Thrombolysis for Acute Wake-Up and Unclear-Onset Strokes with Alteplase at 0.6 mg/kg in Clinical Practice: THAWS2 Study.

INTRODUCTION: The aim of this study was to determine the safety and efficacy of intravenous (IV) alteplase at 0.6 mg/kg for patients with acute wake-up or unclear-onset strokes in clinical practice. METHODS: This multicenter observational study enrolled acute ischemic stroke patients with last-known-well time >4.5 h who had mismatch between DWI and FLAIR and were treated with IV alteplase. The safety outcomes were symptomatic intracranial hemorrhage (sICH) after thrombolysis, all-cause deaths, and all adverse events. The efficacy outcomes were favorable outcome defined as an mRS score of 0-1 or recovery to the same mRS score as the premorbid score, complete independence defined as an mRS score of 0-1 at 90 days, and change in NIHSS at 24 h from baseline. RESULTS: Sixty-six patients (35 females; mean age, 74 ± 11 years; premorbid complete independence, 54 [82%]; median NIHSS on admission, 11) were enrolled at 15 hospitals. Two patients (3%) had sICH. Median NIHSS changed from 11 (IQR, 6.75-16.25) at baseline to 5 (3-12.25) at 24 h after alteplase initiation (change, -4.8 ± 8.1). At discharge, 31 patients (47%) had favorable outcome and 29 (44%) had complete independence. None died within 90 days. Twenty-three (35%) also underwent mechanical thrombectomy (no sICH, NIHSS change of -8.5 ± 7.3), of whom 11 (48%) were completely independent at discharge. CONCLUSIONS: In real-world clinical practice, IV alteplase for unclear-onset stroke patients with DWI-FLAIR mismatch provided safe and efficacious outcomes comparable to those in previous trials. Additional mechanical thrombectomy was performed safely in them.

Thrombolysis With Alteplase at 0.6 mg/kg for Stroke With Unknown Time of Onset: A Randomized Controlled Trial.

Background and Purpose- We assessed whether lower-dose alteplase at 0.6 mg/kg is efficacious and safe for acute fluid-attenuated inversion recovery-negative stroke with unknown time of onset. Methods- This was an investigator-initiated, multicenter, randomized, open-label, blinded-end point trial. Patients met the standard indication criteria for intravenous thrombolysis other than a time last-known-well >4.5 hours (eg, wake-up stroke). Patients were randomly assigned (1:1) to receive alteplase at 0.6 mg/kg or standard medical treatment if magnetic resonance imaging showed acute ischemic lesion on diffusion-weighted imaging and no marked corresponding hyperintensity on fluid-attenuated inversion recovery. The primary outcome was a favorable outcome (90-day modified Rankin Scale score of 0-1). Results- Following the early stop and positive results of the WAKE-UP trial (Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke), this trial was prematurely terminated with 131 of the anticipated 300 patients (55 women; mean age, 74.4±12.2 years). Favorable outcome was comparable between the alteplase group (32/68, 47.1%) and the control group (28/58, 48.3%; relative risk [RR], 0.97 [95% CI, 0.68-1.41]; P=0.892). Symptomatic intracranial hemorrhage within 22 to 36 hours occurred in 1/71 and 0/60 (RR, infinity [95% CI, 0.06 to infinity]; P>0.999), respectively. Death at 90 days occurred in 2/71 and 2/60 (RR, 0.85 [95% CI, 0.06-12.58]; P>0.999), respectively. Conclusions- No difference in favorable outcome was seen between alteplase and control groups among patients with ischemic stroke with unknown time of onset. The safety of alteplase at 0.6 mg/kg was comparable to that of standard treatment. Early study termination precludes any definitive conclusions. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02002325.

Cerebral microbleeds development after stroke thrombolysis: A secondary analysis of the THAWS randomized clinical trial.

