Chuanhui Li

Influence of hemodynamics on recanalization of totally occluded intracranial aneurysms: a patient-specific computational fluid dynamic simulation study

OBJECT Some totally occluded intracranial aneurysms may recur. The role of hemodynamic mechanisms in this process remains to be elucidated. The authors used computational fluid dynamic analysis and investigated the local hemodynamic characteristics at the aneurysm neck before and after total embolization, attempting to identify hemodynamic risk factors leading to recurrence of totally embolized aneurysms. METHODS Between May 2008 and June 2010, the authors recruited 17 consecutive patients with totally occluded intracranial aneurysms (7 recanalized and 10 stable lesions). Using patient-specific 3D digital subtraction angiography data, the hemodynamic features before and after embolization were retrospectively characterized. RESULTS The overall preembolization blood flow patterns were nearly the same in the recanalized and stable groups, with no significant difference in either the maximum wall shear stress (WSS) (p = 0.914) or the spatially averaged WSS (p = 0.322) at peak systole at the aneurysm neck. After occlusion, the overall flow pattern changed, and the WSS distribution at the treated aneurysm neck differed in the 2 groups. In all of the 7 recanalized cases, both the maximum WSS and spatially averaged WSS at peak systole at the treated aneurysm neck were higher than those at the aneurysm neck before embolization. In contrast, both parameters were decreased in 70%-80% of the stable cases. After embolization, both the maximum WSS (p = 0.021) and spatially averaged WSS (p = 0.041) at peak systole at the treated aneurysm neck were higher in the recanalized group than in the stable group. CONCLUSIONS Higher WSS at the treated aneurysm neck after total embolization can be an important hemodynamic factor that contributes to aneurysm recurrence after endovascular treatment.

Stent alone treatment for dissections and dissecting aneurysms involving the basilar artery

Background and purpose: Dissections and dissecting aneurysms involving the basilar artery (BA) are rare lesions with a poor prognosis, and controversies exist on treatment strategy. We describe the clinical presentation, radiologic features, and clinical outcomes of 11 consecutive patients with these lesions, treated using stent alone placement. Materials and methods 11 patients were studied (10 men, one woman), with a mean age of 51 years (range 30–68 years). Clinical and angiographic data were reviewed retrospectively. Results It was technically feasible to place stents in all 11 cases, and a multiple stents technique was used in nine patients. Procedure related posterior circulation ischemic complications occurred in two cases. One patient presenting with locked-in syndrome died of a pulmonary embolism 3 months after treatment although the clinical condition was gradually improving after stent placement. In the other eight cases, improvement in initial symptoms or a stable condition was observed on follow-up at 1–48 months. Angiographic follow-up was obtained in nine cases using DSA (n=8) or CT angiography (n=1). Successful occlusion of the aneurysm or dissection sac was noted in two cases, BA occlusion in one case, disappearance of double lumen sign in one case, and delayed retention of contrast medium in one case. For the remaining four patients there was no change in the configuration of the lesions on follow-up angiographic results. Conclusions Stent alone treatment as a potential and disputable alternative therapeutic option for the treatment of BA dissection and dissecting aneurysms, although technically feasible, was effective in only certain lesions, and this treatment carries substantial risks of complications and a high failure rate. The true effect of this strategy is questionable. A study involving larger populations and a longer follow-up is necessary to evaluate the efficacy of this treatment modality.

Clinical, morphological, and hemodynamic independent characteristic factors for rupture of posterior communicating artery aneurysms

Objective To identify clinical, morphological, and hemodynamic independent characteristic factors that discriminate posterior communicating artery (PCoA) aneurysm rupture status. Methods 173 patients with single PCoA aneurysms (108 ruptured, 65 unruptured) between January 2012 and June 2014 were retrospectively collected. Patient-specific models based on their three-dimensional digital subtraction angiography images were constructed and analyzed by a computational fluid dynamic method. All variables were analyzed by univariate analysis and multivariate logistic regression analysis. Results Two clinical factors (younger age and atherosclerosis), three morphological factors (higher aspect ratio, bifurcation type, and irregular shape), and six hemodynamic factors (lower mean and minimum wall shear stress, higher oscillatory shear index, a greater portion of area under low wall shear stress, unstable and complex flow pattern) were significantly associated with PCoA aneurysm rupture. Independent factors characterizing the rupture status were identified as age (OR 0.956, p=0.015), irregular shape (OR 6.709, p<0.001), and minimum wall shear stress (OR 0.001, p=0.038). Conclusions We combined clinical, morphological, and hemodynamic characteristics analysis and found the three strongest independent factors for PCoA aneurysm rupture were younger age, irregular shape, and low minimum wall shear stress. This may be useful for guiding risk assessments and subsequent treatment decisions for PCoA aneurysms.

