Background: Aortic dilation is an inadequately understood, asymptomatic disease and currently unpredictable with life-threatening major adverse aortic events (MAAE). Today, the method of risk stratification that is used for aortic dilation is the aortic diameter. However, this method remains insufficient due to many patients developing MAAE well before reaching the predicted risk diameters for the specific patient population. Therefore, new diagnostic methods are needed that use a non-size approach, to better risk stratify the patient population to achieve optimal medical and surgical treatment.

Aim: The study aims to investigate the relationship between ascending aortic dilation, and the varying angles formed by the left ventricle and the left ventricular outflow tract. 

Methods: Left ventricle-to-outflow tract angle (LVOA) was retrospectively measured in 113 study participants, 56 cases and 57 matched controls, on cardiac magnetic resonance (MR) images obtained via the Swedish CArdioPulmonary bioImage Study (SCAPIS). The LVOA was compared against the haemodynamic markers obtained via SCAPIS 4D flow MR data, as well as against traditional cardiovascular risk factor data also obtained via SCAPIS.

Results: The study population consisted of mostly male participants (18.6% female) with median age of 59.6 years. Diastolic LVOA was significantly smaller in the cases group (median 120.0° (IQR 11.0°)), compared to the control group (median 124.3° (7.9°)) (p=0.004). Diastolic LVOA correlated significantly with both systolic (r=-0.258 (p=0.007)) and diastolic aortic diameter (r=-0.221 (p=0.020)). Smoking (r=0.186 (p=0.048)) and sex (r=0.374 (p<0.001)) showed to correlate positively with diastolic LVOA, while BSA (r=-0.260 (p=0.005)) had a negative correlation. Diastolic LVOA was shown to be a poor predictor of aortic diameters with no significant association. Haemodynamic parameters had no significant associations with diastolic LVOA. The LVOA generally became smaller with addition of cardiovascular risk factors (p=<0.001).

Conclusion: No associations were found between LVOA and aortic diameters nor between LVOA and haemodynamic parameters.