Carotid Duplex Imaging on a Patient with a Temporary Left Ventricular Assist Device

Abstract

Introduction

In a carotid Duplex scan, the spectral Doppler examination is used to quantify stenosis by using the peak systolic and end diastolic velocities and ratios of the systolic velocities. The carotid spectral waveform is markedly different when a patient has a temporary left ventricular assist device (LVAD) that is nonpulsatile or continuous because of the oxygenated blood being redirected from the left atrium into the femoral artery via a centrifugal pump. This continuous-flow device provides complete circulatory support, preserving organ function and allowing quick restoration of hemodynamic stability.

Case Report

A 23-year-old man with idiopathic dilated cardiomyopathy, end-stage congestive heart failure, and cardiogenic shock required emergent placement of a TandemHeart temporary LVAD. Carotid Duplex imaging was performed the next day as a routine examination ordered for preheart transplant evaluation. No atherosclerotic disease was noted on B-mode images; however, intermittent bubbles were visualized and appeared as high-intensity transient signals within the Doppler spectral waveform. Flow was continuous in the carotid and vertebral arteries bilaterally.

Discussion

Percutaneous LVAD devices are increasingly being used as a short-term “bridge to cardiac transplantation.” Vascular sonographers should be aware that peripheral arterial flow will be nonpulsatile in patients who are sustained on these continuous flow devices. If significant disease is present we will need to rely on B-mode and color images and calculation of percent area or diameter reduction instead of waveform and velocity data.