François Guilbert

Endovascular Treatment of Intracranial Unruptured Aneurysms: Systematic Review and Meta-Analysis of the Literature on Safety and Efficacy

PURPOSE To report an updated, systematic review of medical literature from January 2003 to July 2008, on endovascular treatment (EVT) of intracranial unruptured aneurysms (UAs) (a) to assess the morbidity and case fatality rate of EVT of UAs, (b) to understand how bias can affect results, and (c) to estimate the efficacy of EVT by using reported digital subtraction angiographic (DSA) results and clinical follow-up events. MATERIALS AND METHODS This article was prepared in accordance with the Meta-Analysis of Observational Studies in Epidemiology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The literature was searched by using PubMed and the EMBASE and Cochrane Library databases. Eligibility criteria were (a) explicit procedural mortality and morbidity rates; (b) at least 10 patients; (c) saccular, intradural, nondissecting UAs; (d) original study published in English or French between January 2003 and July 2008; and (e) a methodological quality score higher than 6, according to Strengthening the Reporting of Observational Studies in Epidemiology criteria. End points included procedural mortality and morbidity, defined as a modified Rankin scale score of 3-6 at 1 month, and efficacy, estimated by using immediate and follow-up digital subtraction angiographic results, as well as delayed hemorrhagic events. RESULTS Seventy-one studies were included. Procedural unfavorable outcome was found in 4.8% (random-effect weighted average; 189 of 5044) of patients (99% confidence interval [CI]: 3.9%, 6.0%). Immediate angiographic results showed satisfactory occlusion in 86.1% (2660 of 3089) of UAs. Recurrences were shown in 321 (24.4%) of 1316 patients followed up for 0.4-3.2 years. Retreatment was performed in 9.1% (random-effect weighted average; 166 of 1699) of patients (99% CI: 6.2%, 13.1%). The annual risk of bleeding after EVT was 0.2% (random-effect weighted average; nine of 1395) of patients (99% CI: 0.1%, 0.3%), but clinical follow-up was short, limited to the first 6 months for 76.7% (n = 1071) of reported patients. CONCLUSION EVT of UAs can be performed with relative safety. The efficacy of treatment as compared with observation has not been rigorously documented.

Association of endovascular therapy of very small ruptured aneurysms with higher rates of procedure-related rupture

OBJECT Procedure-related rupture during endovascular therapy of intracranial aneurysms is associated with a mortality rate of more than one third. Previously ruptured aneurysms are a known risk factor for procedure-related rupture. The objective of this study was to evaluate whether very small, ruptured aneurysms are associated with more frequent intraprocedural ruptures. METHODS This was a retrospective cohort study in which the investigators examined consecutive ruptured aneurysms treated with coil embolization at a single institution. The study was approved by the institutional review board. Very small aneurysms were defined as < or = 3 mm. Procedure-related rupture was defined as contrast extravasation during treatment. Univariate analysis with the Fisher exact test and the Mann-Whitney U test was performed. RESULTS Between August 1992 and January 2007, 682 aneurysms were selectively treated with coils in 668 patients. Procedure-related rupture occurred in 7 (11.7%) of 60 aneurysms < or = 3 mm, compared with 14 (2.3%) of 622 aneurysms > 3 mm (relative risk 5.2, 95% confidence interval 2.2-12.8; p < 0.001). Among cases with procedure-related rupture, inflation of a compliant balloon was associated with better outcome (Glasgow Outcome Scale Score > or = 4) compared with patients treated without balloon assistance (5 of 5 compared with 7 of 16; p = 0.05). Death resulting from procedure-related rupture occurred in 8 (38%) of 21 patients, and a vegetative state occurred in 1 patient. Clinical outcome was good in the other 12 patients (57%). CONCLUSIONS Endovascular coil embolization of very small (< or = 3 mm) ruptured cerebral aneurysms is 5 times more likely to result in procedure-related rupture compared with larger aneurysms. Balloon inflation for hemostasis may be associated with better outcome in the event of intraprocedural rupture and merits further study.

