Implementation of Non-invasive Point of Care Transient Elastography for Evaluation of Liver Disease in Pediatric Populations with Cystic Fibrosis

Summary

The goal of this protocol is to showcase the technique and use of point-of-care transient elastography for pediatric gastroenterologists monitoring hepatobiliary involvement and advanced cystic fibrosis liver disease in persons with cystic fibrosis.

Abstract

Cystic Fibrosis (CF) is an inherited condition that impacts multiple organ systems, one of which is the liver. The presentation and manifestation of liver disease in CF are varied, and there is ongoing research to better understand its etiology and clinical implications. Some studies have shown that liver disease in CF impacts 10% of people with CF (PwCF) by age 10 and 30% by age 30. Screening and monitoring for hepatic involvement in CF continue to evolve as new guidelines and therapies are created.

In 2023, new consensus guidelines were released regarding the evaluation, nomenclature, and monitoring of liver disease in CF. Two new terms define the impact of CF on the liver: CF hepatobiliary involvement (CFHBI) and advanced cystic fibrosis-associated liver disease (aCFLD). Monitoring and evaluation of the progression of liver disease in CF requires close laboratory monitoring in coordination with imaging. A mainstay of evaluating PwCF for CFHBI includes elastography scanning to determine liver stiffness measurements to assess for possible fibrosis. An affordable, portable, and non-invasive approach to complete elastography evaluations is through point-of-care transient elastography (POCTE).

This article will cover the use and utility of POCTE as it pertains to the evaluation of CFHBI and aCFLD in the pediatric CF population. More specifically, this article will provide background information regarding guidelines for when and how to use POCTE in the care of PwCF. It will also provide detailed instructions on how to perform POCTE, how to interpret results, the next steps in care, limitations of POCTE, as well as other considerations in its use. Lastly, this article will describe a quality improvement project implementing POCTE for the first time in a large pediatric CF clinic.

Introduction

The cystic fibrosis transmembrane conductance receptor (CFTR) encodes an epithelial cAMP-activated chloride channel that regulates exocrine mucus secretions within multiple systems, including lungs, pancreas, intestines, intrahepatic bile ducts, gallbladder, sweat glands, and reproductive organs. Errors in protein synthesis of CFTR lead to cystic fibrosis (CF), a disease marked by systemic thickened mucus production, impaired mucus flow, and increased inflammation. CF transmembrane receptor (CFTR) modulator therapies target errors in protein synthesis and correct or stabilize the defective protein causing the disease¹. Effective modulator thera....

Protocol

The clinic in which this was implemented was a large pediatric Cystic Fibrosis clinic located in Dallas, TX, with a patient population of nearly 300 PwCF. This project was IRB-exempt given that it was deemed quality improvement. Appropriate positioning of the patient and tool selection is necessary to create accurate liver stiffness measurements. Once properly set up, the probe should be positioned to get the best results, which is followed by the interpretation of the data.

1. Selecting a probe size

1. Use a medium-sized probe first to establish the intercostal space for the patient. If the probe is not in the int....

Results

To implement improved liver screening and, specifically, the use of POCTE in our clinic, a quality improvement (QI) project was designed. Quality improvement tools such as Global Aim, SMART Aim, Process Maps, and Key Driver Diagrams were created. Interventions were implemented via Plan-Do-Study-Act (PDSA) cycles, with a total of four cycles. By the last PDSA cycle, with a date range of September 1, 2023, to August 31, 2023, the group scanned 163 unique patients, 174 scans total, with 71.8% of eligible patients having at .......

Discussion

The use of POCTE in clinical settings allows for affordable, efficient, and well-tolerated evaluations of liver stiffness in PwCF^{1,4,5,6,7,8,9}. The new guidelines for evaluating liver disease in CF prominently focus on imaging as patients begin to show signs of hepatic involvement

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
FibroScan or other POCTE	Echosense or other POCTE	N/A	POCTE Machine
Ultrasound Gel	As available	N/A	For use with POCTE
Ultrasound Probe (assorted sizes)	Echosense	N/A	POCTE Probe