The presence of air bubbles in the aorta of a patient with a HeartMate II left ventricular assist device: a novel sign of outflow graft obstruction.

Microbubbles formed by cavitation have been frequently reported in patients with mechanical heart valves, but have not previously been described in patients with continuous-flow left-ventricular assist devices (LVADs). Obstruction of the LVAD circuit by thrombus, outflow graft kinking, or cannula malposition may cause high-pressure gradients and turbulent flow, often resulting in hemolysis. The article is the first in the field to describe the presence of microbubbles in the ascending aorta of a patient with severe LVAD-associated hemolysis. It is proposed that these bubbles were formed by cavitation in the presence of a high-pressure gradient due to LVAD outflow graft obstruction and suggested that this may be a novel imaging sign of LVAD obstruction in patients with continuous-flow LVADs.