Associations between blood biomarkers, cardiac function and adverse outcome in a young tetralogy of Fallot cohort

Background: To determine the potential prognostic value and clinical correlations of blood biomarkers in a cohort of patients with Tetralogy of Fallot (TOF). Methods: In the setting of multicenter prospective research studies TOF patients underwent blood sampling, cardiopulmonary exercise testing and low-dose dobutamine stress cardiac magnetic resonance (CMR) imaging. In the blood sample NT-proBNP, GDF-15, Galectin-3, ST-2, DLK-1, FABP4, IGFBP-1, IGFBP-7, MMP-2, and vWF were assessed. During subsequent follow-up, patients were evaluated for reaching the study endpoint (cardiac death, arrhythmia-related hospitalization or cardioversion/ablation, VO₂ max ≤65% of predicted). Regression analysis was used to explore the correlation between blood biomarkers (corrected for age and gender) and other clinical parameters. The potential predictive value of blood biomarkers and events were assessed with Kaplan-Meier analysis and Cox proportional hazard analysis. Results: We included 137 Fallot patients, median age 19.2 (interquartile range: 14.6–25.7) years, median age at TOF-repair 0.9 (0.5–1.9) years. After a median follow-up of 8.7 (6.3–10.7) years, 20 (14.6%) patients reached the composite endpoint. In a multivariable cox-regression analysis corrected for age at study baseline, elevated IGFBP-7 and MMP-2 levels were associated with the composite endpoint. We also noted a correlation between DLK-1 and relative change in right ventricular end systolic volume during dobutamine stress CMR (β = −0.27, p = 0.010), a correlation between FABP4 and Max VO₂ (β = −0.41, p ≤0.001 and between MMP-2 and tricuspid valve E/A ratio (β = −0.15, p = 0.037). Conclusions: IGFBP-7, MMP-2 and DLK-1 levels are related to cardiac function and long-term outcome in TOF patients.