Basilar Tip Aneurysm Research Articles

Risk factors for recanalization of basilar tip aneurysm after endovascular treatment: a retrospective cohort study

ABSTRACT Objectives Endovascular treatment (EVT) of basilar tip aneurysms (BTAs) is arduous because of the lesions’ angioarchitecture and the relatively high recanalization rate after EVT. In this study, we aimed to report the clinical characteristics of BTAs and evaluate the incidence of and risk factors for recanalization. Methods One hundred twenty-five patients with BTAs (11 ruptured, 114 unruptured) treated with EVT between 2009 and 2019 at one institution were retrospectively reviewed. Among them, 113 patients were included in statistical analyses. The anatomical parameters of the aneurysms and clinical data were analyzed. Univariate (chi-square test and t-test) and multivariate (multiple logistic regression) analyses were performed to identify risk factors for recanalization. Results Recanalization of the BTA occurred in 15 patients (13.3%). One patient (0.9%) was retreated endovascularly. The mean follow-up duration was 49.8 months. Neck size, posterior cerebral artery (PCA) angle, maximum diameter, and the rupture rate differed significantly between the recanalization and non-recanalization groups (P=.007, P<.001, P=.006, and P=.048, respectively). The maximum diameter (odds ratio, 1.483 per mm; 95% confidence interval, 1.145–1.919; P=.003) and PCA angle (odds ratio, 1.020 per degree; 95% confidence interval, 1.001–1.039; P=.036) were independently associated with recanalization. Conclusions Of all investigated BTAs, 96.8% were wide-neck aneurysms. The recanalization rate of BTAs after EVT was 13.3%. The PCA angle and maximal aneurysmal diameter were independently associated with recanalization; no associations were observed regarding vertebral artery dominance or modality of treatment. As such, BTA patients with wide PCA angles should be carefully monitored over time.

Endovascular therapy versus microsurgical clipping of unruptured wide-neck aneurysms: a prospective multicenter study with propensity score analysis.

Numerous techniques have been developed to treat wide-neck aneurysms (WNAs), each with different safety and efficacy profiles. Few studies have compared endovascular therapy (EVT) with microsurgery (MS). The authors' objective was to perform a prospective multicenter study of a WNA registry using rigorous outcome assessments and to compare EVT and MS using propensity score analysis (PSA). Unruptured, saccular, not previously treated WNAs were included. WNA was defined as an aneurysm with a neck width ≥ 4 mm or a dome-to-neck ratio (DTNR) < 2. The primary outcome was modified Rankin Scale (mRS) score at 1 year after treatment (good outcome was defined as mRS score 0-2), as assessed by blinded research nurses and compared with PSA. Angiographic outcome was assessed using the Raymond scale with core laboratory review (adequate occlusion was defined as Raymond scale score 1-2). The analysis included 224 unruptured aneurysms in the EVT cohort (n = 140) and MS cohort (n = 84). There were no differences in baseline demographic characteristics, such as proportion of patients with good baseline mRS score (94.3% of the EVT cohort vs 94.0% of the MS cohort, p = 0.941). WNA inclusion criteria were similar between cohorts, with the most common being both neck width ≥ 4 mm and DTNR < 2 (50.7% of the EVT cohort vs 50.0% of the MS cohort, p = 0.228). More paraclinoid (32.1% vs 9.5%) and basilar tip (7.1% vs 3.6%) aneurysms were treated with EVT, whereas more middle cerebral artery (13.6% vs 42.9%) and pericallosal (1.4% vs 4.8%) aneurysms were treated with MS (p < 0.001). EVT aneurysms were slightly larger (p = 0.040), and MS aneurysms had a slightly lower mean DTNR (1.4 for the EVT cohort vs 1.3 for the MS cohort, p = 0.010). Within the EVT cohort, 9.3% of patients underwent stand-alone coiling, 17.1% balloon-assisted coiling, 34.3% stent-assisted coiling, 37.1% flow diversion, and 2.1% PulseRider-assisted coiling. Neurological morbidity secondary to a procedural complication was more common in the MS cohort (10.3% vs 1.4%, p = 0.003). One-year mRS scores were assessed for 218 patients (97.3%), and no significantly increased risk of poor clinical outcome was found for the MS cohort (OR 2.17, 95% CI 0.84-5.60, p = 0.110). In an unadjusted direct comparison, more patients in the EVT cohort achieved a good clinical outcome at 1 year (93.4% vs 84.1%, p = 0.048). Final adequate angiographic outcome was superior in the MS cohort (97.6% of the MS cohort vs 86.5% of the EVT cohort, p = 0.007). Although the treatments for unruptured WNA had similar clinical outcomes according to PSA, there were fewer complications and superior clinical outcome in the EVT cohort and superior angiographic outcomes in the MS cohort according to the unadjusted analysis. These results may be considered when selecting treatment modalities for patients with unruptured WNAs.

