Raphaël Blanc

Flow Diverters at and Beyond the Level of the Circle of Willis for the Treatment of Intracranial Aneurysms

Background and Purpose— Flow Diverters (FD) are a new emerging therapy for intracranial aneurysms. Initial reports focused on the treatment of proximally located aneurysms. We report our experience with FDs in the treatment of aneurysms at and beyond the circle of Willis. Methods— We treated 30 aneurysms at and beyond the circle of Willis with FDs (silk and pipeline). Aneurysms were treated with FDs alone in 73.3% (22/30) and with FDs and coils in 23.3% (7/30). One procedure was converted in parent vessel occlusion. Results— Thirty aneurysms (21/30, 70.0% saccular; 7/30, 23.3% fusiform; 2/30, 6.7% blister-like; sizes 1.2–19.6, mean 6.8 mm) were treated in 26 patients (17 women, 9 men; mean age, 49 years) during 27 procedures. Access site complication was noted in 3.7% (1/27). Reversible neurological complications were noted in 7.4% (2/27), permanent neurological complication in 3.7% (1/27). There was no mortality. No aneurysms bled or rebled after treatment. Aneurysms treated with FDs alone were significantly smaller than those treated with FDs and coils (5.7 and 10.0 mm, respectively; P=0.0174). Immediate angiographic occlusion was achieved in 18.2% (4/22) with FDs alone, in 0.0% (0/7) with FDs and coils. Twenty-four aneurysms (80.0%) had been followed (mean, 13 months). Fifteen of 19 aneurysms (78.9%) treated with FDs against 4 of 4 of aneurysms (100%) treated with FDs and coils were occluded. There was no angiographic recurrence of initially totally occluded aneurysms. Conclusions— Aneurysms at and beyond the circle of Willis are amenable to selective treatment with FDs.

Effect of Endovascular Contact Aspiration vs Stent Retriever on Revascularization in Patients With Acute Ischemic Stroke and Large Vessel Occlusion: The ASTER Randomized Clinical Trial

Importance The benefits of endovascular revascularization using the contact aspiration technique vs the stent retriever technique in patients with acute ischemic stroke remain uncertain because of lack of evidence from randomized trials. Objective To compare efficacy and adverse events using the contact aspiration technique vs the standard stent retriever technique as a first-line endovascular treatment for successful revascularization among patients with acute ischemic stroke and large vessel occlusion. Design, Setting, and Participants The Contact Aspiration vs Stent Retriever for Successful Revascularization (ASTER) study was a randomized, open-label, blinded end-point clinical trial conducted in 8 comprehensive stroke centers in France (October 2015-October 2016). Patients who presented with acute ischemic stroke and a large vessel occlusion in the anterior circulation within 6 hours of symptom onset were included. Interventions Patients were randomly assigned to first-line contact aspiration (n = 192) or first-line stent retriever (n = 189) immediately prior to mechanical thrombectomy. Main Outcomes and Measures The primary outcome was the proportion of patients with successful revascularization defined as a modified Thrombolysis in Cerebral Infarction score of 2b or 3 at the end of all endovascular procedures. Secondary outcomes included degree of disability assessed by overall distribution of the modified Rankin Scale (mRS) score at 90 days, change in National Institutes of Health Stroke Scale (NIHSS) score at 24 hours, all-cause mortality at 90 days, and procedure-related serious adverse events. Results Among 381 patients randomized (mean age, 69.9 years; 174 women [45.7%]), 363 (95.3%) completed the trial. Median time from symptom onset to arterial puncture was 227 minutes (interquartile range, 180-280 minutes). For the primary outcome, the proportion of patients with successful revascularization was 85.4% (n = 164) in the contact aspiration group vs 83.1% (n = 157) in the stent retriever group (odds ratio, 1.20 [95% CI, 0.68-2.10]; P = .53; difference, 2.4% [95% CI, −5.4% to 9.7%]). For the clinical efficacy outcomes (change in NIHSS score at 24 hours, mRS score at 90 days) and adverse events, there were no significant differences between groups. Conclusions and Relevance Among patients with ischemic stroke in the anterior circulation undergoing thrombectomy, first-line thrombectomy with contact aspiration compared with stent retriever did not result in an increased successful revascularization rate at the end of the procedure. Trial Registration clinicaltrials.gov Identifier: NCT02523261

