Abstract 3252: Clinical Improvement Ater Cardiac Resynchronization Therapy Foretells Lower Serum Levels of Biomarkers Reflecting Cardiac Collagen Deposition
Introduction: Cardiac resynchronization therapy (CRT) decreases adverse mechanical remodeling in patients with heart failure (HF), but the mechanisms of these salutary effects are not fully elucidated. We investigated whether the serum level of carboxy-terminal propeptide of procollagen type I (PICP), a biomarker of collagen synthesis and cardiac deposition, correlates with response to CRT.
Methods: Patients enrolled in the Genetic Risk Assessment of Defibrillation Events study who had serum drawn ≥2 months after CRT implantation were enrolled. Patients were classified as clinical responders if their NHYA class of HF decreased by ≥1 and as echocardiographic responders if their EF increased by ≥5% after CRT.
Results: Data on 22 patients (age=64±12 years, 68% men, EF=21±5%, 59% coronary disease) were analyzed. The mean (range) time from CRT implantation to serum collection was 19±11 (2.7–46.9) months. The NYHA class (2.8±0.3 vs. 2.0±0.7, p<0.001) and EF (21±5% vs. 25±8%, p=0.05) improved after CRT. There were 64% clinical and 36% echocardiographic responders. Compared to non-responders, clinical (135±43 ng/ml vs. 88±42 ng/ml, p=0.021) [figure⇓] but not echocardiographic (121±49 ng/ml vs. 86±42 ng/ml, p=0.202) responders had lower PICP levels. BNP levels were also lower in clinical (3859±1836 fM/ml vs. 1864±1072 fM/ml, p=0.004) but not echocardiographic (p=0.846) responders.
Conclusion: These data suggest that clinical response to CRT may be associated with lower levels of serum collagen synthesis and that collagen metabolism may underlie some of the mechanisms of benefit from CRT. Future studies should focus on whether baseline PICP levels can predict response to CRT.