Pulmonary artery to aorta ratio and risk of all-cause mortality in the general population: the Rotterdam Study

A pulmonary artery to aorta ratio (PA: A) >1 is a proxy of pulmonary hypertension. It is not known whether this measure carries prognostic information in the general population and in individuals with chronic obstructive pulmonary disease (COPD). Between 2003 and 2006, 2197 participants from the population-based Rotterdam Study (mean +/- SD age 69.7 +/- 6.7 years; 51.3% female), underwent cardiac computed tomography (CT) scanning with PA: A quantification, defined as the ratio between the diameters of the pulmonary artery and the aorta. COPD was diagnosed based on spirometry or clinical presentation and obstructive lung function measured by a treating physician. Cox regression was used to investigate the risk of mortality. We observed no association between 1-SD increase of PA: A and mortality in the general population. Larger PA: A was associated with an increased risk of mortality in individuals with COPD, particularly in moderate-to-severe COPD (hazard ratio 1.36, 95% CI 1.03-1.79). We demonstrated that the risk of mortality in COPD was driven by severe COPD, and that this risk increased with decreasing diffusing capacity. Larger PA: A is not associated with mortality in an older general population, but is an independent determinant of mortality in moderate-to-severe COPD. Measuring PA: A in CT scans obtained for other indications may yield important prognostic information in individuals with COPD.