Direct cervical arterial access for intracranial endovascular treatment

IntroductionTortuous vasculature is a cause of failure of endovascular treatment of intracranial vascular lesions. We report our experience of direct cervical accesses in patients in whom the arterial femoral route was not attainable.MethodsIn this retrospective study, 42 direct punctures of the carotid or the vertebral arteries at the neck were performed in 38 patients. The vessel harboring the intracranial lesion was punctured at the neck above the main tortuosity, a sheath was then positioned under fluoroscopic control to allow a stable access to the intracranial circulation. After the procedure, the sheath was removed and hemostasis was gained either by manual compression or by an arterial closure device (4 of 42, 9%).ResultsThe cervical route allowed access to all intracranial lesions in all 42 procedures. A complication was encountered in six procedures (14%) related to the direct puncture. In 2 of the 42 procedures (4%), a transient vasospasm was encountered. A cervical hematoma formed in 3 of the 42 procedures (7%) after sheath withdrawal (one patient in whom an 8F sheath had been used, required surgical evacuation of a hematoma compressing the upper airways; the other patients did well without surgical evacuation). In the remaining patient (1 of 42 procedures, 2%), a small asymptomatic aneurysm at the puncture site was seen on the follow-up angiogram.ConclusionDirect cervical arterial approaches to accessing the intracranial circulation is effective in patients in whom the femoral route does not allow the navigation and stabilization of guiding catheters.

“Y” and “X” Stent-Assisted Coiling of Complex and Wide-Neck Intracranial Bifurcation Aneurysms

BACKGROUND AND PURPOSE: Stent-assisted coiling with two stents has been described in some series for the treatment of complex and wide-neck bifurcation aneurysms. Our aim was to report our experience of a stent-assisted coiling technique with double stents in “Y” and “X” configurations, with emphasis on safety, feasibility, and efficacy. MATERIALS AND METHODS: Clinical and angiographic outcomes of patients for whom the strategic therapeutic option was the stent-assisted coiling technique in a Y or X configuration for neck scaffolding from June 2006 to June 2013 were retrospectively analyzed. RESULTS: One hundred five aneurysms in 97 patients were treated during 100 consecutive procedures. There were 54.2% (57/105) MCA, 28.6% (30/105) anterior communicating artery, 16.2% (17/105) basilar tip, and 1.0% (1/105) ICA termination aneurysms. A Y stent placement was used to treat 87 aneurysms in 85 procedures; an X stent placement was used to treat 7 aneurysms in 6 procedures, while 9 procedures failed for 11 aneurysms. There were 10.0% (10/100) procedure-related permanent neurologic deficits and 1.0% (1/100) death. The immediate angiographic controls showed a complete occlusion in 47.6% (50/105) of the aneurysms and a partial (neck or sac remnant) occlusion in 52.4% (55/105). To date, 81.0% (85/105) of the aneurysms have been followed up (mean, 17 months) with angiography, disclosing a recanalization in 5.9% (5/85) and an improvement in 42.4% (36/85). At discharge and follow-up, the mRS score was 0 in 83.5% (81/97) of patients, 1 in 4.1% (4/97), 2 in 3.1% (3/97), 3 in 4.1% (4/97), 4 in 3.1% (3/97), and 6 in 2.1% (2/97). CONCLUSIONS: Y and X stent-assisted coiling of complex and wide-neck intracranial bifurcation aneurysms is an effective technique.

A Direct Aspiration, First Pass Technique (ADAPT) versus Stent Retrievers for Acute Stroke Therapy: An Observational Comparative Study

