The optimal cut-offs for HFrEF prediction were the following: 9531 pg/mL for NT-proBNP (SP 0.70, SE 0.50), 13 for the number of total B-lines (SP 0.69, SE 0.85) and 1 for the number of intercostal spaces of pleural effusion (SP 0.55, SE 0.89) (Fig. 1). Here, NPPB is linked to Pleural effusion.