Small intracranial aneurysms of the anterior circulation: A negligible risk?

Patients' Characteristics Associated With Size of Ruptured and Unruptured Intracranial Aneurysms

OBJECTIVE

The size of unruptured intracranial aneurysms (UIA) remains the most crucial risk factor for treatment decisions. On the other side, there is a non-negligible portion of small ruptured IA and large stable UIA. This study aimed to identify the patients' characteristics related to IA size in the context of IA rupture status.

METHODS

A total of 2152 patients, with 1002 being hospitalized for an acute aneurysmal subarachnoid hemorrhage (SAH), were included from our institutional IA database. Different demographic and clinical characteristics of patients and IA were collected. IA size was the study endpoint, assessed as continuous variable in univariate and multivariable linear regression analysis, separately for ruptured (R) IA and UIA.

RESULTS

The mean IA size was 8.3 and 7.3 mm in the UIA and RIA subpopulations, respectively. Higher age (p = 0.003) and baseline blood urea level (p < 0.001) were independently associated with increasing UIA size. In contrast, location at the posterior circulation (p < 0.001), familiar intracranial aneurysms (p < 0.001), serum potassium (p = 0.006), and total serum protein (p = 0.019) were related to smaller UIA size in the multivariate analysis. For RIA, a statistically significant and independent association was detected for location (p = 0.019), history of gastrointestinal diseases (p = 0.042), and levothyroxine intake (p = 0.002).

CONCLUSIONS

Identification of clinical characteristics related to the size of ruptured and unruptured IA allows a more differentiated view on the genesis of RIA and UIA and the value of sack size as a basis for therapeutic decision-making. More research is needed to verify the identified risk factors.

Development and Validation of a Risk Predictive Model for Small Intracranial Aneurysms in Adults Over a Five-Year Period

Objective The optimal management of a small intracranial aneurysm (sIA) remains a challenge due to the lack of a size-specific risk predictive model for aneurysm rupture. We aimed to develop and validate a nomogram-based risk predictive model for sIA. Methods A total of 382 patients harboring 215 ruptured and 167 unruptured small intracranial aneurysms (uSIAs) (≤ 7 mm) were recruited and divided into training and validation cohorts. Risk factors for the construction of a nomogram were selected from clinical and aneurysmal features by least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression. The nomogram for risk of rupture was evaluated in both the training and validation cohorts for discrimination, calibration, and clinical usefulness. Results Hyperlipidemia (odds ratio (OR)=2.74, 95% confidence interval (CI)=1.322~5.956, P=0.008), the presence of a daughter dome (OR=3.068, 95%CI=1.311~7.598, P=0.012), larger size-to-neck ratio (SN) (OR=1.807, 95%CI=1.131~3.063, P=0.021) and size ratio (SR) (OR=2.221, 95%CI=1.262~4.025, P=0.007) were selected as independent risk factors for sIA rupture and used for construction of nomogram. Internal validation by bootstrap sampling showed the Concordance index (C index) of 0.756 for the nomogram. The calibration by the Hosmer-Lemeshow test showed a P value of 0.847, indicating the model was well-fitted. Additionally, decision curve analysis (DCA) demonstrated that the predictive model has good clinical usefulness, providing net benefits across a range of threshold probabilities, thus supporting its application in clinical decision-making. Conclusion The risk prediction model can reliably predict the risk of sIA rupture, which may provide an important reference for optimizing the therapeutic strategy.

Factors Affecting the Outcome after Surgical Clipping of Ruptured Distal Anterior Cerebral Artery (DACA) Aneurysms

Objective  The purpose of this study is to assess demographic, clinical, and unique morphological characteristics of distal anterior cerebral artery (DACA) aneurysm. The relation of outcome included Glasgow Outcome Scale (GOS) using various independent variables, Hunt and Hess clinical grade (H&H), Miller Fischer grade, intraoperative rupture, and comparison of outcomes at discharge and last follow-up. Methods  Demographic data, aneurysm characteristics, and treatment outcomes were evaluated in 28 ruptured DACA aneurysms operated over a period of 13 years. Association between independent variables and dependent variables (GOS) at discharge and at last follow-up (13 years) was analyzed, and the interrelationship between these factors and outcome was evaluated. GOS was used to assess functional outcomes. Results  Over a period of 13 years, 500 patients harboring ruptured intracranial aneurysms were surgically clipped, and out of them 28 patients (5.6%) had ruptured DACA aneurysms. In this series, 20 (71.4%) patients had low grade and 8 (28.6%) had high grade H&H. Out of the 28 patients, 19 (67.8%) had good recovery, 6 (21.5%) were severely disabled, and 3 (10.7%) died at the time of discharge. On the last follow-up (13 years), smoking ( p -value 0.03) and use of temporary clip ( p -value 0.00) were significant predictors for unfavorable outcome. Conclusion  The results of our case series show that even with ruptured aneurysm excellent overall outcome after microsurgical clipping can be achieved, even though among cerebral aneurysms, DACA aneurysm is considered to have less favorable outcome. Alcohol consumption and use of temporary clip were the predictors for unfavorable outcome at the time of discharge. On the last follow-up, smoking and use of temporary clip were found to be the risk factors for unfavorable outcome. Although the small sample size of this study is a limitation, smoking and use of temporary clip play an important role on the overall outcome. The aim of this study was to analyze data to determine factors which may influence outcome after surgical clipping of ruptured DACA aneurysms.