Seventy-two patients with chronic obstructive pulmonary disease (COPD) underwent right heart catheterization when they were clinically stable and the relationship between length of survival and acute pulmonary vascular response to 100% oxygen inhalation was studied. Oxygen inhalation significantly reduced mean pulmonary arterial pressure (PPA), cardiac index (CI), and pulmonary arteriolar resistance (PAR). The percent change in PAR (% delta PAR) was used as an index of the acute pulmonary vascular response to 100% oxygen inhalation. Each patient was classified as a responder (% delta PAR > or = 15%) or a nonresponder (% delta PAR < 15%). The cumulative survival rates of these two groups were compared. Responders survived significantly longer than did nonresponders (mean survival times were 2571 days and 1432 days, respectively). The two groups did not differ significantly in anthropometic data, pulmonary hemodynamics, or blood gas data measured at base line during air inhalation. However, FEV1 and VC were significantly lower in nonresponders than in responders. The % delta PAR was not significantly related to age, PPA, PAR on air inhalation, FEV1, FEV1%, VC or VC%. We conclude that the pulmonary vascular response to oxygen inhalation (% delta PAR) may be an independent prognostic factor in patients with COPD.