Jan Namyslowski

Modified Use of the Arrow-Trerotola Percutaneous Thrombolytic Device for the Treatment of Thrombosed Hemodialysis Access Grafts

PURPOSE To assess the safety and efficacy of using the Arrow-Trerotola percutaneous thrombolytic device (PTD) as the sole means of mechanical thrombolysis in hemodialysis access grafts, including in situ treatment of the arterial plug. PATIENTS AND METHODS Fifty consecutive patients (22 women, 28 men; mean age, 58 years; mean graft age, 29 months), in whom mechanical thrombolysis of a thrombosed hemodialysis access graft using the PTD was planned, were included in the study. In all patients, the PTD was used to treat the arterial plug in situ at the arterial anastomosis, instead of using a Fogarty catheter to reposition the plug, as indicated in the PTD product labeling. Prospective data collection included demographic information, technical details of the procedure, immediate outcomes, and complications. Patients were followed for 3 months using definitions and data forms that were identical to those used in the original clinical trial of the PTD. A sample of procedures drawn from the PTD clinical trial database (n = 54) served as control. RESULTS Immediate technical patency was 100%. Complications included arterial embolization (6% versus 2% control; P = NS; all successfully treated with backbleeding); venous rupture (6% versus 2% control; P = NS); and sepsis (n = 1), probably due to occult graft infection. Adjunctive therapy with an Adherent Clot catheter was needed in two procedures (4%). Three month patency using life-table analysis was 42% (versus 39% control; P = NS). The number of subsequent interventions (surgical/percutaneous) to the arterial limb of the graft did not differ from the PTD trial, and no native arterial stenoses were detected during the follow-up period. CONCLUSIONS The PTD is safe and effective when used as the sole means of mechanical thrombolysis of hemodialysis grafts. Treating the arterial plug in situ with the PTD eliminates the need for a Fogarty or Adherent Clot catheter in 96% of procedures. A slight increase in arterial embolic complications was observed but these were easily treated with backbleeding.

Randomized Comparison of High-Flow versus Conventional Hemodialysis Catheters

PURPOSE To evaluate short-term flow rates achieved with a new split-tip polyurethane hemodialysis catheter. PATIENTS AND METHODS This was a prospective, randomized, nonblinded study. Patients referred for a tunneled-dialysis catheter received either a conventional silicone (Bard Hickman 13.5 F) if randomized to the control group, or a split-tip, high-flow polyurethane (MedComp AshSplit 14.5 F) catheter if randomized to the study group. Effective flow rates (QbEff) and recirculation were measured with use of ultrasonic dilution at pump settings (Qb) of 200, 300, 350 and 400 mL/min, as well as maximum Qb (QbMax, up to 500 mL/min) sustainable for at least 3 minutes. Measurements were repeated weekly for 6 weeks. Procedure times and initial and late complications were recorded. RESULTS Twelve patients were enrolled in each group, 11 and eight completed the study in the test and control groups, respectively. Insertion complications, limited to the split-tip group, included asymptomatic air embolus (n = 1), prolonged tunnel bleeding (n = 2), and kinking (n = 2). Recirculation in both groups was low (mean < 6% at all flow rates). QbMax was 499 mL/min in the Ash group and 470 mL/min in the Hickman group. A repeated measures analysis of variance was used. Adjusted (for week) mean effective flow rates (Qbeff, mL/min) were as follows: at Qb = 200, Ash = 211, Bard = 211, P = .93; at Qb = 300, Ash = 301, Bard = 292, P = .28; at Qb = 350, Ash = 341, Bard = 314, P = .03; at Qb = 400, Ash = 375, Bard = 329, P = .01; at QbMax, Ash = 422, Bard = 359, P = .0005. CONCLUSION Both catheters delivered flows within the acceptable range indicated by the Dialysis Outcomes Quality Initiative. The split-tip catheter is capable of higher flow rates (Qb and QbEff) compared with the conventional catheter, which may allow more efficient dialysis. Insertion complications appear to be higher with the new design.

