- Email: [email protected]
Difficult Portal Vein Access in Transjugular Intrahepatic Portosystemic Shunt Placement
Letters
Gianturco Z Stents for Hemodialysis Grafts From: Sumit Roy, MBBS, MD Institute for Surgical Research, Rikshospitalet Pilestredet 32 N-0027 Oslo, Norway. Editor: A small error seems to have crept into the excellent paper by Trerotola et al on the comparative evaluation of stents in hemodialysis grafts (1). The authors suggest that the Gianturco-Rosch stent may be preferable to the Gianturco Z stent for hemodialysis grafts. As the subunits in the former are held together by suture, it is postulated that the problem of fractures of soldered joints causing stent migration will be eliminated. Selection of the Gianturco-Rosch device may in fact simply substitute one drawback with another. The severe inflammatory response noticed by the authors near the soldered joints would probably be exaggerated with the Gianturco-Rosch model. Unlike the Gianturco Z stent, the Rosch-modified version is soldered proximal to every bend in the wire to create an "eyelet," and thus is likely to produce five to six times as many foci of intimal inflammation as the former. The observations of Trerotola et al bring into question the advisability of using solder in the fabrication of this family ofstents. Not only is an alloy of uncertain biocompatibility used (1,2), but soldering is an inappropriate method for bonding stainless steel (3). A completely solder-free Z stent is not just a theoretical possibility (4) and has been successfully used in the urethra (5), the venous. system (6), and the biliary tract (Baijal et aI, unpubhshed data, 1994). The amount of solder on the Gianturco-Rosch stents can also be substantially reduced by eliminating the soldering of adjacent limbs near the be?-ds to cre~te the "eyelets." Though visually pleasing, thIS feature IS superfluous, contributing nothing to the configurational stability of the stent. From benchtop (Roy et aI, unpublished data, 1992) and clinical experience (6) it is evident that the configuration of the wire at this sit~ itself ensures that the suture loop does not migrate and the entire ensemble does not telescope during backloading into the delivery sheath. The results presented by the authors suggest that despite its simple design, the Gianturco Z stent may be' more useful than its counterparts in certain applications. Hence, further modifications should be encouraged to widen the scope of its use and improve its biologic compatibility. References
1. Trerotola SO, Fair JH, Davidson D, Samphilipo MA Jr, Magee CA. Comparison of Gianturco Z stents and Wallstents in a hemodialysis access graft model. JVIR 1995; 6:387-396.
2. Dobben RL, Wright KC, Dolenz K, Wallace S. Gianturco C. Prostatic urethra dilatation with Gianturco self-expandable metallic stent: a feasibility study in cadaver specimens and dogs. AJR 1991; 156:757-761. 3. McGraw-Hill Encyclopedia of science and technology. Vol 16. 6th ed. New York, NY: McGraw-Hill, 1987; 598-599. 4. Roy S, Baijal SS, Phadke RV, Kumar S. Hybrid Gianturco expandable stent. AJR 1994; 162:449-450. 5. Gujral RB, Roy S, Baijal SS, Phadke RV, Ahlawat R. Srinadh ES, Rastogi H. Treatment of recurrent posterior and bulbar urethral strictures with expandable metallic stents. JVIR 1995; 6:427-432. 6. Baijal SS, Roy S. Phadke RV, Kumar S. Idiopathic BuddChiari syndrome: treatment with expandable Z stents (abstr). JVIR 1995; 6:58-59.
Dr Trerotola responds: We appreciate Dr Roy's interest in our work. We were indeed incorrect in stating that the ROsch-modified Gianturco Z stent does not contain solder. This stent does in fact contain solder, although the spiral modification does not. We regret the error and appreciate Dr Roy's comments. In the context of our manuscript (1) we wished to point out that an unsoldered stent such as the spiral Z stent might be less likely to encounter the type of fractures we saw. Like Dr Roy, we agree such an improvement would have to be solder free otherwise it might be at the expense of the type of inflammation we saw in our specimens. Reference
1. Trerotola SO, Fair JH, Davidson D, Samphilipo MA Jr, Magee CA. Comparison of Gianturco Z stents and Wallstents in a hemodialysis access graft model. JVIR 1995; 6:387-396.
