Non-ischemic Primary and Secondary Cardiomyopathy

1349395 - Correlations between Cardiac Magnetic Resonance and Myocardial Histologic Findings in Fabry disease.

Thursday, January 26, 2023

1:00 PM – 2:00 PM

Location: Pacific Jewel

Presenting Author(s)

RD

Raffaello Ditaranto, MD

Cardiologist
IRCCS Azienda Ospedaliero-Universitaria di Bologna
Bologna, Emilia-Romagna, Italy

Primary Author(s)

RD

Raffaello Ditaranto, MD

Cardiologist
IRCCS Azienda Ospedaliero-Universitaria di Bologna
Bologna, Emilia-Romagna, Italy

Co-Author(s)

OL

Ornella Leone, MD

Pathologist
Department of Pathology, Cardiovascular and Cardiac Transplant Pathology Unit. St. Orsola Hospital, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy
LL

Luigi Lovato, MD

Radiologist
IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy
FN

Fabio Niro, MD

Radiologist
IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy
GC

Giovanna Cenacchi, MD

Pathologist
University of Bologna, Italy
VP

Valentina Papa

Biologist
University of Bologna, Italy
HK

Hibba Kurdi, MD, BSc

Cardiology Fellow
Barts Health NHS Trust, London, UK
London, United Kingdom
VP

Vanda Parisi, MD

Doctor
IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy
NG

Nazzareno Galiè, MD

Professor of Cardiology
IRCCS Azienda Ospedaliero-Universitaria di Bologna
Bologna, Emilia-Romagna, Italy
James C. Moon, MD

Clinical Director, Imaging
Barts Heart Centre and UCL
London, England, United Kingdom
EB

Elena Biagini, MD, PhD

Cardiologist
IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy

Background:

Fabry disease (FD) causes cardiac left ventricular hypertrophy (LVH) thought to be due myocyte lipid storage and compensatory sarcomeric increase. Myocardial T1 in FD by cardiac magnetic resonance (CMR) demonstrates T1 lowering, with T1 falling until overt LVH, then normalizing as further LVH occurs. However no histological validation has been provided to date. Therefore, aim of the study was to correlate CMR myocardial values and histologic findings.

Methods:

Fifteen FD patients (49 years [IQR 39-63], 60% females) undergoing CMR (cines, native T1 mapping, LGE) and either endomyocardial biopsy (EMB, n=11) or septal myectomy (n=4). Tissue specimens were analyzed with light/electron microscopy. Histomorphometric analysis measured myocyte vacuolization either as a percent of myocyte number (%VM) or area (%VMA).

Results: Histological changes preceded imaging changes: myocyte hypertrophy preceded LVH and fibrosis preceded LGE. %VM and %VMA correlated with LVH either as maximal wall thickness (MWT r=0.780, p< 0.001; r=0.859, p< 0.0001) or left ventricular mass index (LVMi r_s=0.823, p< 0.001; r_s=0.847, p< 0.0001). LVH patients had high %VM (≥45% and ≥80% by elevated MWT and LVMi respectively) and high %VMA (≥18% and ≥22% respectively). At least 45% of VM and 10% VMA were needed for T1 lowering. In patients without increased LVMi (67%) T1 fell as %VMA increased (r=-0.883; p< 0.001). In patients with increased LVMi, no clear relationship was reported (r=-0.501; p=0.389).

Conclusion:

This study compared CMR with myocardial histology in FD patients focusing on storage (vacuolization), LVH and native T1 values. Main findings were:

Histological changes preceded imaging changes: myocyte hypertrophy pre detectable LVH, storage pre detectable T1 lowering and fibrosis LGE.

Myocyte size increased with storage and clinical LVH.

Significant storage was necessary for both clinical LVH and T1 lowering.

The relationships between storage and clinical LVH was non-linear.

Native T1 values fell with storage until the presence of overt LVH (i.e. increased LVMi), when the relationship trend was lost.