[Management of perianastomotic stenoses complicating vascular accesses for haemodialysis]. / Prise en charge des sténoses périanastomotiques compliquant les abords vasculaires pour hémodialyse.

OBJECTIVE: Perianastomotic stenoses (PAS) complicating native arteriovenous fistulas (AVF) of the forearm can be treated by angioplasty or surgery. The objective of this study was to report primary patency (PP) and primary assisted patency (PAP) rates of surgery and angioplasty of these stenoses. The secondary objective was to identify factors influencing the patency rates of these reoperations. MATERIAL AND METHODS: Seventy-three patients with a mean age, 65 years were treated for PAS between January 1999 and December 2005 in two centres (Tours and Le Mans), which were retrospectively included. PAS were treated by surgery (n=21) or angioplasty (n=52). The two groups were comparable. The mean follow-up was 39 months for the angioplasty group and 49 months for the surgery group (p=0.088). RESULTS: The PP rate was 71+/-10% for surgery and 41+/-6% for angioplasty (p<0.0175). The PAP rate was not significantly different (p=0.462) between angioplasty (92+/-4%) and surgery (95+/-4%). In the endovascular group, the site of stenosis on the anastomosis was a risk factor for early recurrence (95% CI between 0.006 and 0.392; p=0.047). CONCLUSION: These results suggest that anastomotic stenoses should be treated surgically rather than by angioplasty. Angioplasty and surgery give identical patency rates in other types of perianastomotic stenoses at the cost of a higher reoperation rate for angioplasty.

Salvage of immature forearm fistulas for haemodialysis by interventional radiology.

BACKGROUND: The goal of this article is to assess the value of endovascular techniques for the salvage of fistulas that fail to mature. METHODS: Over a 6-year period, 52 dysfunctional and 17 thrombosed immature forearm fistulas (mean age 10 weeks) were treated by interventional radiology. Angiography was performed by puncture of the brachial artery but dilation of underlying stenoses was performed after cannulation of the fistula itself, whenever possible, with a balloon never smaller than 5 mm. Embolization or ligation of any type of vein was never indicated and never performed. For thrombosed fistulas, significant clots were removed by manual catheter-directed aspiration. A covered stent (Passager) was used in cases of dilation-induced rupture not controlled by balloon tamponade. RESULTS: An underlying stenosis was diagnosed in 100% of cases. Half of them were located in the anastomotic area. The initial success rate of interventional radiology was 97%. Dilation-induced rupture occurred in nine cases (13%) but stents were necessary in only two cases. The rate of significant clinical complications was 2.8% (bacteraemia, pseudoaneurysm). Primary and secondary patency rates at 1 year were 39 and 79%, respectively. CONCLUSIONS: Delayed maturation of native fistulas should lead systematically to imaging as an underlying stenosis is diagnosed in all cases. Interventional radiology can treat the majority of cases and achieve a 97% success rate but early recurrence of stenoses can occur. Multidisciplinary re-evaluation of the patient must, therefore, be performed after radiological salvage of the fistula.

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.

Identification of microemboli during haemodialysis using Doppler ultrasound.

BACKGROUND: Doppler ultrasound methods were used during haemodialysis sessions for the detection of microemboli and determination of their origin. METHODS: A 2-MHz ultrasound probe (Multidop X(4) DWL((TM))) was used to assess the number of microembolic signals (MES) in the subclavian vein downstream from the arteriovenous fistula before the dialysis session and over two periods of 15 min at the beginning and end of haemodialysis sessions in 25 patients without previous cardiovascular disease. A similar probe was used during in vitro studies to detect MES at different sites in the dialysis machine (before and downstream from the blood pump, and before and downstream from the air trap). RESULTS: No MES were detected during in vivo studies before haemodialysis sessions. MES were registered in all patients (100%) at the beginning and end of the haemodialysis procedure at an average of 12.7+/-9 and 16. 7+/-11.5 signals/min respectively. The average intensity of MES was 19.2+/-5.0 dB and 19.4+/-3.9 dB respectively. No MES were detected on the arterial line during in vitro studies. In contrast, 19+/-6 MES/min were detected after the blood pump, 13+/-4.2 before the air trap, and 16.5+/-5.5 thereafter. CONCLUSIONS: In all patients, MES were recorded during haemodialysis sessions in the drainage vein from arteriovenous fistulae. The results of in vitro studies indicate that MES are formed by the blood pump of the haemodialysis machine. The intensity of the MES suggests that they correspond to synthetic particles or microbubbles, which are not detected by the air trap. The final destination of these microbubbles will be assessed in further studies.

