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