Basilar Artery Perforator Aneurysms and their Contemporary Management :<b>Mithun G Sattur, Arunprasad Gunasekaran, Alejandro M Spiotta, Jonathan R Lena</b>, Neurololy India

Home

REVIEW ARTICLE

Year : 2020 | Volume : 68 | Issue : 6 | Page : 1301--1306

Basilar Artery Perforator Aneurysms and their Contemporary Management

Mithun G Sattur, Arunprasad Gunasekaran, Alejandro M Spiotta, Jonathan R Lena
Department of Neurosurgery, Medical University of South Carolina, Charleston, SC, USA

Correspondence Address:
Dr. Mithun G Sattur
Suite 301 CSB, 96, Jonathan Lucas Street, Charleston, SC 29425
USA

Abstract

Background: Aneurysms arising in relation to perforators of the basilar artery (basilar perforator aneurysms or BPA) are very rare. Prior literature indicates the need for typically more than one angiogram for diagnosis, and argues for the utility of delayed angiograms in cases of subarachnoid hemorrhage (SAH) with initial negative studies. Different treatment modalities for BPA including endovascular, microsurgical, and conservative management have been described. Contemporary management appears to favor endovascular therapy. We discuss the topic by presenting a case which represents the first instance of BPA diagnosis after a fourth angiogram and subsequent successful endovascular occlusion. A literature review is provided. Objective: To discuss the unique presentation and management dilemmas in the rare entity of basilar artery perforator aneurysms by presentation of a case that was managed successfully by endovascular means. We also indirectly highlight the need for multiple follow-up angiograms in initial angiographically negative subarachnoid hemorrhage. Methods and Materials: We describe a 62–year-old male presenting with good clinical grade SAH and three negative angiograms, whose hospital course was complicated by repeat intraventricular hemorrhage. A fourth angiogram revealed a BPA. Multiple overlapping stents placed in the basilar artery achieved successful aneurysm exclusion. A comprehensive review of the literature was performed on PubMed. Results and Conclusions: Only 57 cases of BPAs have been described in literature. Multiple angiograms may be necessary for diagnosis. These aneurysms present with SAH. Endovascular flow modification is the current treatment of choice by means of overlapping stents or flow diversion.

How to cite this article:
Sattur MG, Gunasekaran A, Spiotta AM, Lena JR. Basilar Artery Perforator Aneurysms and their Contemporary Management.Neurol India 2020;68:1301-1306

How to cite this URL:
Sattur MG, Gunasekaran A, Spiotta AM, Lena JR. Basilar Artery Perforator Aneurysms and their Contemporary Management. Neurol India [serial online] 2020 [cited 2023 May 29 ];68:1301-1306
Available from: https://www.neurologyindia.com/text.asp?2020/68/6/1301/304111

Full Text

Basilar perforating aneurysms (BPA) are very rare vascular lesions that present with subarachnoid hemorrhage. They are mostly low flow, dissecting aneurysms.[1] Their detection is complicated because multiple angiograms may be required for diagnosis. Direct microsurgical or endosaccular treatment is usually not feasible. The most intuitive treatment is endoluminal flow modification of the basilar artery with flow diversion (FD) or multiple overlapping stents (OS). We describe an interesting case of a ruptured BPA detected on the fourth angiogram and successfully treated with multiple OS. An updated literature review is provided, in the context of clinical presentation and management.

Methods

Literature review

A comprehensive review of the literature was performed on PubMed using the search criteria “basilar aneurysm” AND “perforating aneurysm” AND “basilar perforator.” [Figure 1] depicts the search process. 21 papers describing 55 cases were found. 3 cases from 2 papers[2],[3] were excluded due to unclear anatomic location and age. Three papers describing four patients were found from cross-references.[4],[5],[6] Ultimately, 57 cases of basilar perforator aneurysms resulted, including ours [Figure 1].[1],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24] Patient demographics, imaging, treatment modality, ischemic complications, clinical and functional outcome and follow-up duration were collected. Good functional outcome was defined as modified Rankin Score (mRS) of 0–2. Where data was missing, the event rate was described such that the denominator represents the number accounted for in the papers.{Figure 1}

