Use of milrinone to treat cardiac dysfunction in infants with pulmonary hypertension secondary to congenital diaphragmatic hernia: a review of six patients.

Pulmonary hypertension and secondary cardiac dysfunction are important contributors of morbidity and mortality in infants with congenital diaphragmatic hernia (CDH). Milrinone, a phosphodiesterase-3 inhibitor, may be useful in this setting for its combined actions as a pulmonary vasodilator and to improve systolic and diastolic function. This study aimed to assess the effects of milrinone on cardiac function and pulmonary artery pressure in infants with CDH. A retrospective review of echocardiograms performed on infants with CDH who received milrinone was performed. Tissue Doppler imaging velocities were used to assess systolic and diastolic function. Pulmonary artery pressure was assessed from the pattern and velocity of ductal shunting. Six infants with CDH and severe pulmonary hypertension were identified. Systolic and diastolic myocardial velocities were reduced in the right ventricle (RV) and interventricular septum (IVS) at baseline. In the 72 h after commencement of milrinone, there was a significant increase in early diastolic myocardial velocities in the RV, accompanied by increasing systolic velocities in the RV and IVS. Oxygenation index was significantly reduced, blood pressure unchanged, and ductal shunt velocity minimally altered over the same time period. Milrinone use was associated with an improvement in systolic and diastolic function in the RV, corresponding to an improvement in clinical status.