Progressive Occlusion and Recanalization After Endovascular Treatment for 287 Unruptured Small Aneurysms (<5mm): A Single-Center 6-Year Experience

Morphological Factors affecting Coil-Only Embolization of Small Unruptured Aneurysms

Objective When small unruptured aneurysms (SUA) are embolized by coils, manipulation of the microcatheter and coil is limited because of their small size. Previous studies suggested that the morphology of the artery and aneurysm is important. In the present study, we clarified the morphological factors affecting coil-only embolization of SUA.

Patients and Methods We retrospectively identified 17 patients who underwent embolization for unruptured aneurysm with a maximum diameter less than 5 mm. We investigated the following: (1) the relationships among dome/neck ratio (D/N), height/neck ratio (H/N), height/dome ratio (H/D), projection of aneurysm-parent artery, and adverse events, (2) immediate and late occlusion, and (3) number of coils.

Results (1) Adverse events developed in three cases in which the H/D was smaller than 1 (p < 0.02). There was a significant difference in the rate of adverse events by projection of the aneurysm-parent artery (p < 0.03), (2) Occlusion rate: Immediately after coil embolization, 71% (12/17) were neck remnant; however, 88% (15/17) of SUA became complete occlusion in the follow-up term, and (3) 1.5 ± 0.6 coils were used.

Conclusion To achieve successful coil-only embolization in SUAs, it is important to select aneurysms for which the projection of the parent artery is suitable for embolizing and the H/D ratio is larger than 1. In SUAs, occlusion develops naturally after coil embolization.

Small vs. Large Unruptured Cerebral Aneurysm: Concerns With the Age of Patient

Objective: The coiling and clipping of unruptured cerebral aneurysms (UCAs) in older patients has increased rapidly, and aneurysm size was a significant factor for decision-making in the treatment of UCAs. The purpose of the study was to investigate the impact of age on the functional outcomes of patients between the small versus large UCAs. Methods: We conducted a retrospective study for consecutive cases of UCAs admitted from May 2011 to December 2020. According to the maximum diameter of UCA, patients were divided into small UCAs (≤ 5 mm) group and large UCAs (>5 mm) group. Baseline characteristics, clinical complications, and outcomes of patients between the two groups were analyzed. Results: A total of 564 UCA patients received preventive treatment, including 165 small UCAs and 399 large UCAs. Compared with the small UCA group, the incidence of ischemia event in the large UCA group was significantly higher (7.3 vs. 2.4%; p = 0.029). Multivariable analysis demonstrating age (p = 0.006) and treatment modality (p < 0.001) were independent risk factors associated with poor outcome for patients with large UCAs. Conclusions: Preventive treatment of small UCAs is safe and effective, but older patients with large UCAs are at high risk of poor outcome, and the operations should be more cautious.

Evaluation of the Safety and Effectiveness of Coil Embolization for Anterior Communicating and Anterior Cerebral Artery Aneurysms

Objective

Endovascular coil embolization for anterior communicating artery (ACoA) and anterior cerebral artery (ACA) aneurysms is associated with high total and near-total occlusion rates, but the complication rate is high. The development of newer endovascular technologies may improve the clinical outcomes. This study investigated the status of endovascular treatment of ACoA and ACA aneurysms by comparing our results with past reports.

Methods

Between January 2006 and December 2018, we investigated 50 patients who were followed for 12 months or longer to clarify the outcomes of coil embolization. The outcomes of embolization were evaluated using time-of-flight MRA. The safety was evaluated based on procedure-related complications that affected clinical outcomes.

Results

Initial assessments demonstrated complete obliteration in 84% (42 of 50 patients) and a residual neck in 14% (7 of 50 patients). Procedure-related complications developed in 12% (6 of 50 patients). The procedure-related morbidity rate was 2% (1 of 50 patients) and there was no procedure-related death. Recanalization was noted in 14% (7 of 50 patients, median follow-up period, 57 months). The recanalized aneurysms were significantly smaller than the stable aneurysms in maximum size (4.3 mm vs. 5.8 mm; p = 0.017) and height (3.7 mm vs. 4.3 mm; p = 0.035).

Conclusion

We demonstrated the safety and effectiveness of endovascular coil embolization for ACoA and ACA aneurysms. The small size of aneurysms may be related to recanalization.