Clinical presentation

A 62-year-old male presented with Hunt and Hess grade 2 subarachnoid hemorrhage (SAH). CT showed Fisher grade 4 SAH with prominent prepontine clot and intraventricular hemorrhage [Figure 2]a. An external ventricular drain (EVD) was placed. CTA and catheter angiogram were negative [Figure 2]b. Second angiogram at 7 days was negative. A third angiogram for vasospasm and clinical decline at day 12 did not reveal any culprit lesion. The spasm was treated. On day 27 he was noted to have fresh hemorrhage into the EVD. CTA revealed an enhancement off the basilar trunk [Figure 2]c and angiogram confirmed the presence of a left BPA [Figure 2]d. Three overlapping stents were placed in the basilar artery and no further aneurysm filling was noted [Figure 2]e. He eventually made a gradual recovery to being awake and alert and was discharged to rehabilitation on day 48 after shunt placement, with mRS of 4. At 3 months follow-up, he showed excellent improvement to outcome of mRS 2.{Figure 2}

Results

[Table 1] presents patient data. All presented with rupture. There were 34 males and 23 females. Age ranged from 27 to 82 years (mean 57.2, median). Vast majority of patients presented with Fisher grade 3/4 SAH (34/38). 7/49 patients presented in high grade SAH (Hunt and Hess grade 4 or 5). 34 aneurysms were detected on more than one angiogram (59.7%, 5 on third study).{Table 1}

Treatment

[Figure 2] and [Table 1] show modality of treatment. Overall, 38/51 demonstrated complete occlusion of aneurysm at a follow-up range of 0.5–36 months. 1 death was noted. Residual or recurrence was described in 4 patients. Re-hemorrhage was documented in 2 patients. 11/44 (25%) had ischemic complications (both treated and conservative groups). Overall, 9/51 had poor outcome. 15 (26.3%) were treated conservatively. 2/13 (15.4%) in the conservative group had poor outcome. 6/9 showed spontaneous occlusion on short-term follow-up angiograms. 6 patients (10.5%) underwent up-front microsurgical clipping. 1/6 (16.7%) had poor outcome. 3 cases were documented as having complete exclusion.

Endovascular therapy

The majority of patients (n = 37, 64.9%) underwent endovascular therapy. Failure was noted in 10 (27%, exact modality not described). 4 of these showed spontaneous occlusion, 2 underwent subsequent clipping with good outcome. 11 received overlapping stents in the basilar artery, with recurrence noted in 2 (treated with further stent placement and coiling respectively). 11 underwent flow diversion of basilar artery and all showed occlusion at 0.5–12 months follow-up and good outcomes in 10 patients. 8/11 (72.7%) ischemic complications (among the 43 cases that documented this) were from the endovascular group but only one each was from the flow diversion and stent group (9% each). 6/32 patients (18.75%) in the endovascular cohort had poor functional outcome.

Discussion and Conclusions

This paper highlights several unique aspects of BPAs. This is a very rare entity, with only 56 cases described in literature. All documented BPAs presented with rupture. Most patients interestingly present in high Fisher grade (91% grade > = 3) with prominent blood in the prepontine cistern, but good clinical grade (only 15% high grade). Over 60% are detected after the first angiogram. Our case was detected after the fourth angiogram, following re-rupture during hospital course. The data provides impetus to the practice of a third and even fourth angiogram in cases of SAH with initial negative angiograms.[25] While institutional preferences vary, it appears prudent to have a low threshold for performing 3D rotational vertebral artery angiography when the hemorrhage pattern on CT indicates prominent prepontine clot.

The management of BPAs in the literature has varied. Some advocate conservative management, on the premise that follow-up angiograms demonstrated occlusion of the aneurysm. However, there is sparse data on whether delayed angiograms were ever performed. Most authors agree that simple observation of a diagnosed culprit aneurysm in a patient with SAH is not standard of care. Microsurgical clipping has been described in a very small number of cases with inconclusive indications and results. Majority of posterior circulation aneurysms are currently treated with endovascular means.[26]

Most BPAs are treated by endovascular means. Primary coiling is rarely feasible. Flow diversion or overlapping stents in the basilar artery appears to be treatment of choice in the literature. The overlapping configuration provides a degree of “flow diversion” while hopefully preserving perforator patency.[27] Flow diversion in the basilar trunk has traditionally been met with a degree of hesitation because of fear of perforator occlusion. However it appears that flow diverting stents are highly effective and safe for BPAs. Although majority of ischemic complications were noted in the endovascular cohort, these were largely from cases with treatment attempts and failure. In conclusion, the data from literature suggests overlapping stents or flow diversion as the treatment of choice for BPAs.

