Growth characteristics of the aortic arch after the Norwood operation

Objectives. We sought to characterize the growth of the reconstructed aortic arch after the Norwood operation (NO). Background. The first stage of surgical palliation of hypoplastic left heart syndrome (HLHS), the NO, includes augmentation of the aortic arch with homograft. Growth characteristics of the reconstructed aortic arch, which is comprised of both native aortic tissue and homograft, have not been characterized. Methods. Retrospectively, we examined the serial echocardiograms of 50 patients with HLHS who underwent NO to determine the diameter of the reconstructed transverse arch. Measurements were taken immediately after NO and at two other points (1 to 11 years of age). In addition, the autopsy specimens of 10 other patients with HLHS who underwent NO were examined to determine the contribution of native aortic tissue to the overall size of the reconstructed arch at the time of death (12 to 34 months). Results. The diameter of the transverse aort increased after NO in all subjects. Its rate of growth paralleled that seen in the normal population, though the reconstructed arch had significantly larger diameter throughout childhood. Examination of autopsy specimens demonstrated mean increase in circumference of the native aortic tissue of 0.67 cm (p value <0.01), whereas there was no significant change in homograft circumference. Conclusions. After reconstruction of the aortic arch in HLHS, the diameter of the arch continues to increase throughout childhood, and this increase is due to growth of the native aortic tissue.