Comparison of angiographic outcomes and complication rates of WEB embolization and coiling for treatment of unruptured basilar tip aneurysms

Endovascular coiling represents the standard treatment for basilar tip aneurysms. Some of these aneurysms are not amenable to conventional coiling due to a complex aneurysm geometry, hence, novel devices such as the Woven Endobridge (WEB) have been developed. We retrospectively compared WEB embolization and coiling for the treatment of unruptured basilar tip aneurysms. Patients treated with WEB or coiling at four centers were reviewed. Procedure-related complications, clinical outcome and angiographic results were retrospectively evaluated and compared. Forty patients treated with the WEB and 35 patients treated by coiling were included. Stent-assistance was more often necessary for coiling than for WEB embolization (71% vs 2.5%, p < 0.001). The technical success rates were 100% for both methods. The overall complication rates were not significantly different between groups (WEB: 5%, coil: 11%, p = 0.409). Procedural morbidity rates were 9% in the coiling group and 2.5% in the WEB group (p = 0.334). There was no mortality. Treatment duration was shorter for WEB implantation than for coiling (p = 0.048). At mid-term follow-up, complete occlusion, neck remnants and aneurysm remnants were observed in 89%, 4% and 7% for the WEB, respectively, and in 100%, 0% and 0% for coiling. While complication rates and mid-term angiographic outcome was comparable between the groups, the WEB was associated with a shorter treatment duration and required stent-assistance less frequently. The choice of the treatment modality should be made based on the specific aneurysm characteristics, the individual experience of the neurointerventionalist and patient preference.

Comparing treatment outcomes of various intracranial bifurcation aneurysms locations using the Woven EndoBridge (WEB) device

BackgroundThe Woven EndoBridge (WEB) device has Food and Drug Administration approval for treatment of wide-necked intracranial bifurcation aneurysms. The WEB device has been shown to result in adequate occlusion in...

Long-Term Durability and Recurrence Patterns After Endovascular Treatment for Basilar Tip Aneurysms

Treating recurrence after coil embolization of basilar tip aneurysm remains challenging even with the development of endovascular procedures. The present study evaluated long-term durability and recurrence patterns after endovascular treatment of basilar tip aneurysms. Data of 116 consecutive patients treated with endovascular therapy at 3 regional hospitals from 2002-2019 were retrospectively analyzed. Aneurysms were ruptured in 51 cases and unruptured in 65 cases, with a mean maximal diameter of 7.8mm (>15mm in 14 patients) and a mean follow-up period of 5.8±4.3years. Recurrence was observed in 24 of the 116 patients (21%), and 14 patients were retreated. The 5-year recurrence-free survival rate was 75.3%. Cox proportional hazards analysis found that recurrence correlated significantly with maximal aneurysm diameter >10mm (P=0.001; hazard ratio: 3.95, 95% confidence interval: 1.76-8.90) and incomplete occlusion (P=0.003; hazard ratio: 4.43, 95% confidence interval: 1.63-12.00). Recurrence pattern was classified into 3 types: neck type (9 patients), regrowth type (10 patients), and regrowth type of initially thrombosed aneurysms (3 patients). Rerupture occurred in neck type with de novo aneurysm formation adjacent to the neck (n= 3) and regrowth type with dome filling (n= 4). Recurrence after coil embolization for basilar tip aneurysms is associated with large aneurysms and incomplete occlusion at initial embolization. Understanding the patterns of recurrence is useful for predicting recurrence and selecting treatment strategies.

