Association of BNP and Troponin Levels with Outcome among Cardiac Resynchronization Therapy Recipients.

ABSTRACT

BACKGROUND: We conducted a prospective multicenter study to assess the prognostic value of combined baseline preimplant plasma levels of the biomarkers cardiac troponin T (TnT) and B-type natriuretic peptide (BNP) among cardiac resynchronization therapy (CRT) with or without defibrillator capability (CRT-D) recipients. METHODS: At CRT-D implant, patients were stratified based on detectable TnT (≥0.01 ng/mL) and elevated BNP (predefined as >440 pg/mL) levels. Patients were classified into three groups high (both detectable TnT and high BNP), intermediate (either detectable TnT or high BNP), or low (nondetectable TnT and low BNP). Patients were followed for 12 months. Survival curves free from mortality or heart failure hospitalizations (HFH) were assessed. To assess the predictive value of biomarker category, we constructed a multivariate Cox regression model, including the covariates of age, New York Heart Association class, left ventricular ejection fraction (LVEF), and QRS duration. RESULTS: A total of 267 patients (age 66 ± 12 years, males 80%, LVEF 25% ± 8%, ischemic cardiomyopathy 52%, QRSd 155 ± 26 ms) were studied. After 1 year, there were 13 deaths and 25 HFH events. A significant difference in event-free survival among the three groups was observed, with high and intermediate categories having worse survival than low (log-rank test, P < 0.001). In the multivariate model, risk category was a significant predictor of outcome: hazard ratios were 7.34 (95% confidence interval [CI] 2.48-21.69) and 2.50 (95% confidence interval [CI] 1.04-6.04) for high-risk and intermediate-risk groups, respectively (P < 0.0001). CONCLUSION: Among CRT-D recipients, baseline TnT and BNP values alone or in combination provide significant prognostic value for the outcome of mortality or HFH.