Mechanical stresses, arterial stiffness, and brain small vessel diseases: Shimanami Health Promoting Program Study.

BACKGROUND AND PURPOSE Arterial stiffness, a risk factor of brain small vessel diseases (SVD), causes hemodynamic changes. Mechanical stresses, circumferential wall tension (WT), and shear stress (SS) may change with arterial stiffness and be related to SVD. We investigated the associations between mechanical stresses and arterial stiffness and SVD. METHODS A total of 1296 subjects without apparent cardiovascular diseases were recruited. Brachial-to-ankle pulse wave velocity (baPWV) was measured as an arterial stiffness index. Silent lacunar infarction and deep subcortical white matter hyperintensity were evaluated as SVD indices. Circumferential WT and SS at peak systole and end diastole were measured at the common carotid artery. Second peak of systolic blood pressure was obtained from the radial waveform and used as a central systolic blood pressure substitute. RESULTS baPWV was associated positively with WT (P<0.0001) and negatively with SS (P=0.0007) even after correction for confounding parameters including baPWV. SVD was associated with significantly higher WT (P<0.0001) and lower SS (P<0.0001). After adjustment for confounding parameters (including baPWV), second peak of systolic blood pressure WT (odds ratio, 1.30; P=0.0017) and end diastolic WT (odds ratio, 1.60; P=0.0038) were related to presence of silent lacunar infarction, whereas peak systolic (odds ratio, 0.95; P=0.014) and end diastolic SS (odds ratio, 0.94; P=0.014) were associated with presence of deep subcortical white matter hyperintensity grade >3. Regression lines between blood pressure and WT were significantly steeper in subjects with SVD than without SVD (β=0.02; P<0.0001). CONCLUSIONS These findings indicate that SVD is phenotype-specifically associated with alterations in WT and SS independently of arterial stiffness.