The Unexpected Results of a Prospective Study: Effect ofCPAPon Blood Pressure Values in Patients With Obstructive Sleep Apnea Syndrome Associating Severe Resistant Hypertension

Oana Deleanu; Andra Malaut; Alexandra Sandu; Ruxandra Ulmeanu; Florin Mihaltan

PURPOSE: There are few studies regarding the effect of CPAP on blood pressure (BP) values in patients with OSAS and resistant hypertension (RHT), reporting a small and not homogenous BP reduction in patients with BP values very close to normal; only one study analyzed BP after 6 months of CPAP treatment. We analyzed the modification in BP measured with 48h ABPM in CPAP treated patients, comparing values from baseline with those at 3 and 6 months.

METHODS: We studied 27 patients without secondary RHT, mild OSAS, central SAS, hypercapnia, insomnia, restless legs syndrome, CPAP failure (manual PSG titration), modifying HT medication during the study, poor CPAP compliance (<4 h in >70% days used).

RESULTS: 11 patients using CPAP completed the 6 months evaluation: 8 men (73%), mean age 55.1±7.0 years, mean IAH 66.9±20.0/h, baseline SBP 166.6±20.1mmHg and DBP 93.9±12.5mmHg, diagnosed with HT for 11.2±10.9 years, CPAP compliance 5.9±1.2h/night. Only significant difference in BP values was an increase of nocturnal maximum SBP from 3 to 6 months (178.0±22.4 to 204.4±29.0 mmHg, p=0.02), without any significant differences regarding the ABPM dipper pattern, mean/diurnal/nocturnal SBP and DBP or measured by sphygmomanometer, from baseline to 3 or 6 months. The patients were well controlled regarding OSAS by CPAP treatment, with a mean residual AHI=2.84/h, with a significant reduction in Epworth score under CPAP from baseline 10.3±5.7 to 4.0±3.8 after 3 months (p=0.004) and to 1.3±1.2 (p=0.001) after 6 months, with a significant improvement in quality of life (SAQLI) from baseline 4.5±1.5 to 6.3±0.7 after 3 months (p=0.002) and to 6.5±0.4 (p=0.001) after 6 months. This is an on going study and the purpose of this analyze was to compare the modification in BP values within the same group of patients with severe uncontrolled RHT.

CONCLUSIONS: These unexpected results regarding BP values can be justified by myocardial and vascular remodeling after long period of uncontrolled severe RHT. The period of accommodation with CPAP and the psychological burden of disease, with a good compliance but increasing in time can also influence the response of BP values.

Chest. 2014;146(4_MeetingAbstracts):951A. doi:10.1378/chest.1992845