A Comparison of Perinatal Circulatory Transition in Critical Right and Left Heart Obstructive Lesions.

BACKGROUND

During perinatal transition in hypoplastic left heart syndrome (HLHS), reduced systemic blood flow (Qs) and cerebral blood flow and increased pulmonary blood flow (Qp) are observed, contributing to hemodynamic instability. The aim of the present study was to explore whether similar or discordant perinatal changes occur in critical pulmonary outflow tract obstruction (POFO) compared with HLHS and healthy control subjects.

METHODS

Echocardiography was prospectively performed at 36 to 39 gestational weeks and then serially from 6 to 96 hours after birth, before cardiac intervention. Combined cardiac output (CCO), superior vena cava (SVC) flow rate, Qs and Qp, and resistance indices (RIs) in the middle cerebral artery (MCA), celiac artery, and superior mesenteric artery were compared among the three groups.

RESULTS

In fetal POFO (n = 19) and HLHS (n = 31), CCO was comparable with that in control subjects (n = 21) because of elevated stroke volume, but CCO in POFO was lower compared with HLHS (P < .01). Compared with control subjects, POFO CCO was lower at 6 hours after delivery but comparable at 24 to 96 hours. In contrast, from 6 to 96 hours, the HLHS group had higher CCO than POFO and control subjects. Compared with control subjects, both neonates with POFO and those with HLHS had lower Qs and SVC flow (POFO at 24 hours, P < .001; HLHS 6-hour Qs and 6- to 24-hour SVC flow). Compared with control subjects, Qp was increased in POFO at 48 to 96 hours (P < .05) and in HLHS at all time points (P < .001). Compared with fetal MCA RI, postnatal MCA RI was acutely higher in both POFO and HLHS, whereas in control subjects, it tended to decrease postnatally. Celiac artery RI and superior mesenteric artery pulsatility index were higher in POFO and HLHS from 6 to 48 hours vs control subjects.

CONCLUSIONS

POFO and HLHS demonstrate divergent acute hemodynamic changes in the early neonatal period, with early decreased CCO in POFO and increased CCO in HLHS. Both demonstrate early compromise in Qs and SVC (cerebral flow) and ongoing altered splanchnic flow.