Apneia obstrutiva do sono e função endotelial em pacientes com hipertensão arterial resistente

Abstract

Obstructive sleep apnea (OSA) is considered an independent risk factor for cardiovascular disease. There is evidence that individuals with OSA may have increased inflammatory mediators, changes in the metabolic profile, increased sympathetic activity with consequent elevation of blood pressure (BP) and endothelial dysfunction. Resistant hypertension (RH) is defined as uncontrolled blood pressure (BP ≥ 140/90mmHg) despite the current use of three hypotensive drugs at full doses, including a diuretic, or the need for >3 medications to control BP. OSA has been reported as the most common secondary cause of high blood pressure maintenance. The objective was to determine the prevalence of OSA and verify its association with endothelial function and anthropometric parameters in patients with resistant hypertension (RHGroup) and BP controlled by medication (CHGroup). It was a cross-sectional study involving 40 hypertensive patients (20 in RHG and 20 in CHG), aged between 18 and 75 years. Endothelial function and OSA were assessed by peripheral arterial tonometry. BP was measured by oscillometric method on automatic device. Endothelial function was assessed by peripheral arterial tonometry (PAT) by EndoPAT2000 and the OSA diagnosis also through PAT, using the portable device WatchPAT200. Anthropometric evaluation was performed through measurements of waist (WaC), hip and neck circumference (NC), BMI, waist to height ratio (WHtR), and body composition assessed by bioelectrical impedance. Patients were generally late middle-aged (54.95 ± 2.39 in the RH group and 56.15 ± 2.42 in the controlled hypertension [CH] group. The prevalence of OSA in RHG was 85% (17 of 20) [apnea-hypopnea index=12.39±1.89], and 80% (16 of 20) in CHG (AHI=20.74±4.69) and it was more frequent in men (93.7% [15 of 16] vs 75% [16 of 24]; p=0.04, OR=3.86; 95% IC 0.99 to 14.92). Both groups presented similar anthropometric parameters values. Endothelial function evaluated by reactive hyperemia index was similar in both groups (RHG: 1.88±0.09 vs CHG: 2.03±0.09; p=0.28). Although we found differences in oxygen desaturation> 4% (RHG: 28.75 ± 5.08 vs CHG: 64.15 ± 16.97, p = 0.04), total sleep time (RHG: 309.5 ± 15.27 vs CHG: 323.3 ± 18.74 min) and minimum saturation (RHG: 87.8±0.85 vs CHG: 83.3±2.37%) was not different. In general, OSA was correlated with weight (r = 0.51, p = 0.0007), BMI (r = 0.41, p = 0.0078), WaC (r = 0, 44, p = 0.005), NC (r = 0.38, p = 0.01) and WHtR (r = 0.39, p = 0.01) and independently associated with impairment of endothelial function (p = 0.0297, OR = 0.17, 95% CI 0.04 to 0.72). In conclusion, the findings of this study show high prevalence of OSA in patients with resistant hypertension, similar to that of controlled hypertension group. There were no significant differences in endothelial function between resistant and controlled hypertension patients. The presence of OSA in the total group of hypertensive patients was associated with increased risk of impaired endothelial function.