ASPECTS decay during inter-facility transfer predicts patient outcomes in endovascular reperfusion for ischemic stroke: a unique assessment of dynamic physiologic change over time

Abstract

Background Pretreatment Alberta Stroke Program Early CT Scores (ASPECTS) is associated with clinical outcomes. The rate of decline between subsequent images, however, may be more predictive of outcomes as it integrates time and physiology. Methods A cohort of patients transferred from six primary stroke centers and treated with intra-arterial therapy (IAT) was retrospectively studied. Absolute ASPECTS decay was defined as ((ASPECTS First CT -ASPECTS Second CT )/hours elapsed between images). A logistic regression model was performed to determine if the rate of ASPECTS decay predicted good outcomes at 90 days (modified Rankin Scale score of 0-2).Results 106 patients with a mean age of 66±14 years and a median National Institutes of Health Stroke Scale score of 19 (IQR 15-23) were analyzed. Median time between initial CT at the outside hospital to repeat CT at our facility was 2.7 h (IQR 2.0-3.6). Patients with good outcomes had lower rates of absolute ASPECTS decay compared with those who did not (0.14±0.23 score/h vs 0.49±0.39 score/h; p<0.001). In multivariable modeling, the absolute rate of ASPECTS decay (OR 0.043; 95% CI 0.004 to 0.471; p=0.01) was a stronger predictor of good patient outcome than static pretreatment ASPECTS obtained before IAT (OR 0.64; 95% CI 0.38 to 1.04; p=0.075). In practical terms, every 1 unit increase in ASPECTS decline per hour correlates with a 23-fold lower probability of a good outcome. Conclusions Patients with faster rates of ASPECTS decay during inter-facility transfers are associated with worse clinical outcomes. This value may reflect the rate of physiological infarct expansion and thus serve as a tool in patient selection for IAT.

Interfacility Transfer Directly to the Neuroangiography Suite in Acute Ischemic Stroke Patients Undergoing Thrombectomy

“…20 Therefore, compared with the ED-IA cohort, our DAN population likely had a lower average posttransfer CT ASPECTS score, as according to prior research, the posttransfer CT ASPECTS likely declined by 1 point from 9 to 8. Despite containing a patient population who likely had a larger baseline infarct compared with the ED-IA population, 19 we found that the rates of symptomatic intracranial hemorrhage, mortality, and functional outcomes were comparable in the 2 cohorts. The presumed discrepancy in baseline ASPECTS scores between the DAN cohort and the ED-IA cohort likely explains the similar favorable outcome rates in the 2 groups, despite faster door-toreperfusion times in the DAN group.…”

“…The mean follow-up infarct volume for the DAN group versus the ED-IA group was comparable (28 mL versus 29 mL; P=0. 19). To understand the impact of DAN triage on outcomes in patients presenting at early time windows, we investigated the outcomes in patients with last seen well to door (LSWD) within 4 hours versus beyond 4 hours.…”

“…However, based on prior studies, it is reasonable to infer that a certain percentage of the patients grew their core during transfer. It has been shown that ASPECTS can decline by 1 point on average during transfer 19 with ≈31% of patients undergoing interfacility transfer converting from an ASPECTS ≥6 to an ASPECTS <6. 20 Therefore, compared with the ED-IA cohort, our DAN population likely had a lower average posttransfer CT ASPECTS score, as according to prior research, the posttransfer CT ASPECTS likely declined by 1 point from 9 to 8.…”

Association Between Time to Reperfusion and Outcome Is Primarily Driven by the Time From Imaging to Reperfusion

“…The positive impact of shortening this initial interval (prehospital and in-hospital pathways) cannot be measured in this group of treated patients, but a reduction in time to CT would likely result in an increase in the number of eligible patients who would benefit from thrombectomy because the earlier the time point from symptoms onset relative to imaging the higher the likelihood of a higher ASPECTS score. 10 The second studied interval, time from CTR did show a clear negative association with the probability of good outcome. Because we adjusted for main known prognosis factors, and we tried to minimize the risk of selection bias by including also patients who could not be recanalized, the interpretation of this relationship as causal is, at least, plausible.…”

Imaging predictors of procedural and clinical outcome in endovascular acute stroke therapy

“…In the original study ASPECTS score of 7 or below demarcated good from poor outcomes [23]. The rate of change of ASPECTS score in patients transferred to a comprehensive stroke center having already undergone a CT scan at an outside hospital is likely a reflection of collateral perfusion and is also predictive of outcome [25].…”