Simultaneous Multi-Vascular Bed Imaging in a Patient Supported by a Continuous-Flow LVAD

Introduction Patients supported with left ventricular assist devices (LVADs) are burdened by frequent hemocompatibility-related adverse events related to patient-pump interactions. These predominantly vascular events include stroke, gastrointestinal bleeding, and pump thrombosis. Our center performs routine, invasive hemodynamic ramp speed titrations in LVAD patients to determine the optimal rotational speed after implantation. We sought to interrogate changes in vascular hemodynamics during an exercise ramp study to understand the influence of pump speed and exercise on outflow graft and cerebrovascular flow. Case Report A 71-year-old male patient supported by Heartware HVAD operating at a baseline speed of 2700 RPM presented for LVAD ramp and exercise study with vascular imaging. A right heart catheterization, echocardiography with Doppler imaging of the patient's LVAD outflow graft, and vascular Doppler of the left common carotid artery and middle cerebral artery were performed. The patient's LVAD operating speed was reduced to 2400 RPM and then increased stepwise to a maximum speed of 3000 RPM. At each increment of operating speed, Doppler imaging was attempted and right heart catheterization was repeated. After reviewing data from the ramp study, the patient's operating speed was set to 2900 RPM and then a staged exercise protocol with bicycle ergometer was performed. Pertinent findings of vascular imaging include a blunting of peak systolic to end-diastolic velocity ratio in vascular beds with incremental speed increase and partial recovery of pulsatility with exercise (Figure). Summary This case demonstrates the influence LVAD speed adjustment and exercise have on carotid artery and outflow graft pulsatility. With exercise the outflow graft and carotid artery peak systolic and end-diastolic velocities were similar to those at the lowest LVAD pump speed, suggesting that intrinsic contractility and native LV unloading was restored with exercise despite a higher pump speed.