Giant Intracranial Aneurysms Research Articles

Delayed Hyperperfusion Syndrome During the Healing Phase After Flow Diverter Treatment of Giant Intracranial Aneurysms.

Delayed Hyperperfusion Syndrome During the Healing Phase After Flow Diverter Treatment of Giant Intracranial Aneurysms.

Treatment of intracranial aneurysms using the Tubridge flow diverter.

The Tubridge flow diverter (TFD) was recently developed to treat intracranial aneurysm (IA). In this study, we aimed to assess the safety and efficacy of this novel device. A retrospective cohort of consecutive patients with IA was recruited between June 2017 and February 2022. The studied outcomes were perioperative complications, clinical quality of life, and angiographic IA occlusion. Multivariate logistic regression was performed to explore the potential predictors of perioperative stroke events and IA occlusion. A comprehensive literature review was conducted across five databases for evidence synthesis. Among the patients with IA in our cohort, 144 underwent successful TFD implantation. Postoperative stroke was observed in 11 (7.6%) patients, and 130 (90.3%) patients were discharged with modified Rankin scales (mRS) of ≤2. In the last clinical follow-up (mean, 16.9months), 96.6% of the patients reported a satisfactory quality of life (mRS ≤2). IA occlusion was observed in 84.6% of the patients at the last angiographic follow-up (mean, 10.4months). Aneurysmal subarachnoid hemorrhage [odds ratio (OR), 6.98; 95% confidence interval (CI), 1.11-43.91] and giant IA (OR, 5.63; 95% CI, 1.15-27.48) were associated with perioperative stroke events. The evidence synthesis found high rates of satisfactory quality of life (rate, 98.8%; 95% CI, 97.1-99.9%) and IA obliteration (rate, 78.5%; 95% CI, 74.0-82.7%) after TFD treatment. The pooled complication rate was 13.6% (95% CI, 10.9-16.5%). This study identified a high rate of IA occlusion in patients who received TFD treatment. These patients also reported a satisfactory quality of life. Further studies in larger prospective cohorts with longer follow-up periods are warranted to verify our findings. Key message What is already known on this topic Flow diverter (FD) devices are an optimal tool to modify hemodynamics and treat intracranial aneurysms (IAs). However, the safety and efficacy of a novel self-expanding FD, namely the Tubridge flow diverter (TFD), remain to be fully established owing to the short-term follow-up periods and limited sample size of existing studies. What this study adds In our cohort of patients who received TFD treatment, 96.6% of patients reported satisfactory quality of life at the last clinical follow-up (mean, 16.9months); and 84.6% of IAs were successfully occluded at the last angiographic follow-up (mean, 10.4months). Our comprehensive review and evidence synthesis of existing studies on TFD found high rates of satisfactory quality of life (98.8%; 97.1-99.9%) and IA obliteration (78.5%; 74.0-82.7%). How this study might affect research, practice or policy TFD demonstrated satisfactory performance in the treatment of IAs in our cohort. Studies with larger prospective cohorts and longer follow-up periods are warranted to further investigate this promising novel approach.

Intracranial bypass for giant aneurysms treatment assessed by computational fluid dynamics (CFD) analysis