Features of "false positive" unruptured intracranial aneurysms on screening magnetic resonance angiography

BACKGROUND

Physicians can find it challenging to decide whether confirmative digital subtraction angiography (DSA) should be performed in patients who present with "suspicious small aneurysm-like structures" on magnetic resonance angiography (MRA). Factors associated with "false positive aneurysms on MRA" (FPAMs)," which are finally confirmed as negative on DSA, have rarely been reported. This study aimed to identify the clinical or radiologic clues indicative of FPAM on DSA.

METHODS

Patients who had undergone DSA between 2016 and 2019 for suspicious aneurysm-like structures < 5 mm in size on MRA were enrolled. Patient demographics and the details regarding the geometry of the structures were retrospectively reviewed. Univariate and multivariate logistic regression analyses were conducted to identify the associated factors. Receiver operating characteristic curve analysis was performed to assess the clinical implications.

RESULTS

Of the 107 suspicious structures, 46 were indicated as being false positive on DSA (42.96%). Location (positive on C7 and negative on C5-6 ICA) and lower dome to neck ratio were found to be significant parameters in the multivariate analysis. The dome to neck ratio threshold value was 0.99.

CONCLUSION

Suspicious aneurysm-like structures located not on C5-6 but on C7 ICA and having wide neck morphologies (dome to neck ratio < 0.99) are highly likely to be negative on DSA.

Two-Center Experience in the Endovascular Treatment of Intracranial Aneurysms Using the Woven EndoBridge 17 Device Including Midterm Follow-Up Results: A Retrospective Analysis

BACKGROUND AND PURPOSE

The Woven EndoBridge device proved its effectiveness in the treatment of ruptured and unruptured intracranial aneurysms as a stand-alone device. Before 2016, Woven EndoBridge deployment required at least a 0.021-inch microcatheter. In 2016, a smaller device, the Woven EndoBridge 17 with finer size increments that used a 0.017-inch microcatheter, was introduced. We retrospectively analyzed our initial and follow-up results with the Woven EndoBridge 17 in ruptured and unruptured aneurysms.

MATERIALS AND METHODS

One hundred twenty-seven intracranial aneurysms in 117 patients were scheduled for treatment with the Woven EndoBridge 17 between June 2017 and February 2019. Twenty-nine aneurysms were ruptured.

RESULTS

Treatment was performed as intended in 124 of 127 cases (97.6%). Additional devices such as stents or coils were used in 12 cases (9.7%). Five thromboembolic complications and 1 hemorrhagic complication were encountered, resulting in clinical deterioration in 2 patients. The overall morbidity and mortality in the entire series have been 1.7% and 0.0% to date, respectively. The follow-up results at 3 and 12 months revealed complete occlusion in 76.1% (70/92) and 78.0% (32/41).

CONCLUSIONS

The Woven EndoBridge 17 device is safe in the treatment of small broad-based aneurysms without the general need for additional devices. The low complication rate and the promising follow-up results underline the value of this technique in a growing range of endovascular treatment options for intracranial aneurysms.

Influence of Age-Related Complications on Clinical Outcome in Patients With Small Ruptured Cerebral Aneurysms

Background: Small ruptured cerebral aneurysms (≤5 mm) account for the majority of aneurysmal subarachnoid hemorrhages, and its clinical management remains a challenge. The aim of this study was to identify the effect of age-related complications on the outcome of patients with small ruptured aneurysm.

Methods: A retrospective review was performed in patients with small ruptured aneurysms who underwent microsurgical clipping or endovascular coiling from September 2012 to December 2018. According to their ages, the patients were divided into the elderly group and the non-elderly group. Baseline characteristics, clinical complications, and outcome of patients were analyzed between the two groups. A multivariate logistic regression analysis was used to determine the risk factors associated with the poor outcome of the elderly patients.

Results: In the elderly group, 83 patients were treated with clipping and 50 were treated with coiling. In the non-elderly group, 188 patients were treated with clipping and 117 were treated with coiling. The incidence of neurological complications with neurologic deficit in the elderly group was significantly higher compared with that in the non-elderly group (P = 0.006). The elderly patients had a longer hospital stay (P = 0.032) and a poorer outcome (P = 0.001) compared with the non-elderly patients. A multivariate analysis showed that irregular aneurysms (P = 0.045) and ischemic events (P < 0.001) were independent risk factors associated with poor outcome in the elderly.

Conclusions: Neurological complications with neurologic deficit, especially ischemic complications, were clearly more common in the elderly patients. Irregular small aneurysms or postoperative ischemic events should be paid attention as the higher risk of poor outcome in the elderly.

