Abstract 4875: Obstructive Sleep Apnea is Associated With Increased Aortic Stiffening, Microalbuminuria and Endothelial Dysfunction in Hypertensives: A Double Enemy to the Vasculature
Introduction: Incriminating evidence of an adverse effect of obstructive sleep apnea (OSA) on the vasculature is increasing. We investigated the degree of vascular impairment in the high risk population of hypertensives with OSA by diverse atherosclerotic surrogates.
Methods: We studied 62 consecutive patients [49 men, aged 48±7 years, 31 smokers, body mass index (BMI) 32±4kg/m2) with untreated hypertension and OSA diagnosed by polysomnography (PSG) [apnea/hypopnea index (AHI)≥5], and a control group of 70 untreated hypertensives without OSA (AHI<5) matched for age, sex, body mass index, smoking status and 24h systolic blood pressure (BP). All subjects underwent 24h ambulatory BP monitoring, echocardiography and aortic stiffness evaluation by means of carotid - femoral pulse wave velocity (PWV) using an automatic device (Complior SP). Metabolic profile, serum creatinine levels (sCr), glomerular filtration rate (eGFR), and asymmetric dimethyl-arginine (ADMA) were assessed from a morning blood sample. The albumin/creatinine excretion ratio (ACR) was calculated from two non consecutive urine morning samples.
Results: Hypertensives with OSA had similar 24h systolic BP (140±9 vs. 138±6 mmHg, p=NS) but higher 24h diastolic BP levels (87±6 vs. 84±7 mmHg, p=0.03) compared to the control group. Left ventricle mass index was greater in the OSA group (109±23 vs. 100±25 gr/m2, p=0.04), while relative wall thickness (0.43±0.07 vs. 0.43±0.08) and metabolic profile did not differ (p=NS for all). Although sCr and eGFR were similar between the two groups (0.96±0.18 vs. 0.94±0.18mg/dl and 114±30 vs. 116±27 ml/min/1.73m2, p=NS for both), patients with OSA exhibited higher levels of logACR and logADMA compared to those without (1.07±0.31 vs. 0.66±0.38 mg/g, −0.25±0.1 vs. −0.31±0.1 μmol/l, respectively, p<0.0001 for both) even after adjustment for confounders. Furthermore, PWV was elevated in OSA patients compared to the control group. (8.2±0.7vs.7.2±0.9m/sec, p<0.001). In the entire study population logAHI was correlated with PWV (r=0.35, p<0.001), logADMA (r=0.30, p=0.001) and logACR (r=0.34, p<0.0001).
Conclusions: Elevated values of ADMA, PWV and ACR in hypertensives with OSA reveal an atherosclerotic state enhanced by sleep disordered breathing.