Wave intensity analysis in the internal carotid artery of hypertensive subjects using phase-contrast MR angiography and preliminary assessment of the effect of vessel morphology on wave dynamics.

OBJECTIVE: Hypertension is associated with reduced cerebral blood flow, but it is not known how this impacts on wave dynamics or potentially relates to arterial morphology. Given the location of the internal carotid artery (ICA) and risks associated with invasive measurements, wave dynamics in this artery have not been extensively assessed in vivo. This study explores the feasibility of studying wave dynamics in the internal carotid artery non-invasively. APPROACH: Normotensive, uncontrolled and controlled hypertensive participants were recruited (daytime ambulatory blood pressure <135/85 mmHg and >135/85 mmHg, respectively; n = 38). Wave intensity, reservoir pressure and statistical shape analyses were performed on the right ICA and ascending aorta high-resolution phase-contrast magnetic resonance angiography data. MAIN RESULTS: Wave speed in the aorta was significantly lower in normotensive compared to hypertensive participants (6.7 ± 1.8 versus 11.2 ± 6.2 m s-1 for uncontrolled and 11.8 ± 4.6 m s-1 for controlled hypertensives, p = 0.02), whilst there were no differences in wave speed in the ICA. There were no significant differences between the groups for the wave intensity or reservoir pressure. Interestingly, a significant association between the anatomy of the ICA and wave energy (FCW and size, r 2 = 0.12, p = 0.04) was found. SIGNIFICANCE: This study shows it is feasible to study wave dynamics in the ICA non-invasively. Whilst changes in aortic wave speed confirmed an expected increase in arterial stiffness, this was not observed in the ICA. This might suggest a protective mechanism in the cerebral circulation, in conjunction with the effect of vessel tortuosity. Furthermore, it was observed that ICA shape correlated with wave energy but not wave speed.

The Health and Activity Limitation Survey. Disabled aboriginal persons in Canada.

In 1986, out of a total of 711,725 Canadians of aboriginal ancestry, 86,505 reported having some level of disability. This article profiles disabled aboriginal persons living both on-and off-reserve, presenting data from Statistics Canada's 1986 Census of Population and the Health and Activity Limitation Survey (HALS), conducted in 1986 and 1987. Census data provide an overview of selected demographic and socio-economic characteristics of the disabled aboriginal population. HALS data provide details on the nature and number of disabilities, underlying causes of the disabilities, and the degree of assistance required for daily activities. Accidents were frequently cited as the underlying cause of disability among disabled aboriginal people living both on- and off-reserve. Most disabled original persons aged 15 and older were able to perform household duties such as preparation of meals, shopping and housework. On-reserve disabled aboriginal persons did, however, require and receive help more frequently than those who resided off-reserve.