Large Vessel Occlusion

Large vessel occlusion, or LVO, is one of the most serious forms of ischemic stroke. It occurs when a major artery supplying the brain becomes blocked, sharply reducing blood flow and oxygen delivery to brain tissue. Because these blockages can affect large areas of the brain, LVO strokes are associated with a higher risk of severe disability, loss of independence, and death when treatment is delayed.

LVO represents a substantial portion of ischemic stroke cases, although estimates vary depending on how LVO is defined and how patients are screened. Published estimates suggest that LVO may account for roughly 10%–20% of ischemic strokes globally, while other reviews report higher estimates in selected acute ischemic stroke populations. Population-based studies have estimated LVO incidence at approximately 22–24 cases per 100,000 people per year. (PubMed)

LVO primarily affects older adults, reflecting the broader age distribution of stroke. In one population-based study of acute ischemic stroke, patients with ischemic stroke had a mean age of 76 years, and slightly more than half were women. However, LVO can occur across adult age groups, including younger adults, particularly in the presence of risk factors such as atrial fibrillation, hypertension, diabetes, smoking, high cholesterol, and other cardiovascular conditions. (Frontiers)

The impact of LVO is especially significant because many patients may benefit from mechanical thrombectomy, a specialized procedure that removes the clot and restores blood flow. Thrombectomy is typically available only at comprehensive or thrombectomy-capable stroke centers. When LVO is recognized early, emergency teams can make better routing decisions and help patients reach the right hospital faster.

Every minute matters in LVO stroke care. Faster detection and transport can reduce delays to treatment, preserve more brain tissue, and improve the chance of recovery. Better tools for identifying LVO in the field have the potential to transform stroke triage—helping emergency responders move from suspected stroke to the right care pathway with greater confidence.

A clinical study published in the Journal of NeuroInterventional Surgery evaluated whether the Openwater portable optical blood flow monitor could help detect large vessel occlusion (LVO) in patients with suspected stroke. LVO is one of the most serious forms of ischemic stroke and often requires rapid treatment at a thrombectomy-capable or comprehensive stroke center. Because treatment outcomes are highly time-sensitive, earlier identification of LVO may help emergency teams route patients to the right level of care more quickly.

The study enrolled 135 patients undergoing acute stroke evaluation at two comprehensive stroke centers. Each patient received a 70-second bedside scan using the Openwater optical blood flow monitor, a wearable headset that measures cerebral blood flow waveforms from the forehead using speckle contrast-based optical sensing. These waveforms were then analyzed with a deep learning model to classify patients as having a high or low likelihood of LVO.

The Openwater system demonstrated strong diagnostic performance, detecting LVO with 79% sensitivity and 84% specificity. In the study, it outperformed commonly used prehospital stroke severity scales, including RACE and LAMS, which had lower sensitivity for identifying LVO. The Openwater classification achieved an AUROC of 0.82, compared with 0.70 for RACE and 0.65 for LAMS.

These findings suggest that direct, non-invasive measurement of cerebral blood flow may offer a promising new approach for stroke triage. By helping identify patients with a high likelihood of LVO, portable optical monitoring could support faster routing decisions, reduce delays to thrombectomy, and improve the chances that patients receive the right care at the right facility.

The authors note that these results are encouraging but require further validation in an independent test set and in real-world prehospital environments. If confirmed, the Openwater optical blood flow monitor could become an important tool for emergency stroke assessment and patient routing.

Favilla, C. G., Baird, G. L., Grama, K., Konecky, S., Carter, S., Smith, W., Gitlevich, R., Lebron-Cruz, A., Yodh, A. G., & McTaggart, R. A. (2024). Portable cerebral blood flow monitor to detect large vessel occlusion in patients with suspected stroke. Journal of NeuroInterventional Surgery. Advance online publication. https://doi.org/10.1136/jnis-2024-021536

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