O-021 Endovascular treatment significantly improves outcomes compared to IV thrombolysis for strokes secondary to large vessel occlusions. 8-year experience
Authors: Rai A , Carpenter J , Roberts T , Rodgers D 
Published: July 2012

Introduction

New thrombectomy devices for acute ischemic stroke (AIS) may allow endovascular therapy (EVT) to gain traction. However for EVT to have a significant impact on stroke it has to demonstrate improved functional outcomes compared to the conclusively proven IV rt-PA (IVT) administration. Literature supports a higher efficacy of EVT for proximal vessel occlusions. The goal of the current undertaking was to compare EVT and IVT for AIS.

Methods

We analyzed our prospectively maintained database of 425 patients for stroke treatments over an almost 8-year period. Only patients with a documented intracranial vascular occlusion in the anterior circulation on the baseline CTA who had undergone either EVT or IVT, but not both were included. A large vessel was defined as either the internal carotid artery terminus (ICA-T), the middle cerebral artery main stem with or without bifurcation involvement (M1) or isolated involvement of the proximal M2 branches (M2). A good clinical outcome was defined as mRS≤2.

Results

225 patients were anayzed (IVT=101, EVT=124). The baseline NIHSS of 16.1(±7.6) was not different between the two groups (p=0.9). Patients in the IVT-group were older (76.2±12.7 years) than the EVT-group (68.1±17.2 years), (p=0.0001). Lower baseline NIHSS (p<0.0001) and younger age (p<0.0001) predicted a good outcome. There was no difference in the percentage of ICA-T occlusions, 23.4% for EVT vs 17.5% for IVT (p=0.3). The EVT group had a significantly larger number of M1-occlusions compared to IVT, 56.5% vs 37.1% respectively (p=0.004) while there were a significantly larger number of M2- occlusions for IVT vs EVT, 45.4% vs 20.2% respectively (p<0.0001). The overall rate of good outcome was 36% while the mortality was 36.9%. Patients who underwent EVT had significantly higher good outcomes, (n=55, 44.4%) as compared to IVT (n=26, 25.7%), (p=0.003, OR 2.3, 95% CI 1.3 to 4.1). There was no difference in mortality between the two groups, 32.3% in EVT vs 42.6% in the IVT (p=0.1). For all occlusion sites, EVT resulted in significantly better outcomes than IVT. For ICA-T occlusions, a good outcome was seen in 27.6% for EVT vs 0% for IVT (p=0.004). For M1 occlusions, good outcome of 40% for EVT vs 10.5% for IVT (p=0.0007, OR-5.7, 95% CI 1.8 to 17.7) and for M2 occlusions, good outcome of 76% for EVT vs 47.8% for IVT (p=0.02, OR 3.4, 95% CI 1.2 to 10.2). A multi-variable logistic regression analysis was performed accounting for all significant predictors in the univariate analysis and especially controlling for the difference in age groups and occlusion-site composition between the two groups. This showed that accounting for all the variables, patients who underwent EV therapy had more than three times the odds of achieving a favorable outcome than those receiving IV thrombolysis (p=0.0007, OR 3.7, 95% CI 1.7 to 8.5).

Conclusion

This large study of over 200 patients concludes that patients presenting with AIS secondary to a large vessel occlusion in the anterior circulation have significantly higher odds of a favorable outcome with EVT as opposed to IVT. Our data supports the rationale of a randomized trial with head-to-head comparison of EV vs IV therapy for large vessel occlusions.

Competing interests

A Rai: Stryker Neurovascular. J Carpenter: Codman Neurovascular, Genetech. T Roberts: None. D Rodgers: None.