Nikolaos Christeas

Paclitaxel-Coated Balloon Angioplasty vs. Plain Balloon Dilation for the Treatment of Failing Dialysis Access: 6-Month Interim Results From a Prospective Randomized Controlled Trial:

Purpose To report the 6-month results of a prospective randomized trial investigating angioplasty with paclitaxel-coated balloons (PCB) vs. plain balloon angioplasty (BA) for the treatment of failing native arteriovenous fistulae (AVF) or prosthetic arteriovenous grafts (AVG). Methods The enrollment criteria for this non-inferiority hypothesis trial included clinical signs of failing dialysis access with angiographic documentation of a significant venous stenotic lesion in patients with AVF or AVG circuits. From March to December 2010, 40 patients (29 men; mean age 64.1±14.3 years) were randomized to undergo either PCB dilation (n=20) or standard BA (n=20) of a stenosed venous outflow lesion. Regular angiographic follow-up was scheduled bimonthly. Study outcome measures included device success (<30% residual stenosis without postdilation), procedural success (<30% residual stenosis), and primary patency of the treated lesion (<50% angiographic restenosis and no need for any interim repeat procedures). Results Baseline and procedural variables were comparably distributed between both groups. Device success was 9/20 (45%) for the PCB device vs. 20/20 (100%) for standard control BA (p<0.001). Procedural success was 100% in both groups after further high-pressure post-dilation as necessary. There were no major or minor complications in either group. At 6 months, cumulative target lesion primary patency was significantly higher after PCB application (70% in PCB group vs. 25% in BA group, p<0.001; HR 0.30, 95% CI 0.12 to 0.71, p<0.006). Conclusion PCB angioplasty improves patency after angioplasty of venous stenoses of failing vascular access used for dialysis.

Ureteral Metal Stents: 10-Year Experience With Malignant Ureteral Obstruction Treatment

PURPOSE Ureteral patency in malignant ureteral obstruction cases is a therapeutic challenge. We report our long-term experience with palliative treatment for extrinsic malignant ureteral obstruction with percutaneous placement of metal mesh stents. MATERIALS AND METHODS From January 1996 to December 2005, 90 patients with a mean age of 59 years (range 35 to 80) with ureteral obstruction due to extrinsic ureteral compression and/or encasement by primary or metastatic tumors, or retroperitoneal lymphadenopathy underwent implantation of self-expandable metal mesh stents. A total of 119 ureters were managed. Followup included urinalysis, blood biochemistry tests and transabdominal ultrasound or intravenous urography. RESULTS The technical success rate of percutaneous antegrade insertion of ureteral self-expandable metal mesh stents was 100%. Renal biochemistry normalized and hydronephrosis gradually resolved 1 to 2 weeks after stent insertion. Median followup was 15 months (range 8 to 38). Hyperplastic reaction and/or encrustation, or tumor ingrowth developed in 45 stents. Secondary intervention, such as repeat balloon dilation and coaxial stenting, was done to improve patency. Migration was observed in 13 metal stents. The primary and secondary patency rates during followup were 51.2% and 62.1%, respectively. A double pigtail or external-internal stent was inserted in 45 cases in which secondary interventions did not ensure patency. CONCLUSIONS Internal drainage of extrinsic malignant ureteral obstruction with metal mesh stents provides long-term decompression of the upper urinary tract in select cases. Certain problems limit the application of metal mesh stents in the ureter. Further studies are warranted to identify independent predictors of ureteral patency after the application of metal stents for malignant obstruction.

Stent-grafts versus angioplasty and/or bare metal stents for failing arteriovenous grafts: a cross-over longitudinal study.

BACKGROUND A well-established method to preserve failing synthetic arteriovenous grafts (AVGs) dialysis accesses is percutaneous transluminal angioplasty (PTA). Nevertheless, the one-year primary patency rate following PTA is approximately 25%. This study was designed to compare the angiographic and clinical outcomes following stent-graft insertion versus angioplasty and/or bare metal stenting (BMS) of recurrently failing AVGs, because of anastomotic and/or venous outflow stenoses. METHODS Self-expanding stent-grafts were deployed for the treatment of failing AVGs in case of recurrent stenosis after treatment with conventional angioplasty or bail-out BMS. Regular angiographic follow-up was scheduled every two months the first six months and every three months thereafter. Data from previous procedures on the same treatment site were retrieved from our database. Primary patency was defined as a functioning graft with a patent treatment site without angiographic restenosis >50% and without any subsequent repeat procedures. Outcome data were analyzed by Kaplan-Meier analysis. RESULTS In total, 35 patients previously treated with angioplasty and/or BMS for the treatment of recurrent significant AVG stenosis (group PTA), underwent stent-graft placement of the same treatment site (group SG). Of those, 20 patients had undergone angioplasty and 15 bail-out BMS. Mean lesion length was 4.8±1.7cm. Primary patency was significantly improved in the SG group (Hazard Ratio [HR] = 0.2 [95% CI= 0.11-0.36], P=.0001) by log-rank test. The estimated six and 12-month patency rates were 76.9% vs. 25.7%, and 61.4% vs. 8.6% for groups SG and PTA respectively, (P<.0001). CONCLUSIONS Stent-graft placement significantly improves primary patency of anastomotic and venous outflow stenoses in recurrently failing prosthetic arteriovenous grafts.

Paclitaxel-coated balloons in fistula. A prospective randomized controlled trial

Purpose To report the interim (6-month) results of a prospective randomized controlled trial investigating angioplasty with paclitaxel-coated balloons (PCB) versus plain balloon angioplasty (PBA) for the treatment of failing arteriovenous fistulae (AVF). Materials and Methods From May 2011 to September 2012, 40 patients were randomly selected to undergo either PCB dilation (Group PCB, n=20) or PBA (Group PBA, n=20). Enrollment criteria included an angiographic and clinical diagnosis of dysfunctional AVF circuit due to at least one stenotic lesion. Regular angiographic follow-up was scheduled every 2 months. Study primary outcome measures included technical success (defined as residual stenosis of the treated lesion Results Baseline variables were equally distributed between the two groups. Technical success was 100% for both groups. To date, 6-month angiographic follow-up is available in 31 cases (14 in group PCB and 17 in group PBA). Interim calculation of the primary endpoint outcome by Kaplan-Meier survival analysis demonstrated a trend towards significantly higher primary patency in group PCB compared to group PBA (308 days vs. 167 days, respectively; p=0.14 by log rank test). Conclusion Interim study outcomes show that PCB angioplasty might constitute a valid solution in the treatment of failing arteriovenous fistulae. Long-term final data are awaited.