Outcomes of Endovascular Treatments of Aneurysms: Observer Variability and Implications for Interpreting Case Series and Planning Randomized Trials

BACKGROUND AND PURPOSE: Angiographic results are commonly used as a surrogate marker of success of coiling of intracranial aneurysms. Inter- and intraobserver agreement in judging angiographic results remain poorly characterized. Our goal was to offer such an evaluation of a grading scale commonly used to evaluate results of endovascular treatment of aneurysms. MATERIALS AND METHODS: A portfolio of 90 angiographic images from 45 patients selected from the core lab data base of a randomized trial was sent to 12 observers on 2 occasions more than 3 months apart. The variability of a 3-value grading scale used to score angiographic results and of a final judgment regarding the presence of a recurrence was studied using κ statistics. RESULTS: Ten participants responded once and 6 responded twice. Agreement was poor to moderate (κ = 0.28–0.5) for senior and junior observers judging angiographic results immediately or 12–18 months after treatment. Agreement reached a reassuring “substantial” (κ = 0.62) level, with a dichotomous presence-absence of a major recurrence, and intraobserver agreement was better in experienced core lab assessors. CONCLUSIONS: There is an important variability in the assessment of angiographic outcomes of endovascular treatments, rendering comparisons between publications risky, if not invalid. A simple dichotomous judgment can be used as a surrogate outcome in randomized trials designed to assess the value of new endovascular devices.

Endovascular treatment of pericallosal aneurysms.

OBJECT Pericallosal artery aneurysms are uncommon. Their treatment strategy, surgical or endovascular, will present specific challenges. The objective of the study was to compare risks of coil therapy and the recurrence rate of pericallosal artery aneurysms with aneurysms in other intradural locations. METHODS The authors examined data that were stored in a prospectively collected database for pericallosal artery aneurysms in patients who underwent coil placement between 1992 and 2005. Hemorrhagic and thromboembolic complications as well as clinical and angiographic outcomes were reviewed. Angiographically documented recurrences were classified as minor or major. These lesions were compared with a historical cohort of non-pericallosal artery aneurysms in patients who underwent coil therapy between 1992 and 2002. The known risk factors for recurrence and procedure-related hemorrhagic complications were evaluated in both groups to assess baseline imbalances. RESULTS During a 13-year period, 25 pericallosal artery aneurysms were treated with coils in 25 patients. The non-pericallosal artery lesion group included 488 aneurysms of which 344 underwent follow-up imaging. Procedure-related perforations were more frequent for pericallosal artery aneurysms than those in other intradural locations (three of 25 compared with eight of 476, respectively; risk ratio 7.1, 95% confidence interval [CI] 2.1-22.5, p = 0.03). Follow-up imaging studies (obtained at a mean 28 months) were available for 19 patients with pericallosal artery aneurysms. The recurrence rate was not significantly higher in these patients (22.9/100 person-years of observation) than in those with non-pericallosal artery aneurysms (17.9/100 person-years of observation) (incidence rate ratio 1.3, 95% CI 0.6-2.4, p = 0.46). CONCLUSIONS Pericallosal artery aneurysms were associated with significantly higher periprocedural rupture than non-pericallosal artery lesions. No significant intergroup difference was found for aneurysm recurrence.

Value of 3.0 T MR imaging in refractory partial epilepsy and negative 1.5 T MRI

BACKGROUND High-field 3.0 T MR scanners provide an improved signal-to-noise ratio which can be translated in higher image resolution, possibly allowing critical detection of subtle epileptogenic lesions missed on standard-field 1.0-1.5 T MRIs. In this study, the authors explore the potential value of re-imaging at 3.0 T patients with refractory partial epilepsy and negative 1.5 T MRI. METHODS We retrospectively identified all patients with refractory partial epilepsy candidate for surgery who had undergone a 3.0 T MR study after a negative 1.5 T MR study. High-field 3.0 T MRIs were reviewed qualitatively by neuroradiologists experienced in interpreting epilepsy studies with access to clinical information. Relevance and impact on clinical management were assessed by an epileptologist. RESULTS Between November 2006 and August 2009, 36 patients with refractory partial epilepsy candidate for surgery underwent 3.0 T MR study after a 1.5 T MR study failed to disclose a relevant epileptogenic lesion. A potential lesion was found only in two patients (5.6%, 95% CI: 1.5-18.1%). Both were found to have hippocampal atrophy congruent with other presurgical localization techniques which resulted in omission of an invasive EEG study and direct passage to surgery. CONCLUSIONS The frequency of detection of a new lesion by re-imaging at 3.0 T patients with refractory partial epilepsy candidate for surgery was found to be low, but seems to offer the potential of a significant clinical impact for selected patients. This finding needs to be validated in a prospective controlled study.

