Discussion
Likely mechanisms of intra-mural haematoma in this case include surgical
trauma perioperatively or trauma/bruising to the graft from cardiac
massage during the CALS protocol. We routinely use skeletonized mammary
arteries for CABG. Intra-operative surgical trauma seemed unlikely as
there was no visible evidence of damage to the conduit during the
operation. An evolving haematoma would more likely present as
progressive regional ischaemia on ECG with segmental wall motion
abnormality on echocardiogram. There were no ischaemic changes on ECG
post-operatively. This patient had no regional wall motion abnormality
on post-cardiopulmonary bypass transoesophageal echocardiogram (TOE).
Post-resuscitation TOE showed global LV impairment after stabilisation
on VA-ECMO. It could be that the cardiac arrest 2hrs after surgery was
unrelated to the intramural haematoma and the haematoma was as a result
of cardiac massage during CPR.
A much more common cause of early graft failure (failure within 1 month
of surgery) is technical failure or thrombosis which is usually at the
site of the anastomosis. LHC and OCT showed that all anastomoses were
intact with good flow and no sign of intra-lumnal thrombosis.
OCT is a catheter based invasive imaging system which allows for
high-resolution imaging of intra-luminal and trans-mural coronary
structures thus overcoming many of the limitations of angiography. Using
light rather than ultrasound, OCT produces high-resolution in-vivo
images of coronary arteries and deployed stents.
Accumulating data support a clinical role for OCT in a multitude of
clinical scenarios, including assessing the natural history of
atherosclerosis and modulating effects of therapies, mechanisms of acute
coronary syndromes, mechanistic insights into the effects of novel
interventional devices, and optimization of percutaneous coronary
intervention. We have found no previous reports of the use of OCT to
evaluate conduit post-CABG. Potential risks from the procedure include
that it can cause intimal dissection in fresh conduit.
Should OCT be used to routinely evaluate all conduit post-op? We can
advocate its usage when the LHC findings are unclear.
OCT to complement LHC can be a valuable tool to evaluate conduit post
CABG. The absence of proximal aortic anastomoses in total arterial
re-vascularization reduces the risk of graft disruption when early
post-operative LHC/OCT is indicated.