In the Biology Study to Tailored Treatment in Chronic Heart Failure (BIOSTAT-CHF) system, TMAO levels were correlated with mortality and/or rehospitalization, and contrary to BNP levels, TMAO levels have not been reduced by the guideline-recommended pharmacological treatment, noticing that further therapeutic measures need to be considered in heart failure treatment [221]. This evidence concerns the gene NPPB and congestive heart failure.