Use of the Viabahn stent graft for the treatment of recurrent cephalic arch stenosis in hemodialysis accesses.

OBJECTIVE: Cephalic arch stenosis (CAS) is a frequent and challenging failure mode of brachiocephalic fistulas. Natural tortuosity of the cephalic arch requires special consideration in selecting a treatment modality. Typical percutaneous angioplasty and bare-metal stent (BMS) treatments provide a short-term treatment solution for CAS without a durable effect. This study assessed Viabahn (W. L. Gore & Associates, Flagstaff, Ariz) stent grafts (SGs) as a first-line percutaneous option to provide a durable treatment for CAS. METHODS: SG data were collected at a free-standing physician office between July 10, 2009, and January 26, 2011. A single-arm, prospective, observational study was conducted of 50 consecutive CAS patients treated with angioplasty followed by deployment of Viabahn SGs. Outcomes included target lesion primary patency and reintervention rates as well as secondary access patency. Results were compared with historic cohorts of percutaneous balloon angioplasty (N = 50) and angioplasty followed by BMS deployment (N = 50). The cohorts were treated between May 5, 2005, and May 20, 2010, and assessed in chronologic order. RESULTS: The SG cohort target lesion primary patency reported at 3, 6, and 12 months was 90% ± 7%, 74% ± 12%, and 60% ± 14% (±95% confidence interval), respectively. Compared with historic cohorts, the SG cohort demonstrated statistically superior target lesion primary patency (P < .001), with a reduced reintervention rate per access-year (P < .001). Secondary access patency was statistically superior compared with the percutaneous balloon angioplasty cohort (P = .034) but not statistically different from the BMS cohort when assessed during a 2.5-year period. The secondary access patency for the SG cohort at 5 years was 80% ± 15%. CONCLUSIONS: In treatment of a CAS, the Viabahn SG study group demonstrated superior target lesion primary patency and required fewer subsequent interventions compared with historic cohorts treated with angioplasty or angioplasty followed by BMS placement. Given the significant improvement in target lesion primary patency, future studies should challenge Viabahn SGs as a primary percutaneous treatment modality vs durable surgical alternatives.

Sharp needle recanalization for salvaging hemodialysis accesses with chronically occluded peripheral outflow.

PURPOSE: To assess the effectiveness of sharp needle recanalization (SNR) for treatment of chronically occluded venous outflow in hemodialysis access. METHODS: A retrospective analysis of patient records from January 2006 to March 2010 was conducted. Forty-four hemodialysis patients (31 fistulas, 13 grafts) were referred for arm swelling (18%), excessive bleeding after dialysis (29%), and thrombosis (53%). All patients had chronic occlusion of the outflow vein which failed conventional recanalization techniques. A new outflow pathway was established by advancing a 21g needle and dilating the subcutaneous tract to bridge the fistula body to a juxtaposed patent vein. If necessary, uncovered or covered stents were utilized to maintain patency of the newly formed subcutaneous tract. RESULTS: Forty-four patients underwent 45 SNR procedures, with restoration of normal function and complete relief of symptoms in 40 (91%) patients. The average tract length was 15 mm (range, 1 to 32) and the average dilatation diameter was 8 mm. During the initial SNR procedure, bare metal (n=21) or covered (n=5) stents were inserted in 26 patients. The average follow-up was 18.4 months (range, 0.2 to 48 months). No major complications were observed with the procedure. At 12 months, the primary access, primary tract, and secondary access patencies were 10%, 51%, and 92%, respectively. Percutaneous thrombectomy procedures were performed at a rate of 1.16 per access-year and the number of interventions within the tract was 0.94 per access-year. CONCLUSIONS: Sharp needle recanalization is an effective percutaneous treatment for restoring function to hemodialysis accesses with chronically occluded venous outflow pathways.

Percutaneous salvage of thrombosed immature arteriovenous fistulas.

