Left ventricular diastolic dysfunction in obstructive sleep apnoea syndrome by an echocardiographic standardized approach: An observational study.

BACKGROUND: The association between obstructive sleep apnoea syndrome (OSAS), left ventricular (LV) diastolic dysfunction and LV geometry remains controversial because of coexisting disorders.

AIMS: To evaluate LV diastolic dysfunction and its independent predictors in a real-life cohort of OSAS patients, by a standardized approach.

METHODS: We consecutively included 188 OSAS patients after an overnight polysomnography to undergo clinical evaluation, ambulatory blood pressure measurement and complete echocardiography, combining M-mode, two-dimensional Doppler and tissue Doppler imaging modes. Correlations between OSAS severity and clinical and echocardiographical variables were assessed, and logistic regression models were used to identify possible determining factors of LV diastolic dysfunction.

RESULTS: Most patients were hypertensive (n=148, 78.7%) and already receiving treatment by continuous positive airway pressure (n=158, 84.5%). The prevalence of LV hypertrophy, defined by LV mass index (LVMi) normalized by height (2.7), was 12.4%, with a significant correlation with hypertension (P=0.004). The apnoea-hypopnoea index was correlated with body mass index (P<0.0001), 24-hour systolic blood pressure (P=0.01) and LVMi normalized by height (2.7) (P=0.03). Diastolic function assessed by a global approach was impaired for 70 patients (37.2%) and none of the OSAS severity variables was a determining factor after multivariable analysis with adjustment for age and sex.

CONCLUSION: Diastolic dysfunction assessed by a standardized approach is common in OSAS and should be routinely evaluated; it is independently predicted by none of the respiratory severity variables.