[Persistence of fetal circulation. Clinical and angiographic evaluation of two cases. Review of the literature (author's transl)].

: Persistent fetal circulation ("PFC") is a condition characterized by perduring after birth of fetal hemodynamic pattern: persistence of high pulmonary vascular resistance then occurs. "PFC" is a high mortality syndrome recently recognized as a cause of severe cyanosis and tachypnea in full-term newborns. Perinatal hypoxia, hyperviscosity, acidosis etc, may be also responsible of a persistence of high pulmonary vascular resistance. The increased right heart pressures cause a right to left shunt across the ductus arteriosus and foramen ovale not yet completely closed at birth. In this paper the clinical and angiographic evaluation of two full-term newborns, males, 5 days and 5 months old, are described, who presented with tachypnea, cyanosis and heart failure. Moreover we want to make a critical review of medical literature about this subject. The electrocardiogram of both patients showed right ventricular hypertrophy and myocardial ischemia. The chest roentgenograms showed cardiac enlargement and increased pulmonary vascular markings. Lung and central nervous system disorders were excluded by clinical and instrumental exams. Both patients underwent cardiac catheterization and angiocardiography in order to exclude a congenital heart disease. There was just evidence of pulmonary vascular resistance and right to left shunt at ductal and atrial level. O2 100% administration in one patient determined a decrease in pulmonary resistance and the shunting abolition. Clinical and hemodynamic patterns of this syndrome are very different. There are "simple forms" with normal myocardial function and "complex" higher mortality forms with evidence of cardiac involvement. It is often difficult to distinguish such forms from the other causes of central cyanosis and/or cardiac failure in the newborn as transposition of the great arteries, total anomalous pulmonary venous connection: the individualization of the syndrome then may be impossible without cardiac catheterization. A correct diagnosis for a precocious and reasonable treatment are extremely important for the survival of such critical newborns.