Amplatzer vascular plug for occlusion or flow reduction of hemodialysis arteriovenous access.

OBJECTIVE: Use of the Amplatzer vascular plug (AVP; St. Jude Medical Inc, St. Paul, Minn) for percutaneous occlusion of a hemodialysis arteriovenous access (AVA) is an emerging practice, and only a few reports by radiologists have been published. We report here a multidisciplinary experience of this technique not only for AVA occlusion but also for flow reduction in selected patients. METHODS: This preliminary study includes a series of 20 plugs of different generations (I, II, and IV) used in 19 hemodialysis patients (two children, 17 adults). Of these, 15 AVAs were autologous fistulas located at the elbow, 4 were autologous forearm fistulas, and 1 was a brachial-basilic polytetrafluoroethylene graft. AVP deployment was through a 4F to 8F sheath, with oversizing from 30% to 50% to reduce the risk of migration. AVA occlusion (n = 14), by placing the AVP in the vein at its origin, was performed for central vein occlusion after unsuccessful percutaneous recanalization (n = 4), high flow (n = 2), hand ischemia (n = 3), successful kidney transplant (n = 1), and brachial-basilic or brachial-brachial fistula second-stage superficialization technical failure (n = 4). Vein/polytetrafluoroethylene grafts were not removed. AVA flow reduction (n = 6), by placing the AVP in the radial artery, was performed for well-tolerated high flow (n = 3) or high flow associated with distal ischemia (n = 3). All patients underwent a postoperative evaluation at 6-month intervals that included a clinical examination and duplex scan. RESULTS: AVA occlusion or flow reduction was successfully achieved in all patients. Ischemia persisted in one patient and a revascularization with a distal bypass was necessary. Mean follow-up was 1.2 ± 0.8 years (range, 2 months-2.9 years). No plug migration, access revascularization, or other complication was observed. CONCLUSIONS: The results of this short preliminary study suggest that plug insertion for occlusion or for flow reduction in a hemodialysis AVA constitutes a reasonable alternative to coil insertion or to open surgery in selected patients.

Placement of wrist ulnar-basilic autogenous arteriovenous access for hemodialysis in adults and children using microsurgery.

OBJECTIVES: The distal basilic forearm vein is frequently preserved and might be used more frequently for placement of an ulnar-basilic autogenous arteriovenous access (UB-AAVA) in the wrist despite the small size of the two vessels. The scarcity of publications led us to initiate a prospective study regarding the placement and outcomes of UB-AAVAs. METHODS: Seventy patients (63 adults, seven children) with no usable cephalic vein in either forearm were selected consecutively over 4 years for placement of a UB-AAVA. The prerequisite was a clinically visible or palpable forearm basilic vein after placing a tourniquet. Regional anesthesia, prophylactic hemostasis, and a surgical microscope were used systematically. Secondary superficialization was performed in two patients. Most non-matured accesses were abandoned in favor of the placement of a more proximal autogenous access. Mean follow-up was 20 months (SD =15). RESULTS: Immediate patency was obtained in 94% of adults and 100% of children. Success (in-use access) was achieved in 60% of patients (38/63 adults and 6/7 children) after a mean postoperative interval of 80 days (SD = 64; range, 31-277). Failures included four immediate thromboses, one postoperative death, and 21 never-matured accesses. No steal syndrome was observed. Initial failures included, primary patency rates in adults at 1 and 2 years were 42% ± 6% and 30% ± 7%, respectively; secondary patency rates at 1 year and 2 years were 60% ± 6% and 53% ± 7%, respectively. CONCLUSIONS: Although patency rates are not as good as those achieved with radial cephalic-AAVA, the UB-AAVA is an alternative autogenous forearm access before the placement of any other access involving the basilic vein. The use of the surgical microscope is mandatory, and more than usual time is required to achieve maturation.

Stent placement in patients with atherosclerotic renal artery stenosis and impaired renal function: a randomized trial.

