Abstract 15284: Characteristics and Determinants of Cerebral Circulation in Patients after Surgery for Congenital Heart Disease

Background: Neurodevelopmental delay and cerebral atrophy coupled with reduced blood flow are reportedly closely linked in patients with congenital heart diseases (CHD). However, the mechanisms to regulate cerebral flow in the same are unclear. Cardiac output and underlying cerebral arterial resistance that is constructed during infancy may affect blood perfusion. We tested our hypothesis that cerebral blood flow in patients with repaired CHD is affected by the original features of CHD. Method: Ninety children including 50 patients with biventricular repaired CHD (ToF 27, TGA 15, CoA+VSD 8), 15 with a single ventricle (SV: Glenn7/Fontan8) and 25 with negligible shunts and otherwise normal stracture heart were enrolled. During cardiac catheterization, cardiac index (CI), blood pressure, central venous pressure were measured before and after inferior vena cava occlusion. Assuming that cerebral resistance (Rc) and lower body resistance (Ri) are constant during IVC occlusion, the resistance and blood distribution to the brain and lower body were calculated as a parallel resistance circuit. The impacts of hemodynamics on the cerebral circulation were analyzed. Result: The cerebral portion of cardiac index (CIc) was negatively correlated with age (CIc=1.88-0.06*Age, p<.05) and positively correlated with the CI (CIc=0.26+0.35*CI, p<.0001). As expected, the cerebral resistance (Rc) increased significantly with age (p<.05), whereas the resistance ratio defined as the Rc/Ri was independent of age, body size, disease, and surgical history. Multivariate analysis revealed that the CI was the independent determinant of CIc, regardless of the underlying diseases (p<.01, β=0.27). Interestingly, after adjusting for age and CI, repaired CoA exhibited significantly higher Rs/Ri ratio (p<.01) and lower CIc (p<.05) than other groups, whereas SV patients showed significantly increased CIc, CIc/CI ratio and lower Rc compared to other groups (p<.05). Conclusion: Apart from the strong governance of cerebral blood flow by cardiac output, cardiovascular property before anatomical repair and cavo-pulmonary connections have a significant impact on the cerebral circulation. Long-term effects of abnormal cerebral circulation warrants further studies.