Introduction: Hypertension is common in
patients with obstructive sleep apnea (OSA). However, the effect of OSA
on ventricular function, especially diastolic function, is not clear.
Therefore, we have assessed the prevalence of diastolic dysfunction in
patients with OSA and the relationship between diastolic parameters and
severity of OSA.
Methods: Sixty-eight consecutive
patients with OSA confirmed by polysomnography underwent
echocardiography. Diastolic function of the left ventricle was
determined by transmitral valve pulse-wave Doppler
echocardiography. Various baseline characteristics, severity of OSA,
and echocardiographic parameters were compared between patients with
and without diastolic dysfunction.
Results: There were
61 male and 7 female patients with a mean age of 48.1 ± 11.1 years,
body mass index of 28.5 ± 4.3 kg/m2, and apnea/hypopnea
index (AHI) of 44.3 ± 23.2/h (mean ± SD). An abnormal relaxation
pattern (ARP) in diastole was noted in 25 patients (36.8%). Older age
(52.7 ± 8.9 years vs 45.1 ± 11.3 years, p = 0.005),
hypertension (56% vs 20%, p = 0.002), and a lower minimum
pulse oximetric saturation (Spo2) during
sleep (70.5 ± 17.9% vs 78.8 ± 12.9%, respectively; p = 0.049)
were more common in patients with ARP. By multivariate analysis,
minimum Spo2 < 70% was an independent
predictor of ARP (odds ratio, 4.34; 95% confidence interval, 1.23 to
15.25; p = 0.02) irrespective of age and hypertension. Patients with
AHI ≥ 40/h had significantly longer isovolumic relaxation times than
those with AHI < 40/h (106 ± 19 ms vs 93 ± 17 ms, respectively;
p = 0.005).
Conclusion: Diastolic dysfunction with
ARP was common in patients with OSA. More severe sleep apnea was
associated with a higher degree of left ventricular diastolic
dysfunction in this study.