Early CT changes in patients admitted for thrombectomy Intrarater and interrater agreement

Objective: To systematically review the literature and assess agreement on the Alberta Stroke Program Early CT Score (ASPECTS) among clinicians involved in the management of thrombectomy candidates. Methods: Studies assessing agreement using ASPECTS published from 2000 to 2015 were reviewed. Fifteen raters reviewed and scored the anonymized CT scans of 30 patients recruited in a local thrombectomy trial during 2 independent sessions, in order to study intrarater and interrater agreement. Agreement was measured using intraclass correlation coefficients (ICCs) and Fleiss kappa statistics for ASPECTS and dichotomized ASPECTS at various cutoff values. Results: The review yielded 30 articles reporting 40 measures of agreement. Populations, methods, analyses, and results were heterogeneous (slight to excellent agreement), precluding a meta-analysis. When analyzed as a categorical variable, intrarater agreement was slight to moderate (κ = 0.042–0.469); it reached a substantial level (κ > 0.6) in 11/15 raters when the score was dichotomized (0–5 vs 6–10). The interrater ICCs varied between 0.672 and 0.811, but agreement was slight to moderate (κ = 0.129–0.315). Even in the best of cases, when ASPECTS was dichotomized as 0–5 vs 6–10, interrater agreement did not reach a substantial level (κ = 0.561), which translates into at least 5 of 15 raters not giving the same dichotomized verdict in 15% of patients. Conclusions: In patients considered for thrombectomy, there may be insufficient agreement between clinicians for ASPECTS to be reliably used as a criterion for treatment decisions.

Arterial Onyx embolisation of intracranial DAVFs with cortical venous drainage.

PURPOSE To present our experience with the endovascular management of intracranial dural arteriovenous fistulas with direct cortical venous drainage by trans-arterial embolisation using Onyx. MATERIALS & METHODS Between January 2004 and April 2008, 12 consecutive high grade intracranial dural arteriovenous fistulas (Cognard type III (eight patients) or IV (three patients)) were treated by trans-arterial embolisation with Onyx. The majority of cases were treated by Onyx embolisation alone. One case had additional embolisation with n-butyl-2-cyanoacrylate at the same session. Imaging follow-up was obtained in all but one patient (mean 3.6 months). RESULTS Nine patients had a technical success at the end of the embolisation procedure with complete angiographic exclusion of the fistula. Two patients had a small residual fistula at the end of embolisation, one of which had residual mild cortical venous drainage. Both were stable at follow-up angiography. One patient had a residual fistula supplied by the ophthalmic artery, which was thought to be unsafe to embolise and was sent for surgery, which was curative. In one patient the microcatheter ruptured, with a fragment of the distal microcatheter left in the occipital artery. No clinical complications were observed in this series at clinical follow-up (mean 3.3 months). Two patients were noted to have significant radiation dose. CONCLUSION Endovascular management of intracranial dural arteriovenous fistulas with direct venous cortical drainage by trans-arterial Onyx embolisation is a safe and effective treatment according to our experience. Fluoroscopy times and radiation dose may be a concern.

Patients prone to recurrence after endovascular treatment: periprocedural results of the PRET randomized trial on large and recurrent aneurysms.

