Repaired coarctation of the aorta does not affect four-dimensional flow metrics in bicuspid aortic valve disease

OBJECTIVES: The objective of this study was primarily to compare four-dimensional flow magnetic resonance imaging metrics in the ascending aorta (AA) of patients with right–left fusion type bicuspid aortic valve (RL-BAV) and repaired coarctation of the aorta (CoA) to RL-BAV without CoA. Metrics of patients with RL-BAV were also compared to the matched group of patients with common tricuspid aortic valve (TAV). METHODS: Eleven patients with RL-BAV and CoA, 11 patients with RL-BAV without CoA and 22 controls with TAV were investigated. Peak velocity (cm/s), peak flow (ml/s) and flow displacement (%) were analysed at 5 pre-defined AA levels. In addition, regional wall shear stress (WSS, mN/m²), circumferential WSS (WSS_c) and axial WSS (WSS_a) at all levels were quantified in 6 sectors of the aortic circle. Averaged WSS values on each level (WSS_avg, WSS_{c, avg} and WSS_{a, avg}) were calculated as well. RESULTS: Peak velocity at the proximal tubular AA was significantly lower in BAV and CoA group (P ¼ 0.047) compared to BAV without CoA. In addition, the WSS_{a, avg} was found to be higher for the BAV and CoA group at proximal AA respectively (P ¼ 0.040). No other significant differences were found between these groups. BAV group’s peak velocity was higher at every level (P < 0.001–0.004) compared to TAV group. Flow displacement was significantly higher for the BAV group at every level (P < 0.001) besides at the most distal level. All averaged WSS values were significantly higher in BAV patients in distal AA (P < 0.001–0.018). CONCLUSIONS: Repaired CoA does not relevantly alter four-dimensional flow metrics in the AA of patients with RL-BAV. However, RL-BAV majorly alters flow dynamics in the AA when compared to patients with TAV.