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.

Effects of severe protein restriction with ketoanalogues in advanced renal failure.

OBJECTIVE: To compare a severe protein restriction diet supplemented with ketoanalogues to a moderate protein restriction diet in order to limit glomerular filtration rate (GFR) decrease in an advanced renal insufficiency stage. DESIGN: Prospective randomised study conducted to compare a severe protein restriction diet (0.30 g/kg/day) supplemented with a preparation of ketoanalogues, hydroxyanalogues of aminoacids and aminoacids (Group A) to a moderate protein restriction diet (0.65 g/kg/day) (Group B). PATIENTS: 50 uremic patients included (25 in each group) with GFR is <20 mL/min/1.73m2. RESULTS: There were no statistically significant differences between the two dietary regimens for the renal survival. But uremia decreased significantly in Group A (22.7+/-5.2 to 18.5+/-6.7 mmol/L) and increased in Group B (26.8+/-9.0 to 34.9+/-9.9 mmol/L). Calcemia increased in Group A from 2.28+/-0.18 to 2.42+/-0.17 mmol/L, p<0.01 with a stable phosphoremia while calcemia decreased in Group B (2.33+/-0.18 to 2.25+/-0.17 mmol/L, p<0.05). At the end of the study, Group A was different from Group B for calcemia (2.42+/-0.17 vs. 2.25+/-0.17 mmol/L, p<0.01), phosphoremia (1.39+/-0.30 vs. 1.80+/-0.65 mmol/L, p<0.02), alkaline phosphatase (61.42+/-22.93 vs. 78.8+/-27.0, p<0.05) and parathormone plasma levels (2.71+/-1.55 vs. 5.91+/-1.41 ng/mL, p<0.001). COMMENTS: Compared to a moderate protein restriction (0.65 g/kg/day), a severe protein restriction (0.3 g/kg/day) supplemented by ketoanologues does not limit GFR decrease when GFR is below 20 mL/min/1.73m2, but improves phosphocalcic plasma parameters.

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.

Manual thromboaspiration and dilation of thrombosed dialysis access: mid-term results of a simple concept.

PURPOSE: To report the feasibility, safety, and effectiveness of manual thromboaspiration as a single means of declotting dialysis access. MATERIALS AND METHODS: Between April 1994 and December 1996, 59 consecutive conduits (43 polytetrafluoroethylene [PTFE] grafts, 16 native fistulas) were declotted with 8-F or 7-F angulated catheters. Unmasked stenoses were dilated. Clinical and paraclinical nephrologic surveillance (poor flow, palpation, difficulties with cannulation, increased compression times, increasing venous pressures) led to redilations and stent placements. Rethromboses were treated with further declotting by aspiration. The results are presented according to the life-table method. RESULTS: The initial success of 43 of 43 PTFE grafts (mean procedure time, 119 min +/- 29 [standard deviation]) led to a primary patency rate of 85% +/- 5% (SE) at 1 month, 33% +/- 8% at 6 months, and 24% +/- 12% at 1 year. A graft was ligated 6 days after declotting for acute bleeding in one patient given high-dose warfarin. The secondary patency rates were 86% +/- 7% at 6 months and 86% +/- 9% at 1 year, with a mean duration of patency of 5.7 months between two radiologic interventions performed to maintain or to restore patency, and 19 stents were placed at a mean follow-up of 3 months. The success rate was 81% for native fistulas, with primary patency rates of 81% +/- 10% at 1 month, 74% +/- 14% at 6 months, and 60% +/- 27% at 1 year; secondary patency rates of 81% +/- 12% at 6 months and 81% +/- 18% at 1 year. CONCLUSION: Thromboaspiration is a safe and effective method for declotting dialysis access, yielding a low rethrombosis rate during the first month. Overall radiologic management with reintervention on average every 6 months results in high secondary patency rates at 1 year (81%-86%).

