The role of wall shear stress in the parent artery as an independent variable in the formation status of anterior communicating artery aneurysms.

OBJECTIVES: The study aimed to determine which hemodynamic parameters independently characterize anterior communicating artery (AcomA) aneurysm formation and explore the threshold of wall shear stress (WSS) of the parent artery to better illustrate the correlation between the magnitude of WSS and AcomA aneurysm formation. METHODS: Eighty-one patients with AcomA aneurysms and 118 patients without intracranial aneurysms (control population), as confirmed by digital subtraction angiography (DSA) from January 2014 to May 2017, were included in this cross-sectional study. Three-dimensional-DSA was performed to evaluate the morphologic characteristics of AcomA aneurysms. Local hemodynamic parameters were obtained using transcranial color-coded duplex (TCCD). Multivariate logistic regression and a two-piecewise linear regression model were used to determine which hemodynamic parameters are independent predictors of AcomA aneurysm formation and identify the threshold effect of WSS of the parent artery with respect to AcomA aneurysm formation. RESULTS: Univariate analyses showed that the WSS (p < 0.0001), angle between the A1 and A2 segments of the anterior cerebral artery (ACA) (p < 0.001), hypertension (grade II) (p = 0.007), fasting blood glucose (FBG; > 6.0 mmol/L) (p = 0.005), and dominant A1 (p < 0.001) were the significant parameters. Multivariate analyses showed a significant association between WSS of the parent artery and AcomA aneurysm formation (p = 0.0001). WSS of the parent artery (7.8-12.3 dyne/cm2) had a significant association between WSS and aneurysm formation (HR 2.0, 95% CI 1.3-2.8, p < 0.001). CONCLUSIONS: WSS ranging between 7.8 and 12.3 dyne/cm2 independently characterizes AcomA aneurysm formation. With each additional unit of WSS, there was a one-fold increase in the risk of AcomA aneurysm formation. KEY POINTS: • Multivariate analyses and a two-piecewise linear regression model were used to evaluate the risk factors for AcomA aneurysm formation and the threshold effect of WSS on AcomA aneurysm formation. • WSS ranging between 7.8 and 12.3 dyne/cm 2 was shown to be a reliable hemodynamic parameter in the formation of AcomA aneurysms. The probability of AcomA aneurysm formation increased one-fold for each additional unit of WSS. • An ultrasound-based TCCD technique is a simple and accessible noninvasive method for detecting WSS in vivo; thus, it can be applied as a screening tool for evaluating the probability of aneurysm formation in primary care facilities and community hospitals because of the relatively low resource intensity.

Surgical cannulation of the superior ophthalmic vein for the treatment of previously embolized cavernous sinus dural arteriovenous fistulas: serial studies and angiographic follow-up.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of transorbital puncture for the retreatment of previously embolized cavernous sinus dural arteriovenous fistulas (DAVFs) via a superior ophthalmic vein (SOV) approach. MATERIALS AND METHODS: During a 12-year period, 9 consecutive patients with previously embolized cavernous sinus DAVFs underwent retreatment via the transorbital SOV approach. RESULTS: All of the nine cases of previously embolized cavernous sinus DAVFs were successfully embolized. Clinical follow-ups were conducted in all nine cases at the duration of 17-141 months (61.22 ± 39.13 months). No recanalization occurred during the follow-up period. A subtle ptosis appeared in two patients and disappeared in one of the two cases after a 4-year follow-up. One patient suffered from paroxysmal positional vertigo and bruit for nearly 2 years after the treatment, but the follow-up angiography demonstrated no recurrence. One patient had persistent visual impairment caused by the initial venous stasis retinopathy. One patient with a history of a procedure-related transient decrease in visual acuity had it return to the normal level. The remaining four cases had clear improvement in the ocular symptoms and became completely asymptomatic during the follow-up period. No patient worsened or developed new symptoms. CONCLUSION: The approach of surgical cannulation of the SOV for the retreatment of previously embolized cavernous sinus DAVFs was proved feasible and efficient, especially when the transarterial and transfemoral venous approaches were inaccessible. However, if the SOV is not dilated enough or is located deeply in the orbit, transorbital venous puncture access may not be possible.

High wall shear stress beyond a certain range in the parent artery could predict the risk of anterior communicating artery aneurysm rupture at follow-up.

OBJECTIVE: Among clinical and morphological criteria, hemodynamics is the main predictor of aneurysm growth and rupture. This study aimed to identify which hemodynamic parameter in the parent artery could independently predict the rupture of anterior communicating artery (ACoA) aneurysms by using multivariate logistic regression and two-piecewise linear regression models. An additional objective was to look for a more simplified and convenient alternative to the widely used computational fluid dynamics (CFD) techniques to detect wall shear stress (WSS) as a screening tool for predicting the risk of aneurysm rupture during the follow-up of patients who did not undergo embolization or surgery. METHODS: One hundred sixty-two patients harboring ACoA aneurysms (130 ruptured and 32 unruptured) confirmed by 3D digital subtraction angiography at three centers were selected for this study. Morphological and hemodynamic parameters were evaluated for significance with respect to aneurysm rupture. Local hemodynamic parameters were obtained by MR angiography and transcranial color-coded duplex sonography to calculate WSS magnitude. Multivariate logistic regression and a two-piecewise linear regression analysis were performed to identify which hemodynamic parameter independently characterizes the rupture status of ACoA aneurysms. RESULTS: Univariate analysis showed that WSS (p < 0.001), circumferential wall tension (p = 0.005), age (p < 0.001), the angle between the A1 and A2 segments of the anterior cerebral artery (p < 0.001), size ratio (p = 0.023), aneurysm angle (p < 0.001), irregular shape (p = 0.005), and hypertension (grade II) (p = 0.006) were significant parameters. Multivariate analyses showed significant association between WSS in the parent artery and ACoA aneurysm rupture (p = 0.0001). WSS magnitude, evaluated by a two-piecewise linear regression model, was significantly correlated with the rupture of the ACoA aneurysm when the magnitude was higher than 12.3 dyne/cm2 (HR 7.2, 95% CI 1.5-33.6, p = 0.013). CONCLUSIONS: WSS in the parent artery may be one of the reliable hemodynamic parameters characterizing the rupture status of ACoA aneurysms when the WSS magnitude is higher than 12.3 dyne/cm2. Analysis showed that with each additional unit of WSS (even with a 1-unit increase of WSS), there was a 6.2-fold increase in the risk of rupture for ACoA aneurysms.

