LVAD Outflow Graft Compression Presenting as Pump Thrombosis

Abstract

<h3>Introduction</h3> Pump thrombosis is a serious adverse event in patients with left ventricular assist devices (LVAD). Pump thrombosis is a complication of LVAD implantation, affecting approximately five percent of patients. It often presents with clinically significant hemolysis, device alarms and can progress to heart failure and cardiogenic shock. We present a case of a patient with a Heartmate II LVAD who presented with a rising LDH that led to investigation to diagnose a potential pump thrombosis. <h3>Case Report</h3> The patient is a 73 year old male who was implanted with a HeartMate II LVAD as destination therapy (DT) for ischemic cardiomyopathy (ICM). Approximately 3 years after implant, the patient was noted to have a markedly elevated LDH on routine lab work. After 8 months of event-free observation, the patients LDH trended up again and the plasma free hemoglobin level was also elevated. An ECHO with limited ramp study was performed. The power and flow responded appropriately however LVEDD showed no applicable change. To further investigate a potential thrombosis, a CT angiogram was obtained. The CT demonstrated a significant obstruction to the outflow graft within the bend relief. The initial intervention was a balloon angioplasty of the outflow graft. The angioplasty was technically successful, and the balloon fully expanded. A repeat CT 2 weeks later showed the obstruction was still present. Interestingly, the patient remained asymptomatic and his LDH normalized. The decision was made to continue observation. Six months later, his LDH was noted to be increasing. A repeat CT showed that the outflow obstruction was worsening. The outflow graft appeared to be at least 90% obstructed. Again, the patient was taken to the OR for an intervention. Balloon angioplasty was repeated to predilate the lesion. Three endovascular stents were placed in the outflow graft within the bend relief. Completion angiogram confirmed the stents to be fully expanded with no residual obstruction. There were no complications from the procedure. The patient remains event-free 8 months later. <h3>Summary</h3> In conclusion, the patient demonstrated signs of pump thrombosis mediated by an extrinsic compression of the outflow graft. In this case, the problem was treated with angioplasty with excellent result. The patient remains under surveillance but has been event-free for one year.