Evaluation of the Maximum Velocity of Blood Flow in Descending Aorta in Athletes

Background/Objectives: Athletes are characterized by distinct haemodynamic adaptations of the cardiovascular system, including descending aorta haemodynamics, that could influence the diagnosis of coarctation of the aorta. This study aims to evaluate the normal range for the maximum velocity of blood flow in the descending aorta (Vmax-AoDesc) and the predictors of Vmax-AoDesc in apparently healthy athletes without coarctation of the aorta. Methods: We examined 559 asymptomatic healthy athletes with an age of at least 12 years and a tricuspid aortic valve (420 males, age: 29 ± 14 years). We performed evaluations of athletic history, measurements of brachial systolic and diastolic blood pressure, cardiac and aorta ultrasonography and cardiopulmonary exercise testing. Forty athletes were reassessed after a median follow-up of 3.0 (IQR: 2.1) years. Results: The median Vmax-AoDesc was 1.29 (IQR: 0.28) m/s, with a maximum of 2.00 m/s. The Vmax-AoDesc could be independently predicted by age (β = -0.392, p < 0.001), ratio of systole/diastole (β = 0.095, p = 0.023), brachial systolic blood pressure (β = 0.251, p < 0.001), left ventricular stroke volume (β = 0.256, p < 0.001), ascending aorta diameter (β = -0.230, p < 0.001), aortic arch diameter (β = -0.111, p = 0.044) and descending aorta diameter (β = -0.103, p = 0.017). Age accounted for the greatest variability of Vmax-AoDesc (5.8%). Vmax-AoDesc correlated positively with h/week of endurance exercise training (rho = 0.182, p < 0.001) and oxygen uptake at second ventilatory threshold (rho = 0.299, p = 0.001). Vmax-AoDesc did not change significantly during follow-up (p = 0.438). The median change in Vmax-AoDesc was -0.05 (IQR: 0.18) m/s. However, when Vmax-AoDesc was adjusted for all the above-mentioned independent predictors of Vmax-AoDesc apart from age and systolic blood pressure, there was a reduction in adjusted Vmax-AoDesc during follow-up (p = 0.007), indicating a reduction in Vmax-AoDesc with aging. Conclusions: The upper limit of the normal range for Vmax-AoDesc was 2.00 m/s in athletes without coarctation of the aorta. Young age was the most important predictor for the measurement of high Vmax-AoDesc. There was an upregulation of Vmax-AoDesc in athletes with a greater volume of endurance exercise training.