Morphological predictor of remodelling of the descending thoracic aortic false lumen that remains patent after repair of acute type A dissection

OBJECTIVES: Some patients achieve complete recovery through false lumen remodelling in the descending aorta after surgery for acute type A aortic dissection. Our goal was to investigate the relationship between false lumen remodelling during later postoperative stages and quantitative analysis of the true lumen shape during the early postoperative stages. METHODS: We examined 88 surgical patients between January 2007 and December 2016. Three points of the descending aorta were assessed from the 6th (T6), the 9th (T9) and the 11th (T11) vertebral levels. The shape of the true lumen was evaluated during the early postoperative stages, and false lumen remodelling 1 year after surgery was the end point. The parameters obtained by evaluating the shape of the true lumen comprised the first principal component analysis using elliptic Fourier analysis, the minor diameter ratio and the ratio of the area of the true lumen to that of the descending aorta, and the number of contact points on the true lumen wall during the early stages. RESULTS: Using univariate analysis, we detected significant differences in the first principal components, the minor diameter ratio, the area ratio and the number of contact points at each thoracic vertebral level (P < 0.05). The cut-off value of the minor diameter ratio was 0.55, and the area ratio was 0.48 as determined by analysis of the receiver operating characteristic. Multivariable logistic analysis indicated that the first principal component was the most significant predictor from the proximal to the middle descending aorta. CONCLUSIONS: Quantitative evaluation of shape of the true lumen in the early postoperative stages after surgery for acute type A dissection can serve as a viable predictor for false lumen remodelling in later stages. Furthermore, the first principal component could serve as a more astute predictor than other quantitative parameters according to multivariate analysis.