Treatment strategy for patients with unruptured intracranial aneurysms

Towards the mechanical characterisation of unruptured intracranial aneurysms: Numerical modelling of interactions between a deformation device and the aneurysm wall

Intracranial aneurysm is a critical pathology related to the arterial wall deterioration. This work is an essential aspect of a large scale project aimed at providing clinicians with a non-invasive patient-specific decision support tool regarding the rupture risk assessment. A machine learning algorithm links the aneurysm shape observed and a database of UIA clinical images associated with in vivo wall mechanical properties and rupture characterisation. The database constitution is derived from a device prototype coupled with medical imaging. It provides the mechanical characterisation of the aneurysm from the wall deformation obtained by inverse analysis based on the variation of luminal volume. Before performing in vivo tests of the device on small animals, a numerical model was built to quantify the device's impact on the aneurysm wall under natural blood flow conditions. As the clinician will never be able to precisely situate the device, several locations were considered. In preparation for the inverse analysis procedure, artery material laws of increasing complexity were studied (linear elastic, hyper elastic Fung-like). Considering all the device locations and material laws, the device induced relative displacements to the Systole peak (worst case scenario with the highest mechanical stimulus linked to the blood flow) ranging from 375 μm to 1.28 mm. The variation of luminal volume associated with the displacements was between 0.95 % and 4.3 % compared to the initial Systole volume of the aneurysm. Significant increase of the relative displacements and volume variations were found with the study of different cardiac cycle moments between the blood flow alone and the device application. For forthcoming animal model studies, Spectral Photon CT Counting, with a minimum spatial resolution of 250 μm, was selected as the clinical imaging technique. Based on this preliminary study, the displacements and associated volume variations (baseline for inverse analyse), should be observable and exploitable.

In vivo mechanical characterization of arterial wall using an inverse analysis procedure: application on an animal model of intracranial aneurysm

Intracranial aneurysm is a pathology related to the deterioration of the arterial wall. This work is an essential part of a large-scale project aimed at providing clinicians with a non-invasive patient-specific decision support tool to facilitate the rupture risk assessment. It will lean on the link between the aneurysm shape clinically observed and a database derived from the in vivo mechanical characterization of aneurysms. To supply this database, a deformation device prototype of the arterial wall was developed. Its use coupled with medical imaging (spectral photon-counting computed tomography providing a spatial resolution down to 250 μm) is used to determine the in vivo mechanical properties of the wall based on the inverse analysis of the quantification of the wall deformation observed experimentally. This study presents the in vivo application of this original procedure to an animal model of aneurysm. The mechanical properties of the aneurysm wall identified were consistent with the literature, and the errors between the numerical and experimental results were less than 10%. Based on these parameters, this study allows the assessment of the aneurysm stress state for a known solicitation and points towards the definition of a rupture criterion.

Practical Incidence of Complications and Degree of Patient Satisfaction After Endovascular Coil Embolization for Unruptured Intracranial Saccular Aneurysm Based on Patients' Surveys

OBJECTIVE

Endovascular treatment for unruptured intracranial aneurysms (UIAs) has been regarded as second to none management nowadays as the result of its proven efficacy and need for less-invasive treatment. Most researchers have focused on the anatomical outcome after endovascular treatment, so in this study we estimated the real incidence of untoward effect and degree of patients' satisfaction based on s survey.

METHODS

This retrospective study was approved by the institutional review board, and 112 patients treated for saccular UIAs were evaluated among a total of 135 patients. After informed consent was obtained, these patients were sent a questionnaire regarding treatment effectiveness, complications, and patient satisfaction. These data were collected and compared with angiographic and clinical outcome.

RESULTS

The response rate was 87.5% (98/112). Intracranial complications occurred in 10 aneurysms (10.2%): 7 ischemic and 3 hemorrhagic strokes. Other complications occurred in 30 patients (30.6%): 17 alopecia, 15 bleeding tendency, and 3 puncture-site complications. Overall, 89 (90.8%) patients reported being satisfied with their treatment. Patient satisfaction was closely correlated with clinically successful outcome of treatment.

