BDNF and cryohydrocytosis: The main findings of the present study were as follows: (1) serum BDNF levels and VO2peak were lower in non-survivor patients with ChC than in the survivors; (2) serum BDNF concentration of 2.5 ng/mL was the optimal cut-off value to identify patients at risk of adverse outcome; (3) low serum BDNF levels, LVEF, and VO2peak were independent predictors of cardiac death, and (4) the combination of low serum BDNF levels and LVEF are highly predictive of cardiac death in ChC after 39 ± 14 months of follow-up.