Scott O. Trerotola, MD Department of Vascular and Interventional Radiology University Hospital, Room 0279 550 N. University Blvd Indianapolis, IN 46202-5253
Difficult Portal Vein Access in Transjugular Intrahepatic Portosystemic Shunt Placement From: Scott R. Kerns, MD Radiology Associates of Ocala 1490 SE Magnolia Ave Ext Ocala, FL 34471 I enjoyed reading the technique described by Sproat et al (~) for performing transjugular intrahepatic portosystemIC shunt (TIPS) placement successfully in patients in
985
986 • Journal of Vascular and Interventional Radiology November-December 1995
whom there is a sharp angle between the hepatic veins a~~ intrahepatic portal vein branches. The anterior posIt~on of the ~ort.al vein branches relative to the hepatic vems makes It dIfficult to perform TIPS without losing access from the hepatic vein. Several times over the course of 62 TIPS procedures I have encountered the same problem, and would like to congratulate Sproat et al for devising a novel solution to this difficult and at times seemingly insurmountable, problem. ' Although the Ring transjugular intrahepatic access set (Cook, Bloomington, Ind) and the Rosch-Uchida transjugular liver access set (Cook) may sometimes not provide a.n acute enough angle to reach the intrahepatic portal vem branches in these patients, it may not be necessary ~o perform the relatively complicated procedure descnbed by Sproat et al. During the clinical evaluation of a fine-needle portal venous access set (AngioDynamics, Glens Falls, NY) (2) we discovered that while the large guiding cannula (equivalent to a 14gauge Colapinto needle) could not be bent without compromising its lumen, the smaller 22-gauge puncture needle could in most cases be gently bent without affecting its function. If a 0.016-inch wire was kept within the 22-gauge needle when it was bent, the lumen of the needle would not be compromised. The curve of the bent needle would naturally follow the curve of the guiding cannula, thereby effectively extending its curve as well as decreasing its radius of curvature. This allowed for a more acute puncture angle and a greater chance of entering the portal venous system. Since only the small flexible needle is bent, there is no difficulty in inserti~g the outer cannula into the working sheath and no ch~nge in the position of the sheath within the hepatic vem. In effect, the puncture system can be "customized" to the patient's anatomy without performing any other alteration in the overall technique. The fine-needle portal venous access system is available but, as yet, is not widely used. The more commonly used Rosch-Uchida set (3) might be altered so that the curve ofthe 14-gauge guiding cannula is adjusted in a similar fashion. The 0.038-inch solid puncture needle has a flexible tip and therefore is difficult to bend into a curve. By replacing this needle with a 21-gauge hollow puncture needle (4) one can possibly extend the curve of the 14-gauge cannula, allowing puncture of anteriorly located portal vein branches. However, a needle of appropriate length would have to be ordered or manufactured prior to the procedure since the Rosch-Uchida set is not supplied with one. By using one ofthese methods it may be possible to successfully perform TIPS in pa- ' tients with anteriorly located portal vein branches without the additional steps described by Sproat et al. However, in those cases in which these maneuvers fail the technique described by Sproat et al may turn ~ tedhnical failure into a clinical success. Further research into new techniques and equipment should further our abilities in difficult situations such as this one.
