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Effect of intravenous thrombolysis on MRI parameters and functional outcome in acute stroke <6 hours
J Röther1, P D Schellinger, A Gass
1Department of Neurology, University Hospital, Hamburg Eppendorf, Germany. roether@uke.uni-hamburg.de
Background And Purpose:
The goals of this study were to examine MRI baseline characteristics of patients with acute ischemic stroke (AIS) and to study the influence of intravenous tissue plasminogen activator (tPA) on MR parameters and functional outcome using a multicenter approach.
Methods:
In this open-label, nonrandomized study of AIS patients with suspected anterior circulation stroke, subjects received a multiparametric stroke MRI protocol (diffusion- and perfusion-weighted imaging and MR angiography) within 6 hours after symptom onset and on follow-up. Patients were treated either with tPA (thrombolysis group) or conservatively (no thrombolysis group). Functional outcome was assessed on day 90 (modified Rankin Score; mRS).
Results:
We enrolled 139 AIS patients (no thrombolysis group, n=63; thrombolysis group, n=76). Patients treated with tPA were more severely affected (National Institutes of Health Stroke Scale score, 10 versus 13; P=0.002). Recanalization rates were higher in the thrombolysis group (Thrombolysis in Myocardial Infarction criteria 1 through 3 on day 1; 66.2% versus 32.7%; P<0.001). Proximal vessel occlusions resulted in larger infarct volumes and worse outcome (P=0.02). Thrombolysis was associated with a better outcome regardless of the time point of tPA treatment (< or =3 hours or 3 to 6 hours) (univariate analysis: mRS < or =2, P=0.017; mRS < or =1, P=0.023). Age (P=0.003), thrombolytic therapy at 0 to 6 hours (P=0.01), recanalization (P=0.016), lesion volume on day 7 (P=0.001), and initial National Institutes of Health Stroke Scale score (P=0.001) affected functional outcome (mRS on day 90) positively (multivariate analysis). The time point of tPA therapy affected the recanalization rate (P=0.024) but not final infarct volume.
Conclusions:
In this pilot study, tPA therapy had a beneficial effect on vessel recanalization and functional outcome. Multiparametric MRI delineates tissue at risk of infarction in AIS patients, which may be helpful for the selection of patients for tPA therapy. tPA therapy appeared safe and effective beyond a 3-hour time window. This study delivers the rationale for a randomized, MR-based tPA trial.
Insights
Intravenous tissue plasminogen activator (tPA) improved vessel recanalization and functional outcomes in acute ischemic stroke (AIS) patients. Multiparametric MRI aids in selecting patients for tPA therapy, showing effectiveness beyond 3 hours.
Area of Science:
- Neurology
- Radiology
- Emergency Medicine
Background:
- Acute ischemic stroke (AIS) management relies on timely reperfusion therapies.
- Magnetic Resonance Imaging (MRI) plays a crucial role in assessing stroke severity and guiding treatment.
- Intravenous tissue plasminogen activator (tPA) is a key thrombolytic agent for AIS.
Purpose of the Study:
- To evaluate baseline MRI characteristics in AIS patients.
- To assess the impact of tPA on MR parameters and functional outcomes.
- To conduct a multicenter investigation of tPA's efficacy in AIS.
Main Methods:
- Open-label, nonrandomized study of 139 AIS patients with anterior circulation stroke.
- Multiparametric stroke MRI (diffusion, perfusion, MR angiography) within 6 hours of symptom onset.
- Comparison between tPA-treated (thrombolysis) and conservatively managed (no thrombolysis) groups; functional outcome assessed by modified Rankin Score (mRS) at 90 days.
Main Results:
- The thrombolysis group (n=76) showed significantly higher recanalization rates (66.2% vs. 32.7%) compared to the no thrombolysis group (n=63).
- tPA treatment was associated with better functional outcomes (mRS ≤ 2 and mRS ≤ 1) regardless of treatment timing (≤3 or 3-6 hours).
- Multivariate analysis identified age, tPA therapy (0-6 hours), recanalization, lesion volume, and initial NIH Stroke Scale score as significant predictors of functional outcome.
Conclusions:
- tPA therapy demonstrated a beneficial effect on vessel recanalization and functional outcomes in AIS patients.
- Multiparametric MRI is valuable for identifying patients who may benefit from tPA therapy.
- tPA therapy appears safe and effective even when administered beyond the traditional 3-hour window, supporting further randomized trials.