CONCLUSIONS

Ninety percent of patients were satisfied with the results after endovascular treatment of UIAs. Endovascular coil embolization was effective and safe procedure, with high clinical success rate and degree of satisfaction.

Stent-assisted coiling embolization of tiny, wide-necked intracranial aneurysms

BACKGROUND

Tiny, wide-necked intracranial aneurysms pose a significant therapeutic challenge for interventional neuroradiologists because of the small volume for microcatheterization and coil stabilization inside the aneurysm sac. We report our preliminary experience of stent-assisted coiling embolization of these aneurysms.

METHODS

A total of 50 patients with 52 tiny, wide-necked aneurysms who were treated with stent-assisted coiling from January 2007 to December 2014 were reviewed retrospectively. Baseline characteristics, procedure-related complications, angiographic follow-up results and clinical outcomes were statistically analyzed.

RESULT

All aneurysms were successfully treated with the stent-assisted coiling technique, and at the end of the procedure, aneurysm occlusion was complete for 45 (86.5 %), near complete for 3 (5.8 %) and incomplete for 4 (7.7 %). Procedural complications (1 intraprocedural rupture, 2 coil migrations and 1 aneurysm re-rupture) occurred in 4 (8 %) of 50 patients, resulting in permanent morbidity in 1 (2 %) patient and death in 1 (2 %) patient. Follow-up imaging was available in 43 (84.3 %) aneurysms for 6-31 months (mean, 13 months). Complete occlusion was achieved in 40 (93 %) of 43 aneurysms on long-term follow-up. One aneurysm with complete occlusion and one with incomplete occlusion after the initial embolization developed a significant recurrence (4.7 %). Clinical follow-up was available for 43 (86 %) of 50 patients at a mean of 36.7 months (range 15-66 months). Of these 43 patients, 42 (97 %) made an excellent recovery achieving a GOS of 5. None of the patients died or experienced re-bleeding or ischemic cerebral vascular events during follow-up.

CONCLUSION

Stent-assisted coiling embolization is feasible and relatively safe for tiny, wide-necked intracranial aneurysms of carotid arteries. Furthermore, long-term follow-up angiography indicated stent-assisted coiling seems to be effective in preventing early recanalization.

Results of Endovascular Coil Embolization Treatment for Small (≤ 5 mm) Unruptured Intracranial Aneurysms

Objective

Researchers and clinicians have been unable to fully elucidate the natural course of and proper treatment for unruptured intracranial aneurysms (UIAs) smaller than or equal to 5 mm, particularly with regard to whether close observation or surgery is more appropriate. In this retrospective study, we evaluated the safety and efficacy of endovascular coil embolization of small (≤ 5 mm) asymptomatic UIAs by analyzing outcomes and complications associated with the procedure.

Materials and Methods

We analyzed data from 150 patients with small asymptomatic UIAs (≤ 5 mm) treated with coil embolization between January 2011 and December 2015. Three-dimensional angiography was used to measure aneurysm size. We evaluated procedure-related morbidity and mortality, immediate post-operative angiographic results, brain computed thomography follow-up results on post-operative day one, and clinical progress.

Results

UIAs occurred primarily in the anterior circulation area (142 cases, 94.67%), though eight patients exhibited UIAs of the posterior circulation. Following coil embolization, aneurysms with complete occlusion were observed in 137 cases (91.3%). Partial occlusion occurred in five cases (3.33%), while the procedure had failed in eight cases (5.33%). Procedure-related morbidity and mortality were five cases (3.33%) and zero cases, respectively.

Conclusion

The endovascular treatment of small asymptomatic UIAs is associated with good short-term outcomes without permanent neurologic complications as well as low overall complication and morbidity rates. Thus, the procedure should be considered for patients with smaller asymptomatic UIAs.

