Relationship between 3-dimensional aortic geometry and the risk of new-onset heart failure

Abstract Introduction Aortic geometric assessments to date have typically involved cross-sectional imaging of discrete aortic segments. However, the complex 3D geometry of the thoracic aorta, and its relationship to the risk of cardiovascular disease has not been assessed in large studies. Methods We segmented the thoracic aorta in SSFP axial MRI images from 49,282 UK Biobank participants using a deep convolutional neural network (U-Net). We then computed geometric measurements (centerline length, arch height, arch width, arch height-width ratio, arch unfolding index [inverse of tortuosity], curvature and mean, minimum and maximum diameters) in the overall thoracic aorta as well as in 6 subsegments. We quantified their relationship to the risk of cardiomyopathy and heart failure (HF) using multivariable Cox-proportional hazards models. All hazard ratios are standardized. Centerline length was allometrically indexed to body height. Results In models adjusted for age, sex, BMI kg/m2, low-density lipoprotein mg/dl, high-density lipoprotein mg/dl, triglycerides mg/dl, systolic blood pressure and diastolic blood pressure, the curvature of the aorta (HR=0.63; 95% CI=0.39, 0.99; P<0.05), particularly the aortic arch (HR=0.54; 95% CI= 0.35, 0.87; P<0.05) was strongly related to a lower risk of incident cardiomyopathy. A higher arch unfolding index (HR=1.46; 95% CI=1.03, 2.07; P<0.05), higher width-to-height ratio (HR=1.10; 95% CI= 1.02, 1.19; P<0.05) and lower aorta tortuosity (HR=1.20; 95% CI= 1.09, 1.32; P<0.05) were all associated with a higher risk of cardiomyopathy. This aortic geometric pattern was also associated with a greater risk of a new HF diagnosis (arch unfolding [HR=1.23; 95% CI= 1.07, 1.42; P<0.05], width to heigh ratio [HR=1.06; 95% CI= 1.01, 1.11; P0.05]). Conclusion We demonstrate that 3-D thoracic aortic geometric indices are strongly associated with incident cardiomyopathy and HF, independent of classic risk factors. This is likely related to abnormal afterload and ventricular-arterial interactions since adverse geometric remodeling affects left ventricular pulsatile load.Cardiomyopathy & Heart Failure Hazards