NPPB and sleep apnea syndrome: In another study that included fifty patients with chronic heart failure and sleep disordered breathing, adaptive servoventilation (ASV) significantly improved AHI, central apnea index, obstructive apnea index, arousal index, and mean and lowest hemoglobin saturation compared to baseline and reduced NT-proBNP and Cyst C plasma levels (1.391 ± 0.550 at baseline versus 1.348 ± 0.489 mg/L after ASV, p < 0.05 for Cyst C) [36].