Effect of multimodal CT angiography/perfusion sequencing on alteplase door-to-needle time

BACKGROUND AND PURPOSE: Multimodal computed tomography angiography and perfusion (CTA/CTP) is increasingly used in the emergency department (ED) evaluation of acute ischemic stroke (AIS) but may delay thrombolysis. We examined whether the sequencing of multimodal CTA/CTP relative to thrombolytic administration affects door-to-needle (DTN) time. METHODS: We conducted a retrospective cohort study of adult patients with AIS treated with intravenous alteplase at a tertiary, academically affiliated ED that is part of a certified Comprehensive Stroke Center between January 1, 2012, and August 1, 2023. All patients underwent an initial noncontrast CT (NCCT), followed by either a contrast-first workflow (i.e. CTA/CTP) or were given alteplase before proceeding to contrast administration. The primary outcome was DTN time, analyzed using univariate methods and multivariable quantile regression adjusting for stroke severity, pre-alteplase antihypertensive use, thrombectomy (as a correlate for large-vessel occlusion), primary language, and bedside ED pharmacist presence. RESULTS: Among 1,382 AIS encounters, 167 patients met inclusion criteria; 148 underwent CTA/CTP before alteplase and 19 received alteplase before contrast administration. Median DTN time was significantly shorter in the alteplase-first group (20 minutes [interquartile range (IQR), 15-26]) compared with the CTA/CTP-first group (44 minutes [IQR, 32-56]; P<0.001). After adjustment, alteplase-first administration remained independently associated with faster DTN time (-25 minutes; 95% CI, -34 to -16). Higher stroke severity and ED pharmacist presence were also associated with shorter DTN, whereas pre-alteplase antihypertensives, primary language, and thrombectomy were not. CONCLUSIONS: A contrast-first strategy incorporating multimodal CTA/CTP before alteplase administration was associated with approximately twofold longer DTN times. These findings suggest that obtaining CTA/CTP before thrombolytic administration may substantially prolong DTN times. Larger studies are needed to confirm the magnitude of this association and to identify patient populations most likely to benefit from alternative imaging workflows.