Excess of visceral adipose tissue with or without aortic elongation leads to a steeper heart position.

Abstract

The heart's position determined as the heart-aorta angle (HAA) has been demonstrated to associate with ascending aortic (AA) dilatation. Visceral adipose tissue (VAT) and aortic elongation may shift the heart to the steeper position. To investigate whether VAT and aortic length influence the HAA. We examined 346 consecutive patients (58.4% men; mean age = 67.0 ± 14.1 years) who underwent aortic computed tomography angiography (CTA). HAA was measured as the angle between the long axis of the heart and AA midline. The amount of VAT was measured at the level of middle L4 vertebra from a single axial CT slice. Aortic length was measured by combining four anatomical segments in different CTA images. The amount of VAT and aortic length were determined as mild with values in the lowest quartile and as excessive with values in the other three quartiles. A total of 191 patients (55.2%) had no history of aortic diseases, 134 (38.7%) displayed AA dilatation, 8 (2.3%) had abdominal aortic aneurysm (AAA), and 13 (3.8%) had both AA dilatation and AAA. There was a strong nonlinear regression between smaller HAA and VAT/height, and HAA and aortic length/height. Median HAA was 124.2° (interquartile range 119.0°-130.8°) in patients with a mild amount of VAT versus 120.5° (interquartile range 115.4°-124.7°) in patients with excessive VAT (P < 0.001). An excessive amount of VAT and aortic elongation led to a steeper heart position. These aspects may possess clinical value when evaluating aortic diseases in obese patients.