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.

Prolonged tuberculosis-associated immune reconstitution inflammatory syndrome: characteristics and risk factors.

BACKGROUND: In a proportion of patients with HIV-associated tuberculosis who develop paradoxical immune reconstitution inflammatory syndrome (IRIS), the clinical course of IRIS is prolonged necessitating substantial health care utilization for diagnostic and therapeutic interventions. Prolonged TB-IRIS has not been prospectively studied to date. We aimed to determine the proportion of patients with prolonged TB-IRIS, as well as the clinical characteristics and risk factors for prolonged TB-IRIS. METHODS: We pooled data from two prospective observational studies and a randomized controlled trial conducted in Cape Town, South Africa, that enrolled patients with paradoxical TB-IRIS. We used the same diagnostic approach and clinical case definitions for TB-IRIS in the 3 studies. Prolonged TB-IRIS was defined as TB-IRIS symptoms lasting > 90 days. Risk factors for prolonged TB-IRIS were analysed using Wilcoxon rank sum test, Fisher's exact test, multivariate logistic regression and Cox proportional hazards models. RESULTS: Two-hundred and sixteen patients with TB-IRIS were included. The median duration of TB-IRIS symptoms was 71.0 days (IQR 41.0-113.2). In 73/181 patients (40.3 %) with adequate follow-up data, IRIS duration was > 90 days. Six patients (3.3 %), mainly with lymph node involvement, had IRIS duration > 1 year. In univariate logistic regression analysis the following were significantly associated with IRIS duration > 90 days: lymph node involvement at initial TB diagnosis, drug-resistant TB, lymph node TB-IRIS, and not being hospitalised at time of TB-IRIS diagnosis. In our multivariate logistic regression model lymph node TB-IRIS (aOR 2.27, 95 % CI 1.13-4.59) and not being hospitalised at time of TB-IRIS diagnosis (aOR for being hospitalised 0.5, 95 % CI 0.25-0.99) remained significantly associated with prolonged TB-IRIS, and drug-resistant TB was of borderline significance (aOR 3.26, 95 % CI 0.97-12.99). The association of not being hospitalised with longer duration of IRIS might be related to 1 of the 3 cohorts in which all patients were hospitalised at ART initiation with close inpatient follow-up. This could have resulted in diagnosis of milder cases and earlier IRIS treatment potentially resulting in shorter TB-IRIS duration in these hospitalised patients. CONCLUSIONS: Around 40 % of patients with TB-IRIS have symptoms for more than 90 days. Involvement of lymph nodes at time of TB-IRIS is an independent risk factor for prolonged TB-IRIS. Future studies should address whether more prompt anti-inflammatory treatment of lymph node TB-IRIS reduces the risk of prolonged TB-IRIS. TRIAL REGISTRATION: The randomized controlled trial was registered with Current Controlled Trials ISRCTN21322548 on 17 August 2005.