Patent ductus arteriosus ligation in premature infants: who really benefits, and at what cost?

Abstract

Purpose: Patent ductus arteriosus (PDA) ligation in premature infants has been shown to have low surgical morbidity and mortality. Ligation goals include prompt improvement in cardiorespiratory failure, with rapid wean from mechanical ventilation; less risk of prolonged mechanical ventilation and subsequent chronic lung disease (CLD); and survival to discharge. This study was designed to examine true morbidity after ligation and elucidate which preoperative factors might predict favorable outcomes.

Methods: Institutional review board-approved retrospective review of 197 infants less than 38 weeks of gestational age (GA), undergoing PDA ligation via thoracotomy between January 1, 1992, and January 1, 2004. Chronic lung disease defined as need for supplemental oxygen at 36 weeks corrected GA. Student t and chi2 tests were used.

Results: Mean GA was 27 weeks (range, 23-35 weeks), birth weight was 957 g (range, 440-3170 g); infants underwent ligation at 16 days of life (range, 1-132 days). Duration of surgery was 50.5 minutes (range, 13-150 minutes). Mean postoperative times were 27 days to extubation, 60 days to wean from supplemental oxygen, and 84 days to discharge. Early extubation (within 10 days of ligation) occurred in only 54 patients (30%). Only 44 (22%) survived to discharge without CLD. Forty patients (20%) died, with respiratory failure the most common cause (70%). In general, early extubation, survival without CLD and survival to discharge were associated with greater GA and birth weight, higher Apgar scores, greater age and weight at surgery, no preoperative intraventricular hemorrhage, lack of ventilator dependence, and lower ventilator settings (P < .05). Preoperative amount and duration of indomethacin use, chest x-ray findings, and echocardiographic assessment of ductus size did not predict favorable outcomes (all P > .05).

Conclusions: Most premature infants currently undergoing PDA ligation at our institution do not experience the anticipated rapid improvements in cardiorespiratory status and go on to develop CLD. Few preoperative variables (including radiographic and echocardiographic assessments) definitively predict outcomes.