Abstract 12672: More Than 40% of Hypertensive Sleep Apnea Turned to Normotensive by Continuous Positive Airway Pressure Therapy Along With More Substantial Benefit in Having Morning Hypertension
Background: Sleep apnea (SAS) elevates blood pressure (BP) and is one of important causes of resistant hypertension (HT). Continuous positive airway pressure therapy (CPAP) decreases BP in SAS patients. However, the impact of CPAP on BP in hypertensive SAS patients is still obscure. This study is to examine the hypothesis that (1) BP lowering effect of CPAP is more prominent on morning BP than on evening BP in hypertensive SAS patients, and (2) a high percentage of hypertensive SAS patients especially of having morning HT turn to normotensive by CPAP.
Methods: Ninety-three hypertensive SAS patients (74 males, 19 females, age 57.0+/-14.1, BMI 27.2+/-5.3) treated by CPAP were included. All patients were undertaken polysomnography before and after CPAP application and measured morning and evening BP in each occasion. CPAP was applied in patients with apnea-hypoxia index (AHI) > 20. Mean duration of CPAP was 32.7+/-26.1 days. Central SAS shared only 2.1% in these patients. HT was defined as SBP of ≥140 and/or DBP of ≥90 mmHg. Thirty-two of 93 patients were under antihypertensive drugs.
Results: After application of CPAP, AHI decreased dramatically (51.6+/-23.4 to 5.6+/−5.2, p<0.001). Lowest SpO2 (73.4+/−12.5 to 90.5+/−5.1%, p<0.001) and average SpO2 (95.3+/−2.0 to 97.5+/−0.9%, p<0.001) elevated significantly. Notably, morning BP decreased significantly both in SBP (146.5+/−11.5 to 136.3+/−16.0 mmHg, p<0.001) and in DBP (91.2+/−12.7 to 83.4+/−11.3 mmHg, p<0.001), while evening SBP and DBP did not change (138.6+/−14.9/ 80.5+/−13.1 to 135.9+/−16.7/79.4+/−12.6 mmHg). Among these 93 hypertensive SAS patients, 39 (41.9%) patients were shifted to normotensives. Moreover, 27 of 42 (64.3%) SAS patients who had morning HT but not evening HT before CPAP application converted to normotensive, whereas merely 24% of those with morning and evening HT before CPAP were turned to normotensive.
Conclusion: Using CPAP, BP fall was observed by about 7% on morning, while no change in BP on evening. BP decreased into normotensive level in over 40% of hypertensive SAS patients and, amazingly, almost two-thirds of SAS patients having morning HT were turned to normotensive. More widespread applying of CPAP is encouraged in hypertensive SAS patients, especially for having morning HT.
- © 2011 by American Heart Association, Inc.