Endovascular Treatment of Small Ruptured Intracranial Aneurysms (<5 mm) : Long-term Clinical and Angiographic Outcomes and Related Predictors

Purpose

To investigate the long-term clinical and angiographic outcomes and their related predictors in endovascular treatment (EVT) of small (<5 mm) ruptured intracranial aneurysms (SRA).

Methods

The study retrospectively reviewed patients with SRAs who underwent EVT between September 2011 and December 2016 in two Chinese stroke centers. Medical charts and telephone call follow-up were used to identify the overall unfavorable clinical outcomes (OUCO, modified Rankin score ≤2) and any recanalization or retreatment. The independent predictors of OUCO and recanalization were studied using univariate and multivariate analyses. Multivariate Cox proportional hazards models were used to identify the predictors of retreatment.

Results

In this study 272 SRAs were included with a median follow-up period of 5.0 years (interquartile range 3.5–6.5 years) and 231 patients with over 1171 aneurysm-years were contacted. Among these, OUCO, recanalization, and retreatment occurred in 20 (7.4%), 24 (12.8%), and 11 (7.1%) patients, respectively. Aneurysms accompanied by parent vessel stenosis (AAPVS), high Hunt-Hess grade, high Fisher grade, and intraoperative thrombogenesis in the parent artery (ITPA) were the independent predictors of OUCO. A wide neck was found to be a predictor of recanalization. The 11 retreatments included 1 case of surgical clipping, 6 cases of coiling, and 4 cases of stent-assisted coiling. A wide neck and AAPVS were the related predictors.

Conclusion

The present study demonstrated relatively favorable clinical and angiographic outcomes in EVT of SRAs in long-term follow-up of up to 5 years. THE AAPVS, as a morphological indicator of the parent artery for both OUCO and retreatment, needs further validation.

Hemodynamic Features of Microsurgically Identified, Thin-Walled Regions of Unruptured Middle Cerebral Artery Aneurysms Characterized Using Computational Fluid Dynamics

BACKGROUND

Thin-walled regions (TWRs) of aneurysm surfaces observed in microscopic surgery are thought to be vulnerable areas for growth and rupture of unruptured intracranial aneurysms (UIAs).

OBJECTIVE

To identify hemodynamic features of TWRs of aneurysms by using computational fluid dynamics (CFD) analyses of unruptured middle cerebral artery bifurcation (MCAB) aneurysms.

METHODS

Nine patients with 11 MCAB aneurysms were enrolled, and their TWRs were identified. CFD analysis was performed using 3 parameters: pressure, wall shear stress (WSS), and WSS divergence (WSSD). Each parameter was evaluated for its correspondence with TWR.

RESULTS

Among 11 aneurysms, 15 TWRs were identified. Corresponding matches with CFD parameters (pressure, WSS, and WSSD) were 73.33, 46.67, and 86.67%, respectively.

CONCLUSION

WSSD, a hemodynamic parameter that accounts for both magnitude and directionality of WSS, showed the highest correspondence. High WSSD might correspond with TWR of intracranial aneurysms, which are likely high-risk areas for rupture.

Endovascular treatment of small (< 5 mm) unruptured middle cerebral artery aneurysms

Purpose

We report our experience with endovascular treatment of these lesions, with special consideration of angiographic and clinical outcomes and periprocedural complications.

Material and methods

The analysis included treatment results of 19 patients with 20 aneurysms. The aneurysm size ranged from 1.9 to 4.7 mm (mean 3.8, SD 0.7). Clinical examinations with the use of modified Rankin Score and angiographic outcomes were evaluated initially postembolisation and at a minimum follow-up of six months.

Results

Initial post-treatment complete and near-complete aneurysm occlusion was achieved in 19 (95%) cases and incomplete occlusion in one (5%) case. Imaging follow-up, performed in 17 (89.4%) patients, showed no change in the degree of occlusion in 16 (94.1%) patients and coil compaction in one (5.9%). There were no retreatment procedures. The procedure-related mortality rate was 5% (1/20) and was associated with intraprocedural aneurysm rupture. There was a case of a clinically silent coil prolapse into the parent artery. The clinical follow-up evaluation achieved in 17 (89.4%) patients showed no change in clinical status in all followed patients.

Conclusions

Endovascular treatment of small unruptured middle cerebral artery aneurysms is feasible and effective. The procedure-related complications are not negligible, especially in terms of the benign natural course of these lesions.