Reversibility of plexogenic pulmonary arteriopathy following banding of the pulmonary artery.

In 28 patients with congenital heart disease with a shunt and pulmonary hypertension, lung biopsy specimens were taken during a banding procedure of the pulmonary artery; then, in the same patients, lung tissue became available during correction of the cardiac defect some years later. In this way the regression of pulmonary vascular changes could be studied. Medial hypertrophy appeared to have a prominent tendency to regression. With intimal lesions, regression depended to a large extent on the type of lesion. Intimal thickening based on longitudinal smooth muscle tissue was almost completely reversible. Post-thrombotic intimal fibrosis was also potentially reversible. In plexogenic pulmonary arteriopathy, the earlier lesions, particularly cellular intimal proliferation, showed regression. Concentric-laminar intimal fibrosis regressed as long as it was mild, that is, occluding less than one fifth of the average arterial lumen. If more severe, there was no tendency to regression and often it even progressed. Changes like fibrinoid necrosis and plexiform lesions are ominous because of their tendency to progression. Since preoperative open lung biopsies now are often undertaken for evaluation of hypertensive pulmonary vascular disease, when corrective operability is dubious, these findings may serve as a guide in reporting on such biopsy specimens.