Treatment of failed native arteriovenous fistulae for hemodialysis by interventional radiology.

BACKGROUND: We studied the feasibility, technical problems, safety, and effectiveness of percutaneous declotting of thrombosed native arteriovenous fistulae for hemodialysis. METHODS: Between 1992 and 1998, 93 declotting procedures were performed in 73 consecutive upper limb native fistulae (forearm 56 and upper arm 17), and 162 procedures were performed in 78 prosthetic grafts using manual catheter-directed thrombo-aspiration, with or without previous urokinase infusion. Detection of restenosis by clinical surveillance led to redilation or stent placement. Rethrombosis in four forearm and six upper arm fistulae were treated by 20 further declottings by aspiration. RESULTS: The initial success was 93% in the forearm and 76% in the upper arm (99% in grafts). The complications included one pulmonary embolism, one acute pseudoaneurysm, and one blood depletion requiring transfusion. Primary patency rates at one year were 49% in the forearm and 9% in the upper arm (14% in grafts). Secondary patency rates were 81 and 50% at one year, respectively (83% in grafts). Reinterventions were necessary every 19.6 months in the forearm and every 5.7 months in the upper arm (every 6.4 months in grafts, P < 0.05). Stents were placed in 11% of forearm fistulae and in 41% of upper arm fistulae (45% of grafts) for treatment of acute rupture (5 out of 19), stenosis recoil (6 out of 19), and early (< 6 months) recurring stenosis (8 out of 19). CONCLUSIONS: The percutaneous declotting of forearm fistulae by manual catheter-directed thrombo-aspiration was effective in more than 90% of cases and yielded 50% primary and 80% secondary patency rates at one year. The results were poorer in upper arm fistulae. The need for maintenance reinterventions was three times smaller in forearm fistulae than in upper arm fistulae and grafts.

Cragg covered stents in hemodialysis access: initial and midterm results.

PURPOSE: To report midterm follow-up after implantation of covered stents for hemodialysis access. PATIENTS AND METHODS: Over a 2-year period, a Cragg Endopro stent was placed in 14 patients (mean age, 66.6 years +/- 15) to treat angioplasty-induced ruptures (n = 3), pseudoaneurysm (n = 1), postangioplasty residual stenosis (n = 2), and early restenosis (n = 8, four of them in a Wallstent). RESULTS: Initial placement was successful in all cases. A clinical inflammatory reaction was observed in all three cases of placement in the forearm. When the covered stent was placed in a stenotic vessel, restenosis always occurred within 6 months. Primary and secondary patencies were 28.5% +/- 13.9 and 67.8% +/- 14.5, respectively, at 6 months. Covered stents were of undoubtable benefit in one case of rupture after Wallstent failure and in one case of restenosis in a Wallstent. CONCLUSION: Covered Cragg stents are effective in controlling angioplasty- induced rupture and sometimes for maintaining patency after restenosis in a Wallstent. They do not prevent restenosis and are responsible for an inflammatory reaction of unknown origin and long-term effect.

[Drug induced nephrolithiasis: observation of an oxalate and hydroxylated triamterene stone (author's transl)]. / Lithiases urinaires médicamenteuses: observation d'un calcul constitué d'oxalate de calcium et d'un métabolite du triamtérène.

A 54-year old man who had been taking triamterene (150 mg daily) over a period of 8 months, passed a 3 mm stone partly coated with mustard-colored substance. Metabolic evaluation showed only mild-hyperoxaluria. Through IR spectrography after microdissection, thin-layer chromatography, UV light examination, and mass spectrometry, the stone if found to consist of 70% whewellite, 5% protein, 5% carbapatite and 20% triamterene and hydroxylated triamterene, and perhaps also the sulfate conjugate of this metabolite. In spite of the few number of observations (two cases have been reported previously), triamterene seems likely to induce stone formation, both alone and associated with urate or oxalate, and triamterene should be used cautiously in patients with a predisposition for nephrolithiasis.