Abstract 16094: Association of Diurnal Blood Pressure Variation and Nocturnal Hypoxia in Patients With Cardiovascular Risk Factors: Japan Morning Surge-Home Blood Pressure (J-HOP) SAS Study

Abstract

Introduction: Abnormal diurnal blood pressure (BP) variation, such as riser or extreme-dipper, is known as risk factors of target organ damage and subsequent cardiovascular events. Nocturnal hypoxia due to sleep apnea syndrome (SAS) is likely to influence diurnal BP variation and risk increase; however, little has been evaluated in large scale cohort in Asian population. Hypothesis: We assessed the hypothesis that diurnal BP variation is associated with nocturnal hypoxia in high risk Japanese patients. Methods: The study subjects were 1087 participants of the J-HOP Study with one or more cardiovascular risk factors (n=4019). Pulse oximetry oxygen saturation (SpO2) was measured with a validated device (PULSOX Me-300; Teijin Pharma, Tokyo, Japan) simultaneously with ambulatory BP monitoring (ABPM). Results: The frequency of each diurnal BP variation are as follows; dipper (normal circadian rhythm) 42.8%, non-dippers 34.6%, extreme-dipper 13.2%, riser 9.4%. When assessed by 3% oxygen desaturation index (ODI; times/h), 14.2% of patients showed 3%ODI≥15 (suspected moderate sleep apnea), and 2.8% of patients showed 3%ODI≥30 (suspected severe sleep apnea). The likelihood of coexisting severe sleep apnea (3%ODI≥30) was significantly higher (5.9%) in patients with riser pattern compared with that in dipper pattern (1.9%) (odd ratio 3.17; 95%CI 1.10-9.11, p<0.03). Three percent ODI was significantly higher in patients with riser pattern than that in dipper pattern (6.6 vs 5.1 times/h; p=0.01). Furthermore, the patients in the longest time spent with SpO2 <90% category in quintiles had an increased likelihood of extreme-dipper pattern compared with those in the shorter categories (odds ratio 1.71; 95%CI 1.10-2.65; p<0.03). Conclusion: Abnormal diurnal BP variation was associated with nocturnal hypoxia in patients with cardiovascular risk factors. For the patients with riser or extreme-dipper pattern, further evaluations are recommended to detect higher risk patients with nocturnal hypoxia, such as SAS, heart failure or chronic pulmonary diseases.