BackgroundArterial stiffness, as measured by pulse wave velocity (PWV) is dependent on arterial blood pressure but whether this dependence varies with age is unknown. The objective of this study was to determine to what degree pressure-dependence varies with age.Methods83 heathy (43 females) normotensive volunteers from three different age groups (young: 18–30, middle aged: 31–55, older: 56–70 years) were recruited for this study. Aortic PWV (aPWV) was measured at different level of aortic transmural pressure (aTMP). aTMP was calculated as difference between mean arterial pressure and mouth pressure (which is almost equal to intrathoracic pressure). Acute modulation of aTMP was achieved by performing respiratory manoeuvres (Valsalva and Muller manoeuvres) against a mouthpiece with a small leak.ResultsaPWV was higher in older compare to younger subjects (6.6 ± 1.4 vs 5.3 ± 0.9 m/s, p < 0.001). Changes of aTMP in response to respiratory manoeuvres were similar across all age groups. However, changes of aPWV induced by acute modulation of aTMP were age-dependent, with aPWV increasing by 1.7 m/s per 10 mmHg increase in aTMP in older subjects compared to 0.4 m/s per 10 mmHg of aTMP change in younger subjects (p < 0.001).ConclusionPressure-dependence of aPWV increases with age. This may contribute to the age related increased in aPWV and, if reversible, have important implications for therapeutic lowering of PWV through anti-hypertensive treatment.

IntroductionDevelopment of carotid and femoral atherosclerotic plaques proved to be heritable in previous studies. However, no comprehensive ultrasonographic evaluation of the volume and types of plaque has been performed.MethodsComprehensive carotid and femoral arterial ultrasound examination (Samsung RS85, arterial analysis, 15 MHz probe) was performed in 92 Hungarian twins (54 monozygotic, MZ and 38 dizygotic, DZ twin pairs, mean age 54 ± 13 years). The volume of plaques was automatically measured, and the plaque type was grouped according to echogenicity. Raw heritability was evaluated using the Falconer formula.ResultsNo heritability of the total number of carotid and femoral plaques and total plaque volume was detected. Although the number of carotid plaques themselves has been found to be hereditary (h2 = 0.492), the volume of carotid and femoral plaques as well as the number of femoral plaques were not heritable. More MZ twin pairs were discordant in the presence of soft plaques in the carotid artery as DZ twin pairs, but greater similarity in femoral plaques was not detected between MZ twins, which does not indicate a genetic background. The presence of calcified and mixed echogenic carotid plaques in the MZ twins was more concordant as in DZ twins, indicating inheritance.ConclusionThe total number and volume of carotid and femoral plaques are influenced by the environment. Different plaque types have different backgrounds: while calcified and mixed echogenic carotid plaques are more affected by genetics, soft carotid and femoral plaques are more affected by the environment.