Meeting Notes: Society of Cardiovascular and Interventional Radiology Annual Meeting

Washington, DC, March 8-13, 1997




Scott O. Trerotola
Meeting highlights prepared by Scott O. Trerotola, M.D., Associate Professor of Radiology and Director o Vascular and Interventional Radiology at Indiana University. Dr. Trerotola's academic interests include mechanical thrombolysis and venous disease, particularly in hemodialysis patients.


Abstracts are published in JVIR 1997 (Supplement): 8(1) Part 2 (not available on line at this time)


Catheter access for hemodialysis


Trerotola et al (p 187) presented the results of a prospective randomized trial comparing silver coated tunneled dialysis catheters to identical non-coated catheters. One hundred patients were enrolled, and the right internal jugular vein was the site of choice for all catheters. The silver coating, designed to reduce infection, resulted in 2 allergic reactions, but there was no difference in clinical infection or colonization rates between groups. Thus the coating conferred no benefit. Venographic follow-up was obtained in all patients, showing a 2% incidence of central venous stenosis/thrombosis, none of which was symptomatic, indicating that right internal jugular placement of tunneled dialysis catheters by interventional radiologists results in a very low incidence of this complication.

Nazarian et al (p 187) presented a series of 67 patients in whom tunneled catheters were placed for plasmapheresis or infusion therapy. The pheresis catheters (n=29) were identical to those used for hemodialysis and had a silver-impregnated cuff (Vitaphore) attached to them, while the infusion catheters (n=38) did not. This non randomized retrospective study suggested a significant decrease in clinical infection when the cuff was used. The authors have initiated a randomized trial to test this hypothesis. While these cuffs have been shown to decrease infection in nontunneled catheters, this has not been studied in nontunneled catheters.

Egglin et al (p188) presented a series of 17 patients in whom tunneled hemodialysis catheters that had fallen out were replaced with new ones by cannulating the existing tract rather than fresh puncture. The time from catheter falling out to reestablishing access was as long a 5 days. The authors did not use prophylactic antibiotics, and were successful in 16/17 patients. Over a 30 day followup period there were no infectious complications nor catheter failures. The authors conclude that this technique, which they stated is faster and easier than fresh puncture, was safe and effective.

Caridi et al (p188) presented the results of placement of Tesio catheters in 75 patients using the right internal jugular approach. Complications were limited to a single arterial puncture and three hematomas. Successful catheter placement was achieved in all patients, and flow rates were > 375 ml/min in 95% of catheters. Bacteremia occurred in 20 patients, 5 episodes of which required catheter removal.

St. George et al (p 189) reported data concerning flow rates achieved with various catheter designs placed by interventional radiologists, including the Quinton PermCath (n=48), Arrow temporary dialysis catheter (n=23), VasCath (n=10) and Tesio (n=61). Mean flow rates were 216 ml/min for the PermCath, 226 ml/min for the Arrow, 197 ml/min for the VasCath and 287 ml/min for the Tesio. The authors also examined flow by access site and found the best flow from the right internal jugular vein catheters, slightly less from left internal jugular vein catheters, and the worst flows from femoral catheters of all types.

Discussion
in this session centered around flow rates and the advisability of exchanging catheters through existing tracts. While there is a sense that the Tesio provides better flow rates compared with many other catheters, no randomized trial has proved this.

Dialysis Access Interventions


Turmel-Rodrigues (p242) presented results of 9 years of experience in percutaneous management of failing native fistulae (in France). This series included 144 fistulae (135 patients) and consisted of balloon angioplasty (144 initial and 147 repeat dilations), stent placement where appropriate (n=27), and percutaneous thromboaspiration of clotted fistulae (n=12). Primary and secondary rates were 42% and 79% at one year and 33% and 75% at 3 years respectively. The author showed that stent placement for early restenosis prolonged the interval between repeat interventions by a factor of 2. Results were significantly less favorable for brachiocephalic fistulae compared with radiocephalic (Brescia-Cimino) fistulae. This series confirms the value of percutaneous interventions in native fistulae, and documents the need for repeat percutaneous interventions to achieve good secondary patencies.

McDermott et al (p243) reported substantially better 90 day primary patency after surgical revision of failed synthetic access grafts (86%) when surgery was used to treat failures of percutaneous thrombolysis (47% primary 90 day patency). This series only examined primary patency, and the authors concluded that those grafts experiencing early rethrombosis after thrombolysis should have surgical revision. This series was not randomized.

