Effect of Obesity on Left Ventricular Mass: Results from
320 Multi-Slices Computed Tomography
Sutipong Jongjirasiri MD*, Phanloet Waeosak MD*,
Jiraporn Laothamatas MD *, Chanika Sritara MD*, Supakajee Saengruang-Orn PhD**
Affiliation :
* Department of Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
** Academic Affair Division, Phramongkutklao College of Medicine, Bangkok, Thailand
Objective : To determine effects of obesity and gender on left ventricular mass in normotensive and hypertensive Thai patients
using 320-slice cardiac computed tomography (CT).
Material and Method: Left ventricular mass (LVM) obtained from 320-slice coronary CT angiogram was compared in 597
normotensive subjects (175 men [65 obese] and 422 women [133 obese], aged 55±7 years) and 483 hypertensive patients
(180 men [104 obese] and 303 women [170 obese], aged 60±7 years). Obesity in Asian population was defined by body mass
index (BMI) ≥ 25 kg/m2 in both genders. LV mass was normalized for body surface area (BSA)and height2.7.
Results : The upper normal limit of LVM/ height2.7 developed from 244 (197 women, 47 men) low risk subjects (non-smoking
normal-weight adults free from hypertension, diabetes, coronary artery disease & dyslipidemia) was lower than the estab-
lished criteria for left ventricular hypertrophy (LVH) (31 versus 44 g/m2.7 in women; 36 versus 48 g/m2.7 in men). There is
statistical difference between men and women in all groups of analysis. Among both hypertensive and normotensive subjects,
the prevalence of LVH and LVM/height2.7 are higher in the obese group than normal-weight group in both genders (LVM/
height2.7p<0.001; prevalence of LVH – obese versus normal-weight hypertension: 58% versus 34% in women, 43% versus
14% in men; obese versus normal-weight normotension: 35% versus 16% in women, 40% versus 15% in men). The same
differences between obese and normal-weight groups were also present when normalizing LVM for height but not with
LVM/BSA. Logistic regression analysis revealed that systolic blood pressure and BMI were the main predictors of LVH
in the entire population (p<0.001 in both genders). Equations for predicting LVH in men and women were: Risk of
LVH = 1/(1+e-w) where w is as follows: w (men) = 0.02* systolic pressure + 0.25*BMI – 9.86, w (women) = 0.03* systolic
pressure + 0.17*BMI – 8.82.
Conclusion : Obesity is an independent stimulus to increase LVM in normo-tensive subjects, and its effect is additive in
hypertensive patients. Gender and obesity affect LVM and prevalence of LVH.
Keywords : Left ventricular mass, Computed tomographic angiography, Obesity, Hypertension
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