Arterio-venous fistula buttonhole cannulation technique: a retrospective analysis of infectious complications.

BACKGROUND: There are two main methods of accessing arterio-venous fistulas (AVFs); the 'buttonhole' and the 'rope-ladder' cannulation technique. Several small studies have hypothesized that the buttonhole technique is associated with increased rates of fistula-associated infection. This study addresses this hypothesis. METHODS: A retrospective review of all patients attending a large outpatient haemodialysis clinic was performed. Data were collected on the method of cannulation, infection rates, implicated microorganisms, complications of infection and time on haemodialysis. RESULTS: A total of 127 patients had received haemodialysis via an AVF: 53 via the rope-ladder technique and 74 via the buttonhole technique. Nine episodes of clinically significant bacteraemia were recorded in the buttonhole group. This equated to a rate of 0.073 bacteraemia events per 1000 AVF days. There were no episodes of bacteraemia in the rope-ladder group. Eight infections were due to methicillin-sensitive Staphylococcus aureus (MSSA); one was due to Staphylococcus epidermidis. Three patients with MSSA bacteraemia subsequently developed infective endocarditis. Five patients who developed bacteraemia events had been undergoing home haemodialysis. CONCLUSIONS: This study highlights the infectious complications associated with buttonhole cannulation techniques. All organisms isolated in our cohort were known skin colonizers. The reason for the increased rates of infection is unclear. Given this high rate of often life-threatening infection, we recommend regular audit of infection rates. We currently do not recommend this technique to our patients receiving haemodialysis.

The impact of peritransplant warfarin use on renal transplant outcome.

BACKGROUND: The unplanned nature of kidney transplantation necessitates that patients undergo surgery without prior cessation of warfarin. Our study analyses the impact of warfarin treatment in the peritransplant period on graft outcome and perioperative transfusion requirements. METHODS: We identified 31 patients undergoing deceased donor kidney transplantation who were concurrently receiving warfarin therapy, between 2000 and 2008. A random, sex-matched, adult, deceased donor control group of 62 patients was generated from the Irish transplant database. RESULTS: The warfarin group were older (mean 47.5 vs. 42.5 years, p=0.067) and had spent longer on dialysis prior to transplantation (mean 3.5 vs. 2.1 years, p=0.004). Graft survival in the warfarin group was not significantly different at 1-, 3- and 5-year follow-ups. There was no statistically significant difference in red blood cell transfusions between the groups (45% vs. 29%, p=0.2). Warfarin patients had a prolonged mean cold ischaemia time (22.3 vs. 18.5 hours, p=0.002). CONCLUSION: This study demonstrates excellent short- and long-term results for kidney transplantation in patients requiring warfarin at the time of transplantation.

Left versus right deceased donor renal allograft outcome.

It has been suggested that the left kidney is easier to transplant than the right kidney because of the longer length of the left renal vein, facilitating the formation of the venous anastomosis. There are conflicting reports of differing renal allograft outcomes based on the side of donor kidney transplanted (left or right).We sought to determine the effect of side of donor kidney on early and late allograft outcome in our renal transplant population. We performed a retrospective analysis of transplanted left-right deceased donor kidney pairs in Ireland between January 1, 1998 and December 31, 2008. We used a time to death-censored graft failure approach for long-term allograft survival and also examined serum creatinine at different time points post-transplantation. All outcomes were included from day of transplant onwards. A total of 646 transplants were performed from 323 donors. The incidence of delayed graft function was 16.1% in both groups and there was no significant difference in acute rejection episodes or serum creatinine from 1 month to 8 years post-transplantation.There were 47 death-censored allograft failures in the left-sided group compared to 57 in the right-sided group (P = 0.24). These observations show no difference in renal transplant outcome between the recipients of left- and right-sided deceased donor kidneys.

Improved graft survival in highly sensitized patients undergoing renal transplantation after the introduction of a clinically validated flow cytometry crossmatch.