Influence of morphology and hemodynamic factors on rupture of multiple intracranial aneurysms: matched-pairs of ruptured-unruptured aneurysms located unilaterally on the anterior circulation

BackgroundThe authors evaluated the impact of morphological and hemodynamic factors on the rupture of matched-pairs of ruptured-unruptured intracranial aneurysms on one patient’s ipsilateral anterior circulation with 3D reconstruction model and computational fluid dynamic method simulation.Methods20 patients with intracranial aneurysms pairs on the same-side of anterior circulation but with different rupture status were retrospectively collected. Each pair was divided into ruptured-unruptured group. Patient-specific models based on their 3D-DSA images were constructed and analyzed. The relative locations, morphologic and hemodynamic factors of these two groups were compared.ResultsThere was no significant difference in the relative bleeding location. The morphological factors analysis found that the ruptured aneurysms more often had irregular shape and had significantly higher maximum height and aspect ratio. The hemodynamic factors analysis found lower minimum wall shear stress (WSSmin) and more low-wall shear stress-area (LSA) in the ruptured aneurysms than that of the unruptured ones. The ruptured aneurysms more often had WSSmin on the dome.ConclusionsIntracranial aneurysms pairs with different rupture status on unilateral side of anterior circulation may be a good disease model to investigate possible characteristics linked to rupture independent of patient characteristics. Irregular shape, larger size, higher aspect ratio, lower WSSmin and more LSA may indicate a higher risk for their rupture.

Transarterial treatment with Onyx of Cognard type IV anterior cranial fossa dural arteriovenous fistulas

Background and purpose Cognard type IV anterior cranial fossa dural arteriovenous fistulas (DAVFs) are rare lesions with a high risk of intracranial hemorrhage. We present our experience with the use of Onyx via the arterial route in these aggressive lesions. Materials and methods Between October 2009 and October 2011, six consecutive patients diagnosed with Cognard type IV anterior cranial fossa DAVFs were treated transarterially with Onyx in our department. All patients were male; mean age was 55 years (range 38–68). Four patients presented with intracranial hemorrhage as the initial manifestation; one patient presented with seizures at the time of diagnosis and experienced intracranial hemorrhage during the antiepileptic therapy; and the other patient was asymptomatic. Results In five patients, complete obliteration was achieved with transarterial Onyx injection in a single treatment session; in the remaining patient, subtotal occlusion was achieved and gamma knife treatment was followed. The average time of injection was 19 min (range 5–28) for every pedicle catheterized and the average amount of Onyx was 3.2 ml (range 0.4–6.3) for each lesion. All patients recovered uneventfully after embolization. No mortality or permanent morbidity was observed in this series. Follow-up digital subtraction or MR angiography confirmed durable obliteration of the fistulas in five cured cases. No patients suffered intracranial hemorrhage during the follow-up period. Conclusions In this small series, our experience with the use of Onyx for arterial embolization of Cognard type IV DAVFs is encouraging, with durable complete cure in most lesions without severe complications.

Retreatment and outcomes of recurrent intracranial vertebral artery dissecting aneurysms after stent assisted coiling: a single center experience.

