[Acardius or "twin-reversed arterial prefusion" sequence. Report of four cases and review of current therapeutic possibilities].

We describe four cases of acardius (one of hemiacardius, two of holoacardius acephalus, and one of the holacardius amorphus) and present the current range of therapeutic possibilities: control of amniotic fluid by repeated amniocentesis or indomethacin therapy, administration of digoxin to the mother, selective preterm delivery of the acardiac twin by hysterotomy, interruption of the anastomoses by injection of thrombogenic coils, sclerosing agents, umbilical cord ligation, fetoscopic laser coagulation, and thermocoagulation.