Predictors of aortic dilation in patients with coarctation of the aorta: evaluation with dual-source computed tomography

Background: Coarctation of aorta (CoA) may progressively develop aortic dilation at other site of the aorta and can lead to fatal aortic diseases. We aimed to evaluate the occurrence of aortic dilation and related predictors in patients with CoA using dual-source computed tomography (DSCT). Methods: Fifty-three patients with CoA identified by DSCT were retrospectively reviewed. Aortic diameters were measured at six different levels and standardized as z-scores based on the square root of body surface area. Coarctation site-diaphragm ratio (CDR) was used to describe the degree of narrowing. A total of 26 patients were included in mild group (CDR > 50%) and 27 in severe group (CDR < 50%) according to the severity of coarctation. Student's t-test and Spearman correlation coefficients, univariate and multivariable logistic regression analyses were used to assess the risk factors including age, degree of narrowing and other malformations for aortic dilation. Results: Severe group had significantly larger z-scores of ascending aorta (2.41 +/- 0.39 vs. 2.10 +/- 0.57, p < 0.05) and post-coarctation aorta (2.17 +/- 0.48 vs. 1.68 +/- 0.43, p < 0.001) compared with mild group. Degree of coarctation was associated with the z-scores of the ascending aorta (r = -0.356, p < 0.05) and post-coarctation aorta (r = -0.414, p < 0.05). Collateral circulation was related to the z-scores of ascending aorta (r = 0.375, p < 0.05). Increased severity of coarctation was independent predictor of ascending (odds ratio 7.46; 95% CI 1.19-46.76; p < 0.05) and post-coarctation aortic dilation(odds ratio 8.42; 95% CI 1.84-38.56; p < 0.05). Conclusions: Ascending and post-coarctation aortic diameters or dilations were both associated with the degree of coarctation. By comprehensively evaluating the aortic diameters and associated malformations including collateral circulation, DSCT can aid in stratification of risk for aortic dilation in patients with CoA.