Severe chronic obstructive pulmonary disease can lead to cor pulmonale and emphysema and is associated with impaired left ventricular (LV) filling. We evaluated whether emphysema and airflow obstruction would be associated with changes in right ventricular (RV) structure and function and whether these associations would differ by smoking status.
The Multi-Ethnic Study of Atherosclerosis (MESA) performed cardiac magnetic resonance imaging on 5098 participants aged 45-84 years without clinical cardiovascular disease. RV and emphysema measures were available for 4188 participants. Percent emphysema was defined as the percentage of voxels below -910 Hounsfield units in the lung windows on cardiac CT scans. Generalized additive models were used to control for confounders and adjust for respective LV parameters.
Participants were 13% current smokers, 36% former smokers and 52% never smokers. Percent emphysema was inversely associated with RV end-diastolic volume, stroke volume, cardiac output and mass prior to adjustment for LV measures. After adjustment for LV end-diastolic volume, greater percent emphysema was associated with greater RV end-diastolic volume (+1.5 ml; P=0.03) among current smokers, smaller RV end-diastolic volume (-0.8 ml; P=0.02) in former smokers and similar changes among never smokers.
Percent emphysema was associated with smaller RV volumes and lower mass. The relationship of emphysema to cardiac function is complex but likely involves increased pulmonary vascular resistance predominantly with reduced cardiac output, pulmonary hyperinflation, and accelerated cardiopulmonary aging.