Noninvasive assessment of the right and left ventricular function in neonates with congenital diaphragmatic hernia with persistent pulmonary hypertension before and after surgical repair

Abstract

Objective: To measure right and left ventricular function in neonates with congenital diaphragmatic hernia (CDH) and persistent pulmonary hypertension of the newborn (PPHN) before and after surgical repair.

Methods: Ten newborns with CDH and PPHN before and after surgical repair and 24 normal newborns underwent Doppler echocardiographic measurements of the systolic time intervals (STI) and the index of myocardial performance (IMP) or Tei Index to assess pulmonary hypertension and ventricular function, respectively.

Results: In newborns with CDH and PPHN before surgical repair, STI pre-ejection time/ejection time ratio and pre-ejection time/acceleration time ratio (0.39 ± 0.19 and 1.22 ± 0.6) were significantly prolonged when compared to newborns with CDH and PPHN after surgical repair (0.21 ± 0.05 and 0.80 ± 0.2) and normal newborns (0.20 ± 0.04 and 0.59 ± 0.2), respectively (all p < 0.001). Left IMP and right IMP were also significantly prolonged in newborns with CDH and PPHN before surgery (0.38 ± 0.16 and 0.53 ± 0.25) when compared to newborns with CDH and PPHN after surgery (0.30 ± 0.07 and 0.28 ± 0.13) and normal newborns (0.26 ± 0.09 and 0.20 ± 0.10), respectively (p < 0.05, left IMP) and (p < 0.001, right IMP).

Conclusions: Significant pulmonary hypertension and abnormal left and right ventricular function were found in newborns with CDH and PPHN before surgical repair when compared to the newborns with CDH and PPHN after surgical repair and normal newborns. The STI and the IMP or Tei index can accurately estimate the consequences of pulmonary hypertension and left and right ventricular function in neonates with CDH and PPHN, which may affect management in these critically ill neonates.

Keywords: Congenital diaphragmatic hernia; index of myocardial performance; neonate; persistent pulmonary hypertension; systolic time intervals; ventricular function.

Figure. The right and left Tei index or IMP were obtained as follows: Interval a was between the cessation of the A wave and the onset of the next E wave of the tricuspid or mitral valve inflow. The interval b or ventricular ET was the duration of the RV or LV outflow. The interval c was measured from the tallest part of the R wave in the electrocardiogram tracing to the onset of the next E wave of the tricuspid or mitral valve inflow. The interval d was measured from the tallest part of the R wave in the electrocardiogram tracing to the end of the ventricular ejection time of the RV or LV outflow. The isovolumic relaxation time (IRT) was the difference between the interval c and interval d (IRT =c−d), and the isovolumic contraction time (ICT) was obtained by subtracting the interval b and the IRT from the interval a (ICT= [a−b]− IRT). The IMP or Tei index was determined by the following formula: (ICT+IRT)/ET or (a−b)/b.