The New FA₂ST Stroke Screening Score: An Expanding Recognition to Posterior Circulation Stroke

Abstract

Background: Rapid screening and intervention are the keys to successful early treatment of stroke. Generally, the conventional FAST stroke screening score has been used by triage nurses to promptly detect acute stroke. However, the conventional FAST score has a limitation in detecting posterior circulation stroke, which results in high mortality rates. Previous studies have shown that adding ataxia could increase the sensitivity of posterior circulation stroke detection. Objective: To introduce and evaluate the diagnostic performance of a new stroke screening score, FA₂ST score, by adding ataxia to the conventional FAST score. Materials and Methods: The present study was a cross-sectional study. The new FA₂ST and conventional FAST scores were used by triage nurses in patients presented with acute neurological symptoms within seven days at the emergency department of three different types of hospitals in Thailand. Patients with Glasgow Coma Score less than 9 and those having unstable vital signs were excluded. Final diagnosis was made by a neurologist using clinical and neuroimaging information. The diagnostic performance of the new FA₂ST score was calculated using ROC curve in comparison to the conventional FAST score. The rate of posterior circulation stroke detection was calculated as percentage. Results: One hundred forty-six patients were studied. Of these, 127 (86%) had acute ischemic stroke and 19 (14%) had other diagnoses. The overall diagnostic performance of the new FA₂ST score was not statistically different with conventional FAST score in terms of area under the curve (0.642 versus 0.684, p=0.221). However, after in-depth analysis, the rate of posterior circulation stroke detection of the new FA₂ST score was higher compared with the conventional FAST score (94.12% versus 82.35%). Conclusion: The present study introduces the new FA₂ST stroke screening score and emphasizes the importance of posterior circulation stroke detection in acute stroke screening. Future studies should be considered before implementation of this score. Keywords: Screening score; Acute stroke treatment; Stroke; Emergency neurology