The effect of continuous positive airway pressure on blood pressure and left ventricular structure in male patients with obstructive sleep apnea

OBJECTIVES
We investigated the effect of nasal continuous positive airway pressure (CPAP) on blood pressure (BP) and left ventricular structure in male patients with severe obstructive sleep apnea (OSA).

STUDY DESIGN
Thirty-three male patients with severe OSA underwent CPAP treatment for six months. Compliance was defined as the use of CPAP for at least 3.5 hours per night during treatment; thus, 25 patients (mean age 47.9±8.2 years) were compliant with a mean of 5.3±1.9 hours, and eight patients (mean age 48.6±8.4 years) were noncompliant with a mean of 1.0±0.8 hours. Before and after CPAP, echocardiographic assessments were made to determine left ventricular structure (interventricular septum thickness, left ventricular posterior wall thickness, left ventricular mass, and left ventricular mass index) and function (E/A ratio, isovolumic relaxation time, mitral deceleration time, and velocity of mitral flow propagation), and systolic and diastolic blood pressures were measured. In the compliant group, 20 patients had hypertension, 22 patients had diastolic dysfunction, and 16 patients had left ventricular hypertrophy (LVH). All noncompliant patients were hypertensive, four had diastolic dysfunction, and four had LVH.

RESULTS
Systolic and diastolic BPs significantly decreased after CPAP treatment, the decreases being more pronounced in the compliant group (p<0.001 vs p<0.01). Parameters of left ventricular structure and diastolic function significantly improved in compliant patients following CPAP. Left ventricular hypertrophy improved in nine patients (56.3%, p<0.0001) and diastolic dysfunction improved in 11 patients (50%, p<0.001). However, in the noncompliant group, parameters of left ventricular structure and diastolic functions did not differ significantly and the number of patients having LVH or diastolic dysfunction did not change.

CONCLUSION
In severe OSA, CPAP treatment significantly decreases BP and left ventricular wall thickness, and improves left ventricular diastolic function.