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 vasoconstriction. Epinephrine-induced constriction and stretching were investigated in 10 patients with PDA. Age, sex, ductus type, its minimal 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 stretchability. 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 wall, which in turn is determined by preservation of vascular smooth muscle.