Background and purpose The retreatment of recurrent intracranial vertebral artery dissecting aneurysms (VADAs) after stent assisted coiling (SAC) has not yet been studied. The purpose of this study was to evaluate the strategies and outcomes for retreatment of recurrent VADAs after SAC. Methods Between September 2009 and November 2013, six consecutive patients presenting with recurrent intracranial VADAs after SAC were enrolled in this study. They were all male with age ranging from 29 to 54 years (mean age, 46.2 years). The procedures of treatments and angiographic and clinical follow-up were reviewed retrospectively. Retreatment modalities were selected individually according to the characteristics of recurrence. The outcomes of retreatment were evaluated by angiographic and clinical follow-up. Results Six patients with recurrent intracranial VADAs after SAC were retreated, with second SAC in three patients, coil embolization, double overlapping stents placement and endovascular occlusion with aneurysm trapping in one patient, respectively. Immediate angiographic outcomes of retreatment were: complete occlusion in three patients, nearly complete occlusion in two patients, and contrast medium retention in dissecting aneurysm in one patient. All cases were technically successful. No complications related to endovascular procedures occurred. Angiographic follow-up was available in all five patients treated with second SAC or double overlapping stents, which was complete occlusion in four patients, obliteration of parent artery in one patient, showing no recurrence at 4–11 months (mean: 8.6 months). Clinical follow-up was performed in all six patients at 11–51 months after initial endovascular treatment and at 9–43 months after retreatment. The mRS of last clinical follow-up was excellent in five patients and mild disability in only one patient. Conclusions Endovascular retreatment is feasible and effective for recurrent intracranial VADAs after SAC. Individualized strategies of retreatment should be enacted according to the characteristics and reasons for the recurrence.

Clinical and Angioarchitectural Risk Factors Associated with Intracranial Hemorrhage in Dural Arteriovenous Fistulas: A Single-Center Retrospective Study.

Purpose To investigate which clinical and angioarchitectural features were associated with the occurrence of intracranial hemorrhage in patients with intracranial dural arteriovenous fistulas (DAVFs). Materials and Methods We retrospectively reviewed the clinical and angioarchitectural features of 236 consecutive patients diagnosed with DAVF in our department from April 2009 to November 2013. Two groups of patients, with or without intracranial hemorrhage as clinical presentation at the initial diagnosis, were analysed to identify the differences in clinical and angioarchitectural features in univariate analysis. A multivariate logistic regression model was also developed to assess the independent contribution of the potential risk factors. Associations were considered significant for p<0.05. Results Fifty-six patients (23.7%) presented with intracranial hemorrhage at the initial diagnosis of DAVF. In univariate analysis, male patients (p = 0.002), patients with medical history of smoking (p<0.001) or alcohol consumption (p = 0.022), and DAVFs located at the tentorium (p = 0.010), frontalbasal (p = 0.007), foramen magnum (p = 0.043) or cerebral convexity (p<0.001) were associated with an increased risk of intracranial hemorrhage. A higher risk of hemorrhagic occurrence was also observed in DAVFs with superficial cortical venous drainage (p<0.001), deep venous drainage (p = 0.003), occluded venous sinus (p<0.032), or higher Borden type (p<0.001). A multivariate logistic regression model showed that intracranial hemorrhage in patients with DAVFs was correlated with higher Borden classification (OR 5.880; 95% CI, 3.370–10.257; p<0.001). Conclusion Venous drainage pattern was the only independent risk factor of intracranial hemorrhage in our patients with intracranial DAVF. The other potential risk factors may be confounding factors in predicting intracranial hemorrhage.

Remission of neurovascular conflicts in the cerebellopontine angle in interventional neuroradiology.

Background and purpose To investigate the efficacy of endovascular treatment (EVT) for neurovascular conflicts (NVCs) in the cerebellopontine angle (CPA) caused by intracranial aneurysms (IAs) and intracranial arteriovenous malformations (AVMs), including trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia. Materials and methods From January 2010 to January 2014, 14 consecutive patients presenting with three NVCs caused by IAs or intracranial AVMs were admitted to our department. The clinical outcomes of these NVCs after EVT were retrospectively analyzed. Results For four patients with IAs, angiographic follow-up confirmed total occlusion of the lesion in all, and the clinical outcomes of NVC were as follows: gradual relief in two (50%), transient partial relief but recurrence in one (25%), and no palliative effect in one (25%). For the 10 patients with intracranial AVMs, one (10%) experienced transient relief of NVC after angiogram examination (no EVT was performed). Of the other nine patients who received EVT, angiographic follow-up was obtained in seven (70%), demonstrating total obliteration of the lesion in three (30%), subtotal obliteration in two (20%), and partial obliteration in two (20%). Clinical outcomes included immediate relief of NVCs after single EVT in two cases (20%), gradual relief after single EVT in five (50%, one of them experienced transient aggravation), and complete relief after two sessions of EVT in two (20%). Complications of transient cranial nerve paresis related to EVT occurred in two cases (20%) with intracranial AVMs. In all, complete lasting relief of the NVCs was obtained finally in 11 cases (78.6%). Conclusions EVT is a feasible and less invasive approach for relief of NVCs in the CPA caused by IA or intracranial AVM and could be considered as a therapeutic option in these situations.