Unruptured giant intracranial aneurysms (GIA) are those with diameters of 25 mm or greater. As aneurysm size is correlated with rupture risk, GIA natural history is poor. Parent artery occlusion or trapping plus bypass revascularization should be considered to encourage intra-aneurysmal thrombosis when other treatment options are contraindicated. The mechanistic background of these methods is poorly studied. Thus, we assessed the potential of computational fluid dynamics (CFD) and fluid–structure interaction (FSI) analyses for clinical use in the preoperative stage. A CFD investigation in three patient-specific flexible models of whole arterial brain circulation was performed. A C6 ICA segment GIA model was created based on CT angiography. Two models were then constructed that simulated a virtual bypass in combination with proximal GIA occlusion, but with differing middle cerebral artery (MCA) recipient vessels for the anastomosis. FSI and CFD investigations were performed in three models to assess changes in flow pattern and haemodynamic parameters alternations (wall shear stress (WSS), oscillatory shear index (OSI), maximal time averaged WSS (TAWSS), and pressure). General flow splitting across the entire domain was affected by virtual bypass procedures, and any deficiency was partially compensated by a specific configuration of the circle of Willis. Following the implementation of bypass procedures, a reduction in haemodynamic parameters was observed within the aneurysm in both cases under analysis. In the case of the temporal MCA branch bypass, the decreases in the studied parameters were slightly greater than in the frontal MCA branch bypass. The reduction in the magnitude of the chosen area-averaged parameters (averaged over the aneurysm wall surface) was as follows: WSS 35.7%, OSI 19.0%, TAWSS 94.7%, and pressure 24.2%. FSI CFD investigation based on patient-specific anatomy models with subsequent stimulation of virtual proximal aneurysm occlusion in conjunction with bypass showed that this method creates a pro-thrombotic favourable environment whilst reducing intra-aneurysmal pressure leading to shrinking. MCA branch recipient selection for optimum haemodynamic conditions should be evaluated individually in the preoperative stage.

Coanda Effect Displayed in a Giant Intracranial Aneurysm.

The Coanda effect is a fluid dynamics phenomenon in which a fluid jet adheres to a convex or flat surface. This effect occurs when a liquid or gas jet emerging from an orifice clings to an adjacent surface and entrains the surrounding fluid, creating a lower-pressure region along its path that maintains its attachment to the surface. The Coanda effect accounts for the behavior of blood flow in the fetal right atrium and the dispersion of eccentric mitral regurgitation jets along atrial walls. This series of interesting images depicting a large 4 × 3.75 cm saccular intracranial aneurysm suggests that the Coanda effect may play a role in the pathophysiology of intracranial aneurysms and could be an underlying factor in their formation, progression, or rupture.

Advanced Setup and Techniques for Endovascular Treatment of Ruptured Intracranial Aneurysms

Despite advancements in neurosurgical techniques, subarachnoid hemorrhage(SAH) caused by the rupture of a partially thrombosed intracranial giant aneurysm remains a challenging clinical entity. This report describes the successful treatment of an 80-year-old male patient with SAH due to a ruptured, partially thrombosed intracranial giant aneurysm. The patient underwent a staged endovascular strategy using a flow diverter. The patient presented with SAH secondary to a ruptured, partially thrombosed intracranial giant aneurysm located at the C2 portion of the internal carotid artery and involving the origin of the posterior communicating artery(Pcom). Imaging revealed a dorsomedial rupture point on the aneurysm. A two-stage endovascular intervention(IVR) was performed. The first stage involved coil embolization aimed at covering the rupture point. Following the resolution of the vasospasm and the acute phase of SAH, the second stage involved the deployment of a pipeline embolization device. Digital subtraction angiography performed one month after the second stage IVR demonstrated a significant reduction in aneurysm filling, with preserved flow to the Pcom artery. We will discuss the technical details and rationale behind the staged endovascular approach in this complex case.

Investigator-initiated clinical trial of stabilizer device: A novel intracranial exchange guidewire for neuroendovascular treatments.

