Abstract 2539: Evaluation of Emergency Department Acute Ischemic Stroke Patients With and Without Blockage on Computed Tomography Angiography

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Background: CT angiography (CTA) provides early assessment of cerebral vasculature in ED patients presenting with Acute Ischemic Stroke (AIS). Prior studies using 4 row detector CT scanners have suggested that results may be used to determine who receives thrombolytics (tPA). We sought to evaluate the rate of normal CTA and the use of tPA in AIS patients with and without blockages using modern CT technology. Methods: We conducted a retrospective cohort study of all code stroke patients presenting to our ED over a 3 year period ending in February 2011. Inclusion criteria included an ED and neurology diagnosis of AIS with a CTA performed at presentation. All patients had a NIHSS score recorded at presentation and underwent imaging using a 64 row detector scanner (Phillips) with 50cc of non-ionic contrast. Demographic, imaging, and clinical data were collected. Modified Rankin Scores (mRS) were assigned at presentation and hospital discharge. Good clinical outcome was defined as a mRS of 0-2. Data are reported as frequencies and medians with interquartile ranges (IQR) as appropriate. Rates of tPA use were evaluated using χ 2 testing. Changes in mRS were evaluated with the paired t-test. Results: A total of 209 subjects met inclusion for analysis of which 104 (50%) were male and 116 (55%) had no blockage on CTA. The median NIHSS score and mortality rates were 14 (IQR 8-19), 14 (15%) with CTA blockage, and 4 (IQR 2-7), 3 (3%) for those without. The use of tPA occurred in 46(50%) with 29 patients receiving intra-arterial therapy, and 14 (12%) patients with and without blockage respectively. Post tPA bleeding occurred in 12 (13%) patients with blockage on CTA and in 0 patients without blockage. Use of tPA was significantly more frequent in patients with a blockage on CTA, P <0.001. As a group, patients without a blockage had a significant decrease in mRS at discharge, however the overall difference was greater in the tPA group, difference = 0.4 (0.2-0.7) P<0.0002 and 1.9 (1.2-2.6) P<0.0001 respectively. Only AIS patients with a blockage and given tPA had a significant reduction of mRS, difference = 0.6 (0.2-1.0) P<0.005 compared with no tPA, difference = -0.1 (-0.4-0.3) P<0.7. Conclusion: More than half of our AIS patients presenting through our ED have no blockage on CTA. Patients with AIS and no blockage on CTA have less severe strokes and are less likely to receive tPA. Both AIS patients with and without a blockage on CTA appear to derive benefit from tPA.