Objective: To compare the predictable value of different index in evaluating the risk of cardiovascular injury in the patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) by using Framingham Risk Score (FRS).
Methods: 120 OSAHS patients were divided into 2 groups with different levels of cardiovascular injury according to the FRS: low risk group (with the FRS < 10) and non-low risk group (with the FRS > or = 10). Data about medical history, gender, age, blood pressure, height, distribution, BMI, neck circumference (NC) Epworth sleepiness scale (ESS) SCORE were collected. Polysomnography (PSG) was used to measure the apnea-hypopnea index (AHI), oxygen desaturation index (ODI), lowest SaO(2) during sleep (LSaO(2)), time spent below 90% oxygen saturation (TS90). Peripheral blood samples were collected to examine the serum high-sensitivity C-reactive protein (hs-CRP). Correlation analysis was conducted.
Results: Except the traditional risk factors for coronary heart disease, the subjects with higher FRS were found with bigger NC [(40.48 +/- 2.80) cm vs (39.15 +/- 4.31) cm, P < 0.05], longer course of disease [(12.77 +/- 7.89) y vs (9.36 +/- 5.98) y, P < 0.05], higher AHI (47.61 +/- 25.63 vs 34.01 +/- 25.72, P < 0.01), lower LSaO(2) (73.85% +/- 11.10% vs 77.91 +/- 9.77%, P < 0.05), longer TS90 (23.46% +/- 24.46% vs 14.48% +/- 18.85%, P < 0.05), and higher ODI (49.62 +/- 23.75 vs 39.01 +/- 24.87, P < 0.05). Stepwise multivariate regression showed that FRS was positively correlated with AHI and ODI, and negatively correlated with LSaO(2). All the PSG index, AHI had the most important impact on FRS (t = 2.910, P = 0.004). There was no significant difference in hs-CRP level between different groups (P = 0.649).
Conclusion: The cardiovascular injury in OSAHS patients is correlated with repeated hypoxia during sleep-time. AHI is the most important PSG index to predict this kind of damage.