Neuroendovascular procedures, especially those involving significant vessel tortuosity, giant intracranial aneurysms, or distally located lesions, frequently necessitate exchange methods. However, exchange maneuvers pose a risk of inadvertent vessel injury. To address these challenges, a Stabilizer device was developed and evaluated for its efficacy and safety. This clinical trial aimed to assess the efficacy and safety of the Stabilizer device in facilitating the navigation of neuroendovascular devices to target lesions in cases where the exchange technique was necessary. This was a single-arm, prospective, open-label, multicenter clinical trial performed at nine different sites. It focused on investigating the use of the Stabilizer device for treating intracranial aneurysms and atherosclerosis. A total of 31 patients were enrolled across nine centers in Japan from July 21, 2022, to March 10, 2023. The study enrolled 24 (77.4%) patients with intracranial aneurysms and seven (22.6%) patients with intracranial artery stenosis. Majority of the target lesions were in the middle cerebral artery territory (83.9%). The Stabilizer device was used to exchange for 0.027-inch catheters, intermediate catheters, PTA balloons, and Wingspan stent system. The Stabilizer device demonstrated 100% technical success rate. While three complications related to the treatment were noted, there were no complications related to the device, including any vascular damage. This is the first multicenter clinical trial that investigated and demonstrated technical efficacy as well as overall safety profile of the Stabilizer device in neuroendovascular procedures where the use of an exchange method was necessary.

Analysis of rescue strategies for acute thrombosis during STA-MCA bypass surgery and the literature review

Background and objectivesSTA-MCA bypass surgery is mainly used for Moyamoya disease, giant intracranial aneurysms, and resection of intracranial tumors requiring sacrifice of blood vessels. The intraoperative patency of the reconstructive vessels is critical to the efficacy of the procedure. This study aimed to evaluate the efficacy of intra-arterially infused tirofiban for the treatment of acute thrombosis during STA-MCA bypass surgery and countermeasures for acute thrombosis.MethodsThis study involved 209 patients (272 hemispheres) who underwent STA-MCA surgery between November 2020 and December 2023. Intraoperative acute thrombosis occurred in eight patients (3.83%,8 hemispheres). We retrospectively reviewed the clinical and imaging data, surgical procedure, and follow-up outcomes of eight patients. We implemented the different thrombolytic methods to evaluate the optimal thrombosis management during the bypass surgery. After three months, we assessed neurological functions using the modified Rankin Scale (mRS) and conducted a literature review using PubMed.ResultsEight patients (four male patients and four female patients) developed acute thrombosis during the bypass surgery. Of the eight patients, two underwent re-anastomosis after thrombus removal, three received local injections of tirofiban into the anastomosis or the branches of the superficial temporal artery, and three underwent superselective intra-arterial tirofiban infusion using a microcatheter. Thrombosis were resolved, and arteries were recanalized in all patients. The mRS score was 0 in all patients. No major ischemic or hemorrhagic complications occurred.ConclusionOur treatment methods were efficacious in the management of acute thrombosis. Intra-arterial tirofiban administration seems to be a simple and effective treatment option for acute thrombosis during STA-MCA bypass surgery.

Near Complete Giant Intracranial Aneurysm Mimicking Anaplastic Glioma: A Rare Case Report And Surgical Management

Near Complete Giant Intracranial Aneurysm Mimicking Anaplastic Glioma: A Rare Case Report And Surgical Management

Giant cavernous aneurysms occluded by aneurysmal thrombosis, calcification, parent artery occlusion: A case report and review of literature

BACKGROUND Patients with giant intracranial aneurysms (GIAs) are at a high risk of rupture, morbidity, and mortality even after surgical or endovascular treatment. We described a case of a spontaneously occluded GIA secondary to gradual growth of the GIA, continuously progressed aneurysmal thrombosis, complete aneurysmal calcification and complete occlusion of the parent artery-the right internal carotid artery (RICA). CASE SUMMARY A 72-year-old female patient complained of sudden pain in her right eye upon admission to our hospital. She had been diagnosed with a GIA [30 mm (axial) × 38 mm (coronal) × 28 mm (sagittal)] containing an aneurysmal thrombus located in the cavernous sinus segment of RICA diagnosed by magnetic resonance imaging (MRI), enhanced MRI, and magnetic resonance angiography more than 14 years ago. Later, with slow growth of the cavernous carotid GIA, aneurysmal thrombosis progressed continuously, spontaneous occlusion of the RICA, complete aneurysmal calcification, and occlusion of the GIA occurred gradually. She had no history of subarachnoid hemorrhage but missed the chance for endovascular therapy at an early stage. As a result, she was left with severe permanent sequelae from the injuries to the right cranial nerves II, III, IV, V1/V2, and VI. CONCLUSION The risk of rupture of the cavernous carotid GIAs was relatively low and possibly further be reduced by the stasis flow and spontaneous occlusion of the parent artery internal carotid artery (ICA) induced by the mass effect of the cavernous carotid GIAs and the extremely rare aneurysmal calcification. However, nowadays, it is advisable to recommend early endovascular treatment for the cavernous carotid GIAs to prevent injuries to the surrounding intracranial nerves and occlusion of the ICA, mainly caused by the mass effect of the cavernous carotid GIAs.

