External Compression of Right Coronary Cleft Resulting From ECMO Cannula Causing Refractory Ventricular Fibrillation: An Unusual Adverse Event

Abstract

72-year old man with severe left main disease and ischemic cardiomyopathy presented with ventricular tachycardia (VT) and cardiac arrest, and underwent emergency coronary artery bypass grafting and mitral valve repair. He required extracorporeal membrane oxygenation (ECMO) support through the ascending aorta and right atrium. The chest was left open by use of a metal bridge and a vacuum dressing. On the second postoperative day, he experienced refractory VT and ventricular fibrillation, requiring urgent catheterization, which showed that the vein graft to the right coronary artery (RCA) had 80% smooth narrowing in the proximal third (Fig 1, white arrow), and appearance that was consistent with external compression. On urgent reexploration, there was external compression of the RCA graft because the heart was significantly distended and was pushing the vein graft against the venous cannula (Fig 1, black arrow), leading to delayed stenosis. The patient’s rhythm was stabilized by tacking the venous cannula away from the vein graft, with good flows down the graft on measurement. The patient had no VT over the next few days. Although rare, ECMO cannulas can cause myocardial ischemia either by malposition [1] or by external compression, and this possibility should be considered in relevant clinical scenarios. Reference