Cardiovascular Function in Obstructive Sleep Apnea Patients with Controlled Hypertension

Abstract

This study investigated hemodynamic characteristics of obstructive sleep apnea (OSA) accompanied by hypertensive disease in obese men, in whom blood pressure was pharmacologically controlled within the normal range, not exceeding 140/90 mmHg. There were 21 severe OSA patients (mean age 54.1 ± 9.3 years, apnea-hypopnea index of 47.1 ± 18.8 episodes per hour) included in the study, in whom OSA was diagnosed with polysomnography. The control group consisted of healthy normotensive age-matched subjects. Hemodynamic profile was recorded nonivasively with impedance cardiography. Brachial blood pressure and radial artery tonometry were performed to capture and reconstruct peripheral radial and central aortic pressure waveforms in both groups of subjects. Compared to healthy men, OSA patients had a significantly higher body mass index (BMI); the mean increase in BMI amounted to 6.4 ± 1.2 kg/m2. The patients also presented significant differences in the hemodynamic profile. The difference consisted of a faster heart rate, higher peripheral pulse pressure, and reduced blood flow acceleration and velocity indices, describing myocardial contractility. Notably, the significance of hemodynamic differences in OSA patients disappeared in the analysis adjusted for the outstanding increase in BMI. In conclusion, the findings strongly suggest that obesity rather than the hypertensive disease per se is a source of hemodynamic consequences in OSA patients.