Background Patent ductus arteriosus (PDA) ligation is associated with a post ligation cardiac syndrome characterised by circulatory compromise and oxygenation failure, related in part to impaired left ventricular performance. The authors have previously published a PDA staging system based on clinical and echocardiography markers to stratify patients according to disease severity (Arch Dis Child 2007).

Objective To determine whether PDA severity, as adjudicated by the staging system, predicts postoperative cardiorespiratory instability.

Design/Methods A retrospective review of all PDA ligations between 2002 and 2009 was performed. Respiratory morbidity was defined by an increase in respiratory severity score (MAP × FiO₂) by 50%, increase in FiO₂ by 20% or MAP by 2 cm H₂O. Cardiovascular morbidity was defined as mean blood pressure <3rd centile, commencement or increased dose of an inotrope, or need for hydrocortisone. All PDAs were staged (I-IV) on the day of ligation and scored one point for clinical/echo criteria (maximum 8 points). Patients were categorised into two groups (score ≤6 (Group I) and score >6 (Group II)).

Results Forty-eight infants underwent PDA ligation during the period. Ten had score of 6 (Group I) while 38 had score >6 (Group II). Ductal size and left atria: aorta ratio was higher in group II. The frequency of postoperative cardiorespiratory deterioration was higher in group II.

Comparison of demographics and incidence of postoperative haemodynamic instability in the two groups:

Conclusion Neonates with higher-grade PDA stage are at increased risk of postligation haemodynamic instability and require focused postoperative management to minimise morbidity.