Gelbfish (p243) presented results of dialysis graft thrombectomy using a percutaneous suction thrombectomy device. In 30 clotted grafts in 25 patients, a 90% success rate was achieved with 56% primary patency at 30 days. Average blood loss was 107 cc due to the suction used in the procedure.

Trerotola et al (p244) examined arterial emboli occurring during surgical thrombectomy/revision. They reported a series of patients in whom postoperative fistulography was done following surgical thrombectomy and revision in 67 patients. Arterial emboli were present 12% of the time, but only 1 patient was symptomatic. This patient was treated successfully with percutaneous techniques, and no specific therapy was given to the remainder. At mean follow-up of 14 months, no patient had developed ischemia in the involved arm, and most emboli had resolved or diminished on subsequent angiographic evaluation. The authors concluded that arterial emboli occurring during surgical and percutaneous procedures may not need treatment in asymptomatic patients, as the treatment (surgery, thrombolysis) carries significant costs and risks.

Hickman et al (p244) presented their experience with the Amplatz thrombectomy device in a rural private practice setting. They compared the results and costs of surgical thrombectomy (n=20) to percutaneous mechanical thrombolysis (n=20) in a randomized study. True cost-accounting was used, and professional fees were excluded. Primary patency at 90 days was 33% for the device versus 21% for surgery, and costs were $2913 vs $5428 respectively. The authors concluded that mechanical thrombectomy using the device was more cost-effective than surgical thrombectomy.

Peters et al (p244) reported use of metallic stents in dialysis access grafts. 69 stents were placed in 48 grafts. Mean primary patency was 88 days, and mean secondary patency was 356 days, usually requiring several interventions. The authors expressed their belief that stents extended the life of the treated grafts.

Discussion
Discussion in this session centered around the disparity in results of surgical revision. It was pointed out that the Duke series (McDermott et al) reports surgical results far better than anything previously published. Possible explanations offered included variation in techniques, skills, and interests. There was a consensus that each site needed to determine which techniques work best in their own setting. The session emphasized the need for randomized prospective trials examining this issue as well as the role of stents in failed PTA.

Dialysis Access Interventions


Arata et al (p199) presented the results of percutaneous fibrin sheath stripping of failing tunneled dialysis catheters. 114 procedures were performed in 58 patients. Success was defined as restoring flow rates of at least 250 ml/min. 79% of catheters maintained this flow at 2 weeks. Repeated stripping was needed in 54 catheters. Complications included a septic pulmonary embolus. The authors concluded the procedure was effective in salvaging failed catheters.

Topham et al (p200) used static venous pressure to screen for failing dialysis grafts. Pressure ratios (compared with systolic systemic pressure) >0.47 were considered an indication for fistulography, and stenoses of 50% and greater were treated. Following treatment (n=16), grafts were followed for one year without further intervention. The results were compared to a group of 22 patients who had pressure ratios > 0.47 but refused treatment. Thrombosis rates were significantly higher in those patients who refused intervention than in those who had angioplasty. This study confirmed Schwab's landmark study (using static pressures instead of resistance) and the authors concluded that the results justified prophylactic angioplasty of failing access.

Zaetta et al (p200) reported results of percutaneous mechanical declotting of upper arm dialysis grafts from a transjugular approach in 24 patients (31 procedures). Technical success was 86% and long term patency was identical to that of other mechanical techniques. The authors believe the technique reduces radiation exposure to the operator.

Hazlett et al (p201) reported a cost analysis comparing surgical declotting procedures (n=41) to percutaneous thrombolysis using urokinase (n=87). Average duration of patency did not differ between procedures. Mean costs were $2620 for thrombolysis and $3108 for surgery. The authors concluded that the percutaneous approach was more cost-effective. They also showed that the results of percutaneous intervention were not affected by the technique previously used to restore graft patency (surgery vs percutaneous).

Trerotola et al (p201) presented the results of a randomized, prospective clinical trial of pulse-spray pharmacomechanical thrombolysis (PSPMT) versus mechanical thrombolysis with the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) in 122 patients. Technical success rates were identical (95%) as were 90 day patencies (38%). Procedure time was significantly shorter in the PTD group, as were complications, most of which were minor. This device is expected to receive FDA approval by this summer.

Soulen et al (p201) also compared surgical results to mechanical thrombolysis, finding 92% (49/53) technical success with the latter compared to 63% (12/19) for surgery. Costs, mostly due to hospitalizitation, were significantly higher in the surgery group.
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