Objective: This study aimed to examine the role of a key hemodynamic parameter, namely the true and false lumen pressure difference to predict progressive aortic dilatation following type A aortic dissection (TAAD) repair. Methods: Four surgically repaired TAAD patients with multiple follow-up computed tomography (CT) angiography scans (4-5 scans per patient; N =18) were included. Through-plane diameter of the residual native thoracic aorta was measured in various aortic segments during the follow up period (mean follow up: 49.6±31.2 months;). Computational flow analysis was erformed to estimate true and false lumen pressure difference at the same locations and the correlation with aortic size change was studied using a linear mixed effects model. Results: Higher pressure difference between the true and false lumen was consistent with greater aortic diameter expansion during the follow up period (linear mixed effects analysis; coefficient 0.26, 95% confidence interval 0.15 – 0.37; P < 0.001). Based on our limited data points, a pressure difference higher than 5 mmHg might cause unstable aortic growth. Conclusions: Computational fluid dynamic assessment of standard aortic CT angiography offers a non-invasive technique that predicts the risk of aortic dilatation following TAAD. The technique may be used to plan closer observation or intervention in high-risk patients.