Cranial Nerve Dysfunction Associated with Cavernous Dural Arteriovenous Fistulas After Transvenous Embolization with Onyx.

PurposeCranial nerve dysfunction (CND) is not uncommon in patients with cavernous dural arteriovenous fistulas (cDAVFs), and may represent an initial manifestation or a complication after endovascular treatment. This study evaluated the outcome of CND associated with cDAVFs after transvenous embolization (TVE) using Onyx.Materials and MethodsForty-one patients with cDAVFs were treated with TVE in our department between April 2009 and October 2013. For each patient, clinical and radiologic records were retrospectively reviewed and evaluated, with an emphasis placed on evaluating the outcomes of the pre-existing cDAVF-induced CND and the TVE-induced CND.ResultsOf the 41 cases, 25 had a history of preoperative CND. Postoperatively, gradual remission to complete recovery (CR) within 8 months was observed in 17 of these cases, transient aggravation in 7, and significant improvement to be better than preoperative function but no CR in 1. All aggravation of CND occurred immediately or within 1 day after TVE and resolved completely within 5 months. Nine patients developed new CND after TVE. New CND occurred during the perioperative period in 8 cases, but all cases resolved completely within 15 days–6 months. Delayed CND was observed in 3 cases with a time lag of 3–25 months after TVE. Two of these completely resolved within 20 days–1 month and the remaining case significantly improved.ConclusionBoth the pre-existing cDAVF-induced CND and the TVE-induced new or aggravated CND completely resolved in almost all cases after embolization with Onyx.

O-017 Recurrent Intracranial Vertebral Artery Dissecting Aneurysms After Stent-assisted Coil Embolization-A Computational Fluid Dynamic Analysis

Introduction Intracranial vertebral artery dissecting aneurysms (VADAs) tend to recur despite successful stent-assisted coil embolization (SACE). Computational fluid dynamic (CFD) can assess hemodynamic alterations in wall shear stress (WSS) and velocity in the aneurysmal wall. CFD has proven to be useful in evaluating aneurysmal formation, growth and rupture. Our aim was to evaluate the hemodynamic patterns of VADA’s recurrence by CFD. Materials and methods Between September 2009 and November 2013, all consecutive patients presenting with recurrent VADAs after SACE in our institutions were enrolled in the study. Recurrence was defined as recanalization and regrowth. We assessed the hemodynamic alterations in WSS and velocity by CFD simulation after initial SACE and subsequently after retreatment of aneurysms that recurred. Results In the study period, 112 consecutive patients with intracranial veterbrobasilar dissecting aneurysms (VBDAs) underwent endovascular treatment. Seventy-two of them were treated with SACE. Angiographic follow-up was available in 59 patients (81.9%). Recurrence was present in 10 patients (16.9%) and 6 needed retreatment. Finally, 5 patients with VADAs were included (1 was excluded because of inadequate 3D imaging). After initial treatment, three cases showed recanalization and 2 cases showed regrowth. In the 2 regrew cases, the 2 original aneurysms maintained complete occlusion, however de-novo aneurysm regrowth was confirmed near the previous site. Compared with 3 recanalised aneurysms, the completely occluded aneurysms showed high mean reductions in velocity and WSS after initial treatment (77.6% versus 57.7% in velocity, 74.2% versus 52.4% in WSS), however, remaining high WSS at region near the previous lesion where the new aneurysm originated. After the second retreatment, there was no recurrence in all cases. Compared with the 3 aneurysms that recanalised, the 4 aneurysms that maintained complete occlusion showed higher reductions in velocity (62.9%) and WSS (71.1%). Conclusion Hemodynamics by CFD may be useful in predicting recurrence of VADAs after SACE.Abstract O-017 Figure 1Abstract O-017 Figure 2 Disclosures J. Liu: None. L. Jing: None. Y. Zhang: None. Y. Song: None. Y. Wang: None. C. Li: None. Y. Wang: None. S. Mu: None. N. Paliwal: 1; C; National Institutes of Health (R01 NS091075). H. Meng: 1; C; National Institutes of Health (R01 NS091075). I. Linfante: None. X. Yang: 1; C; National Natural Science Foundation of China (Grant No. 81301003, 81171079, 81371315, 81471167 and 81220108007), Special Research Project for Capital Health Development (Grant No. 2014–1-1071).