The chick embryo as a model for intrauterine ultrasound-guided heart intervention.

ABSTRACT

OBJECTIVES: Prenatal minimally invasive therapy represents a challenging option for reducing long-term complications of pathological fetal heart development. Here, the potential of the chick embryo as a model for ultrasound-guided intrauterine cardiac intervention is explored. METHODS: Chick embryos were incubated for 18 days in fenestrated eggs and their hearts were punctured in ovo under ultrasound guidance. Indian ink and Nile blue sulfate were applied to mark the injection channel. After cardiac intervention, embryos were further incubated and subsequently sacrificed for macroscopic and histological evaluation of the heart. RESULTS: Stereomicroscopic analysis revealed that the catheter had successfully penetrated the cardiac ventricular wall in 26/38 embryos. The myocardium was not severely injured. Histological evaluation showed that the myocardium had almost reoccluded after the intervention and that the injection channel was clogged with fibrin. In one case, the embryo was not sacrificed, but was removed from the egg 24 h after the intervention, with no signs of cardiac dysfunction, and was followed up for 6 months. CONCLUSIONS: Intrauterine ultrasound-guided heart intervention in the human fetus can be simulated in the chick embryo. Fenestrated eggs have to be used because the egg shell and shell membrane are impermeable to ultrasound.