Key result
Aortic regurgitation, but not aortic stenosis, was associated with a significant correlation between myocardial fibrosis and reduced beta-adrenoceptor sensitivity (R=0.363, p=0.023).
Why the study?
Disruption of extracellular matrix causes cardiac fibrosis and myocardial dysfunction, while beta-adrenoceptor downregulation reduces adaptation, prompting analysis of the correlation between myocardial fibrosis and beta-adrenoceptor sensitivity in aortic valve disease.
Does myocardial fibrosis correlate with beta-adrenoceptor sensitivity in patients with aortic regurgitation compared to aortic stenosis?
Observational (n=92)
Does myocardial fibrosis correlate with beta-adrenoceptor sensitivity in patients with aortic regurgitation compared to aortic stenosis?
Effect estimate: R 0.363
p-value: p=0.023
In patients with aortic regurgitation, but not aortic stenosis, more severe myocardial fibrosis is associated with reduced beta-adrenoceptor sensitivity, suggesting cellular myocardial dysfunction.
No correlation observed; leaves open whether fibrosis and beta-AR pathways interact independently in aortic valve disease.
Objective: At the tissue level, disruption of the extracellular matrix network leads to irreversible cardiac fibrosis, which contributes to myocardial dysfunction. At the myocyte level, downregulation of beta-adrenoceptors (beta-AR) reduces adaptation to increased workload. The aim of our study was to analyse the correlation between myocardial fibrosis and beta-AR sensitivity in patients with aortic valve (AV) disease. Methods: A total of 92 consecutive patients who underwent elective AV surgery between 2017–2019 were included in our study (51 with aortic regurgitation (AR-group); 41 with aortic stenosis (AS-group) and left ventricular (LV) biopsies were obtained intraoperatively. In vitro force contractility testing was performed by measuring beta-AR sensitivity (−log EC50[ISO]). In parallel, a quantitative analysis of myocardial fibrosis burden was performed. Results: Mean age at the time of AV surgery was not statistically different in both groups (AR: 53.3 ± 15.3 years vs. AS: 58.7 ± 17.0 years; p = 0.116). The LV end-diastolic diameter was significantly enlarged in the AR-group when compared to the AS-group (59.4 ± 15.6 vs. 39.7 ± 21.2; p < 0.001). Analysis of beta-AR sensitivity (AR: −6.769 vs. AS: −6.659; p = 0.316) and myocardial fibrosis (AR: 8.9% vs. AS: 11.3%; p = 0.284) showed no significant differences between patients with AS and AR. There was no correlation between myocardial fibrosis and beta-AR sensitivity in the whole study cohort (R = 0.1987; p = 0.100) or in the AS-subgroup (R = 0.009; p = 0.960). However, significant correlation of fibrosis and beta-AR sensitivity was seen in AR-patients (R = 0.363; p = 0.023). Conclusion: More severe myocardial fibrosis was associated with reduced beta-AR sensitivity in patients presenting with AR but not with AS. Therefore, our results suggest that in patients with AR, cellular myocardial dysfunction is present and correlates with the extent of myocardial fibrosis in the myocardium.
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Petersen et al. (2023) conducted an observational in Aortic valve disease (n=92). Aortic regurgitation vs. Aortic stenosis was evaluated on Correlation between myocardial fibrosis and beta-adrenoceptor sensitivity (R 0.363, p=0.023). Aortic regurgitation, but not aortic stenosis, was associated with a significant correlation between myocardial fibrosis and reduced beta-adrenoceptor sensitivity (R=0.363, p=0.023).
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