BACKGROUND AND AIM: We determined to investigate the incidence and clinical impact of new cerebral microbleeds after intravenous thrombolysis in patients with acute stroke. METHODS: The THAWS was a multicenter, randomized trial to study the efficacy and safety of intravenous thrombolysis with alteplase in patients with wake-up stroke or unknown onset stroke. Prescheduled T2*-weighted imaging assessed cerebral microbleeds at three time points: baseline, 22-36 h, and 7-14 days. Outcomes included new cerebral microbleeds development, modified Rankin Scale (mRS) ≥3 at 90 days, and change in the National Institutes of Health Stroke Scale (NIHSS) score from 24 h to 7 days. RESULTS: Of all 131 patients randomized in the THAWS trial, 113 patients (mean 74.3 ± 12.6 years, 50 female, 62 allocated to intravenous thrombolysis) were available for analysis. Overall, 46 (41%) had baseline cerebral microbleeds (15 strictly lobar cerebral microbleeds, 14 mixed cerebral microbleeds, and 17 deep cerebral microbleeds). New cerebral microbleeds only emerged in the intravenous thrombolysis group (seven patients, 11%) within a median of 28.3 h, and did not additionally increase within a median of 7.35 days. In adjusted models, number of cerebral microbleeds (relative risk (RR) 1.30, 95% confidence interval (CI): 1.17-1.44), mixed distribution (RR 19.2, 95% CI: 3.94-93.7), and cerebral microbleeds burden ≥5 (RR 44.9, 95% CI: 5.78-349.8) were associated with new cerebral microbleeds. New cerebral microbleeds were associated with an increase in NIHSS score (p = 0.023). Treatment with alteplase in patients with baseline ≥5 cerebral microbleeds resulted in a numerical shift toward worse outcomes on ordinal mRS (median [IQR]; 4 [3-4] vs. 0 [0-3]), compared with those with <5 cerebral microbleeds (common odds ratio 17.1, 95% CI: 0.76-382.8). The association of baseline ≥5 cerebral microbleeds with ordinal mRS score differed according to the treatment group (p interaction = 0.042). CONCLUSION: New cerebral microbleeds developed within 36 h in 11% of the patients after intravenous thrombolysis, and they were significantly associated with mixed-distribution and ≥5 cerebral microbleeds. New cerebral microbleeds development might impede neurological improvement. Furthermore, cerebral microbleeds burden might affect the effect of alteplase.

A topographic study of the evolution of the MR DWI/PWI mismatch pattern and its clinical impact: a study by the EPITHET and DEFUSE Investigators.

BACKGROUND AND PURPOSE: The ischemic penumbra may be classical, with complete annular configuration around the infarct core, or nonclassical with a more fragmented pattern. We tested the hypotheses that these penumbral patterns may: be associated with specific predictive factors, influence infarct growth and clinical outcome, and influence the effect of tissue plasminogen activator (t-PA). METHODS: Using the EPITHET/DEFUSE data set, in which patients received alteplase or placebo 3 to 6 hours poststroke, perfusion-weighted imaging and diffusion-weighted imaging images were analyzed. These mismatch patterns were defined as "classical" or "nonclassical." Multivariate analysis was used to identify variables associated with mismatch patterns, the effect of t-PA, as well as the relationship between mismatch patterns, infarct growth, and clinical outcomes. RESULTS: We included 158 patients (median age, 74 years; median National Institute of Health Stroke Scale score, 12). Multivariate analysis indicated that the factors associated with classical mismatch pattern type were large mismatch volume (P<0.001) and cortical infarct location (P=0.036). Infarct growth, clinical outcome, and the efficacy of t-PA were not statistically different between patterns. CONCLUSIONS: Coregistered mismatch volume and cortical location of infarction were the important factors associated with presence of the classical mismatch pattern. The lack of effect of the type of mismatch patterns on infarct growth, clinical outcomes, or the benefit of t-PA would suggest that mismatch topography is less important during the hyperacute phase of ischemic stroke than during subacute phase.