Impact of single phase CT angiography collateral status on functional outcome over time: results from the MR CLEAN Registry.

BACKGROUND: Collateral status modified the effect of endovascular treatment (EVT) for stroke in several randomized trials. We assessed the association between collaterals and functional outcome in EVT treated patients and investigated if this association is time dependent. METHODS: We included consecutive patients from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in The Netherlands (MR CLEAN) Registry (March 2014-June 2016) with an anterior circulation large vessel occlusion undergoing EVT. Functional outcome was measured on the modified Rankin Scale (mRS) at 90 days. We investigated the association between collaterals and mRS in the MR CLEAN Registry with ordinal logistic regression and if this association was time dependent with an interaction term. Additionally, we determined modification of EVT effect by collaterals compared with MR CLEAN controls, and also investigated if this was time dependent with multiplicative interaction terms. RESULTS: 1412 patients were analyzed. Functional independence (mRS score of 0-2) was achieved in 13% of patients with grade 0 collaterals, in 27% with grade 1, in 46% with grade 2, and in 53% with grade 3. Collaterals were significantly associated with mRS (adjusted common OR 1.5 (95% CI 1.4 to 1.7)) and significantly modified EVT benefit (P=0.04). None of the effects were time dependent. Better collaterals corresponded to lower mortality (P<0.001), but not to lower rates of symptomatic intracranial hemorrhage (P=0.14). CONCLUSION: In routine clinical practice, better collateral status is associated with better functional outcome and greater treatment benefit in EVT treated acute ischemic stroke patients, independent of time to treatment. Within the 6 hour time window, a substantial proportion of patients with absent and poor collaterals can still achieve functional independence.

Does prior antiplatelet treatment improve functional outcome after intra-arterial treatment for acute ischemic stroke?

Background and purpose In patients with acute ischemic stroke who receive antiplatelet treatment, uncertainty exists about the effect and safety of intra-arterial treatment. Our aim was to study whether intra-arterial treatment in patients with prior antiplatelet treatment is safe and whether prior antiplatelet treatment modifies treatment effect. Methods All 500 MR CLEAN patients were included. We estimated the effect of intra-arterial treatment with ordinal logistic regression analysis, and tested for interaction of antiplatelet treatment with intra-arterial treatment on outcome. Furthermore, safety parameters and serious adverse events were analyzed. Results The 144 patients (29%) on antiplatelet treatment were older, more often male, and had more vascular comorbidity. Intra-arterial treatment effect size after adjustments in antiplatelet treatment patients was 1.7 (95% confidence interval 0.9-3.2), and in no antiplatelet treatment patients 1.8 (95% confidence interval: 1.2-2.6). There was no statistically or clinically significant interaction between prior antiplatelet treatment and the relative effect of intra-arterial treatment ( p = 0.78). However, in patients on antiplatelet treatment, the effect of successful reperfusion on functional outcome in the intervention arm of the trial was doubled: the absolute risk difference for favorable outcome after successful reperfusion in patients on prior antiplatelet treatment was 39% versus 18% in patients not on prior antiplatelet treatment (Pinteraction = 0.025). Patients on antiplatelet treatment more frequently had a symptomatic intracranial hemorrhage (15%) compared to patients without antiplatelet treatment (4%), without differences between the control and intervention arm. Conclusions Prior treatment with antiplatelet agents did not modify the effect of intra-arterial treatment in patients with acute ischemic stroke presenting with an intracranial large vessel occlusion. There were no safety concerns. In patients with reperfusion, antiplatelet agents may improve functional outcome.

Treatment in patients who are not eligible for intravenous alteplase: MR CLEAN subgroup analysis.

BACKGROUND AND PURPOSE: Patients with acute ischemic stroke due to intracranial large vessel occlusion benefit from intra-arterial therapy. Uncertainty exists about the effect of intra-arterial therapy in patients with contraindications for treatment with intravenous alteplase treatment. Our aim was to describe the clinical characteristics of this subgroup of patients and whether intra-arterial therapy is as safe and effective as it is after intravenous alteplase treatment. METHODS: All 500 MR CLEAN patients were included and we distinguished between patients who were and were not treated with intravenous alteplase treatment. We estimated the effect of intra-arterial therapy on the shift on the modified Rankin Scale score with ordinal logistic regression analysis and tested for interaction of intravenous alteplase treatment with intra-arterial therapy on outcome. Furthermore, safety parameters and serious adverse events were analyzed. RESULTS: Fifty-five patients (11%) were not treated with intravenous alteplase treatment, mostly because of prolonged coagulation time tests or recent surgery. These patients were older and more often had atrial fibrillation or other vascular comorbidity. There was no interaction between intravenous alteplase treatment and intervention effect (p = 0.927). Intra-arterial therapy effect size in patients without intravenous alteplase treatment was 2.06 [95% CI: 0.69-6.13] and in patients with intravenous alteplase treatment 1.71 [95% CI: 1.22-2.40]. There were no safety issues. CONCLUSIONS: For patients with acute ischemic anterior circulation stroke caused by intracranial large vessel occlusion, who have contraindications for intravenous alteplase, intra-arterial treatment is not less effective or less safe than in patients who receive the treatment after intravenous alteplase. CLINICAL TRIAL REGISTRATION: Clinical trial registration-URL: http://www.trialregister.nl. Unique identifier: (NTR)1804.Clinical trial registration-URL: http://www.controlled-trials.com. Unique identifier: ISRCTN10888758.