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Although the clinical relevance of arterial stiffness is increasingly recognized, the applicability of arterial stiffness for individual cardiovascular risk assessment is hampered due to technical and physiological difficulties. Arterial stiffness is not constant with blood pressure and not constant over the arterial tree. Currently, stiffness is commonly assessed in individuals over a long trajectory and neglects the pressure dependency. To circumvent these problems, we developed a technique to measure pulse wave velocity (PWV) locally using multiple M-line ultrasound. In the common carotid artery, PWV can only be measured using the dicrotic notch of the distension waveform as fiducial time-point, because the systolic foot is subjected to reflective interference. Dicrotic notch PWV provides a measure of stiffness at near systolic pressure level, which is intrinsically different from systolic foot PWV measured at diastolic pressure. To investigate the effect of pressure on local stiffness, we quantified carotid distensibility coefficients for the diastolic and systolic pressure ranges separately. We found that the diastolic-systolic difference in carotid distensibility varies significantly between individuals and is an independent determinant of left ventricular mass index. Moreover, this pressure dependency appears to increase with age (like arterial diameter), suggesting that this property could be used as a marker for structural remodeling of the artery wall. Biomechanically, the pressure dependency of stiffness directly affects pressure and flow waveform characteristics and their phase relation. Ignoring this may lead to overestimation of the impact of wave reflections on central blood pressure. Our work shows that pressure dependency of arterial stiffness can and should be accounted for to evaluate its implication for pressure augmentation and wave separation analysis.

Background and aims There is increasing evidence linking arterial (mainly aortic) stiffness and type 2 diabetes, a risk factor for arterial stiffness, to cognitive impairment and dementia. However, data on carotid stiffness, which may be especially relevant for cognitive performance, are scarce, and few studies have addressed the interplay between arterial stiffness, type 2 diabetes, and cognitive performance. Methods We studied individuals with (n = 197) and without (n = 528) type 2 diabetes, who completed a neuropsychological test battery and underwent applanation tonometry and vascular ultrasound to evaluate aortic (i.e. carotid-to-femoral pulse wave velocity) and carotid stiffness (i.e. distensibility, compliance and Young's elastic modulus). Linear regression analyses were performed and adjusted for demographics, vascular risk factors, and depression. Results Overall, our results showed that carotid, but not aortic, stiffness was associated with worse cognitive performance, primarily in the domains of processing speed (standardized regression coefficient for distensibility −0.083, p = 0.040; compliance −0.077, p = 0.032) and executive function and attention (distensibility −0.133, p = 0.001; compliance −0.090, p = 0.015; Young's elastic modulus −0.081, p = 0.027). These associations did not differ by diabetes status. The differences in cognitive performance between individuals with and without type 2 diabetes (mean difference in domain scores relative to those without diabetes for free recall memory −0.23, processing speed −0.19, executive function and attention −0.23; all p ≤ 0.009 and adjusted for demographics, traditional vascular risk factors, and depression) were not substantially altered after additional adjustment for carotid stiffness. Conclusions Our findings suggest that carotid stiffness is associated with cognitive performance in both individuals with and without diabetes, but does not mediate the relationship between type 2 diabetes and cognitive dysfunction.

A recent article ([1][1]) published in the Journal corroborates the hypothesis that shear stress triggers fibrous cap rupture. In 20 patients with considerable lumen narrowing (maximum area reduction of 80 ± 7%), ulcerative plaque rupture preferentially occurred in areas with locally high wall