease in the swelling with loss of pulsatility. On a 3-monthly follow up visit, the patient neither showed a residual aneurysm nor any clinical deficit [Figure 1] and [Figure 2].
Patient 4 (having two admissions, a and b), an 8-year old male child, with a history of fever and right parotid region swelling for 10 days, presented to us with sudden increase in the size of the swelling and respiratory distress (admission a). On CTA examination, a large PSA was seen arising from the narrowed distal right cervical ICA, with non-visualization of the artery distal to the PSA, along with local necrotic lymph nodes showing peripheral enhancement. Adequate reformation of ipsilateral intracranial ICA, anterior cerebral artery (ACA), and MCA was seen through the anterior communicating and posterior communicating arteries on diagnostic cerebral angiography. There was no neurological deficit on presentation. PAO of the right ICA was performed using 2 Hilal microcoils (Cook Inc., Bloomington, IN 47404, USA) in the proximal ICA. Trapping could not be performed, as the distal ICA could not be cannulated after several attempts. Check angiogram revealed complete non-opacification of the distal cervical ICA and the PSA. Post procedure, the patient did not have any neurological deficit. The patient presented again with a sudden painless increase in the local swelling at 2 years (admission b). The Doppler ultrasound study and CTA revealed recurrence of the PSA. The diameter of the cervical ICA was increased and the previously placed coils were found in subintimal location with a patent arterial lumen. There was faint visualization of the ICA distal to the PSA. Using a double catheter technique, PAO with trapping was performed by deploying coils in the distal and proximal ICA. The check angiogram revealed occlusion of the entire cervical ICA and the PSA. On a 3-year follow up, the patient was keeping fine with no recurrence [Figure 3].
Patient 7, a 23-year old male, presented with multiple episodes of severe epistaxis of 1 week duration with a past history of road-side accident 3 years prior to his ictus. CTA revealed a large left cavernous ICA PSA projecting into the sphenoid sinus. A balloon occlusion test revealed inadequate collateral supply from the anterior communicating and posterior communicating arteries. Coiling of the PSA was performed as the PSA walls were laterally supported by a partial thrombus and medially by the sphenoid sinus. Post-procedural check angiography revealed complete occlusion of the PSA with maintained patency of the ICA. The patient did not have further episodes of epistaxis or any neurological deficit [Figure 4].
Patient 8, a 40-year old diabetic male, presented to the emergency room with recurrent bouts of epistaxis. CT angiography and DSA revealed a PSA involving the left cavernous ICA. Nasal scraping revealed the presence of fungal infection. The patient was given broad spectrum antifungal agents and antibiotics for 4 weeks. Subsequently, a repeat DSA was performed at 4 weeks to assess the status of the aneurysm. The PSA showed a significant increase in the size of PSA. Adequate cross flow was noted during the balloon occlusion test. Parent artery occlusion with trapping of the PSA neck was performed. At follow up, the patient was neurologically intact without further episodes of epistaxis [Figure 5].
Patient 12, a 21-year old female, presented with repeated episodes of epistaxis 2 months following a road traffic accident (RTA). CTA was performed which revealed a lobulated PSA involving the right cavernous ICA. A stent graft (Aneugraft PCS, ITGI Medical, Or Akiva, Israel) was deployed across the neck of the PSA. No opacification of the PSA was noted in the post-procedural check angiography. On a 2-year follow up visit, the patient was asymptomatic [Figure 6].
APSA is defined as a pulsating encapsulated haematoma in communication with the lumen of a ruptured vessel. It forms after an injury to all layers of the arterial wall. This absence of a three-layered structure differentiates a PSA from a true aneurysm , and makes it prone to rupture more often, unlike a true aneurysm. PSAs of internal carotid arteries are rare. These usually occur as a sequelae to iatrogenic causes, infections, blunt trauma and or cancer/radiation necrosis.,,
Iatrogenic extracranial ICA PSAs may occur secondary to FNAC/biopsy from neck lymph nodes/tonsils, tonsillectomy, end-artrectomy, cervical spine surgery, and angioplasty.[8–12] Iatrogenic causes of intracranial ICA PSAs include trans-sphenoidal surgery (Patient 11), aneurysmal clipping, bypass surgery, tumour removal, or other neurosurgical procedures.,
Mycotic PSAs occur usually due to an infection by Staphylococcus aureus and Streptococcus pyogenes. They have a high risk of rupture with a reported mortality of up to 54%. Reisner et al., have reported histological changes of acute arteritis in the resected ICA of paediatric patients. The proposed mechanisms include wall ischemia, septicaemia and/or invasion of the vasa-vasorum. Mycotic PSAs secondary to deep neck space infections occur more often in children as compared to adults due to a higher incidence of deep neck infection in this age group.
The main goals for the treatment of craniocervical PSA are to prevent PSA rupture, embolic events and procedure related neurological deficit. The available treatment options are surgery and endovascular intervention. In the past, surgery was the treatment of choice; however, with improvement in endovascular skills and the availability of hardware, the later technique have provided a less invasive option.
