Aims & Objectives:
Causes of major adverse events (MAE) after systemic-to-pulmonary (SP) shunt procedure are usually shunt occlusion or over-shunting. Outcomes categorised on the basis of these causes will be helpful both for quality improvement and prognostication.
From 2008 to2015, 201 children who had a SP shunt were studied after excluding those who had it for Norwood or Damus-Kaye-Stansel procedure. MAE is defined as one or more of cardiac arrest, chest re-opening or requirement for extracorporeal membrane oxygenation(ECMO). Study outcome is a composite poor outcome, defined as one or more of acute kidney injury(AKI), necrotising-enterocolitis(NEC), brain injury or in-hospital mortality.
Median(IQR) age was 12(6–38) days and median(IQR) time to MAE was 5.5(2–17) hours after admission. Overall, 36(18%) experienced a MAE and reasons were over-shunting (n=17), blocked shunt (n=13) or other (n=6). 15(88%) in over-shunting group suffered a cardiac arrest compared to 2(15%) in the blocked shunt group (P<0.001). The composite poor outcome was seen in 15(88%) in over-shunting group, 4(31%) in the blocked shunt group and 56(34%) in those who did not experience a MAE (p<0.001). There was higher in-hospital mortality, brain injury, NEC and AKI in the over-shunting group compared to other groups.
Infants who suffer MAE due to over-shunting experience considerably poorer outcomes than those who experience events due to shunt block. A mainly hypoxic event with maintenance of systemic perfusion (as often seen in a blocked shunt) is less likely to result in poorer outcomes than those after a hypoxic-ischaemic event (commonly seen in over-shunting).