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.