Abstract 2992: Repetitive Apneic Events Augment Arterial Pressure Fluctuation Associated with Severity of Sleep Apnea Syndrome
Background: Sleep apnea-hypopneas are associated with transient increases in arterial pressure. We test the hypothesis that periodic nocturnal apneic events augment those hemodynamic responses associated with severity of sleep apnea syndrome (SAS).
Methods: We studied eighteen patients who were clinically suspected with SAS (mean age 61 ± 18 years, 17 males). Polysomnography was performed and arterial blood pressure was measured on a beat-by-beat basis by finger plethysmography all through the sleep. Severity of SAS was assessed by apnea-hypopnea index (AHI). The degree of apnea-hypopnea-related arterial blood pressure fluctuation was assessed by spectral analysis of mean blood pressure variability. Spectral plots were calculated in 2-min segments using a maximum entropy method. Power spectrum were averaged and quantified by measuring the area in the very-low-frequency band, which coincides with frequency of apnea-hypopneas (SAS band: 0.01– 0.03 Hz).
Results: There were four patients with non-SAS (AHI < 5), 5 with mild-to-moderate SAS (5 ≤ AHI < 30), and 9 with severe SAS (30 ≤ AHI). Repetitive rises in mean blood pressure coincided with periodic apnea-hypopneas were observed in patients with SAS. The spectral power of mean blood pressure in SAS band was significantly higher in patients with severe SAS compared to those with non-SAS and mild-to-moderate SAS (29.2 ± 21.0 vs. 7.33 ± 2.77 mmHg2, p < 0.05), and was strongly associated with severity of SAS with exponential regression (y = 4.1701e0.0355x, r = 0.80).
Conclusions: Periodic apnea-hypopneas cause arterial blood pressure fluctuation associated with severity of SAS.