Myocardial effects of fetal endoscopic tracheal occlusion in lambs with CDH.

INTRODUCTION: Fetal endoscopic tracheal occlusion in congenital diaphragmatic hernia (CDH) may reduce pulmonary hypertension and ameliorate postnatal cardiac output. The effects of sustained early (ETO) and late (LTO) tracheal occlusion on left ventricular (LV) cells in the lamb model have not been described.

MATERIALS AND METHODS: CDH was created in lambs at 70 days' gestation (term = 145 days). ETO (85 days) or LTO (105 days) was sustained till term. After cesarean section (140 days) fetuses were euthanized and hearts harvested. LV myocardial cells were studied by histological and immunofluorescence (TGF-beta 1, endothelin-1) assays in CDH, ETO, LTO, and the control group (two subjects per group). Small intramyocardial arteries were evaluated by traditional histology.

RESULTS: LV myocardial histology in CDH and LTO was similar. ETO-induced LV myocardial cell enlargement and increased endothelin-1 and TGF-beta 1 staining; a weaker immunofluorescence signal was observed in LTO compared with ETO. Myocardial vascular wall thickness was greater in CDH than in controls. ETO was associated with a vascular wall thickness within the range of controls.

CONCLUSION: With only two fetuses in each group, only an explorative evaluation was possible. The time point at which TO is performed seems to have an effect on cardiac morphology. Functional studies as well as confirmation in clinical samples are mandatory.