Treatment
Five days following initial presentation, the patient was taken to the
operating room for CABG, with planned anastomoses of the left internal
mammary artery (LIMA) to the left anterior descending artery (LAD), and
vein graft to the obtuse marginal artery. Transesophageal
echocardiography (TEE) after induction of anesthesia demonstrated normal
LV function and mild inferior wall hypokinesis, with no evidence of
left-to-right shunting (Figure 3a ).
Of note, while cannulating the right atrial appendage for venous
drainage, the right atrium (RA) and RV immediately gave way and there
was an abrupt change of hemodynamics. Out of concern for an RCA infarct
or an abrupt obstruction of the RCA, an additional piece of vein was
harvested, and the operative procedure was adjusted to include a vein
graft to the right side.
Upon initiation of CPB, the patient was noted to have visibly infarcted
myocardium in the inferior diaphragmatic aspect of the RV with
significant hypokinesis. For this reason, the PDA was bypassed first
before proceeding with the previously planned bypasses of the left
circumflex with vein graft and LIMA to the LAD.
On attempted weaning of the CPB circuit, the aortic valve did not open,
the LV did not distend, and any weaning maneuvers resulted in an
overloaded RV. At this time, echocardiography demonstrated a new finding
of a post-myocardial infarction VSR (Figure 3b ). The location
of the defect was in the basilar portion emanating from the
mid-papillary muscle, consistent with a basal infarction in the
distribution of the PDA.
A left ventriculotomy was made parallel to the LAD. This allowed
visualization of a large, linear VSR with necrotic septum emanating
between the papillary muscles and near the LVOT. The defect was repaired
with a large piece of bovine pericardium secured with interrupted 2-0
Tycron pledgeted sutures. The ventriculotomy was closed and the
cross-clamp removed.
After completion of the repair, the patient was able to be slowly weaned
from bypass, but there was significant RV and LV strain despite
placement of an intra-aortic balloon pump (IABP). Given the residual
hemodynamic instability, the CPB circuit was converted to an ECMO
circuit, with biatrial venous cannulae placed to minimize left to right
shunting. The chest was left open and the patient was taken to the ICU
for further management.
The patient’s hemodynamics improved with resuscitation, but he
demonstrated persistent RV dysfunction due to RV infarction as well as
some residual left to right shunting suggesting an ongoing defect. Seven
days after the index operation, he was returned to the operating room
for sternal washout and attempted VSR repair. On direct visualization he
was noted to have progression of myocardial necrosis. Although the patch
was largely intact, there were small holes near the papillary muscles,
necessitating reinforcement of the entirety of the patch with 2-0 Tycron
pledgeted interrupted sutures.