References 1. Sproat lA, Wojtowycz MM, Gould MJ. Technical modification of transjugular intrahepatic portosystemic shunt placement: anterior transhepatic approach for the cranially located porta hepatis. JVIR 1995; 6:465-468. 2. Kerns SR, Sabatelli FW, Hawkins IF. Fine-needle transjugular portal venous access system. JVIR 1994; 5:835-837. 3. Rosch J, Uchida BT, Barton RE, Keller FS. Coaxial catheter-needle system for transjugular portal vein entrance. JVIR 1993; 4:145-147. 4. Matsui .0, Kadoya M, Yoshikawa J, Gabata T, Miyayama S, Takas~Ima .T. A ne~ coaxial needle system, hepatic artery targetmg WIre, and bIplane fluoroscopy to increase safety and efficacy of TIPS. Cardiovasc Intervent Radiol1994' 17:343-346. '
Wire-assisted Titanium Greenfield Filter Placement From: Daniel Rockey, MD, and David Jacobs, MD Department of Diagnostic Radiology, Meridia Hillcrest Hospital 6780 Mayfield Rd, Mayfield Heights, OH 44124 Editor: On occasion we have encountered problems with advancement of the titanium Greenfield filter (TGF) ~M~di-techJBoston Scientific, Watertown, Mass) through ~ts mtroducer sheath. This usually occurs at the pelvic mlet, secondary to kinking of the sheath as the common iliac vein rises out of the pelvis. This problem has been addressed by the manufacturer by reinforcement of the sheath. Previously, when this problem occurred, we attempted to advance the sheath and filter together, sometimes with a twisting or corkscrew motion. Another technique involves flexing the patient's hip and knee in an attempt to straighten the pelvic veins (1). If these maneuvers fail, the manufacturer recommends abandonment of the femoral approach and consideration of the jugular approach. We have occasionally placed a different, more flexible filter, such as the nitinol filter (Bard Radiology, CR Bard, Covington, Ga) through the sheath of the TGF. Recently we encountered the problem of kinking of the TGF sheath in a 64-year-old man who developed gastrointestinal bleeding after 1 day of heparin therapy for acute left lower extremity deep vein thrombosis. A TGF sheath was advanced into the inferior vena cava (IVC) from a right common femoral vein puncture. On advancement of the filter, the sheath kinked at the pelvic inlet, obstructing passage of the filter. This occurred despite use ofthe reinforced sheath. The customary maneuvers of hip and knee flexion, and sheath and filter advancement as a unit with corkscrew rotation all failed to advance the filter without sheath kinking.
Gianturco Z Stents for Hemodialysis Grafts From: Sumit Roy, MBBS, MD Institute for Surgical Research, Rikshospitalet Pilestredet 32 N-0027 Oslo, Norway. Editor: A small error seems to have crept into the excellent paper by Trerotola et al on the comparative evaluation of stents in hemodialysis grafts (1). The authors suggest that the Gianturco-Rosch stent may be preferable to the Gianturco Z stent for hemodialysis grafts. As the subunits in the former are held together by suture, it is postulated that the problem of fractures of soldered joints causing stent migration will be eliminated. Selection of the Gianturco-Rosch device may in fact simply substitute one drawback with another. The severe inflammatory response noticed by the authors near the soldered joints would probably be exaggerated with the Gianturco-Rosch model. Unlike the Gianturco Z stent, the Rosch-modified version is soldered proximal to every bend in the wire to create an "eyelet," and thus is likely to produce five to six times as many foci of intimal inflammation as the former. The observations of Trerotola et al bring into question the advisability of using solder in the fabrication of this family ofstents. Not only is an alloy of uncertain biocompatibility used (1,2), but soldering is an inappropriate method for bonding stainless steel (3). A completely solder-free Z stent is not just a theoretical possibility (4) and has been successfully used in the urethra (5), the venous. system (6), and the biliary tract (Baijal et aI, unpubhshed data, 1994). The amount of solder on the Gianturco-Rosch stents can also be substantially reduced by eliminating the soldering of adjacent limbs near the be?-ds to cre~te the "eyelets." Though visually pleasing, thIS feature IS superfluous, contributing nothing to the configurational stability of the stent. From benchtop (Roy et aI, unpublished data, 1992) and clinical experience (6) it is evident that the configuration of the wire at this sit~ itself ensures that the suture loop does not migrate and the entire ensemble does not telescope during backloading into the delivery sheath. The results presented by the authors suggest that despite its simple design, the Gianturco Z stent may be' more useful than its counterparts in certain applications. Hence, further modifications should be encouraged to widen the scope of its use and improve its biologic compatibility. References
1. Trerotola SO, Fair JH, Davidson D, Samphilipo MA Jr, Magee CA. Comparison of Gianturco Z stents and Wallstents in a hemodialysis access graft model. JVIR 1995; 6:387-396.
