The Journal of Thoracic and Cardiovascular Surgery, Vol 99, 685-690, Copyright © 1990 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Intrauterine versus postnatal repair of created pulmonary artery stenosis in the lamb. Morphologic comparison
O Bical, P Gallix, M Toussaint, P Landais, D Gaillard, J Karam and JY Neveux
Department of Experimental Surgery, Faculte de Medecine Necker, Enfants Malades, Paris, France.
Experimental lamb models were used for intrauterine creation of pulmonary
artery stenosis and later intrauterine repair or postnatal repair.
Intrauterine creation of pulmonary artery stenosis was performed in 23
fetal lambs at 90 +/- 1 days of gestation. Eight lambs underwent
intrauterine repair of pulmonary artery stenosis at 135 +/- 1 days of
gestation and were studied 110 +/- 13 days after repair. Seven lambs
underwent postnatal repair at 57 +/- 9 days after birth and were studied
162 +/- 32 days after repair. Eight fetal lambs with unrepaired pulmonary
artery stenosis were studied 89 +/- 18 days after birth. All study lambs
were compared with normal control lambs. The systolic right ventricular
pressure was significantly higher after unrepaired stenosis (78.6 +/- 6.8
mm Hg) than in other lambs, but there was no statistically significant
difference after intrauterine repair (23.3 +/- 2.9 mm Hg), postnatal repair
(25.9 +/- 3.4 mm Hg), and normal lambs (21.6 +/- 1.1 mm Hg). The systolic
pulmonary artery pressure was also not statistically different in these
three groups. The weight measurements were age-adjusted for comparison of
postnatal and intrauterine repair with normal lambs. The adjusted heart
weights were similar in the three groups. The comparison of the adjusted
heart weight/adjusted body weight ratio (10(-3) showed a significantly
higher ratio in postnatal repair (7.4 +/- 0.1) than in intrauterine repair
(6.1 +/- 0.1). The adjusted right ventricular weight/adjusted left
ventricular weight ratio was significantly higher in the postnatal repair
group (0.71 +/- 0.01) than in both the intrauterine repair group (0.59 +/-
0.01) and normal lambs (0.59 +/- 0.01). The transverse myocyte diameter was
not statistically different in all groups of animals and there were no
ultrastructural changes even when the pulmonary stenosis was unrepaired. We
conclude that intrauterine repair was more satisfactory than postnatal
repair in terms of age-adjusted heart weight results, but we did not find
any advantages of intrauterine repair in terms of histologic and
ultrastructural changes.