Intermittent Hypoxemia in Patients with Heart Failure with Preserved Ejection Fraction

Abstract

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.