Rationale The only proven therapy for acute stroke is tPA within 4.5 hours of symptom onset. This is the standard of care for patients presenting to our hospital within that time frame. Thrombolysis outside the 4.5 hour window is considered only on experimental or compassionate grounds. Tenecteplase (TNK) is a genetically modified variant of tPA that has many theoretical advantages in acute stroke. Studies show that systemic plasminogen activation is higher after tPA administration, relative to TNK and this is associated with an increased risk of bleeding events. Imaging cerebral blood flow (CBF) with MRI (perfusion weighted imaging-PWI) and CT perfusion (CTP) can be performed routinely with standard clinical scanners. Patients with evidence of large volumes of tissue with low CBF, that is also structurally intact, as demonstrated by either normal signal on Diffusion weighted imaging (DWI) or normal cerebral blood volume (CBV) are considered to have penumbral patterns. Patients with penumbral patterns appear to be the ideal candidates for thrombolytic therapy, regardless of time from onset.
1. The primary aim of this study is to demonstrate the feasibility and safety of TNK based thrombolysis in ischemic stroke patients presenting 4.5-24 hours after symptom onset.
2. It is hypothesized that treatment with TNK in patients with penumbral patterns will be associated with reperfusion, early neurological improvement and penumbral tissue salvage.
Study Design The study is planned as an open label feasibility and safety study of acute treatment with TNK in ischemic stroke patients with penumbral patterns evident on advanced MRI or CT perfusion sequences.
Study Outcomes The primary outcome of this study is a safety endpoint, specifically the frequency of symptomatic hemorrhagic transformation evident on MRI or CT images on 24 h or day 5 scans. The ECASS II system for rating hemorrhagic transformation will be applied to all GRE/SWI images
Significance Current treatment paradigms have not permitted success of tPA to be extended beyond narrow and limiting therapeutic window of 4.5 hours. Clearly, more effective patient selection criteria are required. Penumbral imaging is biologically plausible, practical and has been shown to be predictive of outcome. Application of these imaging techniques to the acute stroke population is the most promising strategy for extending the therapeutic window and for introducing superior thrombolytic agents.
- Tenecteplase (TNK) (0.25 mg/kg, to maximum of 25mg) Drug
Intervention Desc: TNK will be administered within 30 minutes once MRI and CTP inclusion criteria are determined to have been met. ARM 1: Kind: Experimental Label: Tenecteplase
- Allocation: Non-Randomized
- Masking: Open Label
- Purpose: Treatment
- Endpoint: Safety Study
- Intervention: Single Group Assignment
|Type||Measure||Time Frame||Safety Issue|
|Primary||Frequency of symptomatic hemorrhagic transformation evident on MRI or CT||2-5 days post treatment||Yes|
|Secondary||Imaging: Change in volume of hypoperfused tissue at follow up perfusion imaging||At 24 hours follow up perfusion scan||No|
|Secondary||Clinical: Clinical improvement as shown by change in NIHSS||At 24 h, 3, 30 and 90 days||No|