Incidence and Management of Arterial Emboli from Hemodialysis Graft Surgical Thrombectomy

PURPOSE To determine the incidence and significance of arterial emboli resulting from surgical thrombectomy/revision of hemodialysis grafts. This information may help in determining the significance and management of similar emboli resulting from percutaneous hemodialysis graft thrombolysis. PATIENTS AND METHODS Patients undergoing surgical thrombectomy/revision of clotted hemodialysis grafts are studied with postoperative fistulography per institutional protocol whenever possible. For this retrospective study, all postoperative fistulograms from a 1-year period were reviewed for the presence of arterial emboli. Patients with documented arterial emboli were examined for evidence of hand/digital ischemia; only those patients with signs or symptoms of ischemia were treated. At clinical follow-up, repeated evaluation for hand/digital ischemia was performed. RESULTS Ninety-one thrombectomy/revision procedures were performed during the study period. Postoperative fistulograms were obtained after 67 of these procedures in 32 patients. One patient complained of hand pain during dialysis prior to acquisition of the postoperative fistulogram. Arterial emboli were documented in eight patients (12%; brachial, n = 3; radial, n = 2; ulnar, n = 2; radial/ulnar, n = 1). The single symptomatic brachial embolus was percutaneously removed; no intervention was undertaken in the remainder. At mean follow-up of 14 months, no patient had developed hand or digital ischemia. Subsequent fistulograms demonstrated partial (n = 2) or complete (n = 2) resolution of the untreated emboli. CONCLUSION Arterial emboli are a relatively common occurrence with surgical thrombectomy/revision. Conservative management appears to be indicated in asymptomatic patients.

Increase in Hepatic Arterial Blood Flow after Transjugular Intrahepatic Portosystemic Shunt Creation and its Potential Predictive Value of Postprocedural Encephalopathy and Mortality

PURPOSE To determine (i) whether there is a significant increase in hepatic artery blood flow (HABF) after transjugular intrahepatic portosystemic shunt (TIPS) creation and (ii) whether the extent of incremental increase in HABF is predictive of clinical outcome after TIPS creation. MATERIALS AND METHODS Prospective, nonrandomized, nonblinded duplex Doppler ultrasound (US) examinations were performed on 24 consecutive patients (19 men; Child Class A/B/C: 4/12/8, respectively) with a mean age of 52.8 years who were referred for TIPS creation for variceal bleeding. Peak hepatic artery velocity and vessel dimensions were used to calculate the hepatic arterial blood flow (HABF) before and after TIPS creation. Patients were clinically followed in the gastrohepatology clinic and TIPS US surveillance was performed at 1 and 3 months to assess shunt function. The extent of incremental increase in HABF was analyzed as a predictor of post-TIPS encephalopathy and/or death. RESULTS The technical success rate of TIPS creation was 100%. The shunt diameters were either 10 mm (n = 11) or 12 mm (n = 13). TIPS resulted in a significant reduction in the portosystemic gradient from 24.3 mm Hg +/- 5.7 to 9.3 mm Hg +/- 2.9 (P <.001). The hepatic artery peak systolic velocity and HABF increased significantly after TIPS creation, from 60.8 cm/sec +/- 26.7 to 121 cm/sec +/- 51.5 (P <.001) and from 254.2 mL/min +/- 142.2 to 507.8 mL/min +/- 261.3 (P <.001), respectively. The average incremental increase in HABF from pre-TIPS to post-TIPS was 253.6 mL/min +/- 174.2 and the average decremental decrease in portosystemic gradient was 15.0 mm Hg +/- 5.3, but there was no significant correlation (r = 0.04; P =.86) between the two. All shunts were patent at 30 and 90 days without sonographic evidence of shunt dysfunction. After TIPS creation, new or worsened encephalopathy developed in five patients at 30 days and in an additional three at 90 days. They were all successfully managed medically. Three patients (12.5%) died within 30 days of the TIPS procedure. The extent of incremental increase in HABF after TIPS was variable and did not correlate with the development of 30-day and 90-day encephalopathy (P =.41 and P =.83, respectively) or 30-day mortality (P =.2). CONCLUSIONS HABF increases significantly after TIPS but is not predictive of clinical outcome. The significance of the incremental increase is yet to be determined.