Both vessel preserving and PAO techniques can be used for the management of ICA PSAs, depending upon several factors like the etiology of the PSA, the age of the patient, the site of PSA formation, and the status of collateral circulation. Trapping of the aneurysm neck with PAO using coils or balloons, to occlude the parent artery and the aneurysm neck, is a safe and effective strategy for treating ICA PSAs, if the collateral circulation, as assessed on balloon occlusion test, is adequate. Failure to trap the neck increases the risk of recanalization, as was seen in one of our patients (Patient 4) who required recoiling with trapping. On balloon occlusion test, if the collateral circulation is inadequate, an external carotid-middle cerebral artery (ECA–MCA) bypass may be necessary prior to PAO., In our series, none of the patients required an ECA–MCA bypass.
Techniques which maintain the patency of the affected artery include coiling of the PSA itself, stenting, stent assisted coiling, stent graft or flow diverter placement. Use of stents, either bare or covered, remains the treatment of choice as it ensures the patency of the parent artery with progressive/immediate occlusion of the PSA. Bare stents are technically easy to deploy. However, there are multiple reports related to recanalization of the PSAs after using such stents as the blood can flow through the interstices in the stent into the pseudoaneurysm.,, Patients of PSA associated with dissection are best treated with bare self-expandable stents (Patient 14). In the published series from Kadkhodyan et al., (21 patients), and Welleweerd et al.,(7 patients), ICA PSA associated with dissections were treated using bare stents. Both the studies reported a good outcome. One patient in our series also underwent the placement of a bare stent for a dissection associated PSA (Patient 14), which led to the obliteration of the PSA.
Use of covered stents causes immediate obliteration of PSAs. Hoppe et al., reported their experience with carotid artery stent grafts in 25 patients. Their technical success rate was 100%. Procedural dissection and short term complications were seen in 7.4% and 11% of their patients, respectively. No neurological complications were seen. Other series by Li Pan et al., and Wang W et al., have also reported successful utilisation of stent grafts in post-traumatic ICA PSAs. Covered stents are relatively stiffer and their negotiability and deployment is challenging, especially in intracranial ICA., Various reported complications such as embolic strokes, dissection, thrombosis, rupture, and stent kinks are the potential drawbacks. Patients 2, 3, 6, 11, 13, and 15 underwent covered stenting in our study without undergoing any major complications.
The endovascular management strategies depend upon the age of the patient, the site of PSA, the presence of underlying infection and the collateral circulatory reserve. Age plays an important role in deciding the endovascular options. PSAs occurring in the pediatric age group offer unique challenges during treatment. The use of stents in this age group is a matter of debate as long-term patency of such stents has not been established. Parent artery occlusion with trapping may be performed in the patients with adequate collateralisation. All our patients in the pediatric age group revealed a good collateral status and none of them required bypass surgery.
The site of PSA, whether it is extra- or intracranial in location, impacts the choice of hardware to be used. Extracranial ICA is an anatomically straight structure without any major branches. This makes it easy to deploy stiff stent grafts. On the other hand, the intracranial portion of the ICA is a tortuous structure with important side and terminal branches. Unavailability of soft intracranial stent grafts poses a great difficulty during treatment as none of the currently available stent grafts have been designed for primary intracranial usage. Parent artery occlusion and coiling of the narrow-necked well-supported aneurysm  may be used in such cases, especially in patients with a tortuous vascular anatomy. Three of our patients also underwent coiling for a narrow neck ICA PSA of the cavernous segment (Patients 7, 12, and 16).
Mycotic PSAs pose a great difficulty during treatment. The inflammation may invade the adjacent vascular segment and lead to further PSA expansion and bleeding. For patients who are at a high risk with smaller aneurysms, a period of four to six weeks of antimicrobial therapy is recommended (Patients 9 and 16). Invasive management is considered essential if the aneurysm increases in size or stays static despite medical treatment. Obliteration of the aneurysm using only coils or stents is not sufficient as the inflammation may spread to the adjacent normal artery.,,, Hence, PAO along with trapping is the treatment of choice in patients with a good collateralisation. The utility of a stent graft in the management of mycotic PSA is not clearly defined. The risk of stent graft infection is high in these cases. Stent grafts may be used under prolonged antibiotic/antifungal and anticoagulant cover. The management algorithm for ICA PSAs followed at our institute is given in [Table 2].
The limitations of this series include a small sample size, and relatively heterogeneous etiology and age. Further larger series with a long-term follow-up are required to establish the superiority of endovascular management.
In conclusion, our experience through this series suggests that with the advent of better hardware and skills, endovascular therapies provide a safe and effective method of treatment for ICA PSAs; however, the management must be tailored for each patient based on his/her clinical and imaging profile.
The authors declared no conflicts of interest and have not received any funding for this work. The clinical work-ups of Patients 1 and 2 have been published previously as case reports.,
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Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]