Although increased carotid intima-media thickness (IMT) is a well-known risk factor for stroke, carotid IMT alone is not sufficient for risk stratification. The assessment of arterial properties using velocity vector imaging (VVI) represents a new method for quantifying structural changes. We sought to investigate the characteristics and the clinical value of carotid arterial mechanics using VVI in patients with stroke. Fifty male patients (55 ± 5 years) with stroke, 30 healthy age-matched volunteers (54 ± 8 years), and 30 healthy young male volunteers (29 ± 5 years) were evaluated. The peak circumferential strain, strain rate, and the standard deviation of the time to peak strain and strain rate, representing the synchronicity of the arterial expansion, were analyzed using VVI of the left common carotid artery. The circumferential strain and strain rate significantly decreased with age, and patients with stroke showed the lowest degree of strain and strain rate compared with healthy age-matched volunteers. In addition, patients with stroke showed decreased strain and strain rate even in participants with a normal carotid IMT (< 0.8 mm). Although carotid IMT did not improve the incremental predictive value of stroke over that of multiple clinical risk factors (diabetes mellitus, hypertension, coronary artery disease, smoking), adding carotid arterial strain and strain rate provided an incremental predictive value over both multiple risk factors and carotid IMT for stroke. Along with assessment of conventional risk factors, VVI analysis could provide improved risk stratification for stroke.
Keywords: Carotid artery; Stroke; Ultrasound; Velocity vector imaging.