Endovascular treatment for large (> 10mm) basilar tip aneurysms: a retrospective case series.

To report the long-term clinical and angiographic outcomes of the endovascular treatment of large/giant basilar tip aneurysms (BTAs) in our institutions. We retrospectively reviewed cases of BTA larger than 10mm that received endovascular treatment between January 2009 and December 2019. Data on the demographic and clinical characteristics and radiologic severity were obtained from the patients' medical records. The collected clinical follow-up data included neurological evaluation. Magnetic resonance angiography (MRA) was performed 6 to 12months after the procedure, followed by once every 1 to 2years as needed. A total of 12 patients with BTA were included in this study. The median age was 60.08years (27-80years), and the mean clinical follow-up was 66.78months (19.00-142.87months). Almost half of the patients presented with unruptured BTAs (58.33%, n = 7). The median maximum aneurysm diameter was 13.00mm (10.46-20.90mm) and the mean neck size was 8.34mm (4.82-13.04mm). A Modified Raymond Roy Classification (MRRC1) of 1 or 2 was observed in 66.67% of the patients (n = 8) immediately after the first procedure. Procedural morbidity and mortality were 33.33% and 8.33%, respectively. Major recanalization occurred in two patients, one of whom underwent additional coiling with the other being merely observed due to older age. It is very difficult to cure a large BTA completely at once and recanalization occurred often after endovascular treatment. Conducting long-term follow-up studies at short intervals is warranted, as well as improving existing treatment methods and developing new approaches.

Woven Endobridge (WEB) augmented by Y-stent in a shallow basilar tip aneurysm.

The Woven Endobridge (WEB) device can be an effective and simple treatment modality for wide-neck bifurcation intracranial aneurysms. We present a case of a shallow basilar tip aneurysm treated with the WEB device that required stabilization with Y-stent through radial access.

Contrast-induced neurotoxicity presented as transient cortical blindness after stent-assisted coiling of a medium-sized unruptured basilar artery aneurysm: A case report and review of the literature

Background: Contrast-induced neurotoxicity is a rare event after endovascular diagnostic procedures or interventions and presents as transient neurological deficit. Herewith, we present a case of reversible complete cortical blindness after uneventful stent-assisted coiling of a medium-sized unruptured basilar artery aneurysm.Case Description: A 70-year-old woman with a medium-sized 10 mm/6 mm wide neck basilar tip aneurysm was planned for endovascular obliteration of the lesion. The procedure was done under general anesthesia. The contrast agent was iso-osmolar, nonionic. The aneurysm was coiled, and a stent was placed in the left posterior cerebral artery achieving sufficient aneurysm packing. No signs of vessel obliteration were observed during the procedure. On awakening of anesthesia, the patient reported complete visual loss. Ophthalmological examination was normal. The patient was brought back to the angio-suite but there were no signs of parent vessel compromise from the endovascular implants or distal vessel occlusion. An MRI of the brain was done showing no signs of brain ischemia, just mild brain edema in both occipital lobes. Given the results of the radiological studies and clinical presentation, the diagnosis of contrast-induced neurotoxicity was accepted. In 72 h, the patient had complete resolution of the visual loss and was discharged home with no additional neurological worsening.Conclusion: Contrast-induced neurotoxicity is a rare event that can occur after uneventful endovascular interventions of the brain vessels. Knowledge of this rare complication, after exclusion of all other possible reversible causes, is important for the treatment and prognosis of the patient.

Internal Carotid Artery Agenesis Associated with Contralateral Posterior Communicating Artery and Basilar Tip Aneurysms: A Case Report

Background: The absence of the internal carotid artery is an extremely rare congenital anomaly with a reported incidence of 0.01%. As with other anatomical vascular variants, they usually follow a silent course and are typically discovered incidentally. Case Presentation: We report an unusual case of a 30-year-old male medically free who presented to the emergency department with sided numbness involving both upper and lower limbs while he was swimming. Brain imaging revealed a congenital absence of the right internal carotid artery in association with basilar tip saccular aneurysm and right posterior communicating artery aneurysm. The patient was treated successfully with endovascular stent-assisted coiling of the basilar artery and stenting of the right posterior communicating artery. Conclusion: The main significant impact that this condition harbors is the high association with intracranial aneurysms secondary to hemodynamic stress on other intracranial arteries with compensatory increased flow. This case report supports this hypothesis and shows complex endovascular management.