Giant Intracranial Aneurysms in Infants: Case Report and Review of the Literature

Intracranial aneurysms are extremely rare in infants and differ from those in adults in their mode of presentation, location, size, and long-term outcome. Their treatment is very complex. Our case is a 24-month-old infant who featured a giant aneurysm of the basilar trunk diagnosed at the age of 04 months by an alternate syndrome of sudden onset, with a follow-up for 2 years. Therapeutic management is much discussed between surgical treatment, endovascular treatment, and therapeutic abstention which depends on the age, location, size, and mode of installation of these aneurysms.

Treating a Challenging Giant Aneurysm of Middle Cerebral Artery (MCA) with a Staged Procedure of Endovascular Coiling and Flow Diverter (FD): Case Report

Background: Giant intracranial aneurysms pose significant challenges in treatment due to a high risk of postoperative complications, including delayed rupture, cerebral edema, and aggravation of mass effect. Endovascular approaches, such as adjunctive coiling and flow diverter (FD) procedures, have become increasingly recommended for wide-necked, large, and giant aneurysms. Case Description: In this report, we present a challenging case of a staged coiling and FD procedure in a giant unruptured middle cerebral artery (MCA) aneurysm. The patient, a 26-year-old adult female, was admitted to our hospital with a history of convulsions. Digital Subtraction Angiography (DSA) revealed a massive aneurysm measuring 40 mm × 27 mm in the M1 segment of the MCA. To mitigate the risk of mass effect aggravation, we performed a two-staged procedure with a seven-day interval between the interventions. The first step involved partial endovascular coiling to shrink the aneurysm, followed by successful flow diversion. The patient did not experience further convulsions or neurologic deficits, and the follow-up angiogram showed no residual flow to the aneurysm. Conclusion: We report one of the very first cases of adjunctive coiling and FD in ‘unruptured’ giant aneurysms. Our neurovascular intervention provides valuable insights into the approach and treatment of unruptured giant aneurysms in cerebral arteries. By employing a staged procedure, effective flow diversion can be achieved even in giant unruptured aneurysms. Although further research is necessary to confirm its superiority and address critical issues, our findings may contribute to the future management of giant aneurysms and inspire avenues for research in the neurosurgical community. Bang. J Neurosurgery 2023; 12(2): 129-136

Retraction: clinical characteristics and endovascular treatment in patients with intracranial giant serpentine aneurysms.

[This retracts the article DOI: 10.21037/qims-20-698.].

A Giant Stent for Giant Cerebral Aneurysms-The Accero®-Rex-Stent.