2. Dobben RL, Wright KC, Dolenz K, Wallace S. Gianturco C. Prostatic urethra dilatation with Gianturco self-expandable metallic stent: a feasibility study in cadaver specimens and dogs. AJR 1991; 156:757-761. 3. McGraw-Hill Encyclopedia of science and technology. Vol 16. 6th ed. New York, NY: McGraw-Hill, 1987; 598-599. 4. Roy S, Baijal SS, Phadke RV, Kumar S. Hybrid Gianturco expandable stent. AJR 1994; 162:449-450. 5. Gujral RB, Roy S, Baijal SS, Phadke RV, Ahlawat R. Srinadh ES, Rastogi H. Treatment of recurrent posterior and bulbar urethral strictures with expandable metallic stents. JVIR 1995; 6:427-432. 6. Baijal SS, Roy S. Phadke RV, Kumar S. Idiopathic BuddChiari syndrome: treatment with expandable Z stents (abstr). JVIR 1995; 6:58-59.
Dr Trerotola responds: We appreciate Dr Roy's interest in our work. We were indeed incorrect in stating that the ROsch-modified Gianturco Z stent does not contain solder. This stent does in fact contain solder, although the spiral modification does not. We regret the error and appreciate Dr Roy's comments. In the context of our manuscript (1) we wished to point out that an unsoldered stent such as the spiral Z stent might be less likely to encounter the type of fractures we saw. Like Dr Roy, we agree such an improvement would have to be solder free otherwise it might be at the expense of the type of inflammation we saw in our specimens. Reference
1. Trerotola SO, Fair JH, Davidson D, Samphilipo MA Jr, Magee CA. Comparison of Gianturco Z stents and Wallstents in a hemodialysis access graft model. JVIR 1995; 6:387-396.
Scott O. Trerotola, MD Department of Vascular and Interventional Radiology University Hospital, Room 0279 550 N. University Blvd Indianapolis, IN 46202-5253
Difficult Portal Vein Access in Transjugular Intrahepatic Portosystemic Shunt Placement From: Scott R. Kerns, MD Radiology Associates of Ocala 1490 SE Magnolia Ave Ext Ocala, FL 34471 I enjoyed reading the technique described by Sproat et al (~) for performing transjugular intrahepatic portosystemIC shunt (TIPS) placement successfully in patients in
985
986 • Journal of Vascular and Interventional Radiology November-December 1995
whom there is a sharp angle between the hepatic veins a~~ intrahepatic portal vein branches. The anterior posIt~on of the ~ort.al vein branches relative to the hepatic vems makes It dIfficult to perform TIPS without losing access from the hepatic vein. Several times over the course of 62 TIPS procedures I have encountered the same problem, and would like to congratulate Sproat et al for devising a novel solution to this difficult and at times seemingly insurmountable, problem. ' Although the Ring transjugular intrahepatic access set (Cook, Bloomington, Ind) and the Rosch-Uchida transjugular liver access set (Cook) may sometimes not provide a.n acute enough angle to reach the intrahepatic portal vem branches in these patients, it may not be necessary ~o perform the relatively complicated procedure descnbed by Sproat et al. During the clinical evaluation of a fine-needle portal venous access set (AngioDynamics, Glens Falls, NY) (2) we discovered that while the large guiding cannula (equivalent to a 14gauge Colapinto needle) could not be bent without compromising its lumen, the smaller 22-gauge puncture needle could in most cases be gently bent without affecting its function. If a 0.016-inch wire was kept within the 22-gauge needle when it was bent, the lumen of the needle would not be compromised. The curve of the bent needle would naturally follow the curve of the guiding cannula, thereby effectively extending its curve as well as decreasing its radius of curvature. This allowed for a more acute puncture angle and a greater chance of entering the portal venous system. Since only the small flexible needle is bent, there is no difficulty in inserti~g the outer cannula into the working sheath and no ch~nge in the position of the sheath within the hepatic vem. In effect, the puncture system can be "customized" to the patient's anatomy without performing any other alteration in the overall technique. The fine-needle portal venous access system is available but, as yet, is not widely used. The more commonly used Rosch-Uchida set (3) might be altered so that the curve ofthe 14-gauge guiding cannula is adjusted in a similar fashion. The 0.038-inch solid puncture needle has a flexible tip and therefore is difficult to bend into a curve. By replacing this needle with a 21-gauge hollow puncture needle (4) one can possibly extend the curve of the 14-gauge cannula, allowing puncture of anteriorly located portal vein branches. However, a needle of appropriate length would have to be ordered or manufactured prior to the procedure since the Rosch-Uchida set is not supplied with one. By using one ofthese methods it may be possible to successfully perform TIPS in pa- ' tients with anteriorly located portal vein branches without the additional steps described by Sproat et al. However, in those cases in which these maneuvers fail the technique described by Sproat et al may turn ~ tedhnical failure into a clinical success. Further research into new techniques and equipment should further our abilities in difficult situations such as this one.
References 1. Sproat lA, Wojtowycz MM, Gould MJ. Technical modification of transjugular intrahepatic portosystemic shunt placement: anterior transhepatic approach for the cranially located porta hepatis. JVIR 1995; 6:465-468. 2. Kerns SR, Sabatelli FW, Hawkins IF. Fine-needle transjugular portal venous access system. JVIR 1994; 5:835-837. 3. Rosch J, Uchida BT, Barton RE, Keller FS. Coaxial catheter-needle system for transjugular portal vein entrance. JVIR 1993; 4:145-147. 4. Matsui .0, Kadoya M, Yoshikawa J, Gabata T, Miyayama S, Takas~Ima .T. A ne~ coaxial needle system, hepatic artery targetmg WIre, and bIplane fluoroscopy to increase safety and efficacy of TIPS. Cardiovasc Intervent Radiol1994' 17:343-346. '
Wire-assisted Titanium Greenfield Filter Placement From: Daniel Rockey, MD, and David Jacobs, MD Department of Diagnostic Radiology, Meridia Hillcrest Hospital 6780 Mayfield Rd, Mayfield Heights, OH 44124 Editor: On occasion we have encountered problems with advancement of the titanium Greenfield filter (TGF) ~M~di-techJBoston Scientific, Watertown, Mass) through ~ts mtroducer sheath. This usually occurs at the pelvic mlet, secondary to kinking of the sheath as the common iliac vein rises out of the pelvis. This problem has been addressed by the manufacturer by reinforcement of the sheath. Previously, when this problem occurred, we attempted to advance the sheath and filter together, sometimes with a twisting or corkscrew motion. Another technique involves flexing the patient's hip and knee in an attempt to straighten the pelvic veins (1). If these maneuvers fail, the manufacturer recommends abandonment of the femoral approach and consideration of the jugular approach. We have occasionally placed a different, more flexible filter, such as the nitinol filter (Bard Radiology, CR Bard, Covington, Ga) through the sheath of the TGF. Recently we encountered the problem of kinking of the TGF sheath in a 64-year-old man who developed gastrointestinal bleeding after 1 day of heparin therapy for acute left lower extremity deep vein thrombosis. A TGF sheath was advanced into the inferior vena cava (IVC) from a right common femoral vein puncture. On advancement of the filter, the sheath kinked at the pelvic inlet, obstructing passage of the filter. This occurred despite use ofthe reinforced sheath. The customary maneuvers of hip and knee flexion, and sheath and filter advancement as a unit with corkscrew rotation all failed to advance the filter without sheath kinking.