Elodie Ong

Outcomes of stent retriever thrombectomy in basilar artery occlusion: an observational study and systematic review

Background Basilar artery occlusion (BAO) remains one of the most devastating subtypes of stroke with high mortality and poor outcome. Early recanalisation is the most powerful predictor of favourable outcome in patients with stroke, and may be improved with mechanical thrombectomy using stent retriever devices. However, the benefit in functional outcome and safety of stent retrievers are not yet well known. The aim of this study was to assess efficacy and safety profiles of stent retriever thrombectomy in BAO patients with stroke. Methods We analysed data retrospectively from our consecutive clinical series and conducted a systematic review and meta-analysis of all previous studies of stent retriever thrombectomy in BAO patients with stroke between November 2010 and April 2014. Results From March 2010 to March 2013, 22 patients with acute BAO were treated with a Solitaire stent retriever in our series. Favourable outcome was significantly associated with younger age and distal BAO. The literature search identified 15 previous studies involving a total of 312 subjects. In the meta-analysis, including our series data, the recanalisation rate (Thrombolysis In Cerebral Infarction (TICI) score ≥2b) reached 81% (95% CI 73% to 87%). The rate of symptomatic intracranial haemorrhage was 4% (95% CI 2% to 8%), favourable outcome (modified Rankin Scale (mRS) ≤2 at 3 months) was found in 42% (95% CI 36% to 48%) and mortality rate was 30% (95% CI 25% to 36%). Conclusions Stent retriever thrombectomy is a safe treatment modality for patients with stroke presenting with BAO. Although the stent retrievers showed a good recanalisation rate, there are currently no randomised clinical trials to assess its clinical efficacy in comparison with the reference treatment.

Cyclosporine in acute ischemic stroke

Objectives: We examined whether IV administration of cyclosporine in combination with thrombolysis might reduce cerebral infarct size. Methods: Patients aged 18 to 85 years, presenting with an anterior-circulation stroke and eligible for thrombolytic therapy, were enrolled in this multicenter, single-blinded, controlled trial. Fifteen minutes after randomization, patients received either an IV bolus injection of 2.0 mg/kg cyclosporine (Sandimmune, Novartis) or placebo. The primary endpoint was infarct volume on MRI at 30 days. Secondary endpoints included infarct volume according to the site (proximal/distal) of arterial occlusion and recanalization after thrombolysis. Results: From October 2009 to July 2013, 127 patients were enrolled. The primary endpoint was assessed in 110 of 127 patients. The reduction of infarct volume in the cyclosporine compared with the control group was overall not significant (21.8 mL [interquartile range, IQR 5.1, 69.2 mL] vs 28.8 mL [IQR 7.7, 95.0 mL], respectively; p = 0.18). However, in patients with proximal occlusion and effective recanalization, infarct volume was significantly reduced in the cyclosporine compared with the control group (14.9 mL [IQR 1.3, 23.2 mL] vs 48.3 mL [IQR 34.5, 118.2 mL], respectively; p = 0.009). Conclusions: Cyclosporine was generally not effective in reducing infarct size. However, a smaller infarct size was observed in patients with proximal cerebral artery occlusion and efficient recanalization. Classification of evidence: This study provides Class I evidence that in patients with an acute anterior-circulation stroke, thrombolysis plus IV cyclosporine does not significantly decrease 30-day MRI infarct volume compared with thrombolysis alone.

Multi-site laser Doppler flowmetry for assessing collateral flow in experimental ischemic stroke: Validation of outcome prediction with acute MRI

High variability in infarct size is common in experimental stroke models and affects statistical power and validity of neuroprotection trials. The aim of this study was to explore cerebral collateral flow as a stratification factor for the prediction of ischemic outcome. Transient intraluminal occlusion of the middle cerebral artery was induced for 90 min in 18 Wistar rats. Cerebral collateral flow was assessed intra-procedurally using multi-site laser Doppler flowmetry monitoring in both the lateral middle cerebral artery territory and the borderzone territory between middle cerebral artery and anterior cerebral artery. Multi-modal magnetic resonance imaging was used to assess acute ischemic lesion (diffusion-weighted imaging, DWI), acute perfusion deficit (time-to-peak, TTP), and final ischemic lesion at 24 h. Infarct volumes and typology at 24 h (large hemispheric versus basal ganglia infarcts) were predicted by both intra-ischemic collateral perfusion and acute DWI lesion volume. Collateral flow assessed by multi-site laser Doppler flowmetry correlated with the corresponding acute perfusion deficit using TTP maps. Multi-site laser Doppler flowmetry monitoring was able to predict ischemic outcome and perfusion deficit in good agreement with acute MRI. Our results support the additional value of cerebral collateral flow monitoring for outcome prediction in experimental ischemic stroke, especially when acute MRI facilities are not available.

