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|Year : 2014 | Volume
| Issue : 3 | Page : 269-275
Endovascular treatment of ruptured proximal pica aneurysms: A single-center 5-years experience
Vivek Gupta1, Navin Mulimani1, Ajay Kumar1, Chirag Ahuja1, SN Mathuria2, N Khandelwal1
1 Department of Radiodiagnosis, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
|Date of Submission||09-Feb-2014|
|Date of Decision||04-Mar-2014|
|Date of Acceptance||03-Jun-2014|
|Date of Web Publication||18-Jul-2014|
3472, Sector 37-D, Chandigarh - 160 036
Source of Support: None, Conflict of Interest: None
Background and Purpose: Posterior inferior cerebellar artery (PICA) like other intracranial arteries is prone to aneurysm formation. Aneurysms usually arise from the vertebral artery (VA) - PICA junction and the proximal segment of the PICA. The use of endovascular treatment as an alternative treatment to surgery has been increasing. We present our last 5 years experience in treating the ruptured proximal PICA aneurysms. Materials and Methods: Retrospective analysis of records of all patients with ruptured VA-PICA junction aneurysms treated at our referral center between July 2008 and July 2013 was performed. Over the last 5 years, we came across 17 patients who had aneurysms of proximal PICA or VA-PICA junction out of which 13 patients underwent endovascular treatment for ruptured saccular VA-PICA junction aneurysms and were the focus of this research. Follow-up studies ranged from 6 months to 3 years. Results: All the patients presented with an acute intracranial hemorrhage on NCCT. All the aneurysms were at VA-PICA junction with partial or complete incorporation of PICA origin in the sac. Endovascular treatment of all the 13 aneurysm was successful in the first attempt. Aneurysms were treated with balloon assisted coiling either by placing the balloon across the VA-PICA junction (n = 3) or in the vertebral artery proper (n = 9). Stent assisted coiling VA-PICA was performed in one aneurysm (n = 1). There was no intra-procedural rupture of the aneurysms. Conclusion: Endovascular therapy of ruptured proximal PICA aneurysms is possible and safe with the use of adjuvant devices and should be considered as first line treatment.
Keywords: Angiography, endovascular treatment, posterior inferior cerebellar artery aneurysms
|How to cite this article:|
Gupta V, Mulimani N, Kumar A, Ahuja C, Mathuria S N, Khandelwal N. Endovascular treatment of ruptured proximal pica aneurysms: A single-center 5-years experience. Neurol India 2014;62:269-75
|How to cite this URL:|
Gupta V, Mulimani N, Kumar A, Ahuja C, Mathuria S N, Khandelwal N. Endovascular treatment of ruptured proximal pica aneurysms: A single-center 5-years experience. Neurol India [serial online] 2014 [cited 2018 Jan 16];62:269-75. Available from: http://www.neurologyindia.com/text.asp?2014/62/3/269/136914
| » Introduction|| |
Posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery (VA) originating above the foramen magnum in more than 80% cases. It has the most complex and variable course of the cerebellar arteries and is differentiated into anterior, lateral, posterior medullary, supratonsillar segments, and perforating branches based on its relationships to the medulla oblongata and cerebellum. ,, PICA aneurysms account for 0.5-3% of all intracranial aneurysms. ,, Majority of the aneurysms arise from the VA-PICA junction and the proximal segment of the PICA. These aneurysms can be either saccular or fusiform in nature. Treatment of saccular aneurysms can be surgery or endovascular. Surgery at this location is difficult because of the intimate relationship of the proximal PICA to the medulla and lower cranial nerves  and is associated with increased risk of parent vessel sacrifice. Endovascular treatment as an alternative treatment has been increasing because it avoids the manipulation of important posterior fossa structures. ,,,,,, Management of PICA aneurysms is challenging, in particular for the VA-PICA junction and the proximal segment aneurysms as it can result in sacrifice of the parent vessel. The report presents our 5-years experience of treating these aneurysms with an aim to preserve the PICA patency.
