Background and purpose
Pre-hospital stroke scales may help identify patients likely to have large vessel occlusion (LVO) to facilitate rapid triage to thrombectomy-capable stroke centers. Scale misclassification may result in inaccurate decisions and possible harm. Pre-existing leukoaraiosis has been shown to attenuate the association between deficit type and stroke severity. We sought to determine whether leukoaraiosis affects the predictive ability of 5 commonly used LVO scales.
Materials and Methods
We retrospectively analyzed 274 consecutive stroke patients with available brain MRI and vessel imaging. The following LVO scales were used: 3 Item Stroke Scale (3I/SS), Field Assessment Stroke Triage for Emergency Destination (FAST-ED), Rapid Arterial Occlusion Evaluation (RACE), Vision, Aphasia, Neglect (VAN) score, and Cincinnati Pre-hospital Stroke Severity Scale (CPSSS). For diagnostic scale accuracy, we assessed sensitivity, specificity, positive predictive value, negative predictive value, and kappa. Multivariable logistic regression was used to determine the scales' predictive ability after adjustment for leukoaraiosis and potential confounders.
Results
In unadjusted analyses, all scales predicted the presence of LVO (n=46; P<0.01, each); though diagnostic accuracy was attenuated among patients with moderate-to-severe leukoaraiosis. After adjustment, the FAST-ED (OR 3.2 [1.1-9.5]; P=0.033), and RACE (OR 3.7 [1.3-10.8]; P=0.015) but not 3I/SS (OR 5.4 [0.86-33.9]); P=0.073), VAN (OR 2.5 [0.8-7.2]), and CPSSS (OR 2.8 [1.0-8.0]) predicted LVO.
Conclusion
The diagnostic accuracy of the tested LVO scales was attenuated in the presence of moderate-to-severe leukoaraiosis. This information that may aid the design of future studies that require LVO scale screening of patients that are likely to have concomitant leukoaraiosis.