PULMONARY CIRCULATORY PARAMETERS AS INDEXES FOR THE EARLY DETECTION OF ACUTE REJECTION AFTER SINGLE-LUNG TRANSPLANTATION

We investigated the relationship between the changes in the pulmonary blood flow and histology during acute rejection following single lung transplantation. In single lung transplantation using adult mongrel do gs, immunosuppression with cyclosporine and azathioprine was discontin ued after postoperative day 14 to induce rejection. Doppler flow probe s were placed adjacent to the ascending aorta and the left pulmonary a rtery to measure the blood flow on a daily basis. In addition, chest r oentgenograms were also examined daily. The pulmonary pressure was mea sured using a Swan-Ganz catheter prior to and following the induction of rejection. Open lung biopsies were performed when the left pulmonar y artery flow decreased to half of the prerejection value. The pulmona ry artery dow decreased to 14.3% of the aortic flow 5 days after the d iscontinuation of immunosuppression. The graft pulmonary vascular resi stance increased significantly compared to the prerejection values (P < 0.001). This was not accompanied by any abnormalities on chest roent genography, The histology was consistent, with marked perivascular lym phocytic infiltration with little alveolar or interstitial changes. Du ring rejection, the increased pulmonary vascular resistance in the gra ft was probably the result of perivascular inflammatory cell infiltrat ion, which was seen prior to changes on chest roentgenography. Changes in the left pulmonary artery flow and histology thus appear to be clo sely correlated in the early stages of acute rejection.