Insufficient dialysis shunts: improved long-term patency rates with close hemodynamic monitoring, repeated percutaneous balloon angioplasty, and stent placement.

Over 54 months, 70 short stenoses of 63 shunts (32 Brescia-Cimino fistulas, 31 grafts) in 59 patients necessitated a first percutaneous transluminal angioplasty (PTA). Restenosis led to 63 redilations in 38 lesions. Nine stents were inserted in seven grafts and two proximal veins in seven patients, the indication being that stenosis had recurred twice in 6 months. In three of these stenoses, five delayed intrastent redilations were necessary. Three previously dilated occluded grafts were recovered with local thrombolysis. Morbidity was 4.08%, with one immediate rupture, four delayed pseudoaneurysms (1-28 months), and two periprocedural bacteremias. Half (15 of 29) of graft stenoses and only 14% (four of 27) of Brescia-Cimino fistula stenoses had a mean restenosis interval of less than 6 months. The mean restenosis interval increased from 3.6 months +/- 0.5 (standard deviation) before stent placement to 15.2 months +/- 0.4 after stent placement (P < .001). Insertion of a stent can be advised when stenoses of graft venous anastomoses have recurred twice in less than 6 months. The combination of all interventional radiologic procedures allowed a significant improvement in secondary patency rates after PTA, with 82% at 1 year, 79% at 2 years, and 71% at 3 years.

Changes in parathyroid hormone during haemodialysis sessions with two different dialysis membranes: specific adsorption of intact parathyroid hormone.

In patients dialysed with two different membranes (cuprophan and high-flux polysulphone) and using three radioimmunoassays recognizing either intact molecule (iPTH), C terminal (cPTH) or median fragments (mPTH), we compared parathyroid hormone levels at the beginning of and during dialysis. At the beginning of dialysis, cPTH and mPTH levels were always increased but iPTH levels were sometimes within the normal range; during dialysis only iPTH distinctly decreased whichever membrane was used. The behaviour of iPTH cannot be explained by crossing through the membrane because its molecular weight is too high; it cannot be explained by the variation of calcium and phosphate parameters during the session because no correlation exists between the variations in plasma levels of iPTH and the variations in phosphorous and calcium levels. In vitro experimentation with radiolabelled intact iPTH was performed to confirm the specific behaviour of iPTH: these experimental data agree with our in vivo results and suggest an adhesion to the dialysis membrane. Our study shows a specific singular property of iPTH during dialysis and demonstrates the necessity of considering the time of sampling during dialysis and the moiety of parathyroid hormone being measured in patients undergoing dialysis in order to assess osteodystrophy.

Iododerma and acute respiratory distress with leucocytoclastic vasculitis following the intravenous injection of contrast medium.

A 72-year-old woman with chronic renal failure requiring haemodialysis developed acute iododerma twice, after receiving iodide contrast dye for radiological procedures. Iododerma was localized to the face, scalp and elbows and was associated with papular purpura of the legs. Histopathology of the skin lesions showed acute necrotizing vasculitis. During the second skin eruption the patient developed acute respiratory distress, which was treated with corticosteroids. During the first eruption asymptomatic infiltrates were present on chest X-ray which disappeared 2 months later. At the present time iododerma seems more frequent in patients with renal failure. Iodides may also be responsible for pulmonary abnormalities, which are sometimes asymptomatic. All these features may be due to leucocytoclastic vasculitis following iodide ingestion.