A NEW TEFLON CATHETER FOR PERCUTANEOUS CATHETERIZATION AND CONTRAST MATERIAL INJECTION.

Abstract

The percutaneous introduction of catheters in the cardiovascular system (Fig. 1) has multiplied in application and scope in the last few years, rapidly becoming one of the most popular catheterization technics (1–8). Since 1959 we have used this method in 650 clinical cases for a total of over 1,500 visualizations or hemodynamic studies of the cardiovascular system. As experience was gained during a three-year period, we became more and more dissatisfied with the polyethylene tubings, which we had used initially, as well as with commercially available catheters. The disadvantages of the polyethylene tubings were the complete absence of radiopacity, the inability to withstand high-pressure injection, the difficulties encountered in flaring, tapering, and punching side-holes of appropriate sizes. Even less desirable than the polyethylene tubings were the Kifa catheters because of the vascular spasm often encountered with this brand, perhaps caused by the roughness of the external wall. The Lehman catheters would obviate a great many of these disadvantages, but the absence of tapering and of multiple side-holes makes them inadequate for this technic because of the difficulty in inserting the blunt end into the vessel and extreme recoil during pressure injection. The present catheter, made of Teflon, has an extremely low coefficient of friction, a completely water-repellent surface, and radiopacity which equals or is superior to the Lehman catheters. It is available in sizes 5F to 9F, in lengths of 80, 100, and 125 cm., and with an end-hole of either 0.035 in. (for use with an infant spring) or 0.045 in. (for use with an adult-size spring). This instrument is easily cleaned and can be steam-autoclaved for sterilization. If desired, the tip may be bent to various shapes and this shape will be retained by introducing a short wire into the distal end, heating the catheter in the autoclave at 270° F. for ten minutes, and then cooling it. A more permanent molding of the curved tip can be obtained by oven heating at 500–F. The main feature of this instrument is the tip. The tapering of its distal part makes the catheter easy to insert because of reduced friction between it and the vessel (Fig. 2). Furthermore, the end hole is a few thousandths of an inch larger than the diameter of the spring guide and it is possible to slide the catheter over the spring as a sleeve. There are 4 or 6 side-holes with a total area greater than 4 times the end opening and the flow of the contrast material is greatest through the side-holes. This minimizes recoil, improves instantaneous mixing, and avoids injection of small vessels due to accidental wedging of tip. Figure 2 demonstrates how approximately four-fifths of the injected fluid is ejected from the side-holes.