Local variations of pulmonary arterial wedge pressure and wedge angiograms in patients with chronic lung disease.

This study was undertaken in 23 patients with chronic lung disease to determine whether local wedge pressure variability is related to the state of the local perfusion as observed in distal wedge angiograms. We also compared the variability of the pressures obtained after distal (mechanical) and proximal (balloon inflation) wedging of a catheter in three to six different sites in each patient. When the wedge pressure measurements were repeated in the same site (n = 7), the mean of the absolute differences was below 1 mm Hg. In individual patients, the maximal pressure difference between sites ranged from 0 to 6 mm Hg for Ppw and from 1 to 12 mm Hg for Pdw. The range in Pdw increased from normal to abnormal angiograms. These results suggest that when Pdw is high in one region, it may correspond to local perfusion abnormalities. When the wedge pressure is measured repeatedly or under different conditions, it should be determined after wedging the catheter in the same location for all of the periods of observation.