Medical and endovascular treatment of patients with large vessel occlusion presenting with mild symptoms: an observational multicenter study

Background: A significant proportion of stroke patients presenting with mild symptoms does not have a successful recovery, especially when a large vessel is occluded. IV thrombolysis is safe and may benefit patients presenting with mild symptoms. In this study, we tested whether endovascular therapy (ET) is superior to medical therapy in these patients.

Methods: Observational, prospectively collected, multicenter study of 78 consecutive patients admitted from 2009 to 2012 within 6 h of stroke, with NIHSS≤5 at presentation or during initial diagnostic work-up and large vessel occlusion. Data for patients undergoing ET and/or IV thrombolysis were taken from the SONIIA registry of reperfusion therapies in Catalonia, or from our local stroke registry if no reperfusion therapy was delivered. We compared risk factors, clinical course, collateral circulation, revascularization rates, hemorrhagic complications, infarct volume, and the functional outcome at 3 months of patients treated with ET and those not receiving ET. Ordinal regression was used to assess the independent effect of ET on functional outcome.

Results: Baseline characteristics were similar for ET (n=34) and medically (n=44) treated patients, except for older age in the latter. The occlusions were located in the terminal internal carotid artery (1%), M1 segment of the middle cerebral artery (33%), M2 segment (30%), posterior circulation (31%), and 5% of the patients had tandem lesions, with no significant differences between groups. Most patients in both treatment groups had good collateral flow. The rate of successful revascularization (91.2 vs. 63.4%; p=0.006) and the risk of symptomatic intracranial hemorrhage (11.8 vs. 0%; p=0.033) were higher in the ET group. The NIHSS scores were similar at hospital arrival, after initial neuroimaging, and at 24 h in both treatment groups and there were no significant differences in the infarct volume in a follow-up MRI. At 3 months, 35.9% of the patients had some disability. The functional outcome was similar in both treatment groups in univariate analysis and also in models adjusted for age and initial NIHSS or for variables associated to functional outcome on univariate comparison. Conversely, IV thrombolysis was associated with significantly greater chances of full recovery after adjusting for baseline differences (OR 3.70, p=0.015).

Conclusions: One third of stroke patients with mild symptoms and large vessel occlusions do not have a successful recovery. ET is effective to recanalize the occluded vessel but increases the risk of serious bleeding significantly without improving the functional outcome, and is therefore not justified routinely in these patients.