Thrombosed immature fistulas have historically been considered unsalvageable. However, advances in procedure and balloon catheter technologies have expanded the scope of endovascular treatments. This study investigates the efficacy, functionality, and cost associated with the use of percutaneous techniques for the salvage of thrombosed immature fistulas. Over a 2-year period and from a population of 18,000 patients on hemodialysis, 140 consecutive patients with thrombosed immature fistulas underwent attempts at salvage via thrombectomy procedures. All fistulas had thrombosed following access creation and had never been used for hemodialysis. Multiple approaches were utilized to gain access to the fistula, including trans-fistula cannulation, distal arterial puncture, and proximal retrograde venous access. Thrombectomy was performed via balloon maceration and aspiration. Accelerated maturation was achieved through sequential angioplasty of diffusely stenotic veins and elimination of competing branch vessels. Primary access, primary assisted, and secondary access patencies were calculated at 3, 6, 12, and 24 months. A cost analysis was performed based on procedure statistics and the 2009 Medicare reimbursement schedule and compared with data from the 2009 United States Renal Data Survey. Thrombectomy was successful in 119 (85%) immature clotted fistulas, and hemodialysis adequacy was achieved in 111 (79%) fistulas. The average maturation time from thrombectomy to cannulation for dialysis was 46.4 days, with an average of 2.64 interventions per patient. There were 5 (3.5%) cases of angioplasty-induced rupture, all of which were treated with stent placement. Clinically significant pseudoaneurysm formation occurred in 4 (2.8%) patients. At 12 months, secondary access patency of salvaged accesses was 90%. Based on 2009 Medicare outpatient billing rates per patient per initial access-year and the maturation times observed in the New York area, percutaneous salvage of thrombosed immature fistulas costs $4881 to $14,998 less than access abandonment and new access creation. Endovascular techniques can be used for the salvage of thrombosed nonmaturing fistulas. When analyzed within the initial access-year, this approach yields significant cost savings over access abandonment.

Access flow reduction and recurrent symptomatic cephalic arch stenosis in brachiocephalic hemodialysis arteriovenous fistulas.

BACKGROUND: Recurrent cephalic arch stenosis (CAS) has been linked to high flow and has a high rate of recurrence following angioplasty. This study investigates the effectiveness of access flow reduction in decreasing rapidly recurrent symptomatic CAS. METHODS: A retrospective study of patient records from February 2005 to April 2009 was conducted. Patients with brachiocephalic fistulas who had undergone two or more instances of cephalic arch angioplasty within 3 months, and thereafter underwent flow reduction via banding of the access inflow (n=33) were included. A before-and-after analysis was conducted: the rates of cephalic arch angioplasty were calculated for each patient before and after the banding procedure, and compared via a paired t-test. RESULTS: At 3, 6, and 12 months, the cephalic arch primary lesion patency was 91%, 76%, and 57%. The cephalic arch intervention rate was reduced from 3.34 to 0.9 per access-year (t=7.74, p<.001). The average follow-up time was 14.5 months (range, 4.8-32). CONCLUSION: Flow reduction of a brachiocephalic arteriovenous hemodialysis fistula may effectively diminish the incidence of symptomatic CAS.

The MILLER banding procedure is an effective method for treating dialysis-associated steal syndrome.

We evaluated the efficacy of the Minimally Invasive Limited Ligation Endoluminal-Assisted Revision (MILLER) banding procedure in treating dialysis-associated steal syndrome or high-flow access problems. A retrospective analysis was conducted, evaluating banding of 183 patients of which 114 presented with hand ischemia (Steal) and 69 with clinical manifestations of pathologic high access flow such as congestive heart failure. Patients were assessed for technical success and symptomatic improvement, primary and secondary access patency, and primary band patency. Overall, 183 patients underwent a combined 229 bandings with technical success achieved in 225. Complete symptomatic relief (clinical success) was attained in 109 Steal patients and in all high-flow patients. The average follow-up time was 11 months with a 6-month primary band patency of 75 and 85% for Steal and high-flow patients, respectively. At 24 months the secondary access patency was 90% and the thrombotic event rates for upper-arm fistulas, forearm fistulas, and grafts were 0.21, 0.10, and 0.92 per access-year, respectively. Hence, the minimally invasive MILLER procedure appears to be an effective and durable option for treating dialysis access-related steal syndrome and high-flow-associated symptoms.