| » Materials and Methods|| |
Retrospective analysis of records of all patients with ruptured VA-PICA junction aneurysms treated between July 2008 and July 2013 at our center was performed. Pre- and postoperative neuroimaging studies and endovascular operative reports were reviewed. This study has the approval of the ethics board. During the study period, 17 patients had proximal PICA or VA-PICA junction aneurysms of which 13 patients underwent endovascular treatment for saccular VA-PICA junction aneurysms and were the focus of this study. Of the remaining four patients, two underwent surgical treatment, and two refused treatment. Patients with distal saccular aneurysms, proximal and distal dissecting PICA aneurysms were excluded. Follow-up studies ranged from 6-36 months. Post procedure and on follow-up, the aneurysms were classified into three groups for adequacy of coiling: Completely coiled aneurysms, neck remnant seen, and aneurysm filling observed.
All the 13 patients (8 females, 5 males; mean age: 46.9 years, range: 14-60 years) presented with acute onset severe headache and non-contrast enhanced computed tomography (NCCT) documented subarachnoid hemorrhage (SAH). Associated presenting symptoms included loss of consciousness (n = 9), vomiting (n = 12), altered sensorium (n = 3), and seizures (n = 1). Hypertension was documented in five patients. One patient who had SAH twice had associated severe coarctation of aorta for which he was surgically operated followed by endovascular coiling of the VA-PICA aneurysm. Clinical grading was documented from the patients' records using Glasgow coma scale, Hunt and Hess grade and World Federation of Neurological Surgeons Grading System for Subarachnoid Hemorrhage (WFNS) scale. As per institutional management protocol, all patients underwent NCCT head, computed tomography (CT)-cerebral angiography, and four vessels cerebral digital subtraction angiography (DSA) and then were taken up for endovascular treatment. CT grading of SAH was done using Fisher scale.
The type of endovascular treatment of acutely ruptured VA-PICA aneurysms mainly depended on morphology and geometry of the saccular aneurysm and width of the aneurysmal neck based on DSA and 3D rotational angiography, origin of PICA in relation to aneurysm and presence and size of potential collateral vessels: Contralateral PICA, ipsilateral anterior inferior cerebellar artery, and superior cerebellar artery.
All patients were treated during the acute phase of SAH. Baseline pre-procedure NCCT head was done for evidence of re-bleed, infarction, or hydrocephalus. Endovascular coiling was performed on a biplane angiographic unit (Philips Allura Xper FD 20/10; Philips Medical Systems, Best, The Netherlands) with patient under general anesthesia. On the day of procedure, a pre-procedure diagnostic cerebral angiogram was done after administering a bolus of 2500 U of heparin. During entire duration of procedure, drip infusion through the guiding catheter of 1000 U of heparin with 1mg of nimodipine in 1000 ml of normal saline was administered intrarterially. The access to the involved VA was taken with a 6F-guiding catheter. Aneurysm coiling was performed using 2.1-1.7 F microcatheter using platinum coils without [Figure 1] or with [Figure 2] balloon assistance(Hyperform, eV3 Inc). In all the patients, 4 × 7 mm Hyperfoam balloon was used. Balloon remodeling was performed in case of wide necked aneurysms. Otherwise in all other patients, the balloon was placed as a backup protective device and placed in the vertebral artery just proximal to the neck; to be used for flow occlusion in case of intra-procedural rupture of the aneurysm. One patient in whom PICA was incorporated in the aneurysmal sac and appeared could not be preserved even with balloon assistance a dedicated intracranial stent was used [Figure 3].
