Are pulmonary haemodynamics of importance to survival in chronic obstructive lung disease?

Although the magnitude of pulmonary arterial pressure has been shown to be related to mortality from chronic obstructive lung disease, it does not necessarily follow that pulmonary hypertension is an important cause of death. In the majority of patients with chronic obstructive lung disease the degree of pulmonary hypertension is trivial and the cardiac output is unimpaired. The development of oedema in such cases is probably mediated through renal, neural and humoral mechanisms which may be more directly linked to the effects of CO2 retention than to disturbed pulmonary haemodynamics.