Abstract Body: Introduction: CTP is used to distinguish core infarct from penumbral tissue in the 6-24 hour time window from last known well time (LKW). In addition, routine use of CTP inside of 6 hours may increase the sensitivity of detecting medium vessel occlusion (MeVO) as compared with CTA alone. Therefore, some centers apply a strategy of using CTP/CTA routinely in the first 6 hours from LKW while others reserve CTP for the 6-24 hour delayed time window. We hypothesized that use of CTP/CTA inside of 6 hours from LKW is associated with increased EVT especially for MeVO.
Methods: This is a retrospective analysis of acute ischemic stroke (AIS) patients from a multi-state stroke registry between Jan 2018 and Mar 2024 who presented within 6 hours of LKW. The incidence of EVT by triage imaging modality (CTA or CTA/CTP) was analyzed overall and also by occlusion location (Large vessel occlusion (LVO), MeVO) through linear mixed models (LMM). Multivariable models were used to adjust for confounding factors. A two-tailed p value of <0.05 was considered statistically significant. Statistical analyses were performed using the statistical software R (version 4.2.3).
Results: Of the 13,778 AIS patients analyzed, 43% were triaged with CTP/CTA and CTA alone was used for 57%. The unadjusted EVT treatment rate was 9.8% in patients triaged with CTA alone and 22% for patients triaged with CTP/CTA. LMMs adjusted for age at diagnosis, sex, race and ethnicity, NIHSS at admit and comorbidities show a higher statistically significant likelihood of receiving EVT in the CTA/CTP triaged patients (OR 1.6, 95%CI 1.3 to 1.8, p <0.001). For LVO, there was no difference in the likelihood of receiving EVT in the CTA/CTP triaged patients (OR 1.3, 95%CI 0.7 to 2.3, p = .4). However, for MeVO there was a higher likelihood of receiving EVT in the CTA/CTP triaged patients (OR 3.2, 95%CI 2.0 to 5.0, p <0.001) (Fig 1)
Conclusions: The results here show that in a large system of stroke hospitals that AIS patients presenting within 6 hours of LKWT who received CTP/CTA were more likely to undergo EVT than those who received CTA alone. This increased utilization of EVT was accounted for by increased EVT for MEVO but not for LVO. The increased utilization of EVT in MEVO may reflect increased sensitivity of detecting MeVO with the addition of CTP. If MEVO EVT treatment proves effective in ongoing randomized clinical trials, our data argue for more routine use of CTP as a “MEVO detector” in the early time window.