Contrast Microsphere Destruction by a Continuous Flow Ventricular Assist Device: An In Vitro Evaluation Using a Mock Circulation Loop.

David G Platts,Gregory M Scalia,Nicole Bartnikowski,John F Fraser,Shaun D Gregory

doi:10.1155/2017/4907898

Abstract

Objectives Transthoracic echocardiography (TTE) is fundamental in managing patients supported with ventricular assist devices (VAD). However imaging can be difficult in these patients. Contrast improves image quality but they are hydrodynamically fragile agents. The aim was to assess contrast concentration following passage through a VAD utilising a mock circulation loop (MCL). Methods Heartware continuous flow (CF) VAD was incorporated into a MCL. Definity® contrast was infused into the MCL with imaging before and after CF-VAD. 5 mm2 regions of interest were used to obtain signal intensity (decibels), as a surrogate of contrast concentration. Results Four pump speeds revealed significant reduction in contrast signal intensity after CF-VAD compared to before CF-VAD (all p < 0.0001). Combined pre- and postpump data at all speeds showed a 22.2% absolute reduction in contrast signal intensity across the CF-VAD (14.8 ± 0.8 dB prepump versus 11.6 ± 1.4 dB postpump; p < 0.0001). Mean signal intensity reduction at each speed showed an inverse relationship between speed and relative reduction in signal intensity. Conclusion Contrast microsphere transit through a CF-VAD within a MCL resulted in significant reduction in signal intensity, consistent with destruction within the pump. This was evident at all CF-VAD pump speeds but relative signal drop was inversely proportional to pump speed.

Highlights

Continuous flow ventricular assist devices (CF-VADs) are utilised to help manage selected patients with severe heart failure [1,2,3]
There was a significant reduction in contrast signal intensity post-continuous flow (CF)-VAD compared to pre-CF-VAD
Analysis of combined pre- and postpump data at all speeds (Figure 5) showed that there was a 22.2% absolute reduction in contrast signal intensity across the CF-VAD (14.8 ± 0.8 dB prepump versus 11.6 ± 1.4 dB postpump; p < 0.0001)

Summary

Introduction

Continuous flow ventricular assist devices (CF-VADs) are utilised to help manage selected patients with severe heart failure [1,2,3]. With improvements in device design and patient selection, CF-VADs are playing an increasing role in the management of heart failure and the implant rates have risen significantly over the last few years [4, 5]. They are typically used as either a bridge to cardiac transplantation or with increasing frequency, as destination therapy [6, 7].

Objectives

Methods

Results

Discussion

Conclusion