PULSE WAVE REFLECTION AND GENDER DIFFERENCE IN OBESE INDIVIDUALS

Abstract

Objective: Although obesity is considered a cardiovascular risk factor due to its association with metabolic syndrome, recent studies in obese subjects with heart failure have shown that they have reduced adverse outcomes compared to non-obese individuals. This is consistent with the “obesity paradox”. However, body mass index (BMI) conventionally used to classify obesity, does not distinguish body shape or body fat distribution. This study aimed to explore the association between BMI and/or central obesity parameters and measures of arterial hemodynamics to assess the effect of obesity on function of large arteries. Design and method: Data was obtained from 832 normal individuals and stable patients with regular heart rate attending an outpatient health assessment clinic at Ruijin North Hospital, Shanghai. Subjects were divided into 3 groups according to their Body Mass Index (BMI < 24 normal, 24–28 overweight, > 28 obese; Chinese classification). Radial arterial waveforms and carotid-femoral pulse wave velocity (cfPWV) (SphygmoCor, AtCor Medical, Sydney) were measured with subjects recumbent, and calibrated to brachial cuff systolic (BSP) and diastolic pressure (BDP). Results: Central augmentation pressure (CAP), augmentation index (CAIx, a measure of wave reflection) and pressure amplification were lowest in the obese group (p < 0.001). BSP, CSP and cfPWV were highest in the overweight group, but only in females (p < 0.05). In males, CAP, CAIx and pressure amplification were significantly less as BMI increased (p < 0.05). In both sexes, central obesity measure of weight-to-height ratio (WHtR) was significantly different between BMI classes (p < 0.05). WHtR may be more appropriately correlated with hemodynamic parameters despite remaining differences between sexes (p < 0.05). Conclusions: Obesity in humans is associated with changes in the arterial pressure waveforms that are opposite of those usually described in aging and aortic stiffening. Differences are more obvious in males than females, and features of the “obesity paradox” are apparent when obesity is defined by BMI class only. Further study is warranted to investigate differences of associations between males and females, and effect of central obesity in males and females.