The relationship between aortic stiffness and cardiac function in patients with obstructive sleep apnea, independently from systemic hypertension

Objective: We sought to evaluate aortic function and its relationship with left ventricular (LV) function in patients with obstructive sleep apnea syndrome (OSAS), with or without systemic hypertension. Methods: A total of 29 patients with OSAS, 28 patients with systemic hypertension without OSAS, and 19 patients having both disorders were chosen as a study group, and 29 participants without these two disorders were taken as the control group; none of the patients had a history of cardiac disease. All of them underwent echocardiography and polysomnography. Aortic strain and distensibility were calculated from the aortic diameters measured by echocardiography and blood pressure obtained by cuff-sphygmomanometer. Cardiac functions were determined using echocardiography comprising standard 2-dimensional and conventional Doppler and Doppler tissue imaging. Results: Aortic strain (mean +/- SD; 6.1 +/- 2.7% vs 6.4 +/- 2.4%, 4.7 +/- 1.8%, and 13.7 +/- 4.5%, P < .001, respectively) and distensibility (mean SD 2.8 +/- 1.6 vs 2.5 +/- 0.9, 1.7 +/- 0.7, and 6.2 +/- 3.2 10(-6) cm(2) dyn(-1) respectively) were significantly decreased in the patient groups (OSAS, hypertensive, and OSAS and hypertensive) compared with the control group. LV long-axis and diastolic functions were also impaired in the study group. There were good correlations between the aortic stiffness and LV function parameters. In a multivariate analysis, aortic strain was the parameter found to be most strongly associated both with the Doppler tissue imaging mean peak early/late diastolic velocity ratio and the LV mitral lateral annular plane systolic excursion. Conclusion: Aortic stiffness parameters (aortic strain and distensibility), LV systolic long-axis function indicators (mitral lateral annular plane systolic excursion, peak systolic myocardial velocity at lateral annulus, peak systolic myocardial velocity at septal annulus), and Doppler tissue imaging-derived LV diastolic indices were found abnormal in patients with OSAS, hypertension, or both. Thus, subclinical cardiac dysfunction has been found in patients with OSAS independent from the systemic hypertension.