Until now, giant intracranial aneurysms (GIAs) have in many cases been a vascular disease that was difficult or impossible to treat, not least due to the lack of availability of a large-format stent. In this multicentre study, we report on the first five clinical applications of the Accero®-Rex-Stents (Acandis, Pforzheim, Germany) in the successful treatment of fusiform cerebral giant aneurysms. The Accero®-Rex-Stents are self-expanding, braided, fully radiopaque Nitinol stents designed for aneurysm treatment. The stent is available in three different sizes (diameter 7-10 mm, length 30-60 mm) and intended for endovascular implantation in vessels with diameters of 5.5-10 mm. Five patients (all male, age 54.4 ± 8.1 years) with large fusiform aneurysms of the posterior circulation were treated endovascularly using the Accero®-Rex-Stents. There were no technical complications. One major ischemic complication occurred. A significant remodeling and reduction in the size of the stent-covered aneurysms was already seen in the short-term post-interventional course. The Accero®-Rex-Stents were successfully and safely implanted in all five patients with fusiform giant aneurysms, showing technical feasibility with promising initial results and significant aneurysm size reduction in already available follow-up imaging. With the Accero-Rex-Stents, a new device is available that offers another treatment option for rare cerebral fusiform giant aneurysms with very large parent vessels.

Giant Aneurysms: Not So Giant in Behavior.

Giant intracranial aneurysms (GIAs) are very complex in their behavior and treatment procedure. There are various modalities of treatment. The annual rupture rate of GIA (6%) is higher than that of small aneurysms (1-3%). Neurosurgeons handle these aneurysms during operations. We tried to analyze the intraoperative rupture rate (IRR) of GIA in relation to small aneurysms. IRR is concerned with the rupture of the aneurysms during operative handling. For conducting the study, we compared the IRR of 7 GIAs and 45 small aneurysms during a span of 10 years. All the operations were performed by the same team and the same principal surgeon. IRR was compared by statistical analysis. Z-test was done to compare the two rates: Z = 0.68 and P = 0.49. According to our study, the IRR of GIA is not statistically different from small aneurysms. The IRR of GIA is not higher because of three factors which we have analyzed: 1) layers of intraaneurysmal thrombus, 2) fibrin deposition on the aneurysm wall, and 3) blocked neck of the aneurysm by thrombus. The IRR of GIA is not different from small aneurysms.

Microsurgical and endovascular treatment of large and giant aneurysms of the anterior circulation: A systematic review

IntroductionLarge and Giant intracranial aneurysms (LGIAs) have become the paradigm for which endovascular techniques do not provide satisfactory results. Yet, microsurgery is followed by non-negligible rates of morbimortality. This scenario may have changed since the introduction of flow-diversion devices. Research questionContemporary and standardised revision on microsurgical and endovascular results, with emphasis on anterior circulation LGIAs. Materials and methodsA systematic literature search was conducted in two databases (PubMed and Embase) on treatment outcomes of LGIAs of the anterior circulation, after the introduction of flow-diverters 2008/01/01, till 2023/05/20. Small case series (<5 cases), series including >15% of posterior circulation aneurysms, and studies not reporting clinical and/or angiographic outcomes were excluded. Results44 relevant studies (observational cohorts) were identified, including 2923 LGIAs predominantly from anterior circulation. Mean follow-up 22 (±20) months. 1494 (51%) LGIAs were treated endovascularly and 1427 (49%) microsurgically. According to the random effects model, pooled rates of favourable clinical outcomes were 85.8% (CI 95% 82.6–88.4), complete occlusion 69.4% (CI 95% 63.7–7.46), complications 19.6% (CI 95%16–23.9) and mortality 5.6% (CI 95% 4.4–7.1). Focusing on type of treatment, occlusion rates are higher with microsurgical (842/993, 85% vs 874/1,299, 67%), although good outcomes are slightly more frequent with endovascular (1045/1,135, 92% vs 1120/1,294, 87%). Discussion and conclusionsAccording to contemporary data about occlusion rates, functional outcomes, and complications, primary or secondary treatment of LGIAs of the anterior circulation seems justified. Microsurgical occlusion rates are higher in LGIAs. An expert consensus on reporting complications and management strategies is warranted.

Exploring the latest findings on endovascular treatments for giant aneurysms: a review.

