Pathophysiology and Natural History Congenital Heart Disease

At the time of surgical repair, a lung biopsy was performed on patients with congenital heart defects who either had pulmonary hypertension or in whom it would be likely to develop if the lesion were not corrected. Pulmonary vascular changes, assessed morphometrically and also according to the classification of Heath and Edwards (Circulation 18: 533, 1958), were correlated with the postoperative pulmonary hemodynamic findings: mean pulmonary arterial pressure the day after correction and mean pulmonary arterial pressure and pulmonary vascular resistance measured 1 year later. On the first postoperative day, increased mean pulmonary arterial pressure was uncommon in patients with morphometric grade A or B (mild) biopsy findings and Heath-Edwards grade N (normal), and if it was present it was of a mild degree. Mean pulmonary arterial pressure was commonly elevated in those with grade B (severe) or C (mild or severe) and Heath-Edwards grade biopsy results and was more frequently elevated in those with grade findings. Moderate-to-severe elevation of mean pulmonary arterial pressure was invariable in patients with Heath-Edwards grade III changes regardless of the morphometric grade. One year after repair, mean pulmonary arterial pressure and/or pulmonary vascular resistance were normal in all patients whose conditions were corrected surgically before 9 months of age regardless of the severity of the pulmonary vascular changes. Values were normal in patients whose conditions were repaired surgically at 9 months of age or later who had grade A or B (mild) morphometric findings with any Heath-Edwards grade or grade B (severe) morphometric findings with Heath-Edwards grade I but were increased in half of the patients with grade B (severe) morphometric findings and Heath-Edwards grade II or with grade C (mild or severe) and HeathEdwards grade I or LI changes. Pulmonary arterial pressure and pulmonary vascular resistance were increased in all patients whose conditions were repaired after 2 years of age with grade C morphometric findings and to a severe degree if associated with Heath-Edwards grade III. Thus, although the HeathEdwards grade can usually be used to identify patients at risk for pulmonary hypertension in the early postoperative period, both the morphometric and the Heath-Edwards grades as well as the age of the patient at the time of repair can be used to determine whether pulmonary arterial pressure and resistance eventually return to normal or remain elevated. Circulation 69, No. 4, 655-667, 1984. WE PREVIOUSLY analyzed lung tissue obtained at biopsy during surgical repair from patients with congenital heart defects and correlated the morphometric findings with the preoperative pulmonary hemodynamic data.' We observed abnormalities in muscularization and growth of the pulmonary arteries associated with increased pulmonary blood flow, pressure, and resistance. In the present study, both the morphometric From the Departments of Cardiology, Cardiovascular Surgery, and Pathology, Children's Hospital Medical Center, the Departments of Pediatrics, Surgery, and Pathology, Harvard Medical School, Boston. Supported in part by NIH Research grant lROI-24418. Address for correspondence: Marlene Rabinovitch, M.D., Department of Cardiology, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario M5G 1X8, CANADA. Received Nov. 30, 1982; revision accepted Dec. 22, 1983. Vol. 69, No. 4, April 1984 findings and the changes described by Heath and Edwards2 have been correlated with mean pulmonary arterial pressure and pulmonary vascular resistance after surgical repair. Hemodynamic data were assessed both in the immediate postoperative period and about 1 year after surgery at the time of the routine follow-up cardiac catheterization study. We also considered whether severe pulmonary vascular changes may have influenced mortality at surgery or during the follow-up period. Materials and methods Patients undergoing biopsy. At the Children's Hospital Medical Center, Boston, over a 41/2 year period (July 1976 to January 1981 inclusive), patients with congenital heart defects 655 by gest on A ril 2, 2017 http://ciajournals.org/ D ow nladed from