Preoperative noninvasive artery flow volume and maturation of arteriovenous fistulae: A single surgeon's experience from 403 cases.

BACKGROUND: Preoperative Doppler ultrasound evaluation of arteriovenous fistula inflow artery includes measurements of arterial diameter and flow volume. The purpose of this study was to evaluate the significance of flow volume to arteriovenous fistula maturation rate. STUDY DESIGN: Review of consecutive patients who underwent arteriovenous fistula creation by a single surgeon. Cases with available preoperative arterial diameter and flow volume were analyzed. Primary end point was arteriovenous fistula failure to mature. Information collected included demographics, Doppler ultrasound reports, level of inflow artery, operative reports, and outcomes to the time of arteriovenous fistula maturation or failure. Risk factors were identified by logistic regression analysis. Outcomes were compared by odds ratio. RESULTS: Four hundred and three cases were identified. Arterial diameter and flow volume were both independent significant risk factors affecting arteriovenous fistula maturation rate (p = 0.001). Arterial diameter of <2.5 mm and flow volume of <20 mL/min predicted failure to mature with 95% specificity. Further comparison of cases with optimal arterial diameter but flow volume of <20 mL/min showed increased failure to mature rate compared to the combination of optimal arterial diameter with optimal flow volume (p = 0.01). CONCLUSION: Preoperative arterial diameter and flow volume values were both significant independent variables affecting arteriovenous fistula maturation rate. However, flow volume of <20 mL/min remained a significant risk factor to failure-to-mature rate, despite optimal arterial diameter.

Effect of a rapid clinical protocol to the conversion from central venous hemodialysis catheter to arteriovenous access.

PURPOSE: Evaluation of the rapid conversion protocol that includes an ambulatory dialysis access center (DAC), and a three-step clinical pathway, to the conversion rate from central venous hemodialysis (HD) catheter to functioning arteriovenous (AV) access. METHODS: Prospective data were collected on 97 consecutive catheter-dependent HD patients. DAC is defined as an ambulatory unit, able to accommodate clinic visits, ultrasound examinations, surgical, interventional and hybrid procedures. Step I: initial evaluation, vein mapping and creation of AV access. Step II: clinical evaluation in two weeks and if failure identified, secondary procedure to restore function. Step III: evaluation in four weeks after creation, and additional procedure to promote maturation if indicated. The success rate, time to conversion and time to catheter removal were recorded. RESULTS: From the 97 consecutive referred patients, eight patients were excluded. From the remaining 89 patients, 99% were successfully converted to AV access. Seventy-three percent of the patients were converted to native arteriovenous fistulae and 27% of the patients to prosthetic arteriovenous shunts. The median time from creation to HD catheter removal was 63 (SD 41) days. Fifty-two percent of the patients required at least one additional secondary procedure to accomplish successful conversion. CONCLUSIONS: High rates of timely conversion from catheter to AV access, primarily AV fistulae, can be accomplished within the context of the rapid conversion protocol.

Effect of steroid-free low concentration calcineurin inhibitor maintenance immunosuppression regimen on renal allograft histopathology and function.

BACKGROUND: The most common cause of late kidney transplant failure is insidiously progressive renal dysfunction associated with organ scarring and fibrosis. Advanced donor age, delayed graft function, calcineurin toxicity and repeated acute rejection episodes are risk factors for this pathophysiology. METHODS: We employed 3, 12 and 24 months surveillance renal biopsies, scored using the Chronic Allograft Damage Index (CADI), with periodic estimates of glomerular filtration rate (eGFR) to assess the effect of a steroid-free maintenance immunosuppression regimen on allograft histology and function. Ninety-one patients were induced with Alemtuzumab and then treated with mycophenolate sodium and low trough concentrations of tacrolimus. RESULTS: Fifty-six of 91 patients followed for 24 months showed no clinical rejection and in 16 more only minimal histological or borderline changes as defined by Banff criteria were observed. Histologically acute rejection was observed in 14 patients including two detected on surveillance biopsy. Five patients refused biopsies but showed stable eGFR for 24 months. Graft histopathology in the group with no rejection did not worsen. In contrast, nearly half the patients with acute rejection showed progression of CADI scores and a total of four grafts were lost over the 2 years. The 16 patients with borderline rejection changes exhibited stable glomerular filtration rate throughout, but 12.5% showed progression of CADI scores in the 12- to 24-month period. CONCLUSIONS: Following Alemtuzumab induction and in conjunction with low-dose tacrolimus and mycophenolate, continuous steroid therapy was not required to prevent progressive injury or preservation of graft function in patients without biopsy-proven acute rejection. Scored surveillance renal biopsies provide a useful tool to monitor transplanted kidneys.

