Normal Lower Extremity Duplex Findings in Patients with Left Ventricular Assist Devices: A Basis for Vascular Laboratory Interpretation

Background: Left ventricular assist devices (LVADs) have been shown to cause changes in carotid artery duplex-derived flow velocity waveforms; however, possible effects on lower extremity arterial duplex (LEAD) findings have not been characterized. We sought to characterize LEAD findings in patients with LVADs to establish a basis for vascular laboratory interpretation of LEAD in patients with LVADs. Methods: Retrospective single institution review of all patients with LEAD performed after LVAD implantation from 2003 to 2014. Peak systolic velocity (PSVs) of common femoral (CFA), superficial femoral (SFA), popliteal, and posterior tibial arteries (PTA) in asymptomatic extremities in patients with LVADs were compared to a control group of patients at our institution without LVADs who underwent LEAD for nonischemic indications. Arterial brachial index (ABIs) and CFA waveform acceleration times (ATs) and end diastolic velocity (EDV) were also measured. Results: There were 248 LVAD patients, 29 had LEAD of at least 1 lower extremity (34 extremities, 22 asymptomatic, and 12 symptomatic) during the study period and 136 control limbs. Mean PSVs (cm/s) in the control CFA, mid SFA, popliteal, and PTA were 137 ± 4.8, 104.2 ± 4.5, 65.2 ± 2.8, and 64.6 ±3.2. Mean PSVs were significantly decreased in the LVAD patients: 49.5 ± 4.9, 40.6 ± 3.7, 27.2 ± 2.2, and 25.5 ± 2.3, P < 0.001 for each comparison. Average ABI for control limbs was 0.91 ± 0.05 compared to 1.17 ± 0.35 in LVAD extremities (P < 0.001). Mean CFA AT was 97 ms in the controls and 207 ms in LVAD patients, P < 0.001. Mean CFA EDV was 14.7 cm/s in the controls and 18.6 cm/s in the LVAD patients, P = 0.011. Conclusions: This is the first study characterizing LEAD in lower extremity arteries in LVAD patients. PSV is significantly decreased throughout lower extremity vessels, and common femoral artery acceleration time increased. Results can serve as a basis for identifying normal LEAD findings in LVAD patients.