Treatment strategy for aneurysms of the posterior cerebral artery

ENDOVASCULAR MANAGEMENT OF INTRACRANIAL ANEURYSMS ON DISTAL ARTERIAL BRANCHES: ILLUSTRATIVE CASE SERIES AND LITERATURE RETROSPECTION

Intracranial aneurysms located on distal arterial branches are sporadic and scarce. They account for 2%-7% of the middle cerebral artery and 0.7%-2.3% of the posterior cerebral artery aneurysms, where they mainly arise distally from the P2-related sites. Such aneurysms usually remain asymptomatic prior to rupture, making their diagnosis and management really demanding. Endovascular treatment comprising of different neurointerventional techniques is becoming the most operational up-to-date routine to approach distal cerebral branch aneurysms. In this single-institution case series, endovascular selective coiling and/or parent vessel occlusion resulted in successful and total aneurysmal exclusion from cerebral circulation, which brought good recovery. Hereby, we present an illustrative case series of distal arterial branch intracranial aneurysms, discussing their possible etiology and various endovascular management modalities. We also provide a literature retrospection concerned with this rare entity. In conclusion, due to their predisposition for rupture, distal branch intracranial aneurysms should be treated early and aggressively. We do believe that endovascular selective coil occlusion is the management method of choice, while parent vessel occlusion (with liquid embolics) is optimal when aneurysmal coiling cannot be achieved, or when distal cortical territory is well vascularized by strong collateral cerebral circulation.

Outcomes of treatment modalities for ruptured intracranial aneurysms based on age - A meta-analysis

BACKGROUND

Data comparing the effect of age on outcomes of patients who underwent either endovascular coiling (EVC) or neurosurgical clipping (NSC) for ruptured intracranial aneurysms remains limited.

OBJECTIVE

To better elucidate the preferred intervention for ruptured aneurysm management by presenting the results of our systematic review of the literature that evaluated the potential advantages of the two interventions between different age groups.

METHODS

Systematic review of PubMed and Embase was performed (2002 - June 10, 2019) following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2013 guidelines. Median ages of EVC and NSC cohorts were 54 and 56, respectively. Ages below the median were used in our "younger" cohort; ages above the median were used in our "older" cohort.

RESULTS

We reviewed 13 studies on 7,137 patients. In the younger cohort, there were 2840 (EVC: 1412, NSC: 1428) patients. In the older cohort, there were 4297 (EVC: 2552, NSC: 1745) patients. Overall, there was a significant difference in functionality between EVC (77.70%) and NSC (69.23%) (OR=1.69; 95% C.I.: 1.10-2.60, p = 0.0212). In our younger cohort, functionality was significantly different between EVC (77%) and NSC (69%) (OR=1.54; 95% C.I.: 1.29-1.84, p < 0.001). For the older cohort, there was no significant difference in functionality, complications, or efficacy.

CONCLUSIONS

We have highlighted the importance of considering age prior to deciding which intervention is most appropriate for ruptured aneurysms, with higher morbidity and mortality with NSC versus EVC in the younger population.

An experimental investigation of the hemodynamic variations due to aplastic vessels within three-dimensional phantom models of the circle of Willis

A complete circle of Willis (CoW) is found in approximately 30-50% of the population. Anatomical variations, such as absent or surgically clamped vessels, can result in undesirable flow patterns. These can affect the brain's ability to maintain cerebral perfusion and the formation of cerebral aneurysms. An experimental test system was developed to simulate cerebral physiological conditions through three flexible 3D patient-specific models of complete and incomplete CoW geometries. Flow visualizations were performed with isobaric dyes and the mapped dye streamlines were tracked throughout the models. Three to seven flow impact locations were observed for all configurations, corresponding to known sites for aneurysmal formation. Uni and bi-directional cross-flows occurred along the communicating arteries. The greatest shunting of flow occurred for a missing pre-communicating anterior (A1) and posterior (P1) cerebral arteries. The anterior cerebral arteries had the greatest reduction (15-37%) in efferent flow rates for missing either a unilateral A1 or bilateral P1 segments. The bi-directional cross-flows, with multiple afferent flow mixing, observed along the communicating arteries may explain the propensity of aneurysm formation at these sites. Reductions in efferent flow rates due to aplastic vessel configurations may affect normal brain function.

The Current Status of Treatment Strategies for Cerebral Aneurysms in Nagoya University and Affiliated Hospitals Based on a Questionnaire Survey

We investigated differences in the treatment strategies for ruptured aneurysms among 26 hospitals affiliated with Nagoya University and any changes in those strategies based on responses to a questionnaire. We also surveyed the data concerning patients with a ruptured aneurysm collected from our affiliated hospitals between 2001 and 2002. In half of the institutes, angiography is performed immediately after an urgent medical examination, there are only five hospitals (20%) which have a basic policy of terminating the angiography within three to six hours after onset. In half of the institutes, the timing of the treatment also depends on the location of the aneurysm. In particular, the treatment for vertebro-basilar aneurysms tends to be done the next day or later. Low-grade subarachnoid hemorrhage (SAH) patients with mild symptoms tended not to be given any sedative drugs (46%), while patients with SAH in some institutes were sedated without informed consent regardless of the severity. The main treatment method for most anterior circulation aneurysms was clipping. Concerning aneurysms located in the posterior circulation and the origin of the ophthalmic artery, clipping and coiling were equally selected. Almost all the hospitals (92%) responded that their treatment strategy had not changed even after the report of the International Subarachnoid Aneurysm Trial (ISAT). There is a great deal of difference in treatment strategies and indications among institutions. In particular, institutions without neuroendovascular interventionists (NETists) frequently persist in the conventional policy, making it urgently necessary to bring NETists up-to-date on the latest advance in endovascular treatment.