[Development of pulmonary arterial hypertension in chronic obstructive bronchopneumopathies].

In chronic obstructive bronchopneumopathies (COBP), pulmonary artery hypertension (PAH) is usually mild but may markedly intensify during episodes of acute respiratory failure, muscular exercise, and sleep, PAH may, even if of low level, lead to right heart failure. The prognostic value of PAH and its degree in COBP patients has been well established by a number of recent studies. Chronologic changes in pulmonary artery pressure (PAP) tend to be minimal in the majority of COBP patients (of the order of +0.5-0.6 mm Hg/year in most studies). However, in a minority of patients (about 30%) pulmonary hypertension worsens seriously due to progressive deterioration of arterial blood gases. Longterm oxygen therapy (LOT) for 16 h/day rarely serves to normalize PAP but may reverse the progress of pulmonary hypertension, particularly in patients with progressive aggravation thereof. Recent studies have made it clear that LOT has beneficial hemodynamic effects in a relatively large percentage of COBP patients with PAH.