Use of anti-CD20 antibody in the treatment of post-transplant glomerulonephritis.

Post-transplant glomerulonephritis (PTGN) accounts for 4-10% of late graft loss. Six consecutive patients who developed PTGN 3-72 months post-transplant presented to our center with deteriorating kidney function and proteinuria. Three had focal segmental glomerulosclerosis; one had membranoproliferative glomerulonephritis Type 1; one recurrent membranous nephropathy; and one recurrent immunoglobin A nephropathy. All six were treated with an aggressive immunosuppression regimen including rituximab, pulse steroids and/or maximization of mycophenolic acid and calcineurin inhibitor therapy. Four of the six patients received plasma exchange. The patients were followed for a minimum of nine months after treatment. Proteinuria decreased from 7.2 ± 4.4 to 1.4 ± 1.5g (p = 0.04), while mean estimated glomerular filtration rate was 31.2 ± 13.1 and 42.5 ± 21.7 mL/min (p = 0.07) at nine months. No adverse events were noted. These observations suggest that immune modulating therapy may be of benefit in the treatment of PTGN.

Migration of covered stents from hemodialysis A-V access to the pulmonary artery: percutaneous stent retrieval and procedural trends.

Details are presented of two patients with end-stage renal disease (ESRD) who recently experienced migration of a Viabahn covered stent from a peripheral hemodialysis A-V access to the right lower lobe pulmonary artery. Successful percutaneous retrieval was achieved in one patient using a dual snare approach, facilitated by ex vivo product testing. The second patient was managed conservatively. A review of the institution's A-V access salvage procedures, indicated a concomitant trend toward greater use of stent-assisted procedures, and a higher utilization of covered versus uncovered stents.

Cross Reactive Epitope Group antibodies in sensitized kidneys transplant recipients was associated with early acute Antibody Mediated Rejection.

BACKGROUND: Antibody Mediated Rejection (AMR) is a major cause of early graft loss, graft dysfunction, and chronic allograft nephropathy. Patients with elevated pre-transplant Panel Reactive Antibodies (PRA) are at much higher risk to develop AMR. We, retrospectively, studied the attack rate of AMR in sensitized recipients and evaluated whether preformed antibodies to donor Cross Reactive Epitope Group (CREG) and/or choice of induction immunosuppressive agent affected the frequency of this complication. METHODS: From the period between September 2002 and March 2008, we identified 19 sensitized renal transplant recipients (with mean PRA of 44.5+/-26%) and recorded the induction agent, number of HLA antigen mismatches, CREG match, CREG antibodies, PRA levels, clinical course, biopsy proven rejection episodes and presence of donor specific antibody. Nine patients were induced with Alemtuzumab (Campath-1H) and ten received horse or rabbit derived polyclonal antithymocyte antibody ATGAM (Pharmacia) or Thymoglobulin (Genzyme). All recipients were cross-match negative at time of transplant. RESULTS: Out of the 19 patients, 9 patients developed acute rejection (47.4%), 4 had AMR and 5 had Acute Cellular Rejection (ACR). Out of 19 patients, 9 patients had existing CREG antibodies (as per CREG Model proposed by McKenna, Takemoto et al.). All patients who developed AMR were found of have preformed antibodies to donor CREG. The median time interval for the development of acute humoral rejection was only 6 days and biopsies showed acute vascular rejection with Complement (C(4)D) deposition. CONCLUSIONS: Pre-existing CREG antibodies in sensitized renal transplant patients appear to identify a group at high risk to develop AMR.