Objective: To investigate whether antihypertensive medications ameliorate the changes in arterial stiffness and blood pressure associated with obstructive sleep apnea-hypopnea syndrome (OSAHS).
Methods: Sixty-one OSAHS patients (13 female, 48 male, mean age 53 +/- 12 years), among which 26 were normotensive (N group), 7 hypertensive on no antihypertension medications (H group), and 28 hypertensive on various combination antihypertension therapy (HM group), were prospectively diagnosed with standard nocturnal polysomnography. Beat-to-beat blood pressure was continuously recorded from the radial artery by applanation tonometry. Arterial stiffness was measured by arterial augmentation index (AAI). The following conditions:awake, early apnea, late apnea and post apnea for all events with nadir O(2) saturation < or = 89% were analyzed.
Results: Systolic blood pressures (SBP) post-apnea [N group (143 +/- 13) mm Hg, H group (137 +/- 27) mm Hg, HM group (137 +/- 14) mm Hg] were significantly increased from awake [N group (136 +/- 15) mm Hg, H group (136 +/- 23) mm Hg, HM group (130 +/- 14) mm Hg], early apnea [N group (131 +/- 13) mm Hg, H group (124 +/- 25) mm Hg, HM group (126 +/- 13) mm Hg], and late apnea [N group (130 +/- 13) mm Hg, H group (125 +/- 25) mm Hg, HM group (124 +/- 14) mm Hg] respectively (P < 0.01, repeated measures ANOVA). AAI was significantly increased for the N group (P < 0.01) from awake to late apnea [(10.5 +/- 2.6)% vs (14.4 +/- 3.2)%] and from early apnea to late apnea [(10.6 +/- 2.3)% vs (14.4 +/- 3.2)%], and also for H group (P < 0.05) from awake to late apnea [(11.2 +/- 3.9)% vs (16.3 +/- 8.0)%)] and from early apnea to late apnea [(11.8 +/- 3.8)% vs (16.3 +/- 8.0)%]. Meanwhile, no significant differences in AAI among awake, early apnea, late apnea, and post-apnea conditions were found in HM group.
Conclusions: Systemic blood pressure increases significantly during the post-apneic phase of OSAHS even with the combined antihypertensive therapy which normalizes awake BP in the hypertensive patients. However, increases in arterial stiffness during obstructive events can be ameliorated by combined antihypertension medications, in contrast to increased arterial stiffness seen in normotensive OSAHS patients or hypertensive OSAHS patients on no such medications.