New research from Queen Mary University of London, published in the European Heart Journal of Cardiovascular Imaging, has shown that pericardial fat may have a role in driving structural and functional damage to the heart.
Figure: Example automated PAT segmentations and their predicted segmentation quality. The Dice score provides a quality-control measure with scores <0.7 indicating poor segmentation quality.
Pericardial fat is the fatty tissue surrounding the surface of the heart. Previous studies have suggested that greater amount of pericardial fat may have a specific role in increasing the risk of important heart diseases. However, it is unclear whether this increased risk reflects increased body fat or a specific biological property of pericardial fat itself- above and beyond the known harmful effects of general obesity.
In a first-of-its-kind-study, researchers examined the relationship between the amount of pericardial fat and the structure and function of the heart using over 40,000 heart MRI scans from the UK Biobank.
The findings show that having greater pericardial fat is linked to distinct unhealthy changes in the anatomy and function of the heart. This was evident even after accounting for a wide range of other factors that worsen heart structure and function, like diabetes, smoking, and other markers of obesity, such as body mass index and waist circumference.
Dr Zahra Raisi-Estabragh, NIHR Clinical Lecturer at Queen Mary University of London, who supervised the study said: “We found greater pericardial fat to be linked to unhealthy changes in the heart and blood vessels. These relationships were independent of general obesity, visceral obesity (fat accumulation around organs other than the heart), and of key conditions linked to obesity like diabetes and high blood pressure. Our results support a distinct role for pericardial fat in driving poorer heart health.”
As part of the study, the team used a fully automated quality-controlled method for measuring pericardial fat. This tool was developed and validated in-house and previously published in the journal Frontiers in Cardiovascular Medicine. This is the only tool of its kind that allows fully automated measurements of pericardial fat from heart MRI scans.
Dr Maddalena Ardissino, MRC Graduate Scholar at the University of Oxford, who led the study said: “We know that everyone deposits fat across their body in slightly different ways. However, since pericardial fat is closely linked to obesity, it is difficult establish whether having high amounts of pericardial fat specifically is worse having obesity, or if it’s just a mirror image of it. We were able to pick the effects apart in our study for the first time, thanks to the large number of high-quality images in the UK Biobank and the fully automated tool that we developed.”
The findings also suggest that this novel pericardial fat metric may have a role as a novel imaging biomarker to improve risk assessment from routine heart MRI images.