BACKGROUND: Little is known about the efficacy and safety of renal artery stenting in patients with atherosclerotic renal artery stenosis (ARAS) and impaired renal function. OBJECTIVE: To determine the efficacy and safety of stent placement in patients with ARAS and impaired renal function. DESIGN: Randomized clinical trial. Randomization was centralized and computer generated, and allocation was assigned by e-mail. Patients, providers, and persons who assessed outcomes were not blinded to treatment assignment. SETTING: 10 European medical centers. PARTICIPANTS: 140 patients with creatinine clearance less than 80 mL/min per 1.73 m(2) and ARAS of 50% or greater. INTERVENTION: Stent placement and medical treatment (64 patients) or medical treatment only (76 patients). Medical treatment consisted of antihypertensive treatment, a statin, and aspirin. MEASUREMENTS: The primary end point was a 20% or greater decrease in creatinine clearance. Secondary end points included safety and cardiovascular morbidity and mortality. RESULTS: Forty-six of 64 patients assigned to stent placement had the procedure. Ten of the 64 patients (16%) in the stent placement group and 16 patients (22%) in the medication group reached the primary end point (hazard ratio, 0.73 [95% CI, 0.33 to 1.61]). Serious complications occurred in the stent group, including 2 procedure-related deaths (3%), 1 late death secondary to an infected hematoma, and 1 patient who required dialysis secondary to cholesterol embolism. The groups did not differ for other secondary end points. LIMITATION: Many patients were falsely identified as having renal artery stenosis greater than 50% by noninvasive imaging and did not ultimately require stenting. CONCLUSION: Stent placement with medical treatment had no clear effect on progression of impaired renal function but led to a small number of significant procedure-related complications. The study findings favor a conservative approach to patients with ARAS, focused on cardiovascular risk factor management and avoiding stenting.

Transposition of radial artery for reduction of excessive high-flow in autogenous arm accesses for hemodialysis.

OBJECTIVE: All surgical methods published to date for the reduction of excessive high-flow in native elbow fistulas for dialysis have limitations. We report a new surgical approach to flow reduction by transposition of the radial artery to the elbow level. METHODS: From 1992 to 2008, 47 consecutive patients (22 women) with brachial artery to elbow vein autogenous fistula underwent flow reduction via replacement of brachial artery by transposed distal radial artery inflow. Fistulas were side-to-end either brachial-cephalic (19) or brachial-basilic (28). The indications were hand ischemia (4), cardiac failure (13), concerns about future cardiac dysfunction (23), and chronic venous hypertension resulting in aneurysmal degeneration of the vein (7). Mean patient age was 44 years, 11% were diabetic, 17% were smokers, and mean BMI was 22. Mean fistula age before flow reduction was 2.5 years. RESULTS: Technical success was 91% (43 of 47). The mean flow rate dropped by 66% +/- 14%. Clinical success in symptomatic patients was 75% (18 of 24). The fistula eventually had to be ligated in three cases of cardiac failure because of insufficient clinical improvement. All four patients with hand ischemia were cured, with no recurrence during follow-up. Primary patency rates at one and three years were 61% +/- 7% and 40% +/- 8%. Secondary patency rates at one and three years were 89% +/- 5% and 70% +/- 8%. CONCLUSION: Transposition of the radial artery, a safe and effective technique, might now be considered in the surgical armamentarium of flow reduction techniques.

Low-flow maturation failure of distal accesses: Treatment by angioplasty of forearm arteries.

