Effect Of Sex And Agegroup On Pulmonary Artery To Aorta Ratio In Healthy Aging: The Framingham Heart Study

Introduction: An increased ratio of main pulmonary artery (MPA) to ascending aorta (AAo) diameters is associated with excess morbidity and mortality in COPD and pulmonary hypertension. We sought to determine: 1) whether MPA to AAo ratio (MPA:AAo) varies with sex and age in healthy adults; 2) normal upper 90 th percentile (P90) values for MPA:AAo; 3) effect of age on MPA:AAo in the general population. Methods: 1794 adults from the Framingham Heart Study Offspring cohort (65±9 y, 47% men) underwent ECG-gated T2-weighted black blood aortic CMR at 1.5T. MPA and AAo diameters were measured at MPA bifurcation level or the adjacent slice. A referent group free of hypertension, LV focal wall motion abnormality, any history of smoking, asthma, COPD, DVT and obesity was identified and stratified by sex and age group (<55, 55-64, 65-74, ≥75 y). Data are summarized as mean±SD. P90 values were determined from referent participants. We tested for sex differences by 2-sample t test and for within-sex trend across age groups using linear regression. Results: Of the 1794 Offspring, 370 met referent group criteria, among whom men had greater MPA (23.4±2.9 vs 21.3±3.1 mm, p<0.0001) and AAo (31.1±2.9 vs 28.5±3.1 mm, p< 0.0001) diameters than women, but height-indexed AAo/HT (p=0.60) and MPA/HT (p=0.33) were not different between sexes. MPA:AAo did not differ between sexes, men=0.76±0.10, women: 0.75±0.15, p=0.97. P90 values for MPA:AAo were 0.88 (men) and 0.87 (women). MPA:AAo significantly decreased with age in both sexes (see Table) due to increasing AAo; MPA did not vary with age. In the overall population MPA:AAo also decreased with greater age, but here both AAo and MPA tended to increase with advancing age. Conclusions: Among healthy adults free of hypertension, obesity, and common pulmonary risk factors, MPA:AAo ratio does not differ between sexes. In healthy aging MPA:AAo decreases with age in both sexes, due to increased AAo diameters. These patterns are consistent in the general population.