Pulmonary hypertension in patients with congenital heart disease: Pre- and postoperative hemodynamics, pulmonary function, and criteria for surgical closure of defects

Abstract

We have reviewed the catheterization and clinical records of all patients with atrial septal defects, ventricular septal defects and patent ductus arteriosus studied at the University of California Medical Center between June 1951 and June 1961. Patients with normal and elevated pulmonary vascular resistances were contrasted as to age, sex, hemodynamic abnormalities, operative mortality and morbidity. Significant hemodynamic differences were found between those with normal and those with elevated pulmonary vascular resistance, as in patients studied by others. Pre- and postoperative hemodynamic studies were made in seven patients with pulmonary hypertensive atrial septal defects, five with pulmonary hypertensive ventricular septal defects and three with pulmonary hypertensive patent ductus arteriosus. In most of these, together with a few nonoperated patients with Eisenmenger complex, pulmonary function studies also were performed. Criteria of operability in patients with congenital shunt lesions and elevated pulmonary vascular resistance and/or pulmonary hypertension were derived from these studies and from the literature. We believe that corrective surgery should be confined to patients who have a net left to right shunt. The operative risk increases sharply in patients with atrial septal defects whose systolic pulmonary arterial pressure exceeds 75 mm. Hg and in patients with patent ductus arteriosus whose pulmonary artery systolic pressure exceeds 100 mm. Hg. However, defects in patients in either group with pulmonary vascular resistances as high as 12 to 13 mm. Hg per L. per minute have been safely repaired with satisfactory although slow postoperative hemodynamic improvement. In contrast, patients with ventricular septal defects run excessive operative risk and less chance of tolerating definitive repair if they have pulmonary vascular resistances exceeding approximately 6.6 mm. Hg per L. per minute, pulmonary artery systolic pressure exceeding 90 mm. Hg preoperatively or 55 mm. Hg immediately postoperatively, and grade 4 or 5 pulmonary vascular disease. Furthermore, there is evidence suggesting that the postoperative hemodynamic response may be less satisfactory in patients with ventricular septal defects and elevated pulmonary vascular resistance than in those with atrial septal defects or patent ductus arteriosus. All our patients in whom defects were closed completely showed a decrease in pulmonary artery pressure and all but one showed a decrease in pulmonary vascular resistance. The slow postoperative improvement was associated with persistence of an elevated pulmonary resistance. This occurred despite a fall in pulmonary artery pressures with the reduction in pulmonary flow upon closure of the shunt defect. In most cases this persistently elevated pulmonary vascular resistance was associated with restrictive lung disease, evidence of underperfusion of ventilated areas and decreased diffusing capacity for carbon monoxide. These physiologic abnormalities could best be explained by the presence of pulmonary vascular disease with obliteration of some of the pulmonary capillary bed and a decrease in pulmonary capillary blood volume. This concept is compatible with the known pulmonary vascular pathology in these cases. In patients who had incomplete closure or reopening of their defects (especially those with ventricular septal defects), there appeared to be at least a temporary worsening of the hemodynamics, with further elevations of pulmonary vascular resistance.