Objectives: The objective of this study was primarily to compare 4D flow magnetic resonance imaging (MRI) metrics in the ascending aorta (AA) of patients with right-left fusion type bicuspid aortic valve (RL-BAV) and repaired 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: 11 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 (FD, %) were analyzed at five pre-defined AA levels. In addition, regional wall shear stress (WSS, mN/m2), circumferential WSS (WSSc), and axial WSS (WSSa) at all levels were quantified in six sectors of the aortic circle. Averaged WSS values on each level (WSSavg, WSSc, avg and WSSa, avg) were calculated as well.

Results: Peak velocity at the proximal tubular AA was significantly lower in BAV and CoA group (p = 0.047) compared to BAV without CoA. In addition, the WSSa, avg was found to be higher for the BAV and CoA group at proximal AA respectively (p = 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. FD 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 4D 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.