Aggressive approach to salvage non-maturing arteriovenous fistulae: a retrospective study with follow-up.

PURPOSE: To establish a standardized approach for the maturation of non-maturing arteriovenous fistulae. METHODS: Consecutive patients (n=122) with non-maturing fistulae presented to our outpatient vascular access center for percutaneous interventions to assist in maturation. The techniques used included flow rerouting, competing branch vein elimination, staged balloon angioplasty, and limited controlled extravasation. RESULTS: Successful fistula maturations were achieved in 118/122 patients. Fistulae were divided into two classes according to initial vessel size: class 1 (6.0-8.0 mm diameter, >6 mm deep) and class 2 (2.0-5.0 mm diameter) fistulae were evaluated for differences in technical procedures and clinically successful fistula maturation. Class 1 and class 2 fistulae were evaluated for mean number of procedures to maturation (1.6 and 2.6, respectively), and time to maturation (5 and 7 weeks, respectively). Follow-up for 109 of the initial 118 patients was achieved (mean=24 months, range=0.25-60 months). Class 1 and class 2 fistulae had primary patencies of 17 and 39% at 6 months; and secondary patencies of 72 and 77% at 12 months, 53 and 61% at 24 months, and 42 and 32% at 36 months, respectively. Primary and secondary patencies (Mann-Whitney test, p=0.44 and p=0.38, respectively) of class 1 and class 2 fistulae did not differ significantly, and secondary patencies were comparable to other fistula salvage studies. CONCLUSION: Fistula salvage attempts should not be limited by factors such as a diffusely small diameter or an inaccessibly deep position.

Mycophenolate mofetil for the treatment of interstitial nephritis.

Acute interstitial nephritis (AIN) is a clinicopathologic entity that is characterized by acute renal failure and renal biopsy findings of interstitial inflammation and tubulitis. There are multiple causes of AIN, the majority of which appear to respond to immunosuppressive therapy. Corticosteroids are the mainstay of treatment for AIN, but many patients are refractory to or intolerant of treatment or are unable to discontinue therapy without clinical relapse. Herein are reported eight cases of steroid-resistant, biopsy-proven AIN that were treated successfully with mycophenolate mofetil (MMF) at one institution. Patients had a mean decline in serum creatinine from 2.3 to 1.6 mg/dl over a mean of 24.3 mo of treatment. Six of the eight patients had a decline in serum creatinine of at least 0.3 mg/dl, and the remaining two patients had stable renal function during the treatment period. At most recent follow-up, five of the eight patients successfully have discontinued treatment with MMF for a mean of 6.4 mo. MMF was well tolerated by all patients. It is concluded that MMF is a useful therapeutic option for steroid-resistant AIN and may be considered as potential first-line therapy in select populations.

Mycophenolate mofetil (MMF) vs placebo in patients with moderately advanced IgA nephropathy: a double-blind randomized controlled trial.