|Figure 1: (a and b) Oblique and lateral DSA images of right vertebral artery angiogram showing a 6 mm sized narrow neck aneurysm arising from proximal PICA just after its origin. (c and d) Post coiling DSA images showing complete occlusion with preserved fl ow in PICA. (e and f) Follow-up MRA images after 1 year show stable occlusion of the aneurysm with good fl ow in PICA (white arrow in "e") and completely occluded aneurysm (black arrow on "f") DSA: Digital subtraction angiography, PICA: Posterior inferior cerebellar artery, MRA: Magnetic resonance angiography|
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|Figure 2: (a and b) Oblique and lateral projection of left vertebral angiogram showing a small approximately 4-mm-sized aneurysm arising from the PICA vertebral artery junction. The PICA origin is completely incorporated in the aneurysm. (c) Fluoroscopic spot showing balloon protecting the PICA origin with one coil in the aneurysmal sac. (d and e) Post coiling angiographic images showing occlusion of the aneurysm with patent PICA secondary to balloon remodelling. PICA: Posterior inferior cerebellar artery|
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|Figure 3: (a and b) Frontal anf lateral view of right vertebral angiogram showing an approximatelu 5mm aneurysm at PICA origin with incorporation of the origin in the aneurysmal sac. (c). Frontal projection with intracranial Stent in the PICA (arrow showing distal struts) and ipsilateral vertebral artery. (d and e) Post coiling the PICA is patent due to stent and the aneurysm is fully occluded. PICA: Posterior inferior cerebellar artery|
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The aim of coiling was to obtain an optimal packing density of aneurysm and was done until no residual opacification of aneurysmal sac was seen on angiogram or difficulty in placement of the smallest available coil taking utmost care to keep PICA patent. Intra and procedural-related complications (aneurysm rupture or thromboembolism) of coiling and adverse events were recorded. Post-procedure NCCT head were obtained in all the patients after which the patient was monitored in an intensive care unit.
Patients who survived the hospital admission period were scheduled for clinical follow-up in the outpatient clinic at 1 months and either magnetic resonance angiography (MRA) or DSA PICA. Subsequent clinical and imaging follow-up was done at 3, 6, 12, 24, and 36 months. The final clinical outcome was assessed at the last clinical visit using Glasgow Outcome Scale (GOS).
| » Results|| |
Patients and aneurysms characteristics are shown in [Table 1]. All the patients presented with acute intracranial hemorrhage on NCCT. Fisher's grade of SAH was: Grade 2 in 2; grade 3 in 5; and grade 4 in 6 patients. Hunt and Hess grading at admission was as: Grade I in 1; grade II in 8 patients; grade III in 2 patients and grade IV in 2 patients. The aneurysm was located on right side in six patients and left sided in seven patients. All the aneurysms were at VA-PICA junction with partial or complete incorporation of PICA origin in the sac. Size of the aneurysm ranged from 4.1-13.0 mm in longest axis, mean size 5.8 mm. Timing of treatment after SAH was 0-3 days in eight patients, 4-14 days in three patients, and >14 days in one patient. The reason for significant delay in the patient was that the aneurysm was associated severe co-arctation of aorta and atrial septal defect (ASD) and was operated upon for co-arctation prior to the coiling of aneurysm. Pre-procedural neurological deficit was noted in 2 patients one presented with left upper motor neuron (UMN) facial palsy and right hemiparesis and another with left hemiplegia.
|Table 1: Patient and aneurysm characteristics of 13 patients with VA-PICA aneurysms|
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Endovascular treatment of all the 13 aneurysm was successful in the first attempt. Aneurysms with origin of the PICA from the aneurysm sac or with a wide neck based on the PICA were treated with balloon assisted coiling either by placing the balloon across the VA-PICA junction (n = 3) or in the vertebral artery proper (n = 9). Stent assisted coiling VA-PICA was performed in one aneurysm (n = 1). There was no intraprocedural rupture of the aneurysms. Initial angiographic occlusion of VA-PICA aneurysm was complete in 11 (84.61%) and neck remnant was present in 2 (15.38%) aneurysms. No case of filling of aneurysmal sac was seen. This subtotal packing in two patients was done to preserve the PICA due to its origin from the neck of the aneurysm or small wide neck morphology of aneurysm. Complication in the form of migration of one coil loop into the origin of the PICA was seen in two cases causing mild eccentric narrowing, however with maintained patency at 12-month follow-up. In one other patient thrombus formation with occlusion at the PICA origin was observed immediately post coiling which was treated by intra-arterial abciximab infusion [Figure 4]. In one case, PICA was electively occluded as its origin was fully incorporated in the aneurysm sac and it was arising from the dome of aneurysm. There was presence of prominent anterior inferior cerebellar artery (AICA) collaterals in this case.