Classification system

Satti et al. proposed a classification for BPAs but did not provide validation with available cases in literature. Moreover, it is cumbersome and without clear relevance to treatment. We therefore attempted to describe BPAs as trunk (related to the basilar trunk circumference) and non-trunk (afferent and efferent channels being the perforator) types. Therefore Satti types I to IIb are “trunk” type and type III is “non-trunk” type. By reviewing angiographic images where available, we identified 28 non trunk type and 15 trunk type BPAs. No relation to presentation or treatment was evident even under this classification system but it proves to be far simpler in providing a uniform reporting template.

Limitations

Our study suffers from all deficiencies of a retrospective review. Uniform reporting of parameters including follow up (clinical or angiographic) among papers were lacking. The proposed classification without review of source images or inter-rater assessment limits validity.

Conclusions

BPAs are very rare vascular lesions that present with rupture. Multiple angiograms are often necessary for their detection. Although resolution of BPAs has been described on conservative therapy, this does not represent a viable option at most centers. The treatment of choice appears to be endoluminal basilar artery flow modification with overlapping stents or flow diversion. Good outcomes can be achieved with endovascular therapy. Finally, a simpler BPA classification system like the one proposed here may assist in uniform documentation in the literature.

Financial support and sponsorship

No financial support was received.

Conflicts of interest

There are no conflicts of interest.

Disclosures

Drs. Spiotta and Lena are Consultants for Penumbra Inc., Alameda, California, USA.

