Intrauterine creation and repair of pulmonary artery stenosis in the fetal lamb. Weight and ultrastructural changes of the ventricles
Bical, O.; Gallix, P.; Toussaint, M.; Hero, M.; Karam, J.; Sidi, D.; Neveux, J.Y.
Journal of Thoracic and Cardiovascular Surgery 93(5): 761-766
1987
ISSN/ISBN: 0022-5223 PMID: 3573788 Document Number: 301179
Fetal lamb experimental models were employed for intrauterine creation and repair of pulmonary artery stenosis. The study group was composed of 51 fetal lambs including 29 models of pulmonary artery stenosis and 2 control lambs. Gestational age was 89 days at creation of pulmonary artery stenosis. Fourteen fetal lambs (Group A) were studied after ratio of the stenosis at 131 days of gestation and compared to normal age-matched control lambs. The systolic right ventricular pressure was significantly higher after creation of pulmonary artery stenosis (76.6 .+-. 17.8 versus 50.3 .+-. 23.5 mm Hg), but the systolic pulmonary artery pressure was unchanged. The mean right ventricular weight and the mean right ventricular/left ventricular weight ratio were significantly greater after pulmonary artery stenosis than in normal control animals. The transverse myocyte diameter was not modified by pulmonary artery stenosis, but on electron microscopic study the myocytes appeared mature. Ten lambs (Group B) underwent intrauterine repair of pulmonary artery stenosis at 131 days of gestation without cardiopulmonary bypass. The pulmonary artery was clamped and patched. Immediately after repair the right ventricular pressure fell significantly from 85.8 .+-. 18.9 to 62.2 .+-. 14.6 mm Hg/ At birth, 7 .+-. 6 days after repair, Group B was compared to Group C (unrepaired pulmonary artery stenosis, five fetuses) and to normal control lambs. The mean right ventricular weight and the mean right ventricular weight and the mean right ventricular/left ventricular weight ratio were not statistically different in Group B and in the control group. There was no ultrastructural change after intrauterine repair. We conclude that intrauterine creation of pulmonary artery stenosis causes right ventricle hypertrophy with more mature myocytes. Intrauterine repair of pulmonary artery stenosis if feasible without cardiopulmonary bypass and rapidily abolishes the preponderance of right ventricular weight over left ventricular weight.