Effect of Continuous Positive Airway Pressure (CPAP) on Carotid Artery Thickness in Patients with Sleep Apnea Syndrome

The carotid artery intima-media thickness (IMT) measured by ultrasound has attracted attention as a significant predictor of cardiovascular events. An increase of IMT is found earlier in OSAS patients and these changes have been reported to be correlated with the severity of OSAS. This study was performed to clarify the effect of continuous positive airway pressure (CPAP) on the carotid IMT in SAS patients. Twenty-three consecutive male patients (group C; 56 ± 13 years, BMI of 29.9 ± 4.0kg/m^2, AHI of 35.9 ± 15.6/h) who had been newly diagnosed as suffering from SAS by polysomnography (PSG) at our hospital and were given adequate CPAP therapy were and enrolled, as well as 12 consecutive male patients who did not receive CPAP for various reasons (group N; 53 ± 16 years old, BMI of 28.8 ± 5.5kg/m^2, and AHI of 36.8 ± 17.0/h). Carotid artery ultrasonography was performed at the time of PSG and after 18 months of CPAP treatment. The changes of maxmum value of IMT (ΔmaxIMT) and mean value of IMT (ΔmeanIMT) between the two point were compared. There were no differences between the two groups with regard to meanlMT (group C, 0.881 ± 0.235; group N, 0.894 ± 0.086mm; NS) or maxIMT (group C, 1.1241 ± 0.491; group N, 1.070 ± 0.086mm; NS) at the time of PSG. However, it was found that both of ΔmeanIMT (group C, 0.011 ± 0.005; group N, 0.013 ± 0.005mm; p<0.05) and ΔmaxIMT (group C, 0.005 ± 0.002; group N, 0.014 ± 0.006mm; p