BACKGROUND: Forearm artery lesions are a frequent cause of distal fistula maturation failure. Surgical treatment is difficult because of highly calcified arteries. To redo the arteriovenous anastomosis higher up the forearm is technically difficult and often ineffective because arteries cannot be enlarged. It also causes a loss in puncture zone. Creation of brachial accesses leads to a high risk of distal ischemia. METHODS: From September 2000 to September 2006, we performed percutaneous transluminal angioplasty (PTA) of forearm arteries in 25 patients with failing distal access maturation. We reported immediate results of the dilatation and retrospectively analyzed the outcome of the accesses after the procedure. RESULTS: Forearm artery PTA was achieved in all 25 patients. Three main complications occurred: severe spasms precluding precise assessment of the artery patency after dilatation, rupture easily treated by prolonged low-pressure balloon inflation, and early rethrombosis leading to access loss. Follow-up was available in 23 patients. PTA failed to restore a sufficient access flow in two patients (the access loss and an insufficient increase in flow). In the remaining 21 (91%), accesses started to be used for hemodialysis without difficulties. Primary patency access rates after PTA were 83% (range, 60%-93%) at 1 year and 74% (range, 47%-89%) at 2 years. Secondary access patency rates were 86% (range, 64%-95%) at 1 and 3 years. CONCLUSION: When a distal access fails to mature because of forearm artery lesions, PTA should be done and will salvage the fistula without risk of distal ischemia and cardiac failure. Efficacy of PTA clearly influences surgical strategy and is a major argument in favor of attempting to create distal accesses in patients with mild distal artery lesions. Even in cases of failure, such as early occlusion of the fistula, this technique does not jeopardize further proximal access creation. Forearm access creation should be avoided only in cases of extremely severe distal artery lesions.

Lipectomy as a new approach to secondary procedure superficialization of direct autogenous forearm radial-cephalic arteriovenous accesses for hemodialysis.

BACKGROUND: The depth of veins can discourage surgeons from creating radial-cephalic arteriovenous accesses for hemodialysis in obese patients. Elevation and tunneled transposition are the two techniques that have been described to superficialize these veins and make them accessible for cannulation. Unfortunately, such manipulation of veins has potential drawbacks. We report lipectomy, a new technique that removes subcutaneous fat and does not mobilize the vein. METHODS: This single-center prospective study included 49 consecutive patients (17 men, 32 women) who underwent second-stage lipectomy after creation of a radial-cephalic fistula. Mean patient age was 54 years, 36% had diabetes, and the mean body mass index was 31 +/- 5.6 kg/m(2). Subcutaneous fatty tissues were removed after two transverse skin incisions under regional anesthesia and preventive hemostasis. Cannulation was first allowed 1 month later, after clinical and color duplex ultrasound evaluation. Technical success was defined as the ability to remove the fat and to palpate the patent vein immediately under the skin at the end of the operation. Clinical success was defined as the ability to perform at least three consecutive dialysis sessions with two needles. All patients were checked systematically every 6 months by the surgeon. RESULTS: Technical and clinical success rates were 96% (47 of 49) and 94% (46 of 49), respectively. Mean vein depth decreased from 8 +/- 2 to 3 +/- 1 mm according to duplex ultrasound imaging. The mean vein diameter increased from 6 +/- 1 to 8 +/- 2 mm. In one patient, vein tortuosity that was overlooked required conventional repeat tunneling. One extensive hematoma resulted in loss of the fistula. One patient died before the fistula could be used. Primary patency rates were 71% +/- 7% and 63% +/- 8% at 1 and 3 years, respectively, and secondary patency rates were 98% +/- 2% and 88% +/- 7%. Delayed complications were treated by surgery (n = 7) or by endovascular procedures (n = 10). CONCLUSION: Lipectomy is a safe, effective, and durable approach to make deep arterialized forearm veins accessible for routine cannulation for hemodialysis in obese patients. It might even be hypothesized that incident obese dialysis patients will eventually have the highest proportion of radial-cephalic fistulas because they often have distal veins that have been preserved by their fat from previous attempts at cannulation for blood sampling or infusion.

Spontaneous renal artery dissection: long-term outcomes after endovascular stent placement.

