Visceral Fat Obesity Contributes to the Tortuosity of the Thoracic Aorta on Chest Radiograph in Poststroke Japanese Patients

Abstract

Tortuosity of the thoracic aorta on chest radiographs is characteristic of atherosclerotic disease. Aging and hypertension are associated with the tortuosity, but little is known about the influence of other atherosclerotic risk factors on this abnormality. The purpose of this study was to examine which atherosclerotic risk factors are determinants for tortuosity of the thoracic aorta. Forty-five poststroke Japanese patients (31 men and 14 women, age range 41-78 years and mean 60.5 ±8.6) were studied. The distance factor, ie, the ratio of meandering vessel length to the straight-line distance between its end points, was used to measure arterial tortuosity. The hospital records were reviewed for clinical and biochemical variables. Tortuosity of the thoracic aorta had a significant positive relationship with body mass index (BMI) ( r =0.397, p<0.01), waist circumference ( r =0.360, p<0.05), and the cardiothoracic ratio (CTR) ( r =0.526, p<0.001), and a significant negative relationship with ankle-brachial pressure index (ABPI) ( r =-0.360, p<0.05). Stepwise regression analysis showed that waist circumference and CTR were independently correlated with increased tortuosity, whereas ABPI was negatively correlated with it. These results suggest that visceral fat obesity is a novel contributor to tortuosity of the thoracic aorta, which may be as a shortening of the distance between aortic tethering points due to elevation of the diaphragm by excessive intraabdominal fat and as a consequence of aortic elongation due to arteriosclerosis caused by obesity-related metabolic disorders.