Interventional Applications

1352004 - The importance of routine extracardiac evaluation in the follow-up CMR for single-ventricle palliation: an interventional CMR (iCMR) study validating liver elastography

Wednesday, January 25, 2023

Location: E-POSTER

Presenting Author(s)

MA

Maher Abadeer, MD

Pediatric Cardiology Advanced Imaging Fellow
The University of Texas Southwestern Medical Center
Irving, Texas, United States

Primary Author(s)

MA

Maher Abadeer, MD

Pediatric Cardiology Advanced Imaging Fellow
The University of Texas Southwestern Medical Center
Irving, Texas, United States

Co-Author(s)

Joshua Greer, PhD

MRI Physicist
Philips Healthcare
Dallas, Ohio, United States
SR

Suren R. Reddy, MD

Pediatric Interventional Cardiology
University of Texas Southwestern Medical Center
Dallas, Texas, United States
AD

Abhay Divekar, MD

Pediatric Interventional Cardiology
UT Southwestern, United States
BS

Bharti Sharma, MD

Resident
The University of Texas Southwestern Medical Center
Queens, Texas, United States
GS

Gary Schooler, MD

Pediatric Radiology
The University of Texas Southwestern Medical Center, Texas, United States
LZ

Luis Zabala, MD

Anesthesiology
The University of Texas Southwestern Medical Center, Texas, United States
MF

Munes Fares, MD

Assistant Professor
The University of Texas Southwestern Medical Center
Dallas, Texas, United States
JD

Jeanne Dillenbeck, MD

Pediatric Radiology
The University of Texas Southwestern Medical Center
Dallas, Texas, United States
SP

Steven Philip, RT

Cardiac MRI Technologist
Children's Medical Center of Dallas, United States
Tarique Hussain, MD, PhD

Professor, Pediatric Cardiology & Radiology
UT Southwestern Medical Center
Dallas, Texas, United States

Background: Patients with congenital heart disease (CHD) who have undergone Fontan palliation are known to be at risk for progressive Fontan-associated liver disease (FALD). Current guidelines state these patients require routine CMR and non-invasive liver surveillance. Magnetic resonance elastography (MRE) has been suggested as a mode of follow-up for liver stiffness measurement (LSM) but the relative contribution of venous congestion versus fibrosis is unknown. We sought to determine the relationships between mean LSM as measured by MRE, and hepatic venous free (HVP) and hepatic wedge pressure gradients (WPG) during contemporaneous recording using iCMR methods.¹

Methods: This was a retrospective observational study of consecutive patients with single ventricle physiology undergoing iCMR and MRE for clinical reasons between June 15, 2021 to August 16, 2022. Patients were excluded if HVP’s were not recorded at the same procedure. MRE was performed using a passive elastography driver secured to the right upper abdomen with 60 Hz mechanical vibration frequency. 2D gradient echo motion encoded elastography and LSM were performed at four positions centrally through the liver (figure 1). Patients underwent iCMR on a 1.5T scanner using the Philips iSuite system. Heavily T1-weighted sequences with a thick imaging slab were obtained to track catheter position with a gadolinium filled balloon in real-time and overlay this on a high-resolution 3D dataset.²

Results:

A total of 28 patients were included, (13 Fontan and 15 Glenn patients). Mean age was 8.7 ± 7.4 years old, 16 (57%) patients were male, 15 (54%) had hypoplastic left heart and 9 (32%) had hypoplastic right heart variant anatomy as the fundamental cardiac diagnosis. Of the Fontan patients, 10 (77%) had an extracardiac conduit, of which 9 were fenestrated, 2 (15%) had a fenestrated lateral tunnel, and 1 (8%) had an atriopulmonary Fontan. HVP was elevated in Fontan vs Glenn patients (14.2 ± 2.5 mmHg vs 9.1 ± 2.1 mmHg; p < 0.0001). There was no difference in WPG measurements between the two groups (1.2 ± 0.7 mmHg vs 0.8 ± 0.8 mmHg, respectively; p = 0.185).

There was a high correlation between HVP and LSM in the entire cohort (R² = 0.83; p < 0.0001) (figure 2), and in Fontan patients when analyzed separately (R² = 0.64; p = 0.018), however WPG did not show correlation with LSM (R² = 0.36; p = 0.083, and R² = 0.25; p = 0.40, respectively) (figure 3).

Conclusion: Liver stiffness as measured by MRE correlates with hepatic vein free pressure in patients who have undergone stage 2 and stage 3 single ventricle palliation for CHD. This may serve as a marker for non-invasive surveillance of hepatic congestion and portal hypertension, FALD and Fontan deterioration in this population. The lack of MRE correlation with hepatic wedge gradient suggests that MRE may not reliably detect fibrosis, however limited conclusions can be drawn given overall low WPG values and small sample size in this study.