PURPOSE: To report long-term clinical and morphologic results after stent placement for spontaneous renal artery dissection (SRAD). MATERIALS AND METHODS: Between 1991 and 2006, 16 consecutive patients (13 men; mean age, 42 y +/- 12) presented with SRAD in 17 arteries. All patients had uncontrolled hypertension at the time of presentation. Nine patients had lower back pain, 10 had progressive renal insufficiency, and three had both. All patients underwent renal angiography and stent implantation. They were followed up clinically and with renal imaging. RESULTS: Baseline blood pressure and plasma creatinine levels were 176/107 mm Hg and 142 micromol/L, respectively. Successful renal artery recanalization and stent implantation were achieved in all patients. After a mean follow-up of 8.6 years +/- 3.4, mean blood pressure was 118/78 mm Hg, with Seven patients were taking no antihypertensive medication, with five and four patients taking single or double antihypertensive agents, respectively. The most recent follow-up showed that plasma creatinine levels were normal, and imaging of the renal arteries showed no sign of restenosis or occlusion in all patients. CONCLUSIONS: Stent implantation for symptomatic SRAD is an effective treatment in the long term and represents a safe alternative to surgery.

Influence of diagnostic criteria on the interpretation of adrenal vein sampling.

Guidelines promote the use of adrenal vein sampling (AVS) to document lateralized aldosterone hypersecretion in primary aldosteronism. However, there are large discrepancies between institutions in the criteria used to interpret its results. This study evaluates the consequences of these differences on the classification and management of patients. The results of all 537 AVS procedures performed between January 2001 and July 2010 in our institution were interpreted with 4 diagnostic criteria used in experienced institutions where AVS is performed without cosyntropin (Brisbane, Padua, Paris, and Turin) and with criteria proposed by a recent consensus statement. AVS procedures were classified as unsuccessful, lateralized, or not lateralized according to each set of criteria. Almost 5× more AVS procedures were classified as unsuccessful with the strictest criteria than with the least strict criteria (18% versus 4%, respectively). Similarly, over 2× more AVS procedures were classified as lateralized with the least stringent criteria than with the most stringent criteria (60% versus 26%, respectively). Multiple samples were available from ≥1 side for 155 AVS procedures. These procedures were classified differently by ≥2 right-left sample pairs in 12% to 20% of cases. Thus, different sets of criteria used to interpret AVS in experienced institutions translate into heterogeneous classifications and hence management decisions, for patients with primary aldosteronism. Defining the most appropriate procedures and diagnostic criteria is needed for AVS to achieve optimal performance and fully justify its status as a gold standard.

Delayed angioplasty after renal thrombosis.

When renal arterial thrombosis occurs, the etiologic process plays an important role in the impact of ischemia on renal tissue. If the occlusion is caused by trauma, infarction rapidly occurs. However, when renal arterial thrombosis results from other processes, collateral vessels may develop and thus enables a prolonged ischemia without necrosis. The following is a case report of an acute renal failure caused by renal arterial thrombosis of a single functional kidney, which had a favorable outcome despite delayed treatment by percutaneous angioplasty. This report suggests that detection by ultrasonography of a venous renal flow could be of significant value to assess a collateral vascularization and thus should require an arteriography with angioplasty even after a delayed presentation.

A clinical prediction score to diagnose unilateral primary aldosteronism.

CONTEXT: Adrenal venous sampling is recommended to assess whether aldosterone hypersecretion is lateralized in patients with primary aldosteronism. However, this procedure is invasive, poorly standardized, and not widely available. OBJECTIVE: Our goal was to identify patients' characteristics that can predict unilateral aldosterone hypersecretion in some patients who could hence bypass adrenal venous sampling before surgery. DESIGN AND SETTING: A cross-sectional diagnostic study was performed from February 2009 to July 2010 at a single center specialized in hypertension care. PATIENTS: A total of 101 consecutive patients with primary aldosteronism who underwent adrenal venous sampling participated in the study. The autonomy of aldosterone hypersecretion was assessed with the saline infusion test. INTERVENTION: Adrenal venous sampling was performed without ACTH infusion but with simultaneous bilateral sampling. MAIN OUTCOME MEASURES: Variables independently associated with a lateralized adrenal venous sampling in multivariate logistic regression were used to derive a clinical prediction rule. RESULTS: Adrenal venous sampling was successful in 87 patients and lateralized in 49. All 26 patients with a typical Conn's adenoma plus serum potassium of less than 3.5 mmol/liter or estimated glomerular filtration rate of at least 100 ml/min/1.73 m2 (or both) had unilateral primary aldosteronism; this rule had 100% specificity (95% confidence interval, 91-100) and 53% sensitivity (95% confidence interval, 38-68). CONCLUSIONS: If our results are validated on an independent sample, adrenal venous sampling could be omitted before surgery in patients with a typical Conn's adenoma if they meet at least one of two supplementary biochemical characteristics (serum potassium<3.5 mmol/liter or estimated glomerular filtration rate ≥100 ml/min/1.73 m2).

