Introduction: C-terminal telopeptide of procollagen type I (ICTP) and N-terminal propeptide of procollagen type III (PIIINP) are two of the major collagen turnover markers representing collagen degradation and synthesis. Cardiac magnetic resonance (CMR) using delayed enhancement (DE) and T1 mapping, provides a tool for detection and quantification of focal scar and diffuse interstitial myocardial fibrosis.
Hypothesis: Levels of the serum biomarkers of ICTP and PIIINP at baseline are associated with the presence of myocardial scar and diffuse interstitial fibrosis at the 10-year follow-up.
Methods: Of 3000 participants in a case(CVD)-cohort study that measured PIIINP and ICTP in baseline, 827 subjects with had CMRI at follow-up. Participants were initially aged 45-84 years and free of clinical CVD. Baseline serum PIIINP and ICTP concentrations were assayed using radio-immunoassay. DE-CMRI assessed myocardial scar at 10-year follow-up, with T1 mapping indices of extracellular volume fraction (ECV), pre-contrast T1, and T1 at 25 minutes post-contrast measuring diffuse interstitial fibrosis. Logistic (DE scar vs. absence as a dichotomous outcome) or linear (continuous values of T1 indices as outcomes) multivariable regression analysis with ICTP and PIIINP levels weighted for the design as continuous exposures were performed with adjustment for ACC-AHA ASCVD risk score and glomerular filtration rate at baseline (Model 1) and follow-up (Model 2).
Results: Mean (SD) ICTP was 3.1 ± 0.9 μg/L; PIIINP was 5.4 ± 1.3 μg/L; ECV was 27.3 ± 3.1 %; and T1 at 25’ was 517 ± 42 ms. Among 827 participants, 68 had myocardial scar. Increased ICTP and PIIINP levels at baseline were associated with the presence of myocardial scar at follow-up (Table 1). ICTP showed no association with T1 mapping indices.
Conclusions: Increased levels of collagen turnover markers were independently associated with the presence of myocardial scar 10 years later, but not with diffuse interstitial fibrosis.