Abstract 9881: Effects of CPAP on Very Short-Term Blood Pressure Variability Associated With Sleep-Disordered Breathing Determined by Pulse-Transit-Time-Based Blood Pressure Measurements

Abstract

Background: Sleep-disordered breathing (SDB) and blood pressure (BP) variability are closely associated with cardiovascular diseases. We have recently reported that pulse-transit-time (PTT) has enabled to monitor the beat-to-beat BP, identifying a strong relationship between the severity of SDB and the extent to very short-term BP variability. Here, we investigated the effects of continuous positive airway pressure (CPAP) on very short-term BP variability. Methods: We studied 57 patients (mean age 61 years old, male 42) with SDB who underwent the full polysomnography on two consecutive days for diagnosis (baseline) and CPAP. PTT was continuously monitored together, and PTT-based BP values were measured on a beat-to-beat basis. PTT index was defined as the average number of acute transient rises in BP (≥12 mmHg) within 30 seconds per hour. Results: Apnea-hypopnea index (AHI) was decreased from 46.5±22.4 to 13.7±15.0 (P<0.01) by CPAP. CPAP significantly lowered the average value of systolic PTT-based BP from 121±21 to 118±20 mmHg (P=0.04). Importantly, CPAP significantly reduced the PTT index from 31.4±20.1 to 20.8±15.6 (P<0.01) as well as the standard deviation (SD) of systolic PTT-BP from 5.3±1.9 to 4.9±1.4 mmHg (P=0.01), suggesting that very short-term BP variability was improved by CPAP ( Figure ). The changes in PTT index after CPAP were significantly correlated with the improvement in AHI (R=0.55), oxygen desaturation index (R=0.36), minimal SpO 2 (R=0.48), mean SpO 2 (R=0.46), and arousal index (R=0.58). In multivariate linear regression analysis, the change in AHI was the independent factor to determine the reduction of the PTT index after CPAP. Conclusion: PTT-based BP discovered the improvement in very short-term BP variability associated with SDB events by CPAP therapy.