Management of Wide-Necked Basilar tip Aneurysms.

While the frequency of direct surgery for basilar tip aneurysms is decreasing, the need for safe and effective surgical treatments for difficult-to-treat aneurysms, including large or wide-necked aneurysms, is likely to continue. In this chapter, our surgical approach for large wide-necked basilar tip aneurysms using the orbitozygomatic approach, the anterior temporal approach, and hybrid surgery are described.

T- configuration stent assisted coiling treatment of a complex wide-necked basilar tip aneurysm

The advancement of intracranial stent technology and techniques has extended the applications of endovascular coiling methods for complex intracranial aneurysms. Coiling of wide-necked and complex bifurcation aneurysms usually requires double stent implantation. Different configurations for double stent-assisted coil embolization have been described. The T-configuration stent-assisted coiling procedure was recently described as a feasible, effective, and relatively safe endovascular technique used to treat wide-necked complex bifurcation aneurysms. In this article, we present the successful management of a complex wide-neck basilar tip aneurysm using a slightly modified T-configuration stent-assisted coiling technique.

Abstract 1122‐000124: Dural Arteriovenous Fistula and Implications in Aneurysmal Genesis

Introduction : There is a reported association of cerebral arteriovenous malformations and aneurysms, however, data regarding patients presenting with dural arteriovenous fistulas (dAVF) and aneurysms is limited. Here, we present a patient who was incidentally diagnosed with 2 aneurysms in addition to a dAVF; and her treatment course. Previous to her diagnosis, she denied any and all symptomatology that would prompt further evaluation. Methods : Case description: 60‐year‐old female with history of hypertension, hypothyroidism and gastroesophageal reflux disease who initially presented to an outside hospital after a motor vehicle collision in 2016, at that time she reports being diagnosed with multiple aneurysms; but was lost to follow up. In 2020 she was referred to interventional neuroradiology and underwent diagnostic digital cerebral angiogram. Which reported a 13 × 12 × 13.3 mm left para‐ophthalmic internal carotid artery (ICA) aneurysm with a 7 mm neck. A 5.7 × 7.7 × 6.1 mm basilar tip artery aneurysm with a 5.6 mm neck and a right Cognard type four occipital dAVF, with feeding vessels from the right posterior cerebral artery and right occipital artery and anterograde drainage to the dural sinuses. From the time of diagnosis to the initiation of interventions, patient denied any concerning symptomatology. Treatment was initiated 4 months after diagnostic angiogram. She received 5 days of Dual Antiplatelet therapy (DAPT) with aspirin and Plavix previous to the deployment of a woven endobridge device (WEB™ 8‐3mm) into the basilar tip aneurysm; as this was felt to be the aneurysm with highest probability of rupture. Post‐operative course was unremarkable and DAPT was discontinued. Three months after WEB™ deployment, the patient underwent embolization of the right occipital dAVF with a liquid embolic agent (onyx™). Post operatively, she developed decreased peripheral vision in her left eye, though the rest of her hospitalization was unremarkable. 3 months after embolization, she underwent left para‐ophthalmic artery aneurysm flow diversion with a pipeline™ (4‐18mm) flow diverter, with an uncomplicated admission. She was subsequently evaluated by neuro‐ophthalmology who has reported a stable peripheral left eye left inferior quadrantic defect along with a supertemporal defect in her right eye. Results : Discussion: Interestingly, the patient presented 2 aneurysms, one in the anterior circulation and the most concerning, located in the posterior circulation. One could draw conclusions that the dAVF was associated with the basilar aneurysm. As dAVFs are acquired lesions, it is feasible to assume that there may be an association between both types of lesions, perhaps due to flow or pressure being exerted on weakened vessel walls, thus leading to aneurysmal formation. Conclusions : Conclusion: Because a potential for implication in the flow dynamics of the dAVF in aneurysmal formation. We have opted to use computational fluid dynamics to analyze said flow within the dAVF to better understand the causal relationship between aneurysms and dural fistulae. In the long run research into genesis of aneurysms secondary to coexisting vascular lesions could further elucidate the mechanisms by which aneurysms develop.

