No abstract

When I was a young pediatric house officer at the University of Minnesota in the mid 1940s, my chief, Dr. Itvine McQuarrie, frequently spoke of the "experiments of nature" [6]. He challenged us to study these patients in depth as a way to learn about the basic mechanisms of the physiology and the biochemistry of man. Later I studied and worked with Professor John Lind of the Karolinska Institutet in Stockholm on the fetal and neonatal circulations. At that time, we concentrated particularly on the pulmonary circulation, the ductus arteriosus and the first breath. However, even then Professor Lind was working on the blood flow returning from the placenta via the umbilical vein as it traversed through the portal sinus into the liver or through the ductus venosus into the inferior vena cava, and thence into the heart.Lind's monograph on the human foetal and neonatal circulation published in 1964 [4] shows many angiograms on human fetuses depicting the above mentioned circulations. Also on page 10 of the monograph is an excellent color diagram of the liver circulation in the fetus which emphasizes the position of the ductus venosus. Finally, Lind has a section on the "closure of the ductus venosus" (pages 35, 36) stating what was known at the time about the possible mechanisms and the time of closure [4].Later, in 1968, in the 1st edition of our textbook on Heart Disease In Infants, Children, and Adolescents [1] I predicted that it is likely that control of the flow of blood through the liver is regulated by constriction and dilatation of the ductus venosus. It is also likely that disturbances of blood flow through it will be demonstrated in pathologic states in the future [1]. Now in this issue of the European Journal of Pediatrics two case reports appear, [2,5] one from Japan and the other from Switzerland, documenting two "experiments of nature" in which a persistent patency of the ductus venosus beyond birth seems to be related to pathologic conditions. In both cases, a portal systemic shunt was suspected because of an abnormality of metabolism involving the liver. The diagnosis of persistent patency of the ductus venosus was established in both by uitrasonography and aided in one case by angiography and in the other by Doppler color flow mapping. It would appear from both of these cases that a persistent ductus Offprint requests to: F. H. Adams venosus after birth is associated with rather severe metabolic dysfunction. The cause of the persistent patency however, is not clear and more work needs to be done.Professor Lind and his group continued to investigate various aspects of the fetal and neonatal circulations well into the 1970s. Another monograph was published in 1974 [7] which covered in greater detail the anatomy, physiology, and factors related to closure of the ductus venosus.Eventually Drs. Rudolph and Heymann began a series of investigations using the fetal sheep model primarily aimed at a more precise definition of fetal blood flow patterns especially looking at the role of the ductus venosus. These...