Cerebral Microbleeds Could Be Independently Associated with Intracranial Aneurysm Rupture: A Cross-Sectional Population-Based Study.

OBJECTIVE: To determine whether the presence of cerebral microbleeds (CMBs) is independently associated with intracranial aneurysm rupture and to identify the time interval of CMB-related intracranial aneurysm rupture. METHODS: This cross-sectional study included 1847 patients with unruptured and ruptured intracranial aneurysms from January 2010 to November 2017. Clinical records and imaging, including T2-weighted gradient-recalled echo sequence magnetic resonance imaging that identified the presence of CMBs preoperatively, were evaluated. Univariate analysis and multivariate logistic regression were done to determine which parameters were independent factors for aneurysm rupture. The time interval of CMB-related intracranial aneurysm rupture was also evaluated. RESULTS: CMBs confirmed by magnetic resonance imaging were present in 142 patients (142/1847; 7.7%). Of 142 patients with CMBs, 56 patients (including 17 ruptured aneurysms) who received endovascular treatment and another 86 consecutive patients who did not receive embolization or surgery for various reasons were followed for 3-49 months. The incidence of CMB-related intracranial aneurysm rupture was 27.9% (24/86) during the follow-up period. The time interval of CMB-related intracranial aneurysm rupture was 3-27 months (median 9.5 months). Multivariate analyses showed CMBs were significantly correlated with intracranial aneurysm rupture (odds ratio = 1.6; 95% confidence interval, 1.1-2.4; P = 0.010). CONCLUSIONS: CMBs were independently associated with intracranial aneurysm rupture. Patients with CMBs have a 60% increased risk of aneurysm rupture compared with patients without CMBs.

Endovascular treatment of ruptured sausage-shaped intracranial aneurysms with the "interlacing ball" technique.

We applied the "interlacing ball" technique to 18 ruptured sausage-shaped intracranial aneurysms (SSIA) with Hunt and Hess Grades I to III in 18 patients. Coils were joined to form the first three-dimensional ball-like structure at the dome of the aneurysm. A segment of the last coil was purposely left out of the first ball so that it could be joined with the next coil used to form a second "ball". This second ball was woven into the neck portion in a net-like fashion to prevent coil protrusion into the parent artery. An immediate post-procedural angiogram showed complete occlusion in 16 aneurysms (88.9%) and near-complete occlusion in two aneurysms with no complications. Sixteen patients were discharged with a Glasgow Outcome Scale (GOS) score of 5, and two with a GOS score of 4. One patient developed an enlarging aneurysm neck as visualized on an angiogram, while 17 aneurysms (94.4%) demonstrated no recurrence, within 3 months to 37 months of follow-up. We report that this technique is useful for the successful embolization of SSIA.

Factors responsible for poor outcome after intraprocedural rerupture of ruptured intracranial aneurysms: identification of risk factors, prevention and management on 18 cases.

PURPOSE: The paper mainly involved the retrospective approach to risk factors of intraprocedual rerupture (IPR) and illustration of our empirical prevention and management on this event as well as its postembolization outcomes evaluation. MATERIALS AND METHODS: Endovascular treatment was performed in 1308 patients with 1308 ruptured intracranial aneurysms, and IPR occurred in 18 cases. We retrospectively reviewed their clinical records and images, and analysis risk factors of IPR by using multivariate logistic regression. RESULTS: The morbidity of IPR was 1.38% and mortality was 33.33%. Nine patients survived from rapid completion of coiling with immediate reversal of heparin anticoagulation with protamine sulfate, and 3 from emergent external ventricular drainage (EVD). However, 9 of them presented with different degrees of disability and 3 were fully recovered. Small aneurysms (diameter ≤ 3.0mm) (OR 284.212, 95% C.I. 17.368-4650.780, P=0.000), atherosclerosis (OR 7.866, 95% C.I. 1.113-55.570, P=0.039), Fisher Grade III (OR 82.099, 95% C.I. 1.563-431.696, P=0.029), vasospasm (grade I) (OR 32.269, 95% C.I. 2.393-435.132, P=0.009) and vasospasm (grade II) (OR 30.238, 95% C.I. 1.770-516.552, P=0.019) are risk factors of IPR. Aneurysms at proximal part of internal carotid artery (ICA), bifurcation and basilar artery (BA) stem (OR 0.003, 95% C.I. 0.000-0.101, P=0.001) and Hunt and Hess Grade II (OR 0.010, 95% C.I. 0.000-0.346, P=0.011) are identified as protective factors. CONCLUSIONS: Small aneurysms, atherosclerosis, Fisher Grade of SAH and cerebral vasospasm are the predictors of IPR. Aneurysms at proximal part of ICA bifurcation and BA stem and Hunt and Hess Grade II are less associated with IPR. Rapid completion of coiling combined with immediate reversal of heparin anticoagulation is confirmed to be the best strategy in our series.