Hemodynamic and Morphologic Factors Related to Coil Compaction in Basilar Artery Tip Aneurysms

Coil compaction is directly related to the degree of cerebral aneurysmal recanalization. The degree of recanalization (DoR) was quantified by measuring the volume vacated by coil deformation. The purpose of this study was to clarify the hemodynamic and morphologic factors associated with coil compaction. Computational fluid dynamics simulations were performed on 28 middle-size (5-10 mm) unruptured basilar artery tip aneurysms. The DoR was measured by comparing the coil mass shape obtained from three-dimensional digital subtraction angiography data immediately after coil embolization and again within 1-2 years of follow-up. Deployed coils were modeled using a virtual coiling technique for computational fluid dynamics simulations. Hemodynamic and morphologic factors to predict the DoR were derived using multiple linear regression. Aneurysmal neck area, the maximum pressure generated on the neck surface after coil embolization, and the high-pressure position on the neck surface predicted DoR with statistic significance (P < 0.001, P < 0.001, P= 0.004, respectively). The DoR tended to increase when the neck areawas large, the pressure generated on the coils was high, and the high-pressure position was close to the center of the neck surface. The volume embolization ratio was not statistically relevant for the DoR in the cases of this study. Coil compaction occurs in cerebral aneurysms with a wide neck, high pressure generated on the coils, and high pressure in the center of the neck surface. Establishing the DoR can contribute to the prediction of recanalization after coil embolization.

The Analysis of Morphoradiological Parameters in Predicting Risk of Basilar Artery Tip Aneurysm Rupture: A Retrospective Cohort Study.

PurposeBasilar artery tip aneurysms can have fatal consequences and poor prognostic outcomes in case of rupture. We investigated the standard parameters used to evaluate aneurysmal morphology to predict aneurysm rupture.Patients and MethodsWe measured the differences between ruptured and unruptured basilar bifurcation aneurysms in terms of morphological features, including aneurysm size, size ratio, aneurysm height, perpendicular height, aneurysm width, bottleneck ratio, aspect ratio, and present daughter domes, using 3D angiography.ResultsAmong 34 patients, 21 (61.8%) and 13 (38.2%) had ruptured and unruptured basilar tip aneurysms, respectively. In the ruptured group, the mean aneurysm size, and aspect, size, and bottleneck ratios were 6.8 ± 1.9 mm, 3.2 ± 1.0, 2.3 ± 0.5, and 2.2 ± 0.4, respectively, compared to 4.5 ± 1.5 mm, 4.4 ± 2.0, 1.6 ± 0.4, and 2.7 ± 0.7, respectively, in the non-ruptured group. Univariate analysis showed a larger aneurysmal cross-sectional diameter (odds ratio [OR], 0.50; 95% confidence interval [CI], 0.5–5.392; p < 0.05), a larger size ratio (OR, 21.375; 95% CI, 3.283–139.177; p < 0.05), and presence of a daughter dome (OR, 72.0; 95% CI, 6.7–776.5; p < 0.05) with ruptured basilar artery tip aneurysms.ConclusionA larger aneurysm size and size ratio, and the presence of a daughter dome were significantly associated with increased rupture risk in basilar tip aneurysms.

Third Nerve Palsy Due to Intracranial Aneurysms and Recovery after Endovascular Coiling.

The modality of treatment of third nerve palsy (TNP) associated with intracranial aneurysms remains controversial. While treatment varies with the location of the aneurysm, microsurgical clipping of PComm aneurysms has generally been the traditional choice, with endovascular coiling emerging as a reasonable alternative. Patients with TNP due to an intracranial aneurysm who subsequently underwent treatment at a mid-sized Canadian neurosurgical center over a 15-year period (2003-2018) were examined. A total of 616 intracranial aneurysms in 538 patients were treated; the majority underwent endovascular coiling with only 24 patients treated with surgical clipping. Only 37 patients (6.9%) presented with either a partial or complete TNP and underwent endovascular embolization; of these, 17 presented with a SAH secondary to intracranial aneurysm rupture. Aneurysms associated with TNP included PComm (64.9%), terminal ICA (29.7%), proximal MCA (2.7%), and basilar tip (2.7%) aneurysms. In general, smaller aneurysms and earlier treatment were provided for patients for ruptured aneurysms with a shorter mean interval to TNP recovery. In the endovascularly treated cohort initially presenting with TNP, seven presented with a complete TNP and the remaining were partial TNPs. TNP resolved completely in 20 patients (55.1%) and partially in 10 patients (27.0%). Neither time to coiling nor SAH at presentation were significantly associated with the recovery status of TNP. Endovascular coil embolization is a viable treatment modality for patients presenting with an associated cranial nerve palsy.

