How common is severe pulmonary hypertension after pediatric cardiac surgery?

Pulmonary hypertension may result in significant morbidity and mortality after pediatric cardiac surgery. The objective of this study was to determine the incidence and outcome of severe pulmonary hypertension, defined as a ratio of pulmonary to systemic arterial pressure equal to or greater than 1.0, after cardiac surgery in children.

Data from all children younger than 18 years who had undergone cardiothoracic surgery from January 1, 1994, to December 31, 1998, were examined. To find children with severe pulmonary hypertension, we reviewed intensive care unit charts from patients who had been monitored with a pulmonary artery catheter after the operation (n = 151), had received mechanical ventilation for more than 4 days after the operation (n = 124), or had died in the operating room or the intensive care unit (n = 22). Intraoperative and postoperative measurements of mean pulmonary arterial pressure and postoperative echocardiographic studies during the first 3 postoperative days were used to select the children.

During the study period, 1349 children (including 164 neonates and 511 infants, median age 12 months) underwent cardiac operations with an overall perioperative mortality of 22 patients (1.6%). Twenty-seven children (2%, median age 4.2 months) had severe pulmonary hypertension. Of these, 2 (7.4%) died within 30 days of the operation, and 3 others (11%) died within a year (median follow-up 53 months). Nitric oxide inhalation was used in 5 of the 27 cases, and it probably saved the life of 1 patient, may have helped in 1 case, and had no discernible effect in 3 cases. Severe pulmonary hypertension was most common after correction of complete atrioventricular septal defects (14%, n = 12/85). Thirteen of 131 children with Down syndrome (9.9%) had severe pulmonary hypertension.

Severe postoperative pulmonary hypertension occurred after 2% of the cardiac procedures and in most cases was managed successfully with conventional treatment and had a favorable postoperative outcome. The low incidence relative to previous reports may reflect the benefits of early correction and improved intraoperative and postoperative care.