Significance of myeloperoxidase plasma levels as a predictor for cardiac resynchronization therapy response

Objectives This study aimed to determine if changes in myeloperoxidase (MPO) levels correlate with response to cardiac resynchronization therapy (CRT) and the potential role of MPO as a predictor of response to CRT. Background CRT is a well-established treatment option in chronic heart failure (CHF) with 50-80% of patients benefiting. Inflammation and oxidative stress play a key role in CHF pathophysiology. Previous studies have demonstrated increased levels of MPO in CHF patients, but the correlation with CRT response remains incompletely understood. Methods Fifty-three patients underwent CRT implantation. During follow-up, patients were divided into two groups, responders and non-responders to CRT, based on improved physical capacity and NYHA classification. Levels of MPO and NT-pro-brain-natriuretic-peptide (NT-proBNP) were determined prior to implantation, 30 and 90 days after. Physical capacity, including a 6-min walking-test, NYHA class, and LVEF were evaluated at baseline and during follow-up. Results Thirty-four patients (64%) responded to CRT, showing improved physical capacity and LVEF. All responders revealed a significant decrease of MPO levels (503.8 ng/ml vs. 188.4 ng/ml;p < 0.001). Non-responding patients did not show any significant changes in clinical parameters or MPO levels (119.6 ng/ml vs. 134.3 ng/ml;p = 0.672) during follow-up. At baseline, physical capacity and NYHA class, as well as MPO levels differed significantly between both groups (p < 0.001). A ROC analysis identified an MPO cut-off value for response to CRT of 242 ng/ml with a sensitivity of 93.5% and specificity of 71.4%. There was a strong correlation between MPO and improvement of LVEF (Spearman's rho: - 0.453;p = 0.005) and physical capacity (Spearman's rho: - 0.335;p = 0.042). Conclusions Response to CRT and course of MPO levels correlate significantly. MPO levels differ between responders and non-responders prior to CRT, which may indicate an additional value of MPO as a predictor for CRT response. Further randomized studies are required to confirm our data in larger patient cohorts.