The Value of C-Reactive Protein as a Predictor of Vasospasm and Poor Outcome in Spontaneous Subarachnoid Hemorrhage

Abstract Background: Rupture of an intracranial aneurysm carries a high risk of disability or death. Cerebral vasospasm remains the most troublesome complication of acute Subarachinoid-haemorraghe (SAH). Activation of the systemic immune response, manifested by increased levels of circulating cy-tokines, is believed to have a significant role in the pathogenesis of cerebrovascular vasospasm. Aim of Study: The aim of this study is to correlatebetween level of CRP and incidence of vasospasm in spontaneous S.A.H, and being an independent predictor for prognosis. Patients and Methods: Cross sectional study with stratified random sample of 30 patients who admitted in Intensive Care Unit, Neurosurgery Department, Emergency and Trauma Unit at Kasr Al-Ainy, Cairo University Hospitals, from September 2018 till April 2019 diagnosed with spontaneous Subarachnoid hemorrhage and screened for CRP. Results: Out of the 30 included in the study 10 patients (33.3%) diagnosed to have anterior communicating artery aneurysm; 2 patients (6.7%) have basilar tip aneurysm, 2 patients (6.7%) have posterior communicating artery aneurysm, 2 patients (6.7%) have posterior cerebral aneurysm, and 1 patient (1.9%) have middle cerebral artery aneurysm, 2 patient have AVM, 11 patient have no underlying pathology in the conventional 4 vessels angiography. Overall age ranged from 21 years to 80 years with a mean age 53.19 patients (63.3%) were males and 11 patients (36.7%) were females. Out from 30 patients, 14 patients (46.7%) had vasospasm, and 16 (53.3%) patients didn't have vasospasm, out of 14 patients who developed vasospasm, 13 patients (92%) initially had high serum CRP level above 50mg/L, and all patient who had rising CRP level (double to triple folds) had poor outcome. Conclusion: Vasospasm is a serious event complicating spontaneous aneurysmal subarachnoid hemorrhage, it could be diagnosed clinically or radiologically, serum CRP level is an indicator of cerebral vasospasm following aneurysmal subarachnoid hemorrhage and rising serum CRP level is an independent predictor for poor outcome.

Subtemporal, Transapical, and Transcavernous Approach to Clip Low-Lying Basilar Tip Aneurysm: 2-Dimensional Operative Video.

Basilar tip aneurysm clipping is technically challenging because of the depth of operative corridor, rarity in presentation, and important perforators supplying deep, critical structures. Two major approaches to basilar tip aneurysms include (1) a frontotemporal (transorbital) trans-sylvian approach for most aneurysms and (2) a modified subtemporal approach for aneurysms with low-lying necks. A 53-yr-old woman presented to our institution with a large unruptured basilar tip aneurysm notable for a low, broad neck (6.4 mm). After discussion of risks and benefits of endovascular vs surgical options, the patient consented to operative intervention. She underwent a right frontotemporal craniotomy with zygomatic osteotomy, intradural petrous apicectomy, elective sectioning of the fourth cranial nerve (CN IV), and intracavernous removal of the dorsum sellae and posterior clinoid process to provide more space for aneurysm dissection. After temporary clipping of the basilar artery, the perforating arteries were dissected free from the aneurysm and the aneurysm occluded with 2 fenestrated clips. Important technical nuances of the approach include (1) achieving ample working room for temporary occlusion aneurysm dissection, (2) careful dissection of the perforators and contralateral P1, and (3) utilization of 2 fenestrated clips to accommodate and preserve the ipsilateral P1 segment. Postoperative angiogram showed complete aneur-ysmal occlusion. Postoperatively, the patient demonstrated mild cognitive impairment and a right CN IV palsy. At 6-wk follow-up, cognition recovered to normalcy. More recently, at 12-mo follow-up, the patient noted intermittent diplopia. Formal neuro-ophthalmologic assessment confirmed persistence of a CN IV palsy treated with prism lenses but no other neurological deficits.