References

1	Aboukais R, Zairi F, Estrade L, Quidet M, Leclerc X, Lejeune JP. A dissecting aneurysm of a basilar perforating artery. Neurochirurgie 2016;62:263-5.
2	Fiorella D, Albuquerque FC, Deshmukh VR, Woo HH, Rasmussen PA, Masaryk TJ, et al. Endovascular reconstruction with the Neuroform stent as monotherapy for the treatment of uncoilable intradural pseudoaneurysms. Neurosurgery 2006;59:291-300; discussion 291-300.
3	Sanchez-Mejia RO, Lawton MT. Distal aneurysms of basilar perforating and circumferential arteries. Report of three cases. J Neurosurg 2007;107:654-9.
4	Deshaies EM. Enterprise stent-within-stent embolization of a basilar artery perforator aneurysm. World J Neuroscience 2011;1:45-8.
5	Sivakanthan S, Carlson AP, van Loveren H, Agazzi S. Surgical clipping of a basilar perforator artery aneurysm: A case of avoiding perforator sacrifice. J Neurol Surg A Cent Eur Neurosurg 2015;76:79-82.
6	Sahu CD, Ashpilaya A. Case series on perforator aneurysm: Endovascular stenting-A safe strategy. Indian Soc Vasc Interventional Radiol 2017;1:179-83.
7	Ghogawala Z, Shumacher JM, Ogilvy CS. Distal basilar perforator artery aneurysm: Case report. Neurosurgery 1996;39:393-6.
8	Hamel W, Grzyska U, Westphal M, Kehler U. Surgical treatment of a basilar perforator aneurysm not accessible to endovascular treatment. Acta Neurochir 2005;147:1283-6.
9	Mathieson CS, Barlow P, Jenkins S, Hanzely Z. An unusual case of spontaneous subarachnoid haemorrhage-A ruptured aneurysm of a basilar perforator artery. Br J Neurosurg 2010;24:291-3.
10	Chen L, Chen E, Chotai S, Tian X. An endovascular approach to ruptured aneurysms of the circumferential branch of the basilar artery. J Clin Neurosci 2012;19:527-31.
11	Apok V, Tarnaris A, Brydon HL. An unusual aneurysm of a basilar perforating artery presenting with a subarachnoid haemorrhage. Br J Neurosurg 2013;27:105-7.
12	Ding D, Starke RM, Jensen ME, Evans AJ, Kassell NF, Liu KC. Perforator aneurysms of the posterior circulation: Case series and review of the literature. J Neurointerv Surg 2013;5:546-51.
13	Gross BA, Puri AS, Du R. Basilar trunk perforator artery aneurysms. Case report and literature review. Neurosurg Rev 2013;36:163-8; discussion 168.
14	Nyberg EM, Chaudry MI, Turk AS, Spiotta AM, Fiorella D, Turner RD. Report of two cases of a rare cause of subarachnoid hemorrhage including unusual presentation and an emerging and effective treatment option. J Neurointerv Surg 2013;5:e30.
15	Chalouhi N, Jabbour P, Starke RM, Zanaty M, Tjoumakaris S, Rosenwasser RH, et al. Treatment of a basilar trunk perforator aneurysm with the pipeline embolization device: Case report. Neurosurgery 2014;74:E697-701; discussion 701.
16	Chavent A, Lefevre PH, Thouant P, Cao C, Kazemi A, Mourier K, et al. Spontaneous resolution of perforator aneurysms of the posterior circulation. J Neurosurg 2014;121:1107-11.
17	Kim YJ, Ko JH. Sole stenting with large cell stents for very small ruptured intracranial aneurysms. Interv Neuroradiol 2014;20:45-53.
18	Forbrig R, Eckert B, Ertl L, Patzig M, Brem C, Vollmar C, et al. Ruptured basilar artery perforator aneurysms--treatment regimen and long-term follow-up in eight cases. Neuroradiology 2016;58:285-91.
19	Peschillo S, Caporlingua A, Cannizzaro D, Resta M, Burdi N, Valvassori L, et al. Flow diverter stent treatment for ruptured basilar trunk perforator aneurysms. J Neurointerv Surg 2016;8:190-6.
20	Buell TJ, Ding D, Raper DMS, Chen CJ, Hixson HR, Crowley RW, et al. Posterior circulation perforator aneurysms: A proposed management algorithm. J Neurointerv Surg 2018;10:55-9.
21	Finitsis S, Derelle AL, Tonnelet R, Anxionnat R, Bracard S. Basilar perforator aneurysms: Presentation of 4 cases and review of the literature. World Neurosurg 2017;97:366-73.
22	Satti SR, Vance AZ, Fowler D, Farmah AV, Sivapatham T. Basilar artery perforator aneurysms (BAPAs): Review of the literature and classification. J Neurointerv Surg 2017;9:669-73.
23	Chau Y, Sachet M, Sedat J. Super-selective coil embolization of a basilar perforator artery aneurysm previously treated by the stent-in-stent technique, using an extremely soft bare coil delivered through a one-marker microcatheter. Interv Neuroradiol 2017;23:492-6.
24	Bhogal P, AlMatter M, Hellstern V, Pérez MA, Lehmberg J, Ganslandt O, et al. Basilar artery perforator aneurysms: Report of 9 cases and review of the literature. J Clin Neurosci 2019;63:122-9.
25	Dalyai R, Chalouhi N, Theofanis T, Jabbour PM, Dumont AS, Gonzalez LF, et al. Subarachnoid hemorrhage with negative initial catheter angiography: A review of 254 cases evaluating patient clinical outcome and efficacy of short- and long-term repeat angiography. Neurosurgery 2013;72:646-52; discussion 651-2.
26	Spetzler RF, McDougall CG, Zabramski JM, Albuquerque FC, Hills NK, Nakaji P, et al. Ten-year analysis of saccular aneurysms in the Barrow Ruptured Aneurysm Trial. J Neurosurg 2019:1-6. doi: 10.3171/2018.8.JNS181846.
27	Song J, Oh S, Kim MJ, Chung J, Lim YC, Kim BS, et al. Endovascular treatment of ruptured blood blister-like aneurysms with multiple (>/= 3) overlapping Enterprise stents and coiling. Acta Neurochir (Wien) 2016;158:803-9.