BACKGROUND AND PURPOSE: Mechanical thrombectomy with stent retrievers is now the standard therapy for selected patients with ischemic stroke. The technique of A Direct Aspiration, First Pass Technique for the Endovascular Treatment of Stroke (ADAPT) appears promising with a high rate of recanalization. We compared ADAPT versus stent retrievers (the Solitaire device) for efficacy and safety as a front-line endovascular procedure. MATERIALS AND METHODS: We analyzed 243 consecutive patients with large intracranial artery occlusions of the anterior circulation, treated within 6 hours with mechanical thrombectomy by either ADAPT or the Solitaire stent. Th primary outcome was complete recanalization (modified TICI ≥ 2b); secondary outcomes included complication rates and procedural and clinical outcomes. RESULTS: From November 2012 to June 2014, 119 patients were treated with stent retriever (Solitaire FR) and 124 by using the ADAPT with Penumbra reperfusion catheters. The median baseline NIHSS score was the same for both groups (Solitaire, 17 [interquartile range, 11–21] versus ADAPT, 17 [interquartile range, 12–21]). Time from groin puncture to recanalization (Solitaire, 50 minutes [range, 25–80 minutes] versus ADAPT, 45 minutes [range, 27–70 minutes], P = .42) did not differ significantly. However, compared with the Solitaire group, patients treated with ADAPT achieved higher final recanalization rates (82.3% versus 68.9%; adjusted relative risk, 1.18; 95% CI, 1.02–1.37; P = .022), though differences in clinical outcomes between the cohorts were not significant. Use of an adjunctive device was more frequent in the ADAPT group (45.2% versus 13.5%, P < .0001). The rate of embolization in new territories or symptomatic hemorrhage did not differ significantly between the 2 groups. CONCLUSIONS: Front-line ADAPT achieved higher recanalization rates than the Solitaire device. Further randomized controlled trials are warranted to define the best strategy for mechanical thrombectomy.

Hemorrhagic Complications after Endovascular Treatment of Cerebral Arteriovenous Malformations

BACKGROUND AND PURPOSE: Intracranial hemorrhage is the most severe complication of brain arteriovenous malformation treatment. We report our rate of hemorrhagic complications after endovascular treatment and analyze the clinical significance and potential mechanisms, with emphasis on cases of delayed hemorrhage after uneventful embolization. MATERIALS AND METHODS: During a 10-year period, 846 embolization procedures were performed in 408 patients with brain AVMs. Any cases of hemorrhagic complications were identified and divided into those related or unrelated to a periprocedural arterial tear (during catheter navigation or catheter retrieval). We analyzed the following variables: sex, age, hemorrhagic presentation, Spetzler-Martin grade, size of the AVM, number of embolized pedicles, microcatheter used, type and volume of liquid embolic agent injected, and the presence of a premature venous occlusion. Univariate and multivariate multiple regression analyses were performed to identify risk factors for hemorrhagic complications. RESULTS: A hemorrhagic complication occurred in 92 (11%) procedures. Forty-four (48%) complications were related to a periprocedural arterial perforation, and 48 (52%) were not. Hemorrhagic complications unrelated to an arterial perforation were located more commonly in the cerebral parenchyma, caused more neurologic deficits, and were associated with worse prognosis than those in the arterial perforation group. Only premature venous occlusion was identified as an independent predictor of hemorrhagic complication in the nonperforation group. Premature venous occlusion was significantly related to the ratio of Onyx volume to nidus diameter. CONCLUSIONS: Higher injected volume of embolic agent and deposition on the venous outflow before complete occlusion of the AVM may account for severe hemorrhagic complications.

Impact of Modified TICI 3 versus Modified TICI 2b Reperfusion Score to Predict Good Outcome following Endovascular Therapy

BACKGROUND AND PURPOSE: The TICI score is widely used to evaluate cerebral perfusion before and after the endovascular treatment of stroke. Recent studies showing the effectiveness and safety of mechanical thrombectomy combine modified TICI 2b and modified TICI 3 to assess the technical success of endovascular treatment. The purpose of this study was to determine how much clinical outcomes differ between patients achieving modified TICI 2b and modified TICI 3 reperfusion. MATERIALS AND METHODS: We analyzed 222 consecutive patients with acute large intracranial artery occlusion of the anterior circulation having achieved modified TICI 2b or modified TICI 3 reperfusion after thrombectomy. The primary end point was the rate of favorable outcome defined as the achievement of a modified Rankin Scale score of 0–2 at 3 months. RESULTS: Patients with modified TICI 3 more often had favorable collateral circulation and atherosclerosis etiology, with a shorter time from onset to reperfusion than patients with modified TICI 2b (all P < .05). The number of total passes to achieve reperfusion was higher in the modified TICI 2b group (median, 2; interquartile range, 1–3, 1–9) versus (median, 1; interquartile range, 1–2, 1–8) in the modified TICI 3 group (P = .0002). Favorable outcome was reached more often for patients with modified TICI 3 than for those with modified TICI 2b (71.7% versus 50.5%, P = .001), with a similar difference when considering excellent outcome. In addition, patients with modified TICI 3 had a lower intracerebral hemorrhage rate (23.0% versus 45.0%, P < .001). CONCLUSIONS: Patients with modified TICI 3 reperfusion have better functional outcomes than those with modified TICI 2b. Given the improving reperfusion rates obtained with thrombectomy devices, future thrombectomy trials should consider modified TICI 2b and modified TICI 3 status separately.

