Abstract 277: The Relationship Between Aortic And PA Diameter Among Individuals With Genetic Conditions Of The Thoracic Aorta: A Report From The NIH Gentac Registry

Abstract

Background The aorta and pulmonary artery (PA) share structural similarities, and thus genetic conditions affecting the thoracic aorta may also affect the PA. We evaluated the relationship between aortic and pulmonary artery dimensions on chest CT among a subset of participants in the Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions Registry (GenTAC). Methods Data Adults in GenTAC without a history of aortic surgery or aortic dissection (N = 144) and with computed tomography of the chest were included. Standardized double oblique measurements of the pulmonary artery, and thoracic aortic dimensions at 8 sites (sinus of Valsalva through the suprarenal aorta) were measured in a core laboratory. The relationship between the PA and aortic dimensions were analyzed using bivariate correlations, and multivariable linear regression controlling for age and body size. Results Mean age was 45±13 years. The mean maximum ascending aortic dimension was 3.8±0.9 cm (range 2.4-7.9 cm); mean PA dimension was 3.1±0.5 cm (1.8-4.8 cm). Using a cutoff of 2.8 cm defining the 90 th percentile value for PA diameter, 65% of the study population had dilated PA. Correlations between the aortic and pulmonary artery diameter were higher for the descending aorta than the ascending aorta. The highest observed correlation between PA and aortic diameter was observed for the thoracoabdominal aorta at the level of the diaphragm (r = 0.40; P <0.001). In a linear regression model evaluating relationships between PA diameter and various aortic segments, after controlling for age and body size, the PA and descending thoracic aorta were independently related (partial correlation r = 0.28; P<0.001). Similar relationships were not observed for the ascending aorta. Conclusions A dilated PA is common among individuals with genetically-associate thoracic aortic dilatation. The diameter of the PA relates modestly to aortic dimensions, most strongly with the descending thoracic aorta.