Biomarker sST2 in Adults with Transposition of the Great Arteries Palliated by Mustard Procedure: A Five-Year Follow-up.

The Mustard procedure was an early cardiac surgery for transposition of the great arteries (TGA). Despite being successful, it has been associated with long-term arrhythmias and heart failure. A key factor complicating management in adults with congenital heart disease (CHD) is the deficiency of biomarkers predicting outcome. Soluble suppression of tumorogenicity-2 (sST2) is secreted by cardiomyocytes in response to mechanical strain and fibrosis. We hypothesized that adults with a Mustard procedure would have higher levels of sST2 than healthy individuals, and this would correlate with clinical outcome. We performed a single-center study in patients managed during childhood with a Mustard procedure versus age-matched controls. Clinical and demographic data were collected and biomarkers (sST2, cTnI, BNP, lipid panel, insulin, and glucose) were obtained. There were 18 patients (12 male) in the Mustard cohort and 18 patients (6 male) in the control group (22-49 years, mean of 35.8 vs. mean 32.6 years, respectively, p = ns). Nine Mustard subjects were NYHA class II, and 9 subjects were class III. The control group was asymptomatic. sST2 in the Mustard group was elevated in 56% vs. 17% in controls (p = 0.035). Of the Mustard subjects with elevated sST2, 60% had elevated cTnI and BNP, and 90% had low HDL. Over five years, the Mustard patients with elevated sST2 values had greater medication use, arrhythmias, hospitalizations, and ablation/pacer implantations than Mustard subjects with normal sST2. Mustard subjects with elevated sST2 had other biomarker abnormalities and clinically worse outcomes. Thus, sST2 may add a predictive value to cardiac-related morbidity and mortality.

A multi-national trial of a direct oral anticoagulant in children with cardiac disease: Design and rationale of the Safety of ApiXaban On Pediatric Heart disease On the preventioN of Embolism (SAXOPHONE) study.

Anticoagulation in children is problematic for multiple reasons. Currently used anticoagulants have significant disadvantages and may negatively affect quality of life (QOL). This manuscript describes the design, rationale, and methods of a prospective, randomized, open label phase II multi-national clinical trial of a direct oral anticoagulant (DOAC), apixaban, in children and infants with congenital and acquired heart disease. This trial is designed to gather preliminary safety and pharmacokinetics (PK) data, as well as generate data on QOL of individuals taking apixaban compared to the standard of care (SOC) anticoagulants vitamin K antagonists (VKA) or low molecular weight heparin (LMWH). A key issue this trial seeks to address is the practice of using therapeutics tested in adult trials in the pediatric population without robust pediatric safety or efficacy data. Pediatric heart diseases are not common, and specific diagnoses often meet the criteria of a rare disease; thus, statistical efficacy may be difficult to achieve. This trial will provide valuable PK and safety data intended to inform clinical practice for anticoagulation in pediatric heart diseases, a setting in which a fully powered phase III clinical trial is not feasible. A second consideration this trial addresses is that metrics besides efficacy, such as QOL, have not been traditionally used as endpoints in regulated anticoagulation studies yet may add substantial weight to the clinical decision for use of a DOAC in place of VKA or LMWH. This study examines QOL related to both heart disease and anticoagulation among children randomized to either SOC or apixaban. There are considerable strengths and benefits to conducting a clinical trial in pediatric rare disease populations via an industry-academic collaboration. The SAXOPHONE study represents a collaboration between Bristol-Myers Squibb (BMS)/Pfizer Alliance, and the National Heart, Lung, and Blood Institute's (NHLBI) Pediatric Heart Network (PHN) and may be an attractive model for future pediatric drug trials.