REM Sleep Imposes a Vascular Load in COPD Patients Independent of Sleep Apnea

Arterial stiffness, a marker for cardiovascular risk, is increased in patients with Chronic Obstructive Pulmonary Disease (COPD) and Obstructive Sleep Apnea (OSA). The specific influence of both on arterial stiffness during sleep is unknown. Nocturnal arterial stiffness (Pulse Propagation Time (PPT) of the finger pulse wave) was calculated in 142 individuals evaluated for sleep apnea: 27 COPD patients (64.7 ± 11y, 31.2 ± 8 kg/m2), 72 patients with cardiovascular disease (CVD group, 58.7 ± 13y, 33.6 ± 6 kg/m2) and 43 healthy controls (HC group 49.3 ± 12y, 27.6 ± 3 kg/m2). Sleep stage related PPT changes were assessed in a subsample of COPD patients and matched controls (n = 12/12). Arterial stiffness during sleep was increased in COPD patients (i.e. shortened PPT) compared to healthy controls (158.2 ± 31 vs. 173.2 ± 38 ms, p = 0.075) and to patients with CVD (161.4 ± 41 ms). Arterial stiffening was particular strong during REM sleep (145.9 ± 28 vs. 172.4 ± 43 ms, COPD vs. HC, p = 0.003). In COPD, time SaO2