Neuro-developmental impairment which follows management of complex congenital heart disease is a major issue. Balloon dilation is a frequent procedure, which can lead to brain injury. Whereas the pressure and diameter of balloon for inflation are quite normalized, there are no written guidelines for time of inflation. Our aim was to study the brain perfusion with the NIRS (Near Infra Red Spectroscopy) during catheter procedure.

We prospectively enrolled 20 consecutive children (mean±SD: age=2.8±3.4y.o.; weight=15.6±13.6kg) who underwent transcatheter balloon dilation of pulmonary valve, trunk or conduit stenosis. Procedure was done under general anesthesia with regular monitoring. SpO2 was used by physician for patient safety. Cerebral oxygen saturation (Rso2) was monitored by NIRS. Each brain desaturation events were collected. 40% of rSO2 was considered as the cut-off limit below which brain injury may occurs. Time to reach this limit (TTR40), time to recover (TTR95), area under curve and deepness of the events were extracted (Appendix 1).

The total number of inflation was 56, with a mean of 2,8 inflations per patient (min=2; max=10). The NIRS curve had two parts: it decreased during balloon inflation due to CO interruption and then increased during the reperfusion. Both were easily detected (Se=100%) whereas the SpO2 remained wrongfully high. Near 36% of desaturation were under the cut-off (NIRS<40%). TTR40 was 56.76s and TTR95 was 34.85s for the whole group. The linear regression based on NIRS shows two significant (P<0.0001) slopes: −0.68rSO2%/s for TTR40 and +0.70 rSO2%/s for TTR95. Our results suggest that a cumulative time over 44s (95% CI) of multiples occlusions without recovery may cause brain injury. A recovery delay of 40s (95% CI) after each set of balloon inflation is therefore mandatory.

Pulmonary valve, trunk or conduit dilatation requires short occlusion and total recovery before any new inflation.