BACKGROUND AND PURPOSE: Some patients with large or recurrent aneurysms may be at increased risk of recurrence postcoiling. The Patients Prone to Recurrence after Endovascular Treatment (PRET) trial was designed to assess whether hydrogel coils were superior to platinum coils in these high-risk patients. This article reports periprocedural safety and operator-assessed angiographic results from the PRET trial. MATERIALS AND METHODS: PRET was a pragmatic, multicenter, randomized controlled trial. Patients had ≥10-mm aneurysms (PRET-1) or a major recurrence after coiling of an aneurysm of any size (PRET-2). Patients were randomly allocated to hydrogel or control arms (any platinum coil) by using concealed allocation with minimization. Assist devices could be used as clinically required. Aneurysms could be unruptured or recently ruptured. Analyses were on an intent-to-treat basis. RESULTS: Four hundred forty-seven patients were recruited (250 PRET-1; 197 PRET-2). Aneurysms were recently ruptured in 29% of PRET-1 and 4% of PRET-2 patients. Aneurysms were ≥10 mm in all PRET-1 and in 50% of PRET-2 patients. They were wide-neck (≥4 mm) in 70% and in the posterior circulation in 24% of patients. Stents were used in 28% of patients (35% in PRET-2). Coiling was successful in 98%. Adverse events occurred in 28 patients with hydrogel and 23 with platinum coils. Mortality (n = 2, unrelated to treatment) and morbidity (defined as mRS >2 at 1 month) occurred in 25 patients (5.6%; 12 hydrogel, 13 platinum), related to treatment in 10 (4 hydrogel; 6 platinum) (or 2.3% of 444 treated patients). No difference was seen between hydrogel and platinum for any of the indices used to assess safety up to at least 30 days after treatment. At 1 month, 95% of patients were home with a good outcome (mRS ≤2 or unchanged). Operator-assessed angiographic outcomes were satisfactory (complete occlusion or residual neck) in 339 of 447 or 76.4% of patients, with no significant difference between groups. CONCLUSIONS: Endovascular treatment of large and recurrent aneurysms can be performed safely with platinum or hydrogel coils.

Surgical construction of an in vivo carotid siphon model to test neurovascular devices.

OBJECTIVE:We developed an animal model to evaluate vascular trauma induced by endovascular devices that are proposed for the treatment of cerebrovascular diseases. METHODS:The model was constructed in six domestic swine by elongating the common carotid artery using interpositional grafts. Balloon catheters (n = 3), stents (n = 2), and a snare were tested 9 to 13 days after surgery. Device performance was evaluated by angiography, macroscopic photography, and histopathological examination. RESULTS:Animals tolerated the surgical procedure well, and artificial siphons were thought to provide realistic conditions for device testing. Balloon catheters induced minimal trauma, whereas coronary stents caused severe spasm or thrombosis and extensive macroscopic changes. CONCLUSION:Construction of an in vivo siphon model is feasible and potentially useful for testing neurovascular devices.

Endoluminal Cryotherapy to Prevent Recanalization after Endovascular Occlusion with Platinum Coils

PURPOSE Endovascular embolization with platinum coils is sometimes followed by recanalization. The present study was undertaken to assess whether cryoablation of the endothelial lining could prevent recanalization after coil occlusion. MATERIALS AND METHODS Recanalization rates of canine maxillary and vertebral arteries (n = 20) occluded with platinum coils with or without previous cryoablation (with temperatures of -40 degrees C to -45 degrees C for 90 seconds) were analyzed by angiography immediately and at 1 and 3 months in five animals. Pathologic recanalization and fibrosis was assessed at 3 months with use of a qualitative scoring system. Findings were compared with Mann-Whitney tests. RESULTS Recanalization after coil occlusion occurred in 50% and 60% of cases with cryoablation at 1 and 3 months, respectively, compared with 100% without ablation (P = .012 and P= .029). There was no significant difference in pathologic scores (P = .348). The brachial plexus in the vicinity of vertebral arteries was injured by cryotherapy in three animals in which an ipsilateral neurologic deficit developed. CONCLUSIONS Cryotherapy was moderately effective in the prevention of recanalization after coil occlusion. Deep nerve injury was excessive with the protocol used in the present study.