Abstract 18067: Maladaptive Aortic Properties after the Norwood Procedure: an Angiographic Analysis of the Pediatric Heart Network Single Ventricle Reconstruction Trial

Abstract

Objectives: Aortic arch reconstruction in patients with single ventricle lesions may predispose to circulatory inefficiency and maladaptive physiology leading to increased myocardial workload. We sought to describe potentially maladaptive aortic anatomy and physiology, risk factors, and impact on right ventricle (RV) function in patients with single RV lesions after Norwood. Methods: Pre-stage II angiograms for subjects from the Single Ventricle Reconstruction (SVR) Trial were compared to 50 single left ventricle controls with no prior arch reconstruction. Arch geometry was defined as normal, crenel (elongated), or gothic (angular). Aortic index (ascending /descending aorta diameter) and distensibility index (systolic aortic area - diastolic area) / (diastolic area x pulse pressure) were calculated. Univariable tests were used for comparisons, and Spearman’s rho was used for correlation. Results: Interpretable angiograms were available for 326/389 (84%) SVR subjects. Table 1 summarizes findings. Age at catheterization was similar for SVR subjects and controls. SVR subjects more often demonstrated abnormally elongated (crenel) arch geometry with dilated ascending and transverse aortae tapering to a small isthmus. Distensibility was reduced in both the ascending and descending aorta. Risk factors for ascending aortic dilation (aortic index ≥ 2.5) included native aortic stenosis (OR = 2.2 [95% CI: 1.2, 3.8] vs. aortic atresia) and receipt of a RV-pulmonary artery shunt (OR = 2.6 [1.47, 4.5] vs. Blalock-Taussig shunt). There was no association between reduced distensibility and any demographic, anatomic, or reported surgical factors. Aortic dilation and reduced distensibility did not correlate with RV function at 14-month echocardiogram (p=0.5). Conclusions: After Norwood single RV surgery, the reconstructed aorta demonstrates abnormal anatomy and physiology. Further study is needed to evaluate the longer-term impact of these findings.