Thrombus detected in computed tomography angiography images of HeartMate II outflow graft: A cautionary tale

Abstract

Almost 10,000 adults received a left ventricular assist device (LVAD) in the United States during the past 8 years. With the significant increase in volume and duration of support, comes the potential risk for increased complications. There has been increasing awareness of the risk for HeartMate II LVAD (HM II) pump thrombosis, a potentially fatal complication, now cited in slightly 450% of device exchanges. We report the case of a patient with HM II thrombosis in which computed tomography angiography (CTA) findings led us to a more aggressive LVAD exchange technique than was necessary. A 49-year-old Hispanic man with ischemic cardiomyopathy had worsening heart failure symptoms with rapid clinical deterioration and, due to his body habitus, an HM II was implanted as destination therapy. Three months later the patient presented with heart failure symptoms and power spikes, and low-flow alarms were noted on interrogation of his implanted device. A LVAD RAMP study was suggestive of poor LV unloading, and elevated serum lactate dehydrogenase and plasma free hemoglobin and low haptoglobin were all suggestive of pump thrombosis. There was no clinical improvement despite therapeutic anti-coagulation. CTA demonstrated a laminar thrombus in the LVAD outflow graft near the bend relief (Figure 1). This finding was reviewed with Thoratec and, at their recommendation, a pump exchange via median sternotomy with outflow graft revision was performed. After explant, thrombosis was noted in the pump bearings and the rotor (Figure 2); however, the inner aspect of outflow graft did not reveal a thrombus. The “thrombus” reported on CTA was actually between the bend relief and the outer wall of the outflow graft (Figure 2). The surgery was complicated by massive bleeding and profound vasoplegia refractory to further interventions. The patient developed multiorgan failure and died the following day. Although many VAD centers may have noticed the existence of a laminar thrombus between the bend relief and outflow graft by CTA, to the best of our knowledge, this is the first report of such radiologic finding. This was incidentally noted on subsequent HM II LVADs in other patients at the time of LVAD removal before heart transplantation (Figure 1). Recognition of the common http://www.jhltonline.org