EPINEPHRINE-INDUCED CONSTRICTION OF THE PERSISTENT DUCTUS-ARTERIOSUS AND ITS RELATION TO DISTENSIBILITY

The aim of this study was to investigate whether distensibility of the persistent ductus arteriosus (PDA) might predict its potential for va soconstriction, Epinephrine-induced constriction and stretching were i nvestigated in 10 patients with PDA. Age, sex, ductus type, its minima l diameter, its stretched minimal diameter, and its stretch index were compared between epinephrine responders and non-responders. Age, sex, weight or the configuration or size of the PDA did not predict stretc hability. The stretch index was significantly greater in responders (1 .7-2.0, 1.8+/-0.1) than in non-responders (1.3-1.7, 1.4+/-0.2, p<0.01) . Stretching of the PDA may depend on the elasticity of the vascular w all, which in turn is determined by preservation of vascular smooth mu scle.