In vitro evaluation of mechanical characteristics of a novel Patent Ductus Arteriosus (PDA) occlusion device with a new lateral pressure measurement study.

Persistence of the ductus arteriosus (DA), connecting the aorta to the pulmonary artery, after birth leads to a congenital heart disease known as Patent Ductus Arteriosus (PDA). The objective of this study was to propose a new intraductal design for PDA occlusion and determine the efficacy of the new device by means of an in vitro mechanical evaluation. A novel intraductal design device called the Novel design 36 (ND36) was proposed, fabricated and tested. Mechanical tests included tests to determine the mechanical characteristics, force-displacement characteristics, stiffness, device slenderization, minimum diameter attained, insertion force required to pull device at site and lateral pressure exerted on the PDA walls. Comparative analysis was carried out with the Amplatzer Duct Occluder (AGA Medical Corporation, Golden Valley, MN). The results showed that the ND36 when fully stretched was shorter than the ADO implying an easier in vivo movement. The minimum diameter attained by ND36 is 2.52 mm which is compatible with standard catheter bores of 6-8 Fr (2-2.7 mm) bore sizes. A new setup was devised in order to carry out comparative lateral pressure measurements between the ND36 and ADO. The results showed that the ND36 exerted a pressure of 10 KPa (=75 mm Hg) and the ADO exerted 80 KPa (=600 mm Hg) over the walls of the tubes which is a physiologically promising result for the ND36 as it shows that the ND36 would exert lesser stress on the walls of the duct. The results suggest that the novel intraductal design (ND36) would prove to be a safer, reliable and effective device for PDA occlusion.