[Intermittent Hypoxemia in Patients with Heart Failure with Preserved Ejection Fraction].

Objective To investigate the characteristics of nocturnal intermittent hypoxemia in patients with heart failure(HF) with preserved ejection fraction(HFpEF).Methods Patients(n=854) who completed sleep test and echocardiography from January 2011 to December 2014 were retrospectively studied. HF patients with an ejection fraction(EF) of ≥50% were included in the HFpEF group(n=112) while HF patients with an EF of <50% included in the group of HF patients with reduced EF(HFrEF)(n=104). Respiratory events and minimum nocturnal saturation(minSaO₂) were recorded by home sleep testing,and the percentage of total sleep time with saturation <90%(T90SaO₂) were calculated.Results Compared with patients without HF,subjects with HFpEF and HFrEF had more breathing events[13(5,29)/h vs. 18(6,36)/h,and 21(8,45)/h,P<0.001],lower minSaO₂[85(80,87)% vs. 82(77,86)% and 83(78,87)%,P<0.001] and relatively longer T90SaO₂[3.0(0.4,15.5)% vs. 6.0(1.5,24.8)% and 6.7(1.3,14.4)%,P<0.001]. The HFpEF group had significantly higher odds of moderate-severe hypoxemia(minSaO₂<85%) during sleep than those without HF(OR=2.02,95%CI=1.34-3.11,P<0.001),with the significance persisting after adjusting for covariates including age,gender,hypertension,diabetes,coronary heart disease,renal dysfunction,and smoking(OR=1.85,95%CI=1.20-2.90,P=0.006).Conclusion Patients with HFpEF have frequent nocturnal intermittent hypoxemia,which warrants further investigations to evaluate if remission of night-time hypoxemia may improve long-term prognosis in this cohort.