Obesity and right ventricular structure and function: the MESA-Right Ventricle Study

Abstract

Background: The relationship between obesity and right ventricular (RV) morphology is not well studied. We aimed to determine the association between obesity and RV structure and function in a large multiethnic population-based cohort.

Methods: The MESA-Right Ventricle Study measured RV mass and volumes by cardiac MRI in participants aged 45 to 84 years without clinical cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis (MESA). Participants were divided into three categories based on BMI: lean ( ≤ 24.9 kg/m(2)), overweight (25-29.9 kg/m(2)), and obese ( ≥ 30 kg/m(2)).

Results: The study sample included 4,127 participants. After adjustment for demographics, height, education, and cardiovascular risk factors, overweight and obese participants had greater RV mass (6% and 9% greater, respectively), larger RV end-diastolic volume (8% and 18% greater, respectively), larger RV stroke volume (7% and 16% greater, respectively), and lower RV ejection fraction ( ≥ 1% lower) than lean participants (all P < .001). These findings persisted after adjusting for the respective left ventricular (LV) parameters.

Conclusions: Overweight and obesity were independently associated with differences in RV morphology even after adjustment for the respective LV measure. This association could be explained by increased RV afterload, increased blood volume, hormonal effects, or direct obesity-related myocardial effects.

Figures

Figure 1.

Study population. LV = left ventricle; MESA = Multi-Ethnic Study of Atherosclerosis; RV = right ventricle.

Figure 2.

Scatterplot and running line smoother (solid line) with 95% CI (dashed lines) of the association between BMI and RV mass after adjusting for age, sex, race/ethnicity, height, education, systolic BP, cigarette smoking, pack-years, total cholesterol, diabetes and impaired fasting glucose, antihypertensive medication, and lipid-lowering medication (P < .001). See Figure 1 legend for expansion of abbreviation.

Figure 3.

Generalized additive model of the association between BMI and standardized RV mass (black line) and 95% CI (dashed lines) after adjusting for age, sex, race/ethnicity, height, education, systolic BP, cigarette smoking, pack-years, total cholesterol, diabetes and impaired fasting glucose, antihypertensive medication, lipid-lowering medication, and right ventricular end-diastolic volume (P for nonlinearity = .03). For comparison, the association between BMI and standardized LV mass (gray line) after adjusting for age, sex, race/ethnicity, height, education, systolic BP, cigarette smoking, pack-years, total cholesterol, diabetes and impaired fasting glucose, antihypertensive medication, lipid-lowering medication, and LV end-diastolic volume is shown (P for nonlinearity < .001). A proportional increase in ventricular mass and end-diastolic volumes with increasing BMI should appear as a horizontal line. See Figure 1 legend for expansion of abbreviations.