Cryosurgery of the fetal ductus arteriosus

The effects of cryosurgical treatment of the fetal ductus arteriosus (DA) on the structure and function of the neonatal DA are assessed for the first time. A cryosurgical probe, cooled with nitrous oxide, was used to freeze the wall of the DA in 5 fetal lambs. Six fetal lambs were used as control animals. After birth, all the cryosurgically treated lambs had a patent DA whereas all the control lambs had a closed DA. Only the cryosurgically treated group had these histologic findings: calcific deposits, necrosis, and focal ganglion cell necrosis in the outer one third to two thirds of the media with a decrease or loss of muscle cells and elastic fibers. This study suggests the feasibility of developing a cryosurgical approach for maintaining patency of the DA.