Aortic elastic-properties in offspring of hypertensive patients

ABSTRACT

The main objective of this study is to detect the changes might affect the elastic properties of large central arteries in normotensive offspring of known hypertensive parents, and to compare these changes to normal age-matched offspring of normal individuals. Also, to correlate age and gender effects on the results obtained. Arterial stiffening is associated with a number of known cardiovascular disease risk factors, raising the possibility that increased arterial stiffness may be a marker for advanced atherosclerotic vascular disease. The vascular dynamics of children with a parental history of hypertension is a cornerstone of early detection of functional and morphologic abnormalities of the arterial wall that may be responsible for many cardiovascular and cerebro-vascular complications in their future life. The study includes sixty subjects [ages 15-30 years], all were clinically healthy by applying exclusion criteria, full history and clinical examination. They are divided based on their family history of hypertension into two groups, group-I 30 offspring with a parental history of hypertension and group-Il 30 off-spring of normotensive parents. All subjects were evaluated to obtain systolic, diastolic and pulse pressure readings then, M-mode echocardiography is done to study their aortic elastic properties. After collection of both clinical [blood-pressure] and Echocardiographic data, analyses of the results revealed a significant elevation of all blood pressure parameters in group-I than group-Il with systolic Bp of mean +/- SD [118.5 +/- 9.7 in group-I versus 106 +/- 4.9 mmhg in group-Il], diastolic Bp [66.8 +/- 5.7 for group-I versus 62.8 +/- 8.0 mmhg in group-II] and a net increase in pulse pressure in group-I than group-Il [51.6 +/- 10.5 versus 43.1 +/- 6.2]. Comparing aortic diameters of two groups revealed that, a non-significant increase in systolic diameter in group-I [p=non-significant], significant increased diastolic diameter in group-I with mean +/- SD [29.8 +/- 2.3 versus 28.0 +/- 1.3 mm in group-II, p=0.01]. Group-Il subjects exhibit an increased Ao-diameter change property with mean +/- SD [3.7 +/- 0.4 versus [2.6 +/- 0.5 mm in group-I] reflecting impression of enhanced their aortic elastic feature. Comparing aortic stiffness parameters in between the two groups revealed a significant [p=0.001] difference in all parameters. Group-I showed decreased aortic strain, decreased distensibility and increased aortic stiffness in relation to group-II with Ao-strain of mean +/- SD [8.9 +/- 1.8 in group I versus 13.4 +/- 1.6 for group-II], Ao-distensibility [3.1 +/- 0.8 in group-I versus 5.0 +/- 1.1 cm2 dyne-1 in group-Il], and Ao-stiffness is [0.21 +/- 0.02 in group-I versus 0. 12 +/- 0.02] in group-Il. In a trial to study the effect of blood pressure on aortic stiffness, It was found that, systolic blood pressure is positively correlated to increased aortic stiffness, with p-value of 0.001 and coeffIcient correlation r 0.66 and is negatively correlated to both aortic strain and distensibility [p value 0.001, r - 0.61 and p 0.001 and r - 0.57] respectively. Correlation made to study the effect of age and gender on Ao elastic properties revealed that, there's a positive age related increased aortic stiffness [p value = 0.02, r 0.28] and a negative correlation to aortic distensibility [p = 0.01, r - 0.32]. Detection of the effect of gender variation on the results was obvious in group-I as males were found to have a significantly [p=0.001] higher Ao stiffness than females with mean +/- SD [0.20 +/- 0.002] in males versus [0.14 +/- 002] in females. Females are found to have a significant higher aortic strain and distensibility [p=0.001 for strain and 0.03 for distensibility] with mean +/- SD Ao strain [12.2 +/- 2.3 for females and 9.7 +/- 2.9 for males], however, Ao distensibility was [4.4 +/- 0.9 for females and 3.6 +/- 1.7 for males]. Group-I was found to have a higher PP and less change in Ao diameters between systole and diastole, and this is reflected on increased Ao stiffness parameters in their results with lower distensibility and strain. Age is found to be highly correlated to increased Ao stiffness and decreased distensibility. Also, males possessing a higher than females Ao stiffness results: