Catheter Biopsy Experimental Technic for Transvenous Liver Biopsy

Abstract

This report deals with experimental biopsy catheters used and under development at the University of Oregon Medical School. The initially constructed biopsy catheter (1) consists of a long, fairly stout coilspring (obtained from a percolator spout cleaner), at the exploring end of which is soldered a 3/4-inch length of 14-gauge needle tubing, square-cut and sharpened at its open or free end. In several dogs this was passed (via polyethylene tubing previously introduced through a jugular vein) so as to impact against and then perforate the wall of a small hepatic venous radicle. Before removal, the resulting core of liver parenchyma was transfixed within the catheter by a corkscrew-tipped wire introduced through the spring lumen. These samples compared well with those obtained by conventional needle biopsy, and the procedure did not result in noticeable harm to any of the animals. Instrument and sample biopsy are shown in Figure 1. A modification led to the biopsy catheter shown in Figure 2. During the passage of this instrument, a miniature helicoid cutting auger is safely stowed within a short length of tubing attached to the end of the spring. Appropriate rotation and emergence of the cutter is achieved by means of a central wire driveshaft connected to a knob at the outer end of the instrument. With ease and apparent safety, this device was used in taking 9 successive samples from various areas within the right ventricle of a normal anesthetized dog. Considerable refinement in this and other technics involving the transluminal transmission of rotary power will result if an appropriate low-torsion flexible shaft can be found or devised to replace the present central wire. (The writer would appreciate receiving the knowledge or suggestions of others in this connection.) Yet another biopsy catheter analogous in operating principle to the Vim-Silverman biopsy needle is now under construction. Discussion Continuing work should make possible the clinical application of catheter biopsy to an important variety of lesions normally requiring surgical exposure for tissue diagnosis. A few of the many obvious possibilities are shown in Figures 3 and 4. There is no substantial reason to believe that the complications of catheter biopsy will approach those of conventional surgery and general anesthesia; on the contrary, there is reason to hope that the attendant cost, trauma, and patient discomfort will be much less with the transluminal approach. Broadly considered, vascular catheterization, though widely employed during the past third of a century, has generally been limited to a passive role in diagnosis, chiefly through the site-specific sampling of blood, determination of blood pressure, and introduction of indicator substances including angiographic agents.