The Geometry of Y-Stent Configurations Used for Wide-Necked Aneurysm Treatment: Analyzing Double-Barrel Stents In Vitro Using Flat-Panel Computed Tomography

Stent-assisted coil embolization of wide-necked bifurcation aneurysms often employs a Y configuration stent. A similar stent configuration, termed kissing/double-barrel (KDB), is used often at the aortoiliac bifurcation. Studies of KDB stents in aortoiliac disease show that rates of thromboembolic complications vary with the cross-sectional geometry of the stent pair, a function of the radial crush resistive force of each stent. We assessed cross-sectional geometry of intracranial stent pairs in an invitro model of the basilar artery using flat-panel computed tomography. In a silicone model of a wide-necked basilar tip aneurysm, 6 simulated KDB stent deployment trials were performed using combinations of 5 stents (Enterprise 1, Enterprise 2, Neuroform Atlas, LVIS, LVIS Jr.). Flat-panel computed tomography reconstructions were used to assess cross-sectional stent geometry. Relative conformability, defined by ovalization and D-ratio, radial crush resistive force (predicted vs. actual), and radial mismatch fraction were compared by stent type (braided vs. laser-cut). Several distinct forms of cross-sectional stent geometry were observed. Braided stents had lower ovalization and D-ratio (P= 0.015) than laser-cut stents. The Neuroform Atlas/LVIS combination yielded the lowest radial mismatch fraction (19.7% vs. mean 44.3% ± 0.7%). Braided stents tended to have a deployed stent radius closer to the expected (nominal) diameter (i.e., higher relative crush resistive force) than laser-cut stents (measured vs. nominal diameter discrepancy+38.6% ± 21.1% vs. -10.7% ±16.1%, P= 0.14). In constant anatomy, cross-sectional geometry of the KDB stent configuration will vary depending on the design and structure of the stents employed.

Management of a double basilar tip aneurysm

Complex basilar tip aneurysms are still challenging to secure with coils or stent-assisted coiling. Double aneurysms at the basilar bifurcation and the basilar artery-superior cerebellar artery are a rare particular situation that usually requires more appropriate treatment. This case reports details of our experience with a double basilar tip aneurysm treated in two steps by coiling repair and stent-assisted coiling.

An in vitro study of pressure increases during contrast injections in diagnostic cerebral angiography.

During diagnostic cerebral angiography, the contrast bolus injected into a vessel can cause substantial changes in baseline pressures and flows. One potential, and serious complication is the re-rupture of aneurysms due to these injections. The goals of this in vitro study were to evaluate the effect of injection conditions on intraneurysmal pressure changes during angiography. A silicone replica of a complete circle of Willis model with ophthalmic, anterior communicating, and basilar tip aneurysms was connected to a physiologically accurate flow pump. Contrast injections were performed under different conditions (carotid or vertebral vessel imaging, catheter diameter, injection rate, injection time, and arterial blood flow rate) and the pressure in each aneurysm was recorded before and during each injection. The effect of injection conditions on percentage increase in aneurysm pressures was statistically assessed. Additionally, the effect of the distance between the aneurysm and the catheter-tip on aneurysmal pressures was assessed. Mean intraneurysmal pressures during injection (84.5 ± 10.8 mmHg) were significantly higher than pre-injection pressures (80.4 ± 10.6 mmHg, p < 0.0001). Only 3 of the 5 conditions - carotid injections, higher injection rates, and smaller catheter diameters - significantly increased intraneurysmal pressures. The catheter-tip distance showed no correlation to pressure increases. Increasing contrast injection rates and decreasing catheter diameters are correlated to intraneurysmal pressure increases during angiography irrespective of the distance to the catheter tip. Future in vivo studies are required to confirm these findings and determine whether the amplitude of pressure increases with commonly used injection rates can be clinically detrimental.