Association between left ventricular strain and fibrosis in severe aortic regurgitation with preserved ejection fraction: a magnetic resonance and histology study

• Published in: European heart journal cardiovascular imaging Vol. 24; no. Supplement_1
• Main Authors: Kockova, R, Hlubocka, Z H, Medilek, K M, Linkova, H L, Paskova, E P, Mraz, T M, Prokopova, M P, Sedmera, D S, Kelen De Oliviera, E K, Cerny, S C, Skalsky, I S, Penicka, M P
• Format: Journal Article
• Language: English
• Published: 19-06-2023
• ISSN: 2047-2404; 2047-2412
• DOI: 10.1093/ehjci/jead119.142

Abstract
Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Institutional Grant Na Homolce Hospital
Background
The presence and extent of myocardial fibrosis are associated with poor outcomes in patients with severe aortic regurgitation. In the present study, we tested a correlation between left ventricular (LV) strain derived by using feature-tracking cardiac magnetic resonance (MRI) and diffuse myocardial fibrosis percentage (DMF%) at quantitative histology.
Methods
A study population included 23 patients (age 51 ± 12 years, 78% males) who underwent perioperative myocardial biopsy during aortic valve surgery for severe aortic regurgitation and who had a satisfactory pre-surgery MRI. Myocardial specimens obtained with a deep needle technique from the basal interventricular septum were stained with picrosirius red, digitalized, and analyzed using Image J software by a pathologist blinded to imaging findings. The DMF% was calculated as a ratio of the total collagen content to the total area. MRI-derived global longitudinal-(GLS), circumferential- (GCS), and radial (GRS) strain, as well as their ratio to heart rate and systolic blood pressure, were assessed using a feature-tracking technique by a certified imager blinded to histological analysis.
Results
Compared to normal values, all patients showed increased DMF% (19 ± 9%) and decreased GLS (15 ± 2%) despite preserved LV ejection fraction (64 ± 7%). Out of all the imaging parameters, only GLS/heart rate ratio, GCS/heart rate ratio and extracellular volume fraction showed a significant correlation with DMF% (Table 1, Figure 1). In contrast, GLS and GCS only tended to correlate with DMF%. The remaining parameters including GRS did not show a significant association. Patients with focal midwall scar in late gadolinium enhancement imaging (n=8, 35%), which was mainly localized in the basal septum, had similar GLS as than patients without focal scar (14.5±2.3 vs 15.3±2.3, p = 0.768).
Conclusions
Feature-tracking-derived ratios of LV GLS and GCS over heart rate are the most promising indices for non-invasive assessment of diffuse myocardial fibrosis in severe aortic regurgitation with preserved ejection fraction.
Figure 1 Legend
Correlation of a GLS/HR ratio 1A) and GLS 1B) with diffuse myocardial fibrosis %. Myocardial histology stained with Picrosirius red (collagen fibers are in red).