Reduced LVEDD following a 12 week exercise training program in patients with symptomatic chronic heart failure is associated with reduction in serum levels of Troponin I

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Norwegian University of Science and Technology Danish Research Council Background Exercise training (ET) exerts many beneficial effects on the cardiovascular system, and longitudinal observational data from epidemiological studies suggest that higher physical activity is associated with lower concentrations of cardiac troponins. We have previously shown that ET can reduce Left Ventricle End-diastolic diameter (LVEDD), and improve exercise capacity. Purpose Our aim was to explore the relationship between changes in LVEDD and changes in high-sensitive plasma troponin I (hs-TnI) levels in patients with symptomatic heart failure undergoing a 12 week structured exercise training program in the randomized multicenter SMARTEX trial. Methods This was a post hoc analysis in 199 patients with symptomatic HF with LVEF <35% and NYHA II-III that were randomly assigned to High Intensity Interval Training (HIIT, n = 73), Moderate Continuous Training (MCT, n = 59) or Recommendation of Regular Exercise, (RRT, n = 67) for 12 weeks. Log-transformed Hs-TnI measurements and clinical data acquired before (BL) and after a 12 week exercise training intervention (12 weeks) and at 1 year follow-up (1 year) were analysed using a linear mixed model. For Troponin analysis the STAT Troponin-I from Abbott Diagnostics was used. Nakagawa’s marginal R2 and conditional R2 were used to evaluate variance explained by fixed effects only and by fixed and random effects together, respectively. Changes of LVEDD between baseline and 12 weeks and baseline and 52 weeks were evaluated using linear mixed model. The outcome variable were measures of LVEDD, while age, sex, visit and training group and their interaction [visit × training group] were included as fixed effects. Patient id and training center were random effects. Covariance structure was compound symmetry. Linear association between log-transformed TnI and LVEDD baseline was evaluated using Pearson correlation coefficient (R). Results Serum was available for hs-TnI analyses in 199 patients. In the HIIT group there was a sustained significant reduction in LVEDD at both 12 and 52 weeks. In the MCT group this reduction was statistically significant at 52 weeks only. Mixed model analysis predicts that each 1 mm decrease in LVEDD is associated with 1.2% decrease in TnI levels (95% CI: 0.6 – 1.9%, p <0.001). Neither time nor training group were associated with changes of TnI (overall test p = 0.739 and p = 0.987, respectively). Dynamics of TnI is highly patient-specific with Intraclass correlation coefficient (ICC) = 0.86. Mixed model explains 87% variation of the data (conditional R2), however, only 7% is attributed to the fixed effects (marginal R2). At baseline, TnI and LVEDD have modest but statistically significant correlation (R = 0.2, p= 0.004). Conclusions A reduction of LVEDD following a 12-week exercise-training program is associated with a reduction in plasma troponin levels, in patients with mild to moderate chronic heart failure. Abstract Figure.