Treatment of stenosis and thrombosis in haemodialysis fistulas and grafts by interventional radiology.

BACKGROUND: There are no large series reporting the long-term results after radiological treatment of both stenosis and thrombosis in native fistulas (AVFs) and prosthetic grafts. METHODS: Between 1987 and 1999, 726 dilations, 135 stent placements and 257 declotting procedures were performed in 209 consecutive forearm AVFs, 74 upper arm AVFs and 156 prosthetic grafts. The stents used were the Wallstent*, the Craggstent*, and the Passager*. Declotting was performed by manual catheter-directed thromboaspiration, with or without previous urokinase infusion. RESULTS: The initial success rates ranged from 78 to 98%. The rate of significant complications was 2%. Primary patency rates at 1 year were twice as good for forearm AVFs (50%) than for grafts (25%) (P<0.05), and were 34% for upper arm AVFs. Secondary patency rates were similar in the 3 groups at 1 year (80-86%) and at 2 years (68-80%). Reintervention was necessary every 18 months in forearm AVFs compared to every 9 months in grafts (P<0.05). Thrombosed grafts fared worse than failing grafts. Accesses of less than 1 year's duration needed more reinterventions than older accesses (every 16 months versus 30 in forearm AVFs, every 7 months versus 13 in grafts, P<0.05). CONCLUSIONS: The percutaneous treatment of stenosis and thrombosis in haemodialysis access achieves patency rates similar to those reported in the surgical literature and confirms that grafts must be avoided as much as possible given their poorer outcome, especially after the first thrombosis. Poorer outcome is also demonstrated in accesses of less than 1 year's duration.

Wallstents and Craggstents in hemodialysis grafts and fistulas: results for selective indications.

PURPOSE: To report the value of selective placement of self-expandable stents (Wallstent and Craggstent) for the treatment of limitations and, occasionally, of complications of dilation in hemodialysis access, and especially for delaying restenosis. MATERIALS AND METHODS: This is a retrospective study of a 7-year period, during which 41 Wallstents and 11 Craggstents were placed in 26 polytetrafluoroethylene (PTFE) grafts, 15 native fistulas, and nine central veins of 47 patients. The indications were stenosis recoil (n = 13), recurrent restenosis within 6 months (n = 33), restenosis after 6 months (n = 3), and acute angioplasty-induced rupture (n = 1). Restenosis after stent placement necessitated redilation and percutaneous declotting and 10 additional stent placements. RESULTS: Two initial misplacements were corrected immediately. Primary patency rates for PTFE grafts were 58% +/- 10% at 6 months and 23% +/- 10% at 1 year, respectively. Secondary patency rates were 100% at 6 months and 88% +/- 8% at 1 year, respectively. For native fistulas, primary patency rates were 47% +/- 12% at 6 months and 20% +/- 18% at 1 year. Secondary patency rates were 95% +/- 6% at 6 months and 79% +/- 14% at 1 year. It was necessary to reintervene after stent placement to maintain or to restore patency every 9 months for PTFE grafts and every 7.3 months for native fistulas. When stents were placed for treatment of early recurring restenosis, the mean interval between radiologic interventions (redilations or declottings) performed to maintain or to restore patency before stent placement was multiplied by 2.1 after stent placement for both grafts (3.2 months increased to 6.9, P < .01) and native fistulas (2.9 months increased to 6.2, P < .02). CONCLUSIONS: Wallstents and Craggstents are valuable for the treatment of failure of regular dilation and they double the intervals between reinterventions for early (< 6 months) recurring stenoses in PTFE grafts and native fistulas.

[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.

Vaccine against hepatitis B--18 months prevention in a high risk setting.

The development of a vaccine against hepatitis B prepared with purified and inactivated HBs Ag is described. This vaccine has been applied in patients and staff members of haemodialysis centres. Safety and efficiency of the vaccine are very satisfactory. The response of patients to immunisation was significantly lower compared to the response of the staff members. None of the volunteers who had a primary response to immunisation developed signs of clinical or biological hepatitis.

[Vaccination against hepatitis B in man]. / La vaccination contre l'hépatite B chez l'homme

The preparation of a vaccine against hepatitis B is described. The vaccine is prepared from the HB viral coat (HBs Ag) purified and formalin inactivated. The HBs Ag is isolated and purified from the blood of healthy HBs Ag positive donors by means of an immunoadsorbent technique. The inocuity and efficacy were tested on chimpanzees. Vaccination was then applied in an attempt to protect patients and ward staff in a high risk haemodialysis unit. The efficacy of the vaccine was assessed by humoral and cellular anti-HBs immune reactions. The study of HBs antigenaemia in vaccinated and non-vaccinated subjects indicate that this vaccine protects against hepatitis B. Many arguments are in favor of aetiological role of the hepatitis B virus in the genesis of primary liver cancer in tropical areas. Immunization against hepatitis B could be the first example of prevention of a potentially oncogenic viral infection.