Giant intracranial aneurysms represent a very challenging aspect of aneurysmal pathophysiology with very high mortality and morbidity if left untreated. Their variety in clinical presentation (subarachnoid hemorrhage, cranial nerve palsy, etc.) and pathological and imaging properties (location, anatomy, presence of collateral circulation) pose serious questions regarding the best treatment option. Admirable advances have been achieved in surgical techniques, while endovascular modalities with flow diversion techniques have become widely used. However, there is still lack of data regarding whether a single endovascular technique can be the universal treatment for such cases. In this review, we aim to summarize the current funds of knowledge concerning giant intracranial aneurysms and the role of endovascular management in their treatment.

Proximal Clipping and Distal High-Flow Bypass in the Treatment of Giant/Complex Intracranial Aneurysm: An Opportunity or a Risk from a Fluid-Structural Interaction Analysis.

Conventional clipping and endovascular treatment are difficult to apply for some giant intracranial aneurysms (GIAs), and sometimes extracranial-to-intracranial (EC-IC) bypass becomes the optional choice. However, not all GIA patients can benefit from it. This study aims to recognize the underlying problems. We included eligible patients in our care. Then, we researched from three levels: a retrospective review of clinical data, fluid-structural analysis from two representative patient-specific models, and fluid-structural interaction analysis for idealized models to investigate the hemodynamic and biomechanical mechanisms. In this article, we report nine patients with GIA who underwent EC-IC surgery. Of them, three experienced dangerous postoperative hemorrhage, and one patient died. Among these three patients, two lacked the A1 segment of the anterior cerebral artery (ACA). The numerical simulation showed that after surgery, for the patient with an unruptured aneurysm and existence of ACA, the wall deformation, wall stress, pressure, and area of the oscillatory shear index (OSI) > 0.2 were decreased by 43%, 39%, 33%, and 13%, while the patient without A1 segment having postoperative hemorrhage showed 36%, 45%, 13%, and 55% increased, respectively. Thus, we postulated a dangerous "stump phenomenon" in such conditions and further demonstrated it from idealized models with different sizes of ACA. Finally, we found a larger anastomosis angle and smaller diameter of the graft can alleviate this effect. Neurosurgeon should cautiously evaluate the opportunity and risk for such patients who have aplasia of the A1 segment of ACA when making clinical decisions.

A Case Report of an Intracranial Giant Aneurysm in a 10-Year-Old Female

Pediatric intracranial aneurysms are rare and differ from aneurysms in adults in terms of location, etiology, natural history and management. This is a case report of giant aneurysm in a 10-year-old patient presenting with symptoms of headache and vomiting. Cerebral catheter angiogram revealed a large aneurysm in the left middle cerebral artery, M1 segment. The patient underwent left pterional craniotomy, clip reconstruction of the patent artery, and aneurysmectomy. Post operatively the patient had an unremarkable course and was discharged improved after 1 week. Cerebral catheter angiogram was performed after 2 months and revealed no residual aneurysm. Intracranial aneurysms in children are rare; 0.5% to 4.6% of intracranial aneurysms occur in patients aged 18 years or younger. Aneurysms occurring in very young children and infants are exceedingly rare. Unlike their adult counterparts, pediatric aneurysms have been reported to exhibit features such as male predominance, a higher incidence in locations such as the internal carotid bifurcation and posterior circulation, and greater numbers of giant aneurysms. By far, pediatric aneurysms present more commonly as subarachnoid hemorrhage, with peaks at ages 2-5 years and in adolescents older than 15 years. However, the rate of subarachnoid hemorrhage in children is far lower than in adults. This may be due to high incidence of giant aneurysms that present as space-occupying lesions rather than hemorrhage. In the Philippines, intracranial aneurysms are more common in adults rather that in children. Moreover, there has been no published data about pediatric intracranial aneurysm. Presented here is a case of a 10-year-old female with left middle cerebral artery (MCA) giant aneurysm. This report discusses the epidemiology, signs and symptoms and management of the pediatric patient with a giant aneurysm. Conclusions: Intracranial aneurysms in children differ from those in adults in location, morphology, etiology, natural history, and management. Giant aneurysms produce neurologic compromise related to mass effect. The most efficacious form of treatment involves complete elimination of this lesion from cerebral circulation. Regardless of whether these aneurysms are treated or observed, children with intracranial aneurysms require follow-up imaging and clinical surveillance, given their expected long-life span during which treated aneurysms could recur or additional aneurysms could arise. Key words: pediatric, giant aneurysm, craniotomy, clip reconstruction, aneurysmectomy

