0493 A new perspective on exploring the predictive factors of blood pressure reduction during CPAP treatment in OSA

Abstract

Abstract Introduction The predictive factors of BP response to continuous positive airway pressure (CPAP) in obstructive sleep apnea (OSA) are still being explored. We aimed to assess the antihypertensive effect of CPAP considering the obstructive respiratory event-triggered BP surge profiles in 130 subjects with severe OSA and untreated hypertension. Methods Nocturnal BP was monitored continuously and synchronized with polysomnography. Event-triggered BP surge profiles were studied: BP surge as the value of event-related systolic BP elevation; BP index as the number of BP surge events of ≥10 mmHg per hour. Patients were then divided into two groups according to the median BP index (high and low BP surge groups) and assigned to 4 weeks of CPAP. Changes in BPs and plasma biomarkers were compared. After the initial evaluation, patients with a better BP response in the high BP surge group were then followed up for the second evaluation at 24 months. Results Overall, a modest decrease was observed in both office and asleep BPs at the 4-week follow-up; however, BPs dropped more markedly in patients in high BP surge group than those in low BP surge group, in both office systolic BP (SBP:5.3 mmHg vs.2.2 mmHg, P=.005) and diastolic (DBP:4.0mmHg vs.1.2 mmHg, P=.011), especially the asleep SBP (9.0mmHg vs.2.1 mmHg, P<.001). For 30 cases in the high BP surge group, optimal BP control was achieved in 60.0% of patients and BP < 140/90mmHg reached up to 83.3% after 24 months of CPAP. Linear regression revealed that BP index was significantly associated with BP decrease during CPAP treatment. Conclusion Our results suggest that high event-triggered BP surge was a sensitive predictor of BP response to CPAP in patients with severe OSA and hypertension. Support (if any)