Radiocephalic fistula complicated by distal ischemia: treatment by ulnar artery dilatation.

Hand ischemic steal syndrome due to a forearm arteriovenous fistula is a rare occurrence. However, its frequency is increasing with the rise in numbers of elderly and diabetic patients. This complication, which is more common for proximal than for distal accesses, can be very severe and may cause loss of hand function, damage to fingers, and even amputation of fingers or the hand. Its treatment is difficult and often leads to access loss. We report here a case of severe hand ischemia related to a radiocephalic fistula successfully treated by ulnar artery dilatation.

Percutaneous manual aspiration embolectomy of renal vein thrombosis due to acute pyelonephritis.

We report the case of a 50-year-old man who presented to our institution with septic thrombosis of the renal vein which had not resolved despite several days of antibiotic therapy. Optimal restoration of renal vein flow was obtained by percutaneous manual aspiration embolectomy (PMAE) in this patient with contraindication to fibrinolytic therapy and surgery.

Arterial percutaneous angioplasty in upper limbs with vascular access devices for haemodialysis.

BACKGROUND: The purpose of this study was to evaluate retrospectively the clinical context and effectiveness of arterial percutaneous transluminal angioplasty (PTA) of arterio-venous fistulae in chronic haemodialysis patients. METHODS: Between May 1992 and June 1997, arterial PTA was performed in 33 patients with a total of 35 angioaccess devices of the upper limbs (18 arterio-venous fistulae and 17 PTFE grafts). Clinical indications for arterial PTA were unexplained acute thrombosis in 12 patients (34.3%), insufficient blood flow in 13 patients (37.1%), and severe limb ischaemia in 10 patients (28.6%), two of whom had skin ulcerations and one had severe neurological damage. Follow-up periods varied between 1 and 55 months (mean 15.5 months). RESULTS: PTA was attempted in 22 radial, 10 brachial and seven ulnar arteries. Angioplasty was successful (i.e. residual stenosis of

Split renal function outcome after renal angioplasty in patients with unilateral renal artery stenosis.

The general use of bilateral rather than separate renal function evaluation has led to the publication of conflicting results concerning the effect of percutaneous transluminal renal angioplasty (PTRA) on renal function, especially in patients with atherosclerotic renal artery stenosis. The aim of this study was to evaluate prospectively, in standardized conditions, split renal function (SRF) and GFR outcome after successful PTRA, by measuring single kidney GFR with synchronous inulin or (51)Cr-ethylenediaminetetraacetic acid clearance and (99m)Tc-diethylenetriamine pentaacetic acid scintigraphy, in a well-defined population of patients with unilateral renal artery stenosis. Thirty-two consecutive hypertensive patients (18 with atherosclerotic and 14 with dysplastic disease) with significant unilateral stenosis of the main native renal artery (> or = 60%) and normal renal function were included in the study. Renal and angiographic follow-up evaluations were performed 6 mo after PTRA. PTRA alone or combined with stenting (n = 2) was technically successful in all patients. Repeat PTRA was necessary in two patients, evaluated 6 mo after the second PTRA. Six mo after PTRA, total GFR had increased slightly but significantly in the 29 patients with positive lateralization indices. SRF and single-kidney GFR of the stenotic kidney increased significantly, whereas concurrently the GFR and SRF of the nonstenotic kidney decreased significantly. Six mo after successful PTRA reducing renal ischemia, a reversal of both the hypoperfusion of the stenotic side and the hyperperfusion of the nonstenotic side was observed, which was accompanied by a slight increase in total GFR.