[Pulmonary hypertension in patients with pure obstructive sleep apnea]

Patients with obstructive sleep apnoea (OSA) every night experience recurrent episodes of alveolar hypoxia. Alveolar hypoxia is the most potent pulmonary vasoconstrictor causing remodeling of pulmonary arteries and pulmonary hypertension. Development of pulmonary hypertension in patients with OSA is rather rarely observed but still discussed. We studied pulmonary haemodynamics, using Swan Ganz thermodilution catheter, in 67 patients (64 M and 3 F, mean age 45 years) with severe OSA (in full polysomnography mean AHI = 62) and normal pulmonary function data. We observed normal mean haemodynamic values at rest: PPA 15,8 mm Hg, PW 6.8 mm Hg, CO 5.6 L/min. PVR 150 dyn.sec.cm(-5). In 11 pts (16%) the pulmonary artery pressure at rest was elevated (PPA 23.9 mm Hg and PVR 234 dyn.sec.cm(-5)), they were younger, more obese and had higher number of apneic episodes per hour of sleep. During mild exercise (44 pts) PPA rose from 15.8 mm Hg to 29.8 mm Hg and was abnormally high in 17 pts.

we observed pulmonary hypertension at rest in 16% patients with severe OSA, but during exercise in about 40%.