Cardiac magnetic resonance imaging characterization of acute rejection in a porcine heterotopic heart transplantation model.

Preclinical disease models are important for the advancement of therapeutics towards human clinical trials. One of the difficult tasks of developing a well-characterized model is having a reliable modality with which to trend the progression of disease. Acute rejection is one of the most devastating complications that can occur following organ transplantation. Specifically in cardiac transplantation, approximately 12% of patients will experience at least one episode of moderate or severe acute rejection in the first year. Currently, the gold standard for monitoring rejection in the clinical setting is to perform serial endomyocardial biopsies for direct histological assessment. However, this is difficult to reproduce in a porcine model of acute rejection in cardiac transplantation where the heart is heterotopically transplanted in an abdominal position. Cardiac magnetic resonance imaging is arising as an alternative for serial screening for acute rejection in cardiac transplantation. This is an exploratory study to create and define a standardized cardiac magnetic resonance screening protocol for characterizing changes associated with the presence of acute rejection in this preclinical model of disease. Results demonstrate that increases in T1 mapping, T2 mapping, left ventricular mass, and in late gadolinium enhancement are significantly correlated with presence of acute rejection.

Sacubitril/valsartan and cardiovascular biomarkers among patients with recent COVID-19 infection: The PARACOR-19 randomized clinical trial.

AIMS: The PARACOR-19 randomized controlled trial (RCT) was designed to examine the effects of sacubitril/valsartan on markers of cardiac injury, inflammation, structure, and function among patients who have recovered from acute coronavirus disease 2019 (COVID-19) infection. METHODS AND RESULTS: PARACOR-19 was a single-centre, double-blind RCT of patients with cardiovascular risk factors and a history of COVID-19 infection 4-16 weeks prior to enrolment. Patients were randomized to sacubitril/valsartan (titrated to the maximum dose of 97/103 mg twice daily) versus matching placebo. Co-primary endpoints were change from baseline to 12 weeks in high-sensitivity cardiac troponin T (hs-cTnT) and soluble ST2 (sST2). Exploratory endpoints included change from baseline to 12 weeks in additional circulating biomarkers. Overall, 42 patients were randomized between August 2021 and March 2023 (n = 20 sacubitril/valsartan, n = 22 placebo). Median (25th-75th) time from COVID-19 diagnosis to enrolment was 67 (48-80) days. Median age was 67 (62-71) years, 48% were female, and 91% were White. Compared with placebo, sacubitril/valsartan did not have a significant effect on the co-primary endpoints of change from baseline in hs-TnT and sST2 (all p ≥ 0.29). In exploratory analyses, sacubitril/valsartan led to a 46% greater reduction in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and 51% greater reduction in C-terminal telopeptide of collagen type I (CITP). Permanent drug discontinuation occurred in four patients in the sacubitril/valsartan group and three patients in the placebo group. There were no deaths and one patient was hospitalized in each group. CONCLUSION: In this pilot RCT of patients who recovered from acute COVID-19, sacubitril/valsartan did not lower hs-cTnT or sST2 compared with placebo. Exploratory analyses suggested potential benefits of sacubitril/valsartan on cardiac wall stress and collagen turnover as measured by NT-proBNP and CITP. Sacubitril/valsartan was well tolerated. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT04883528.