PURPOSE: Morning blood pressure (BP) surge is associated with the increased cardiovascular and cerebrovascular events among patients with hypertension (HT). It was reported that obstructive sleep apnea (OSA) was strongly associated with both daytime and nighttime HT and it was suggested that increased sympathetic overactivation induced by OSA resulted in such HT. However, there were few reports which showed the relation between OSA and HT with morning BP surge.
METHODS: We investigated 431 consecutive OSA patients who were not treated with antihypertensive drugs and underwent overnight polysomnography (PSG) in 2005. BP was measured in the early morning and just before overnight PSG. HT was defined as average BP [(morning BP + nighttime BP)/2] ≥ 135/85 mmHg and morning BP surge was defined as ▹BP (morning BP-nighttime BP) ≥ 15/10 mmHg. According to these criteria, all patients were classified into 4 groups; HT with morning BP surge, sustained HT, normotensive with morning BP surge, normotensive. Anthropometric data, PSG findings and LF/HF which was computed from the analysis of heart rate variability using electrocardiogram during PSG, were assessed and compared among 4 groups.
RESULTS: Sixty two patients (14.3%) revealed HT with morning BP surge, 74 patients (17.2%) revealed sustained HT, 112 patients (26.0%) were normotensive with morning BP surge, 183 (42.6%) were normotensive. Patients with HT with morning BP surge revealed significantly older (54.3 ± 10.5, P<0.01), higher body mass index (28.0 ± 3.7kg/m2, P<0.01), apnea-hypopnea index (54.5 ± 22.9 events/h, P<0.01), arousal index (48.8 ± 21.3 events/h, P<0.01) and LF/HF (7.83 ± 5.15, P<0.05).
CONCLUSION: The prevalence of HT with morning BP surge among patients with OSA was high, and increased sympathetic overactivity plays an important role in the association between OSA and HT with morning BP surge.
CLINICAL IMPLICATIONS: High prevalence of HT with morning BP surge might be associated with the increased risk of cardiovascular and cerebrovascular events among patients with OSA.
DISCLOSURE: Minae Kamata, No Financial Disclosure Information; No Product/Research Disclosure Information