|Figure 4: (a) Right vertebral angiogram having an 8 mm aneurysm in the proximal PICA segment with partial incorporation of the artery (b) Coiling was done in this with balloon placed in the vertebral artery as a good cage formation within the sac could be achieved. (c and d) Post coiling a small thrombus formation was observed in PICA (arrow in c) likely because of reduced fl ow in the PICA which rapidly progressed to complete occlusion of PICA (arrow in d). (e) Intrarterial infusion of abciximab was given through the microcatheter placed at PICA origin which partially canalized the PICA Abbreviation: PICA posterior inferior cerebellar artery Post coiling the PICA is patent due to stent and the aneurysm is fully occluded|
PICA: Posterior inferior cerebellar artery
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Out of 13 patients, 11 patients (84.61%) had no neurological deficit post procedure and 2 patients (15.38%) had poor outcome. One patient with grade 4 SAH developed a large left middle cerebral infarct secondary to severe vasospasm for which craniectomy with duraplasty was done. However this patient died due to large MCA territory infarction and resultant cerebral edema. Lateral medullary syndrome, secondary to occlusion of PICA was seen in one patient (n = 1) in which elective PICA occlusion was done because of good AICA collaterals. Two patients (n = 2) had focal pinpoint infarcts in posterior cerebral artery region on post procedure MRI with no clinical sequel.
Long-term, (up to 3 years) clinical outcome on follow up using the Glasgow out-come scale (GOS) was available for 12 patients. None had rebleeding after the endovascular treatment or during the follow-up period. Follow-up angiographic studies were performed in 12 patients. Recanalization of the aneurysm was seen in one patient. This patient had large PICA aneurysm (13.0 mm) and was coiled. He presented with recurrent SAH 12 months post procedure due to previously un-ruptured and uncoiled second aneurysm at the basilar top. Partial recanalization of the PICA aneurysm was observed in this patient due to coil compaction. This patient however died post coiling of basilar top aneurysm due to poor clinical condition and severe vasospasm.
Out of 12 patients, PICA was patent in 11 patients on follow-up (in one patient PICA was occluded during the initial coiling of the aneurysm). In one patient, PICA was patent for 12 months and presented with symptoms of posterior circulation transient ischemic attacks (TIAs) 14 months post procedure. On cerebral angiograms his aneurysm was optimally coiled but his PICA showed occlusion of its proximal half with good distal reformation. He was put on 150 mg aspirin per day and his symptoms gradually improved with no permanent neurological deficit. Patient is doing well now 3 years post procedure.
| » Discussion|| |
The relatively rarity and proximity of PICA aneurysms to brainstem poses high risk neurosurgical management. Additionally, an unfavorable relationship of the aneurysmal sac with the parent artery, which is often the case with PICA aneurysms, cause the surgical clipping or endovascular coiling procedures ,,,,,,,,,,,, to be difficult and sometimes even impossible without sacrificing the PICA. However, endovascular treatment has been increasingly used as an alternative to surgery. ,, Endovascular treatment techniques include selective coiling of aneurysm without any adjuvant device, coiling with neck remodeling technique or with stent assistance, and parent vessel sacrifice of PICA with either coils or glue embolization. Selective coiling is the preferred treatment in patients with PICA aneurysms having favorable geometry (narrow neck and PICA origin not significantly incorporated in the aneurysm). However, in patients with aneurysms with the PICA originating from the sac or having a wide neck, PICA preserving treatment options consist of selective subtotal coil occlusion of the aneurysmal sac sparing the PICA origin or coil occlusion of the aneurysmal sac with preservation of the PICA origin with a stent or balloon assistance.
In our study of 13 patients who were treated endovascularly, there were 8 aneurysms in whom the origin of the PICA was from the aneurysm sac or with a wide neck based on the PICA which were then treated with balloon assisted coiling by placing the balloon across VA-PICA junction or with stent assisted coiling VA-PICA. In rest of the four patients, on imaging PICA origin was incorporated in the aneurysm however simple coiling was successful and we did not use balloon/stent remodeling technique. In these patient first chosen coil was always a 3D coil, which formed a cage sparing the PICA origin and subsequent coils were carefully deposited within it to form a stable coil mass. Often, due to small aneurysmal size and complex morphology readjustment of the coil loops was required which was however successful in all these patients. In the rest of the aneurysms (n = 5) simple coiling was sufficient. In all the patients who did not warrant neck remodeling with balloon, a balloon was still placed in VA to have option of temporary flow occlusion in the eventuality of aneurysmal re-rupture (all the aneurysms were ruptured aneurysms) during the procedure.
