We 1,hypothesized that patients with a known history of atrial fibrillation (AF) who were not anticoagulated (AF variable) would more frequently have a LVO; 2, determined whether this historical feature performed as well as the LVO scales; 3, determined whether the addition of the AF variable improved the accuracy of the LVO scales. 

We reviewed medical records of patients with AIS admitted to a Comprehensive Stroke Center between 2014-2015. The detection of LVO was compared using univariable analyses for the AF variable, RACE, C-STAT, LAMS, and FAST-ED scores.  The areas under the receiver operating curves (AUCs) were then compared for the AF variable, each score, and each score with the addition of the AF variable.

The sample included 233 patients without and 188 patients with LVO. AF variable (11.3% vs 27.0%, p≤ 0.001), RACE score (mean 2.10±0.15 vs 5.12±0.22, p≤ 0.001), C-STAT score (mean 0.90±0.07 vs 2.21±0.10, p≤ 0.001), LAMS score (1.66±0.11 vs 3.29±0.13, p≤ 0.001) and FAST-ED score (1.88±0.12 vs 4.55±0.18, p≤ 0.001) were each associated with LVO in univariable analysis. The AUCs for FAST-ED (0.792, 95% CI 0.748, 0.836), LAMS (0.746, 95% CI 0.698, 0.794) RACE (0.779,95% CI 0.734, 0.824), C-STAT (0.764,0.719,0.809). The addition of the AF variable did not appreciably change the AUCs.

On comparison of the historic features, the only variable found to have significant association with proximal vessel occlusion was history of AF. No significant difference was found when the AF variable was added to different LVO identification instruments to improve accuracy of EMS identification of LVO.