Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
1998-07-27
2001-09-25
Recla, Henry J. (Department: 3731)
Surgery
Instruments
Internal pressure applicator
C606S192000, C604S264000
Reexamination Certificate
active
06293958
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to angiographic and other diagnostic or therapeutic catheters and more particularly to a feature of such catheters which prevents high velocity jetting of contrast media, fluid or the like from the distal end opening of such catheters.
2. Discussion of the Prior Art
In diagnostic catheters designed for left ventricular injection of contrast media or dyes or for higher pressure injections into coronary arteries during angiographic and therapeutic procedures, the outside diameter of such catheters is necessarily small, typically in the range of from 3 to 10 Fr. When it is considered that radiographic contrast media is commonly injected at a rapid rate by means of either a power injector or by hand, the liquid contrast media exits the distal end opening of the catheter as a high velocity jet. This may cause “whipping” of the catheter tip and resulting damage to delicate endothelial tissues lining the blood vessels being examined. The velocity and impact of the jet itself may be sufficiently high to damage the vessel wall. Experience has shown that such tissue damage may form the nidus of stenotic lesions and dissections and ultimately to occlusion of such blood vessels.
As is pointed out in the introductory portion of the Cragg Patent U.S. Pat. No. 5,085,635, to minimize undesirable effects of the high velocity jet, prior art catheter designs had sealed distal ends with a plurality of side holes near the distal end to allow the contrast media to exit in a radial direction through several ports, thereby reducing somewhat the overall velocity of the exiting contrast liquid. Even here, it was often too high. Having a closed distal end effectively precluded such catheters from being fed over a guidewire. This, of course, makes it difficult and sometimes unsafe to appropriately place the distal end of the catheter prior to contrast ejection. To address this problem, the angiographic catheter particularly described in the Cragg '635 patent incorporates a normally completed closed leaflet valve arrangement over the end hole of the catheter which permits passage of a guidewire therethrough, but which effectively blocks the flow of contrast media therethrough. Thus, the contrast media exits a plurality of apertures formed through the wall of the catheter tubing proximate the distal end thereof.
SUMMARY OF THE INVENTION
The intravascular catheter of the present invention is adapted to provide higher volume flow through a relatively small lumen and with a reduced exit flow velocity than with conventional, prior art catheters for the same purpose. The catheter comprises an elongated, flexible, tubular body member having a proximal end, a distal end and a lumen extending therebetween. A plurality of circumferentially spaced cuts or slits are formed through the wall of the tubular body member to the lumen so as to define a plurality of hinged flaps that are symmetrically arranged such that flow of a stream of fluid through the lumen above a predetermined velocity causes the hinged flaps to vibrate in and out of the stream to diffuse it and to dissipate the kinetic energy of the fluid. The contrast fluid not only exits the distal end opening of the catheter at a greatly reduced velocity, but also, the contrast fluid exits through the ports defined by the flaps to effectively create a diffuse cloud of contrast fluid surrounding the distal tip portion of the catheter. The symmetric placement of the flap covered openings also distributes the Newtonian forces acting on the tip by the existing fluid so that no whipping occurs. The distal end may be open or may include a short segment having a virtual opening that is normally closed to block flow of contrast fluid from the distal end of the catheter, but which may allow the passage of a guidewire therethrough. Alternatively, the short tip segment may have a longitudinal bore for receiving a guidewire therealong, but the bore is made to close to prevent flow of contrast fluid out the distal end of the short tip segment due to the pressure of the contrast fluid present within that tip segment.
REFERENCES:
patent: 4961731 (1990-10-01), Bodicky et al.
patent: 4995863 (1991-02-01), Nichols et al.
patent: 5085635 (1992-02-01), Cragg
patent: 5085636 (1992-02-01), Burns
patent: 5163928 (1992-11-01), Hobbs et al.
patent: 5224983 (1993-07-01), Fenton, Jr.
patent: 5250034 (1993-10-01), Appling et al.
patent: 5267979 (1993-12-01), Appling et al.
patent: 5616137 (1997-04-01), Lindsay
patent: 5807349 (1998-09-01), Person et al.
Berry David
Holmes David R.
Schwartz Robert S.
VanTassel Robert A.
Acist Medical Systems, Inc.
Ngo Lien
Oppenheimer Wolff & Donnelly LLP
Recla Henry J.
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