O062 Relationship between pulse oximetry derived markers of obstructive sleep apnoea severity and cardiac function in heart failure with preserved ejection fraction

Abstract Introduction The pathophysiological implications of Obstructive Sleep Apnoea (OSA) in patients with Heart Failure with Preserved Ejection Fraction (HFpEF) remains unclear. While novel pulse oximetry-derived measures of OSA-related cardiovascular risk have recently been described, these have not been comprehensively assessed in HFpEF. Methods Clinical, cardiovascular and polysomnography assessments have been conducted in thirty-five HFpEF patients to date. Pulse oximetry-derived measures of hypoxic burden (HB, cumulative area of respiratory event related SpO2 dips, %min/h) and pulse-wave amplitude drops index (PWADIn, drops in pulse wave amplitude of >30% per hour, events/h) were compared in HFpEF patients with and without moderate to severe OSA (Apnoea-Hypopnoea Index ≥15 events/h). Associations between HB, PWADIn and cardiovascular function were explored. Results Twenty-two HFpEF patients had moderate to severe OSA (Age 66±12y; BMI 35.4±7.7kg/m2; BNP 367±554ng/L) and thirteen had no or mild OSA (Age 65±13y; BMI 32.7±8.0kg/m2; BNP 159±142ng/L). Age, BMI, BNP and PWADIn (40.6±20.2 vs 37.4±25.6 events/h, p=0.699) were comparable between groups, while HB (99.4±70.0 vs 29.0±23.5 %min/h, p<0.001) and right ventricular end-diastolic volume (RVEDV, 150±21ml vs 122±22, p=0.016) were higher in moderate to severe OSA. PWADIn correlated with left ventricular (LV) volume (R=0.621, p=0.006), while HB correlated with RVEDV (R=0.463, p=0.014) and aortic augmentation index (R=0.506, p=0.002). Conclusions These findings indicate that pulse oximetry-derived measures of hypoxic burden and pulse wave amplitude characteristics may provide additional insight into the severity and pathophysiology of OSA in HFpEF. The impact of nocturnal pulse wave amplitude drops and oxygen desaturations on LV and RV remodelling requires further investigation.