Outflow Graft Obstruction Causing Recurrent Heart Failure after Left Ventricular Assist Device Implantation

Abstract

Outflow graft obstruction is a poorly described complication following continuous flow-left ventricular assist device (CF-LVAD) surgery. We sought to define the incidence of CF-LVAD outflow graft obstruction and assess clinical outcomes with a percutaneous treatment strategy. From January 2012 to June 2019, 252 CF-LVAD patients were managed at our institution. Patients with suspected LVAD outflow graft obstruction underwent comprehensive evaluation with Doppler echocardiography, cardiac computed tomography with angiography and invasive hemodynamic assessment followed by percutaneous intervention. Fourteen patients (5.6%) developed hemodynamically significant LVAD outflow graft obstruction at a rate of 0.03 events per patient-year. Outflow graft obstruction presented a mean of 34±18 months after surgery. Patients presented with heart failure (HF; 86%), low LVAD pump flow (93%), or both (79%). LVAD flow declined by an average of 2.1±0.8L/min (p<0.001). Outflow graft obstruction was caused by external graft compression (77%), stenosis of the aortic anastomosis (46%) and discrete kinking of the outflow cannula (46%); most patients presented with 2 or more lesions (69%). There were no cases of outflow graft thrombosis. External graft compression was uniformly due to build-up of fibrinous material between the outflow cannula and the protective external GoreTex graft. Outflow graft stenting was 100% successful and reduced the gradient from 80mmHg (IQR 58-100mmHg) to 13mmHg (IQR 10-20mmHg, Figure). There was no in-hospital mortality and few complications. Outflow graft stenting was durable; over a mean follow-up of 13±7 months, no patients had recurrent outflow graft obstruction. LVAD outflow graft obstruction is a relatively common and underappreciated cause of recurrent HF and LVAD dysfunction. Outflow graft stenting can be achieved with low morbidity and provides a long-term solution to this complication.