As demonstrated in a previous subgroup analysis of the MAGELLAN study, patients with more severe HF, as defined by high NT-pro-BNP, were at increased risk of VTE and derived benefit from rivaroxaban.7Findings from the current analysis in patients with HF selected on the basis of their lower bleeding risk further illustrate the importance of patient selection when using thromboprophylaxis for VTE events in medically ill patients with HF. The gene discussed is NPPB; the disease is hydrops fetalis.