Single-Step Dilation for Large-Bore Percutaneous Gastrostomy and Gastrojejunostomy

O SCVIR, 1998 PERCUTANEOUS gastrostomy and gastrojejunostomy are well established techniques that have excellent technical success rates and very few complications (1-5). One of the differences between percutaneous interventional radiologic techniques and surgical and percutaneous endoscopic techniques is the size of the catheter placed. Most percutaneous gastrostomy tubes are 12-14 F and percutaneous jejunostomy tubes range from 12 to 24 F, while endoscopically and surgically placed tubes are typically much larger (6). Smaller bore tubes may be more prone to clogging, as well as to mechanical problems such as kinking and breakage (5,7). Our experience with patient and referring physician complaints about smallbore gastrostomy and gastrojejunostomy tubes led us to consider placement of larger bore tubes. Several such tubes are available, most commonly consisting of Silastic balloon tip catheters ranging in diameter from 18 to 24 F. Smaller gastrojejunostomy tubes can be placed coaxially through these catheters and have adapters to fit them conveniently to the existing gastrostomy tube. One of the problems in initial placement of large-bore gastrostomy and gastrojejunostomy tubes is tract dilation. Even when gastropexy is used, the forces associated with serial dilation with rigid dilators mav cause detachment of the gastropexy and even inadvertent placement of the tube into the peritoneal cavity. Furthermore, with each dilator exchange there is a risk of spillage of gastric contents into the peritoneal cavity with subsequent peritonitis. We describe a technique for single-step tract dilation and peel-away sheath placement that circumvents these potential problems.

Central venous access: A new task for interventional radiologists

SummarySelected issues regarding radiological placement of CVA devices have been reviewed with emphasis on those aspects that place an interventional radiologist in the unique position of being able to offer an all-inclusive VAS, the quality of which equals or exceeds that of other specialists providing venous access, and may offer it at a lower cost.

Percutaneous imaging-guided Access for the treatment of calculi in continent urinary reservoirs

Purpose: To describe our long-term experience with percutaneous access to continent urinary reservoirs for calculus removal. Patients and Methods: A retrospective study of 13 procedures in 10 patients was performed. In 2 of the 13 procedures, access and calculus removal was performed in a single session. In the other 11 procedures, initial access was obtained using ultrasonography, fluoroscopy, and/or computed tomography. The patients then returned at a later date for a second step where the access was dilated and the calculi were removed. Results: Access was achieved successfully in all cases with no complications. At mean follow-up time of 13.6 months (range 1–94 months) one patient had died of complications unrelated to her continent urinary reservoir. Another patient had been placed on suppressive antibiotics for recurrent calculi. The remaining patients were stone free and without late complication. Conclusions: Percutaneous removal of reservoir calculi can be performed safely, avoiding potential injury to the continence valve mechanism by a direct cystoscopic approach. We propose a two-stage procedure using CT guidance for initial access as the preferred technique.

Use of Balloon-expandable Stents in Transjugular Intrahepatic Portosystemic Shunts in Cases of Wallstent Endoprosthesis Technical Failure and Revision of Shunt Stenosis

Thirteen patients underwent placement of a balloon-expandable stent either at initial transjugular intrahepatic portosystemic shunt (TIPS) creation (n = 3) because of immediate technical failure of the Wallstent or at shunt revision because of failure of the Wallstent to reduce the portosystemic gradient <or=12 mm Hg despite overdilation (n = 2), stenosis of the Wallstent (n = 1), or parenchymal tract shunt stenosis (n = 7). The mean duration of primary patency when balloon-expandable stents were used at initial shunt creation was 162.7 days +/- 110.1 (SD). The time from initial TIPS creation or shunt revision with a Wallstent to placement of a balloon-expandable stent was 88.6 days +/- 115.3. The time from balloon-expandable stent placement to shunt revision (n = 6), most recent follow-up (n = 2), death (n = 1), or liver transplantation (n = 1) was 171.9 days +/- 121.6. No significant difference in shunt patency was found between the Wallstent and balloon-expandable stent (P =.31). Because no added benefit in patency was seen between the balloon-expandable stent and Wallstent, it appears that balloon-expandable stent placement is valuable only when placement of a Wallstent technically fails as a result of its limited radial force or when precision in placement is needed to treat a hepatic vein stenosis near the confluence with the inferior vena cava.

Embolization of Large Gastric Varices Using Vena Cava Filter and Coils

A 40-year-old male with alcoholic cirrhosis and portal hypertension presented with acute variceal hemorrhage. Abdominal CT scan and endoscopy revealed large gastric varices. The patient underwent a TIPS procedure. Portal venography demonstrated persistent filling of the large gastric varices with associated high-flow spontaneous splenorenal shunt. Because of the large size of the varices, a Simon-Nitinol filter was used in conjunction with multiple embolization coils to enable successful occlusion of the varices.