Treatment of Unruptured Intracranial Aneurysms and Cognitive Performance: Preliminary Results of a Prospective Clinical Trial

BACKGROUND

Few studies have addressed the effect of treatment of unruptured intracranial aneurysm (UIA) on cognitive function.

OBJECTIVE

Neuropsychological assessment after UIA treatment is underreported, and prospective trials have repeatedly been demanded. In 2014, we conducted a prospective controlled study to evaluate the differences in cognitive processing caused by the treatment of anterior circulation UIAs.

PATIENTS AND METHODS

Thirty patients were enrolled until September 2015. Ten patients received endovascular aneurysm occlusion (EV), 10 patients were treated microsurgically (MS), and 10 patients with surgically treated degenerative lumbar spine disease (LD) served as control. All patients underwent extended standardized neuropsychological assessment before (t₁) and 6 weeks after treatment (t₂). Tests included verbal, visual, and visuospatial memory, psychomotor functioning, executive functioning, and its subdomains verbal fluency and cognitive flexibility. We statistically evaluated intragroup and intergroup changes.

RESULTS

Intragroup comparisons and group-rate analysis showed no significant impairment in overall neuropsychological performance, either postinterventionally or postoperatively. However, the postoperative performance in cognitive processing speed, cognitive flexibility, and executive functioning was significantly worse in the MS group than in the EV (P = 0.038) and LD group (P = 0.02). Compared with the EV group, patients with MS showed significant postoperative impairment in a subtest for auditory-verbal memory (Wechsler Memory Scale, Fourth Edition, Logical Memory II; MS vs. EV P = 0.011). The MS group trended toward posttreatment impairment in subtests for verbal fluency and semantic memory (Regensburg Word Fluency Test; MS vs. EV P = 0.083) and in auditory-verbal memory (Wechsler Memory Scale, Fourth Edition, Logical Memory II; MS vs. LD P = 0.06).

CONCLUSIONS

Our preliminary data showed no effect of anterior circulation UIA treatment on overall neuropsychological function but impaired short-term executive processing in surgically treated patients.

Endovascular coil embolization of 435 small asymptomatic unruptured intracranial aneurysms: procedural morbidity and patient outcome

BACKGROUND AND PURPOSE

Whether treatment of small asymptomatic aneurysms is appropriate or not remains controversial. We performed a retrospective study on the procedural morbidity and mortality of coil embolization of small asymptomatic unruptured intracranial aneurysms (UIAs) to obtain a more generalized estimate of procedural risk.

MATERIALS AND METHODS

A total of 435 small (maximum diameter < or = 7 mm) asymptomatic UIAs in 370 patients were treated by coil embolization. Aneurysm sizes were determined by using 3D angiograms. We assessed procedure-related morbidity and mortality, immediate postprocedural angiographic results, short-term imaging follow-up results, and clinical outcomes.

RESULTS

Initial aneurysm occlusion was complete in 334 aneurysms, near complete in 78, and incomplete in 22. One internal carotid artery (ICA) aneurysm that ruptured during the procedure was treated with parent artery occlusion. Two hundred wide-neck aneurysms were coiled with the aid of various neck-remodeling techniques. The 44 procedure-related complications were the following: 24 thromboembolisms, 11 coil protrusions or prolapses into the parent vessel, 4 intraprocedural ruptures, 3 device-related complications, and 2 femoral-access complications. We had a total of 44 (10.1%) procedure-related complications with only 1 leading to persistent neurologic deficit. Procedure-related permanent morbidity and mortality were 0.27% (1/370) and 0%, respectively.

CONCLUSIONS

In this series of small unruptured asymptomatic aneurysms, endovascular treatment was achieved with good short-term angiographic outcome and low permanent neurologic impairment. The goal of this study was not to provide a conclusion about treatment guidelines for small UIA but rather to help guide future recommendations by presenting a more generalized estimate of endovascular treatment risk than is currently available.