DISCUSSION
After congenital heart surgery in the early postoperative periods some children become critically ill either due to residual lesions, severe myocardial dysfunction, low cardiac output or inability to wean from CPS/ECMO support. Cardiac catheterization may play a role not only in the diagnosis but also in management of such patients. Cardiac catheterization is an invasive procedure that may carry a high risk in patients that their transfer from the operating room or the PICU to the catheterization laboratory itself is risky. Despite the advance in the field of pediatric cardiac catheterization that makes it possible to be performed in small weight and critically ill babies, cardiac catheterization in the early period post-operative period is thought to carry a prohibitive high risk6,10. It is believed that at least 6 weeks should pass post cardiac surgery before any attempt for interventional cardiac catheterization to allow a scar tissue to be formed around the suture lines and anastomotic sites despite no studies to support such thoughts 7. In this cohort we aimed to study the safety, success and outcome of cardiac catheterization performed < 5weeks post congenital heart surgery.
In this cohort, a multidisciplinary team including the surgeon, the intensivist, cardiac anesthesiologist, cardiac interventionist, ECMO team and respiratory therapist was ready to intervene at any time during catheterization procedures or patients’ transportation to the catheterization lab. No complications were reported during patients’ transportation to the catheterization laboratory ,and this was concordant with previous published data7,11.
Diagnostic cardiac catheterization: Diagnostic cardiac catheterization in the early post-operative period can play a great role in evaluation of the adequacy of surgical repair and detection of significant residual lesions that may affect the hemodynamics and postoperative course and hence can help for taking a proper decision either for conservative management, redo surgery or further catheter intervention. There was no significant difference between patients underwent diagnostic catheterization and those underwent interventional procedures regarding hospital stay, PICU stay, complications and survival, Nicholson et al reported similar results in their cohort6.
Angioplasty and vascular stenting: Theoretically angioplasty (ballooning/ stenting) in the early post-operative period, when less time is allowed for a scare tissue to be formed around vascular suture lines may cause catastrophic disruption of the freshly formed sutures. In this cohort angioplasty was performed in 12 procedures, 9 of them done on fresh suture lines with no reported vascular tear or suture disruption and this was concordant with report by Zahn et al who attributed that to the distensibility of Prolene filaments that can afford elongation up to 34% before disruption and enlargement of the circumference of the suture line (increased distance between parallel throws) in response to balloon inflation. They thought that continuous Prolene suture lines can be expanded safely without disruption when using balloon stenosis ratio ≤2.5/17. Rosales et al. Reported a 20% mortality due to vascular disruption after balloon angioplasty of the branch pulmonary arteries in the early postoperative period9. In majority of cases stent placement is better than balloon dilatation because it prevents the recoil giving better results for a considerable period of time7.
Cardiac catheterization for patient on ECMO support: Several reports studied the safety of catheter intervention for patients on ECMO support12–15. Still the results are less promising in our cohort as despite 72% successfully disconnected from ECMO support, survival to discharge was 45.4% and overall survival was 36%. This is likely as a result of their complex anatomy, associated comorbidities or unsuccessful surgical intervention. It is not clear if the early cardiac catheterization contributed to the 72 % successful ECMO discontinuation or its natural progress. This needs to be explored separately and with a larger sample. Similar results were reported by Kojima et al (overall survival rate was 29%) while DesJardins et al reported lower survival rate ( overall survival was 14%) . Booth et al , Zahan et al , Panda et al and Callahan et al reported higher over all survival rate in their series ( 43%, 56%, 64% , and 69% respectively).10,13–16