Effect of the obstructive sleep apnea hypopnea syndrome treatment on blood pressure in patients with resistant hypertension

Abstract

Objective: To investigate the effect of the treatments for obstructive sleep apnea hypopnea syndrome (OSAHS) on the resistant hypertension (RH) of patients. Methods: Eighty patients with OSAHS and RH (blood pressure could not be controlled under 140/90 mmHg (1 mmHg=0.133 kPa) even with more than three kinds of antihypertensive drugs including diuretics) received surgery or continuous positive airway pressure (CPAP) treatment. The results of polysomnography monitoring, ambulatory blood pressure monitoring, and the dosage of antihypertensive medication were recorded before and six months after the treatment. Results: Apnea hypopnea index (AHI) decreased from (32.9±10.8) before treatment to (9.4±6.5) after treatment, while the lowest oxygen saturation (SaO(2)) increased from (0.682±0.062) to (0.884±0.056), with significant differences (t value was 18.863 and 26.614, respectively; both P<0.001). Twenty-four hours systolic blood pressure (SBP)/diastolic blood pressure (DBP) decreased respectively from ((150.5±9.8)/(97.8±7.3)) mmHg to ((140.7±6.8)/(88.6±6.3)) mmHg, daytime SBP/DBP decreased from ((154.3±8.9)/(100.6±7.4)) mmHg to ((144.8±5.8)/(91.3±5.5)) mmHg, and nighttime SBP/DBP decreased from ((145.5±8.8)/(93.8±6.4)) mmHg to ((135.8±5.7)/(84.6±5.9)) mmHg, with significant differences (t value was 7.832, 6.903, 7.005, 6.848, 8.025, 7.554, respectively; all P<0.001). The reduction of nighttime SBP /DBP was ((11.5±2.2)/(10.2±3.1)) mmHg, and the reduction of daytime SBP/DBP was ((9.0±2.8)/(7.9±3.5)) mmHg. The reduction of nighttime SBP/DBP was more obvious than daytime SBP/DBP, with significant differences (t value was 9.732 and 6.936, respectively; both P<0.001). Before treatment, nighttime blood pressure decrease rate below 10% was showed in 75 percent of patients, and after treatment, this rate only in 37.5 percent of patients (χ(2)=22.857, P<0.01). The numbers of required antihypertensive drugs decreased in 45 (56.3%) cases, the average numbers of antihypertensive drugs decreased from (3.2±0.4) before treatment to (2.6±0.5) after treatment, with a significant difference (t=9.276, P<0.01). Conclusions: After treatment of OSAHS, the blood pressure of the patients with OSAHS and RH dropped significantly, the circadian rhythm of blood pressure condition was better, the varieties of antihypertensive drugs taken in these patients were reduced significantly.