Abstract WP220: Onset to Needle Times Differ in Patients with Varying Stroke Severity: A Retrospective Review of a National Stroke Audit

Abstract

Introduction: Outcomes following stroke thrombolysis have been observed to be largely dependent on time to treatment. Patients with more severe strokes have more obvious symptoms and are easily diagnosed while patients with milder strokes are often in a grey area where misdiagnosis (particularly as resolving TIA) is common, therefore leading to delayed thrombolysis. Time to treatments are not only influenced by in-hospital factors, but pre-hospital factors as well. Delaying treatment in minor stroke patients might have detrimental effects and diminish chances of good outcome. We wished to examine the effects of stroke severity on onset to needle times (OTN) and door to needle times (DTN) using a national stroke data set. Methods: A retrospective analysis was done on patients who were eligible for and treated with recombinant tissue-type plasminogen activator (rt-PA). Data for all patients in Scotland treated with alteplase between 2010 and 2013 was available from the Scottish Stroke Care Audit (SSCA). Components of the thrombolysis service delivery pathway was compared between minor (NIHSS score of ≤5) and more severe stroke (NIHSS score of ≥6) patients. Results: OTNs and DTNs are both negatively correlated to pre-treatment NIH scores. However, OTN shows greater correlation to pre-treatment NIH scores (r=-0.212 p<001) than did DTN (r=-0.057, p=0.021). Minor stroke patients have longer onset to admission times (105.5 vs. 83 minutes; p<0.001), OTNs (180 vs. 160 minutes; p<0.001), admission to scan times (37 vs. 31 minutes; p=0.004), and were younger (71.22 vs. 74.18 years; p<0.001). Conclusion: This study confirms evidence that minor stroke patients are experiencing delayed thrombolysis, which could reduce the opportunity for benefit for stroke survivors. The reasons for this delay appear to include pre-hospital stroke recognition and response, and also in-hospital patient/clinician decision making as the risks and benefits may be viewed differently in milder strokes. Stroke care guidelines could consider using OTNs as a stroke care standard instead of DTNs in future reviews of management standards.