Peluso et al.,  in their review of 46 patients of proximal PICA aneurysms in which 47 aneurysms were treated, 43 aneurysms were occluded with coils and 4 were treated with proximal vertebral artery (VA) occlusion. In their series 79% of the aneurysms were ruptured and 21% were unruptured. Our series differ in this respect as all our patients were of ruptured aneurysms and presented in acute phase. Aneurysmal rupture during coiling occurred in 9 patients in their series vis. a vis. none in our series possibly reflecting evolution in techniques and hardware in the last decade. Their combined mortality and morbidity was 8.6%. They observed good clinical outcome in 35 of their patients and moderate in 3 patients at 6 monthly follow-up. In our series, 76.92% of the patients had good clinical outcome on long term follow up. 15.38% died, both related to severe vasospasm. One during post procedure period secondary to left MCA spasm and infarction and other secondary to ruptured of additional basilar top aneurysm at a later date unrelated to the procedure). Only one patient (7.69%) had permanent neurological deficit secondary to elective PICA occlusion. In another study by Crowley et al.,  they treated 17 patients of PICA aneurysms of which 13 aneurysms were of proximal PICA like in our series. Though they have not given their results separately for proximal and distal PICA aneurysms, out of 17 patients PICA was preserved in 12 patients and in rest parent vessel sacrifice was done. They could achieve complete occlusion in 65% of the patients as opposed to 84.16% in the present series. The complication rates were similar to our study. They had clinically significant infarcts in two patients after the procedure. They also reported 15% rate of aneurysm rupture during the procedure, which fortunately in our series was none. Pasco et al.,  in their study of 39 PICA aneurysms reported procedural morbidity of only 3.8% proving the safety of endovascular treatment of these aneurysms. In a recent study by Chalouhi et al.,  of the 76 patients with both proximal and distal PICA aneurysms, results further validates the role of endovascular treatment for these aneurysms. In their 10 years review, out of 76 patients of PICA aneurysms 54 were of proximal PICA. The mean age of these patients was 55.6 years, which is much higher that reported in our series. The average size of the PICA aneurysm in that series and the index series are quite similar (5.8 and 6.1 mm respectively). They could achieve complete or near complete occlusion of aneurysms in close to 91% of the cases, which is probably the highest reported so far. They also resorted to parent vessel sacrifice as last resort in 11 out of 76 patients out of which 9.6% were for proximal PICA aneurysms. They reported overall complication rate for proximal PICA aneurysms was 13.5%, which is slightly lower than what we encountered in our series.
There are certain differences in our series as compared with the other similar series of proximal PICA aneurysms. The first is that all our patients were of ruptured aneurysms. This was because of the regional differences as in our country pre rupture aneurysmal detection rate is abysmally low due to almost non-existent screening protocol for cerebral aneurysms. Secondly, we did not have any intra-procedural rupture, though we did all the patients with proximal balloon in situ to avoid any significant hemorrhage in case of rupture. This is likely due to advances in the hardware available and also because of local expertise, as majority of our patient referral (more than 95%) is of ruptured aneurysms. Also, parent artery occlusion for treating the aneurysm has been employed by all the authors in selected cases. The proportion of the cases in which this was done ranged from 8.5 to 29.41%. ,, We also had to resort to this in one case (7.69%) with consequential neurological deficit. In cases with deliberate proximal PICA occlusion, the risk of ischemia in the PICA territory is high. However, when infarctions do occur, the risk of permanent morbidity is low. , The incidence of complications like loop prolapse in PICA or intra-procedural thrombosis of PICA is quite similar to what has been reported in the literature.
Once coiled these proximal PICA aneurysm have a good long-term prognosis, also echoed in our study as none of our patient presented with re-bleed from the coiled aneurysm in the follow up period. In the largest series of Chalouhi et al.,  also only 1 patient (1.4%) had re-bleed on day 15 of treatment.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]