The influence of circadian blood pressure changes on aortic distensibility and left ventricular diastolic function in hypertensive individuals

Failure to decrease blood pressure (BP) normally during nighttime, which is called non-dipper, in hypertensive individuals is associated with higher cardiovascular morbidity and mortality. In addition, non-dipper BP leads to structural changes in the left ventricle; however, the influences of non-dipper BP on aortic elastic properties and left ventricular diastolic function have not been studied yet. In this study, we evaluated aortic elastic properties and left ventricular diastolic function of 22 subjects with non-dipper hypertension, and 15 subjects with dipper hypertension using transthoracic second harmonic standard and tissue Doppler echocardiography (Acuson Sequoia C256). None of the subjects had any systemic disease or coronary risk factor except hypertension. Age, gender, body mass index, lipids, and standard echocardiographic findings including left ventricular mass index were similar between the groups. Office BP recordings were similar between non-dipper and dipper groups (147.9+/-6.1/93.9+/-4.3 vs. 144.0+/-8.0/93.0+/-3.7). Daytime and 24-h ambulatory BP measurements were similar within the groups, but nighttime BPs were significantly greater in non-dipper group than those were in dipper group. Left ventricular diastolic parameters obtained by both standard and tissue Doppler did not differ between the non-dipper and dipper groups. However, aortic distensibility was found to be slightly lower (4.1+/-2.4 vs. 4.9+/-1.9, p=0.08), and aortic stiffness index (6.3+/-0.5 vs. 6.1+/-0.4, p=0.08) and elastic modulus (6.2+/-2.5 vs. 4.8+/-2.3, p=0.08; groups non-dipper and dipper respectively) higher in non-dipper group than in dipper group. However, these differences were not statistically significant. Left ventricular remodeling and diastolic function were similar in patients with non-dipper and dipper hypertension. However, aortic elastic properties were slightly impaired in non-dipper hypertensives than those were in dipper ones, but these differences did not reach statistically significance.