Failure of Reconstructive Technique to Repair a Giant Intracranial Fusiform Aneurysm of the Basilar Artery: Case Report and Literature Review in the Pediatric Population

AbstractTreatment of giant basilar aneurysm presents a major treatment challenge, especially in the pediatric population. Morbidity and mortality approach 80 and 30%, respectively. Both reconstructive and deconstructive techniques are associated with high rates of complete occlusion and good neurological outcomes. We report a 14-year-old male with a giant basilar trunk aneurysm treated with an endovascular approach. Clinical symptoms began following an ischemic stroke 2 weeks prior to admission. Endovascular treatment was performed through a reconstructive technique by single flow diverter device (FDD) in the basilar artery; however, this technique failed. At 1-year follow-up, without additional endovascular treatment, the mid-basilar artery and aneurysm were occluded, with vertebrobasilar flow maintained through collaterals from the right posterior communicating artery. We present a challenging management of giant basilar aneurysm in a pediatric patient experiencing a failure of FDD deployment; however, we highlight the importance of collateral flow development in progressive occlusions.

Risk factors for perianeurysmal vasogenic oedema (pavo) following embolization therapy: literature review.

Perianeurysmal vasogenic oedema (PAVO) is a rare complication associated post-embolisation of intracranial aneurysms. The prevalence, risk factors predisposing to susceptibility, and pathologic mechanisms underlying this process are not clearly understood. Since this complication may be associated with poor clinical outcomes, the authors designed this study to describe possible risk factors, underlying mechanisms, and management of PAVO through published case reports.Developing a priori protocol according to PRISMA guidelines, we searched MEDLINE/PubMed, Embase and Web of Science to identify case studies and reports of adult patients with intracranial aneurysms who developed perianeurysmal oedema following coil embolization therapy. Data extracted from these studies included patient demographics, aneurysm characteristics, coil type, PAVO characteristics, treatment, and outcomes. Quality was assessed using a standardized tool.21 eligible studies of acceptable quality were identified, comprising 40 unique cases from 9 countries. The mean patient age was 56.4years and 25 (62.5%) were female. Aneurysm size ranged from 6 to 30mm, with a mean size of 15.2mm; only 6 (15%) of cases were giant intracranial aneurysm (≥ 25mm). The more frequent locations of intracranial aneurysms associated with PAVO were the ICA (50%) and posterior circulation (32.5%), with 7.5% and 10% of cases occurring in MCA and anterior circulation, respectively. 16 cases (40%) were treated with bare platinum coils, and 14 (35%) with a combination of BPCs and bioactive coils; in 10 cases (25%), the coil type was not mentioned. PAVO presented between 0days and 8years of coil embolization, with 23 (57.5% cases) presenting symptomatically in relation to brain region affected. Management strategies for PAVO included conservative, steroids, re-embolization, clipping, stenting, parent artery occlusion either as monotherapy or as combination therapy. Of reported studies, 26 treated cases (65%) resolved, with 8 (20%) remaining stable, and 4 (10%) deteriorating.PAVO can be associated with small or large intracranial aneurysms, bare and bioactive platinum coils, and all regions of the intracranial circulation. The understanding of the risk factors of this complication lies in the underlying mechanisms, which will ultimately guide appropriate patient follow-up and subsequent optimal management.