Objective: Many examine patient outcomes following endovascular therapy for acute ischemic stroke, but we wanted to better understand why patients presenting within the window for this therapy did not receive it and their outcomes.
Methods: We retrospectively examined a cohort of 275 patients with a discharge diagnosis of ischemic stroke, NIHSS≥6 and last known normal (LKN) time<6 hours prior to arrival. We determined why patients did not receive endovascular therapy and collected demographics, admission NIHSS, pre-admission modified Rankin scale (mRS), LKN time, decision time for no endovascular therapy, discharge NIHSS, disposition and mRS at follow-up. We used STATA 12.0 for statistical analysis and student’s t-test to compare mean decision time for individual groups of patients to other patients in the cohort.
Results: Reasons patients did not receive intervention were patent major intracranial vessels (32%), no penumbra on CT or MRI (11.7%), large core infarct (16%), low NIHSS or significant improvement (8%), cerebral ischemia not suspected at admission (6.6%), poor baseline (6.2%) and advanced age (4.4%). Mean decision time for patients without penumbra or large core infarcts was not different from other patients in the cohort. Inability to treat patients within 6 hours was associated with a longer decision time (119 minutes longer, CI 54-185, p value =0.0004), but the time increase was due to transfer, not decision time relative to arrival at the tertiary care center. Patients for whom ischemic stroke was not considered at admission were most likely to present with seizure (33%) or posterior circulation symptoms (22%). Patients not receiving endovascular therapy due to mild/improving symptoms had significant deficits at discharge (mean mRS of 3; 18% discharged to a skilled nursing facility; 41% to an acute rehabilitation facility). At 3 months the mean mRS was 2.
Conclusion: The most common reasons patients did not receive endovascular therapy were patent major intracranial vessels, no penumbra and large core infarct. These patients would be unlikely to benefit and might be harmed by intervention. Conversely, patients not treated due to mild/improving symptoms had significant deficits at discharge and 3 months and may have benefited from intervention.