Analysis of Complications and Recurrences of Aneurysm Coiling with Special Emphasis on the Stent-Assisted Technique

BACKGROUND AND PURPOSE: Stent-assisted coiling has expanded the treatment of intracranial aneurysms. With the use of continuously compiled data, we reviewed the role and drawbacks of stent-assisted coiling. MATERIALS AND METHODS: We compiled data from consecutive patients from 2003–2012 who underwent coiling, with or without stent assistance. Clinical and angiographic results were analyzed retrospectively. RESULTS: Of 1815 saccular aneurysms in 1505 patients, 323 (17.8%) were treated with stents (299 procedures) and 1492 (82.2%) without stents (1400 procedures). Procedure-related complications occurred in 9.4% with stents versus 5.6% without stents (P = .016, relative risk 1.5; 95% CI, 1.1–2.7). Ischemic complications were more frequent in the stent group than in the no-stent group (7.0% versus 3.5%; P = .005; relative risk, 1.7; 95% CI 1.2–2.5), as were hemorrhagic complications (2.3% versus 1.9%, P = .64). Procedure-induced mortality occurred in 2.7% (8/299) with stents versus 1.1% (15/1400) without stents (P = .029; relative risk, 2.0; 95% CI, 1.1–3.5). Logistic regression analysis identified wide-neck aneurysms as the most significant independent predictor of complications. A total of 64.1% (207/323) of aneurysms treated with stents and 70.3% (1049/1492) treated without stents have been followed, disclosing angiographic recurrence in 15.5% (32/207) versus 35.5% (372/1049), respectively (P < .0001). Logistic regression analysis showed that the presence of a stent was the most important factor for the reduction of angiographic recurrence (P < .0001; relative risk, 2.3; 95% CI, 1.6–3.3). CONCLUSIONS: The stent-assisted coiling technique is associated with a significant decrease in recurrences but a significant increase in complications. The treatment of wide-neck aneurysms remains hazardous.

An improved biogeography based optimization approach for segmentation of human head CT-scan images employing fuzzy entropy

The present paper proposes the development of a three-level thresholding based image segmentation technique for real images obtained from CT scanning of a human head. The proposed method utilizes maximization of fuzzy entropy to determine the optimal thresholds. The optimization problem is solved by employing a very recently proposed population-based optimization technique, called biogeography based optimization (BBO) technique. In this work we have proposed some improvements over the basic BBO technique to implement nonlinear variation of immigration rate and emigration rate with number of species in a habitat. The proposed improved BBO based algorithm and the basic BBO algorithm are implemented for segmentation of fifteen real CT image slices. The results show that the proposed improved BBO variants could perform better than the basic BBO technique as well as genetic algorithm (GA) and particle swarm optimization (PSO) based segmentation of the same images using the principle of maximization of fuzzy entropy.

An in vitro study of silk stent morphology

IntroductionMorphology of the Silk stent (Balt, Montmorency, France) after deployment is not fully understood, especially in tortuous vessels. An in vitro study was conducted to study morphology and flow-diverting parameters of this stent.MethodsTwo sets of different-sized and curved polytetrafluoroethylene tubes were studied. To simulate the aneurysm neck, a small hole was created in a tube. A stent was placed in each of the different tubes. Angiographic computerized tomography and macroscopic photography were then obtained. The images were analyzed to calculate a Percentage of Area Coverage (PAC).ResultsGood stent conformability was observed. The PAC was 21% in the straight model with matched stent and vessel diameter. In the straight model with an oversized stent, the PAC was increased. In the curved models, dynamic wire repositioning occurred. The repositioning was affected by the size of the stent and the angle of the vessel curve. Compared to the straight model, this increased the PAC in two instances: on the convexity (oversized stent), and on the concavity (matched stent and vessel diameter). The PAC did not significantly change at the sides of the curve.ConclusionsBy design, the wires of the silk stent move relative to each other. In a curved model, the PAC is different at the convexity, concavity, and lateral walls. The stent diameter affects the PAC. These results are clinically relevant because it is desirable to maximize and minimize the PAC across the aneurysm neck and branch vessel orifice, respectively.