Aterial stiffness and abdominal obesity are associated with the relaxation abnormality of left ventricle in human hypertension

Abstract

Background and Objectives: Aging is a major factor related to a relaxation abnormality of the left ventricle. Increased arterial stiffness and central distribution of body fat are common physiologic changes observed in the elderly. To further elucidate the relationship between aging and a relaxation abnormality of the left ventricle, we investigate the relationship between the pulse wave velocity, abdominal obesity and diastolic function parameters of the left ventricle. Subjects and Methods: In 490 subjects (153 normotensive, 128 prehypertensive, 120 untreated hypertensive and 89 hypertensive on anti-hypertensive drugs, aged 59.8 ± 12.6 (21-88) years), the brachial-ankle pulse wave velocity (baPWV) and echocardiographic indices for a relaxation abnormality, i.e. transmitral E, A, E/A, DT, IVRT, were measured. A relaxation abnormality was defined by an E/A <1 or a DT >240 ms in the young (<55 years), an E/A <0.8 and a DT >240 ms in the old (<55 years). Subjects with normal relaxation of the left ventricle (group I, n=252) were compared to the subjects with abnormal relaxation of the LV (group II, n=238), with respect to the baPWV and abdominal circumference. Results: In a multiple linear regression analysis, the mean baPWV (cm/sec) was independently correlated with pulse pressure, age, blood pressure, abdominal circumference (AC), body mass index (BMI) and heart rate (R2=0.492, SEE= 261.898). However, neither gender nor the left ventricular mass index (g/m2.7) was associated with the mean baPWV. A logistical regression analysis showed abdominal obesity (AC ≥ 90 cm in male, ≥ 80 cm in female, OR: 2.34), a high baPWV (≥ 1,600 cm/sec, OR: 3.96) and a high BMI (≥ 25 kg/m 2, OR: 0.60) to be independent determinants of a relaxation abnormality. The age adjusted mean baPWV (1526.9 ± 119.4 vs. 1577.1 ± 106.9 cm/sec, p < 0.0001) and AC (86.2 ± 9.8 vs. 88.5 ± 7.7 cm, p=0.005) were higher in group II than group I. Conclusion: Arterial stiffness is the major determinant of a relaxation abnormality of the left ventricle. Abdominal obesity and a high BMI were found to be independent of each other, and an inverse relationship was found with respect to a relaxation abnormality of the left ventricle in a rural Korean population, including hypertensive patients.