Development and Experimental Study of a Polytetrafluoroethylene-Tipped Microcatheter Poorly Adhesive to n-Butyl-2-Cyanoacrylate

Purpose: We have developed a new microcatheter (designated "NSX") with an outer layer of polytetrafluoroethylene (PTFE) at its tip. We compared the adhesion of the new NSX microcatheter and a conventional microcatheter with n-butyl-2-cyanoacrylate (NBCA) in vitro and in swine blood vessels.Materials and Methods: The 3 cm tip of the NSX microcatheter is composed of PTFE, which can be identified by double platinum markers. The tips of the NSX and conventional microcatheters were inserted into a vascular model filled with porcine blood with no flow, and NBCA mixed with lipiodol (1:2) was injected from the microcatheters. Two minutes after the injection of NBCA, the microcatheter was withdrawn and the degree of its adhesion to NBCA was evaluated by measuring the resistance value (N) during catheter removal with a digital force gauge. These measurements were repeated with 20 catheters of each type. Similarly, 5 injections were performed with both the NSX and conventional microcatheters in swine vessels. The degree of adhesion of the catheter and blood vessel was evaluated by 2 radiologists under X-ray fluoroscopy on a 3-point scale: 1, no adhesion; 2, mild adhesion; 3, strong adhesion.Results: The mean resistance values (N) for the NSX and conventional microcatheters were 0.503 +/- 0.186 and 1.051 +/- 0.367 (N), respectively (p<0.001). The NSX adhered negligibly to the NBCA and was easily removed, whereas the conventional microcatheter adhered strongly to the NBCA in the blood vessels and was difficult to remove from the swine vessels (p=0.008).Conclusions: The new NSX microcatheter with a PTFE tip exhibits poorer adhesion to NBCA than do conventional microcatheters and allows for safer injection of NBCA than conventional microcatheters, without requiring immediate catheter retrieval.