Background: Early detection of acute stroke with large vessel occlusion (LVO) in both pre-hospital and emergency room settings results in favorable clinical outcomes. There is still no universal guideline for LVO screening.
Method: We proposed that the presence of any of the following signs (Pomona scale): gaze deviation, expressive aphasia or neglect has a high sensitivity and accuracy to predict LVO. We reviewed a historical cohort of all acute stroke activation patients at Pomona Valley Hospital during February 2014 to January 2016. We tested Pomona scale in both groups. The predictive performance of Pomona scale was compared with different NIHSS cutoffs ( ≥4, ≥6, ≥8, ≥10), Los Angeles Motor Scale (LAMS), Cincinnati Prehospital Stroke Severity (CPSS) scale, Vision Aphasia and Neglect scale (VAN) and Prehospital Acute Stroke Severity (PASS) scale.
Results: LVO was detected in 129 of the 777 acute stroke activation (17%). Two hundred and forty-two patients had nonLVO stroke (31%). NIHSS ≥4 and Pomona scale had highest sensitivity (0.99 and 0.98 respectively) to predict LVO. LAM scale had lowest sensitivity (0.68). Pomona scale had moderate accuracy (0.61) which was comparable with VAN (0.66) and PASS (0.67). NIHSS ≥4 had the least accuracy (0.28). When Pomona scale was combined with arm weakness, it had highest accuracy (0.77) and high sensitivity (0.92) to predict LVO in acute ischemic stroke subgroup. Using various NIHSS cut off to screen for LVO had lower accuracy than using other LVO screening tools.
Conclusion: Pomona scale is very sensitive to predict LVO. It may be used as a screening tool for LVO in emergency room setting. Combination of arm weakness and Pomona scale may be used as a Pre-hospital LVO screening with moderately high accuracy.