Cerebral Near-Infrared Spectroscopy: A Potential Approach for Thrombectomy Monitoring

Background and Purpose— Regional brain oxygen saturation (rSO2) changes, assessed by cerebral near-infrared spectroscopy, are likely influenced by cerebral hemodynamic fluctuations induced by thrombectomy of acute proximal occlusion. We studied the correlations between rSO2 and baseline magnetic resonance imaging perfusion parameters and the relationship between rSO2 changes, recanalization, and clinical outcome. Methods— Seventeen acute ischemic stroke patients, treated with mechanical thrombectomy, were monitored using bilateral near-infrared spectroscopy before, during, and continuously for 24 hours after the procedure. All patients had baseline brain magnetic resonance imaging with perfusion weighted imaging. Results— rSO2 was only correlated with baseline Tmax (&rgr;=−0.42; P<0.05) and mean transit time (&rgr;=−0.45; P<0.05) within forehead explored areas. Before thrombectomy, an interhemispheric rSO2 difference was noted, and this diminished over time when recanalization had occurred (median [interquartile range], −8 [−12 to −5] to 3 [−3 to 7]; P=0.01). rSO2 changes were not correlated with clinical outcome. Conclusions— rSO2 was merely correlated with baseline Tmax and mean transit time magnetic resonance imaging perfusion parameters. Multiple sites recording beyond frontal pole explored areas may provide more relevant correlation with hemodynamic parameters.

MRI Profile and Collateral Status in Patients with a Transient Ischemic Attack and an Intracranial Artery Occlusion: High-Risk TIAs and Intracranial Artery Occlusion

Transient ischemic attack may rarely reveal an intracranial artery occlusion. We analyzed acute magnetic resonance imaging (MRI) patterns and early outcome after reperfusion therapy in these cases.

Impact of the Thrombectomy Trials on the Management and Outcome of Large Vessel Stroke: Data From the Lyon Stroke Center

Introduction: Randomized trials (RT) have recently validated the superiority of thrombectomy over standard medical care, including intravenous thrombolysis (IVT). However, data on their impact on routine clinical care remains scarce. Methods: Using a prospective observational registry, we assessed: (1) the clinical and radiological characteristics of all consecutive patients treated with thrombectomy; (2) the outcome of all patients with M1 occlusion (treated with thrombectomy or IVT alone). Two periods were compared: before (2013–2014) and after (2015–2016) the publication of RT. Results: Endovascular procedures significantly increased between the two periods (N = 82 vs. 314, p < 0.0001). In 2015–2016, patients were older (median [IQR]: 69 [57-80]; vs. 66 [53-74]; p = 0.008), had shorter door-to-clot times (69 [47-95]; vs. 110 [83-155]; p < 0.0001) resulting in a trend toward shorter delay from symptom onset to reperfusion (232 [185-300]; vs. 250 [200-339]; p = 0.1), with higher rates of reperfusion (71 vs. 48%; p = 0.0001). Conversely, no significant differences in baseline NIHSS scores, ASPECTS, delay to IVT or intracranial hemorrhage were found. In 2015–2016, patients with M1 occlusion were treated with thrombectomy more often than in 2013–2014 (87 vs. 32%, respectively; p < 0.0001), with a significant improvement in clinical outcome (shift analysis, lower modified Rankin scale scores: OR = 1.68; 95% CI: 1.10–2.57; p = 0.017). Conclusion: Following the publication of RT, thrombectomy was rapidly implemented with significant improvements in intrahospital delay and reperfusion rates. Treatment with thrombectomy increased with better clinical outcomes in patients with M1 occlusion.

Effect of Cyclosporine on Lesion Growth and Infarct Size within the White and Gray Matter

Background In a recent trial, cyclosporine A (CsA) failed to reduce infarct size in acute stroke patients treated with intravenous thrombolysis. White matter (WM) and gray matter (GM) may have distinct vulnerability to ischemia and response to therapy. Using final infarct size and lesion growth as endpoints, our objectives were to (1) investigate any tissue-specific effect of CsA and (2) compare WM and GM response to thrombolysis. Materials and methods We analyzed 84 patients from the randomized and placebo-controlled CsA-Stroke trial, who underwent MRI both on admission and at 1 month. Lesion growth was defined voxel-wise as infarcted tissue at 1 month with no visible lesion on baseline diffusion-weighted imaging. After automatic segmentation of GM/WM, final infarct size and lesion growth were compared within the GM and WM. Results Occlusion level was distal (>M1) in 51% of cases. No significant difference in GM/WM proportions was observed within final infarcts between treatment groups (P = 0.21). Infarct size within the GM or WM was similar between the CsA and control groups [GM: 9.2 (2.4; 22.8) with CsA vs 8.9 (3.7; 28.4) mL with placebo, P = 0.74; WM: 9.9 (4.7; 25.4) with CsA vs 14.1 (5.6; 34.1) mL with placebo, P = 0.26]. There was no significant effect of CsA on lesion growth in either the GM or WM. Pooling all patients, a trend for increased relative lesion growth in WM compared to GM was observed [49.0% (14.7; 185.7) vs 43.1% (15.4; 117.1), respectively; P = 0.12]. Conclusion No differential effect of CsA was observed between WM and GM. Pooling all patients, a trend toward greater lesion growth in WM was observed.