PURPOSE: To study the long-term effect of nasal CPAP on carotid artery intima-media thickness (IMT) in patients with Obstructive sleep apnoea syndrome (OSAS).
METHODS: A prospective study of patients newly diagnosed with OSAS receiving CPAP versus those on conservative treatment (CT) over 12 months. IMT was assessed with B-mode Doppler for both carotid arteries using images of the far wall of the distal 10 mm of the common carotid arteries. Two end-diastolic frames were selected, digitized, and analyzed for mean IMT, and the average reading from these 2 frames was calculated for both right and left carotid arteries.
RESULTS: [mean (SE)]: There were 28 and 22 patients in CPAP and CT group respectively with no significant differences in age 49(2) yrs, BMI 28.2(0.7) kg/m2, ESS 13.6(0.9), AHI 38(4)/hr, arousal index 30(2)/hr, minimum SaO2 75(2)%, and existing co-morbidities. The CPAP usage was 4.8(0.4) hrs/night for the CPAP group over 1 year. The mean carotid IMT at baseline, 6 months and 12 months were 0.7605(0.03), 0.7205(0.02), and 0.7038(0.02)mm for the CPAP group whereas the IMT data for the CT group were 0.7600(0.03), 0.7757(0.03), and 0.7777(0.03)mm respectively, with p =0.001(ANOVA for repeated measures). Among those free of existing cardiovascular diseases, the mean carotid IMT at baseline, 6 months and 12 months were 0.7217(0.04), 0.6908(0.04), and 0.6592(0.03)mm for the CPAP group (n=12) with CPAP usage 4.71(0.74) hrs/night over 12 months whereas the IMT data for the CT group (n=12) were 0.6600(0.02), 0.6954(0.02), and 0.6900(0.02)mm respectively, with p =0.004(ANOVA for repeated measures).
CONCLUSION: 12 months of nasal CPAP leads to a significant reduction in carotid IMT in patients with OSAS.(Project funded by the CUHK Direct Grants #2041204).
CLINICAL IMPLICATIONS: Compliance with nasal CPAP may confer cardio-protective effects in patients with OSAS.
DISCLOSURE: David Hui, No Financial Disclosure Information; No Product/Research Disclosure Information