BACKGROUND: IgA nephropathy (IgAN) is the most common form of glomerulonephritis worldwide. Up to 40% progress to end-stage renal disease (ESRD) over 10-20 years. Currently, treatment is limited. We studied the use of mycophenolate mofetil (MMF) vs placebo in a group of North American IgAN patients at high risk for progressive disease. METHODS: Included were 32 patients aged 18-75 years from multiple centres who had their biopsies read at Columbia and who had at least 1 g of proteinuria per day plus at least two of the following risk factors: (i) male sex; (ii) hypertension >150/90 mmHg or requiring antihypertensive medications; (iii) creatinine clearance, measured by 24 h urine collection, <80 and >20 ml/min at time of enrolment; and (iv) presence of glomerulosclerosis or tubulointerstitial atrophy and fibrosis on renal biopsy. Patients were randomized to either 1 year of MMF, titrated up to a dose of 1000 mg bid, or placebo. Total follow-up was 2 years. All patients received angiotensin inhibition medication. The primary outcome was a 50% increase in baseline serum creatinine (SCr). Secondary outcomes were an increase of 0.5 mg/dl SCr, ESRD and a 50% reduction in proteinuria. RESULTS: The mean baseline SCr was 2.4 mg/dl. No statistically significant differences were observed for any outcome. Five of 17 who received MMF vs two of 15 patients in the placebo group reached a 50% increase in SCr (P = 0.4). In both groups, all patients who reached the primary outcome also reached ESRD. Ten who received MMF vs seven who received placebo had a 0.5 mg/dl increase in SCr (P = 0.7) Only three MMF and two placebo patients had a 50% reduction in 24 h proteinuria. No serious adverse events occurred in either group. CONCLUSION: No benefit was seen in patients who received MMF in this high risk group, probably reflecting the relatively advanced stage of disease of our population. We conclude that MMF is probably not effective in patients with IgAN who already have moderate renal insufficiency.

Relative effects of angiotensin converting enzyme inhibitors and calcium antagonists in advanced diabetic nephropathy.

OBJECTIVE: We have previously observed that calcium antagonists (CA) were associated with poorer renal survival in African Americans (AA) with diabetic nephropathy (DN). Here, we investigate further the effects of CA alone, or in combination with angiotensin converting enzyme inhibitors (ACEI) in advanced DN. DESIGN: Retrospective study. SETTING: Academic nephrology clinic. PATIENTS: 1) Patients who entered the endstage renal disease (ESRD) program in years 1993-1998 with a primary diagnosis of DN. 2) A cross-sectional analysis of pre-ESRD patients with DN, first seen in the clinic in 1996, then followed until 2000. Over 80% of patients were AA, and approximately 75% were female in both cohorts. INTERVENTIONS: Patients were categorized according to whether they were on either an ACEI or a CA, alone, or a combination of these, at presentation to the clinic, and during follow up. MAIN OUTCOME MEASURES: Renal survival (time to ESRD) and effects on blood pressure. RESULTS: In both data sets, patients presented with advanced renal disease. Those on CA tended to have lower blood pressure on presentation, and during follow up, and were more likely to experience a significant decrease in blood pressure over the course of follow up. Using a Cox proportional hazards model, ACEI-CA status was not found to be significantly associated with renal survival. CONCLUSIONS: Calcium antagonists (CA) are effective at lowering blood pressure in advanced DN, and do not appear to negatively affect renal survival, especially when combined with an ACEI.

Therapeutic controversies in hypertension management: angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers for diabetic nephropathy? A case for ACE inhibitors.

Diabetic nephropathy is the number one cause of endstage renal disease in the United States. Blockade of the renin angiotensin system (RAS) is important in the treatment of diabetic nephropathy. With the reports of recently completed trials examining the role of angiotensin receptor blockers (ARBs) in type 2 diabetic nephropathy, the question has arisen as to which agents are best to block the RAS in type 2 diabetes. ACE inhibitors have been to preserve renal function in type 1 diabetics with nephropathy in large, randomized, placebo controlled trials, but such data is lacking in type 2 diabetes. Neverthelesss, ACE inhibitors have been recommended for use in type 2 diabetic nephropathy for some time. In type 2 diabetics, ACE inhibitors may have a role in preventing development of nephropathy, and, importantly, ACE inhibitors have been shown to reduce cardiovascular disease in diabetics with and without nephropathy. In addition, ACE inhibitors have beneficial effects on other diabetic complications such as retinopathy and neuropathy. Until better comparative data between ACE inhibitors and ARBs on nephropathy and cardiovascular outcomes is available, ACE inhibitors should remain an important consideration for treatment of diabetic nephropathy.