A study protocol to characterise pathophysiological and molecular markers of rheumatic heart disease and degenerative aortic stenosis using multiparametric cardiovascular imaging and multiomics techniques.

INTRODUCTION: Rheumatic heart disease (RHD), degenerative aortic stenosis (AS), and congenital valve diseases are prevalent in sub-Saharan Africa. Many knowledge gaps remain in understanding disease mechanisms, stratifying phenotypes, and prognostication. Therefore, we aimed to characterise patients through clinical profiling, imaging, histology, and molecular biomarkers to improve our understanding of the pathophysiology, diagnosis, and prognosis of RHD and AS. METHODS: In this cross-sectional, case-controlled study, we plan to recruit RHD and AS patients and compare them to matched controls. Living participants will undergo clinical assessment, echocardiography, CMR and blood sampling for circulatory biomarker analyses. Tissue samples will be obtained from patients undergoing valve replacement, while healthy tissues will be obtained from cadavers. Immunohistology, proteomics, metabolomics, and transcriptome analyses will be used to analyse circulatory- and tissue-specific biomarkers. Univariate and multivariate statistical analyses will be used for hypothesis testing and identification of important biomarkers. In summary, this study aims to delineate the pathophysiology of RHD and degenerative AS using multiparametric CMR imaging. In addition to discover novel biomarkers and explore the pathomechanisms associated with RHD and AS through high-throughput profiling of the tissue and blood proteome and metabolome and provide a proof of concept of the suitability of using cadaveric tissues as controls for cardiovascular disease studies.

High-Throughput Metabolomics Applications in Pathogenesis and Diagnosis of Valvular Heart Disease.

High-throughput metabolomics techniques are a useful tool to understand many disease conditions including cardiovascular disease such as valvular heart disease(s) (VHD). VHD involves damage to heart valves, mostly presenting as stenosis, regurgitation or prolapse and can be classified into degenerative, rheumatic, congenital, or prosthetic valve disease. Gaps remain in our understanding of the pathogenesis of the common VHD. It is now fitting to place into perspective the contribution of metabolomics in the mechanism of development, diagnosis, and prognosis of VHD. A structured search for metabolomics studies centred on human VHD was undertaken. Biomarkers associated with the pathogenesis of bicuspid aortic valve disease, mitral valve disease, rheumatic heart disease, and degenerative aortic valve stenosis are reviewed and discussed. In addition, metabolic biomarkers reported to prognosticate patient outcomes of post-valve repair or replacement are highlighted. Finally, we also review the pitfalls and limitations to consider when designing metabolomics studies, especially from a clinician's viewpoint. In the future, reliable and simple metabolic biomarker(s) may supplement the existing diagnostic tools in the early diagnosis of VHD.

Chronic rheumatic heart disease with recrudescence of acute rheumatic fever on histology: a case report.

Background: Rheumatic heart disease (RHD) is endemic in sub-Saharan Africa where it is the leading cause of cardiovascular mortality in the young. Rheumatic heart disease results from recurrent episodes of acute rheumatic fever (ARF), which are often difficult to diagnose clinically. Acute rheumatic fever may be diagnosed based on the revised Jones Criteria 2015 for the diagnosis of ARF. Histologically, acute rheumatic valvulitis manifests with active inflammation characterized by lymphocytic infiltration, Aschoff bodies, and Anitschkow cells. Chronic rheumatic valvulitis is associated with neovascularization, and/or dystrophic calcification. The combination of histological features of both ARF and chronic RHD is a rare finding. Case summary: Here we report on a case of a 59-year-old woman with mixed aortic and mitral valve disease of probable rheumatic aetiology (elevated C-reactive protein and prolonged PR interval) and with histological evidence of lymphocytic infiltration, Aschoff bodies, and fibrinoid necrosis admixed with features of chronic RHD. Discussion: Cases of chronic RHD admixed with ARF are very rare; however, they should be considered in regions with a high prevalence of RHDs.