Pulmonary artery remodeling modifies pulmonary hypertension during exercise in severe emphysema

To clarify the relation between the vessel remodeling and the physiology of pulmonary circulation in chronic obstructive pulmonary disease (COPD), we studied the pulmonary hemodynamics at rest and during exercise (25W) and th e morphology of pulmonary arteries with external diameters of 100-200 mu m in ten patients with severe emphysema. The wall thickness (WT) was defined as the intima plus media. The percent WT of the external diameter (% WT) in emphysema (36.0 +/- 4.3%) was significantly increased compared with that ( 22.6 +/- 3.3%) in five control lungs. The % WT was not related to pulmonary arterial pressure (Ppa) at rest, but was highly correlated with exercise P pa (r = 0.721, P = 0.02) and with Delta Ppa (Ppa during exercise-Ppa at res t) (r = 0.899, P = 0.0004). These findings suggest that pulmonary artery re modeling leads to reduced recruitability and distensibility of pulmonary ve ssels and is closely related to exercise pulmonary hypertension. (C) 2000 P ublished by Elsevier Science B.V. All rights reserved.