Reliability and agreement of point-of-care carotid artery examinations by experts using hand-held ultrasound devices in patients with ischaemic stroke or transitory ischaemic attack

OBJECTIVES: To investigate the reliability and agreement of hand-held ultrasound devices (HUDs) compared with conventional duplex ultrasound (HIGH) in examination for carotid stenosis in patients with suspected transitory ischaemic attack (TIA) or ischaemic stroke. METHODS: Cardiologists, experienced in carotid ultrasound, examined patients admitted to a community hospital with suspected stroke or TIA. Patients were first examined by an HUD and second by HIGH as per usual care. Different operators performed HUD and HIGH blinded to each other. On clinical discretion, CT angiography (CTA) was performed, and analysed by a radiologist blinded to the results from the ultrasound. RESULTS: Of 80 patients included, 9 (11%) were found to have >50% internal carotid artery (ICA) stenosis on reference examination. Agreement for classification of the degree of ICA stenosis was good for HUD versus HIGH (weighted Kappa 0.76) and HUD versus CTA (weighted Kappa 0.66). Agreement between HUD and HIGH examinations was excellent when ICA was classified as <50% diameter stenosis by HUD (99% agreement), but significantly lower when ICA diameter stenosis was classified as >50% by HUD (OR 0.15, 95% CI 0.06 to 0.42). Overall, HUD tended to overestimate the degree of carotid stenoses rather than underestimate (p=0.048). CONCLUSION: Hand-held carotid ultrasound performed by experts demonstrated good agreement with conventional duplex ultrasound. The use of HUDs was reliable for ruling out significant carotid artery disease, but less reliable for ruling in significant disease.