BACKGROUND: Flow cytometric techniques are increasingly used in pretransplant crossmatching, although there remains debate regarding the clinical significance and predictive value of donor-specific antibodies detected by flow cytometry. At least some of the discrepancies between published studies may arise from differences in cutoffs used and lack of standardization of the test. METHODS: We selected cut-off values for pretransplant flow cytometric crossmatching (FCXM) based on the correlation of retrospective results with the occurrence of antibody-mediated rejection. The impact on long-term renal graft survival of prospective FCXM was determined by comparing graft survival between patients crossmatched with complement-dependent cytotoxicity (CDC) only with those prospectively crossmatched with both CDC and FCXM. RESULTS: Chosen cut-off values gave a positive predictive value of FCXM for antibody-mediated rejection of 83%, and a negative predictive value of 90%. After the introduction of prospective B- and T-cell crossmatching by flow cytometry in addition to CDC in our center, there was a significant improvement in renal graft survival in highly sensitized patients (P=0.017). Four-year graft survival in highly sensitized patients after the introduction of FCXM was 89%, which did not differ significantly from that seen in nonsensitized patients (93%; P=0.638). CONCLUSIONS: Our data demonstrate that prospective FCXM improves renal transplant outcome in highly sensitized patients, provided that cut-off values are carefully validated and results interpreted in the context of sensitization history and antibody screening results.

The importance of serum albumin and phosphorous as predictors of mortality in ESRD patients.

Secondary hyperparathyroidism and abnormal calcium/phosphate balance are common complications of ESRD and significant cardiovascular risk factors. It has also been demonstrated that malnourished dialysis patients have a much higher mortality than well-nourished patients. There is a lack of research looking at combined mortality with altered mineral metabolism and a low serum albumin. Using our renal database, we analyzed outcomes on 1,007 chronic dialysis patients, commencing dialysis between January 1990 and December 2004. The association between median values of serum phosphate, calcium, albumin (between three and six months post-commencement of dialysis), and long-term survival was examined. Cox proportional hazards models were used to determine the combined effects of these variables on patient outcome. The results showed that 18% of patients had serum phosphorous >1.8 mmol/L (5.5 g/dL), and the five-year survival of these patients was 48.4% compared with 58.6% for those with a serum phosphorous <1.8 mmol/L (p = 0.047). For serum albumin, 34.9% had a value <35 g/L, and this group also had a highly significant risk of increased mortality (p < 0.001). When combined with corrected calcium, 40.9% of patients reached all three target levels and had the greatest long-term survival (five-year survival of 62.5% for all three targets reached, compared to 30.7% for 0 or 1 targets reached). Poor control of calcium/phosphorous balance appears to have long-term deleterious effects on patient survival in ESRD patients. This risk of death is increased by poor serum albumin levels reflecting inadequate nutrition.

The impact of donor spontaneous intracranial haemorrhage vs. other donors on long-term renal graft and patient survival.

BACKGROUND: Donor cause of death has a significant impact on transplant survival in heart transplants recipients. The objective of this study was to determine if long-term renal allograft and patient survival differed between grafts donated by donors who died of spontaneous intracranial haemorrhage (SIH) compared with those with other causes of death (OCOD). METHODS: Between 1990 and 2001, 1526 renal transplants were performed (711 SIH donors and 815 OCOD donors) at our unit. Serum creatinine levels at 1 yr, graft half-life and annual graft failure rate were measured for both groups. Renal graft and patient survivals between the groups were compared. Relative risk for SIH donors and other confounding variables was measured using Cox proportional hazards models. RESULTS: Graft half-life results were obtained for SIH (8 yr) and OCOD (10.13 yr) recipients. Graft and patient survival at 5 and 10 yr was 68.5% and 39.3% respectively for the SIH group vs. 76.8% and 51.9% respectively for the OCOD group (p < 0.001). However, SIH graft recipients were significantly older with more females. After adjustment for differences in baseline variables between the groups, donor cause of death did not have an independent effect on long-term graft or patient survival. CONCLUSION: Spontaneous intracranial haemorrhage as a cause of donor death, failed to have a significant independent effect on long-term allograft and patient survival.

A comparison of long-term graft survival rates between the first and second donor kidney transplanted--the effect of a longer cold ischaemic time for the second kidney.

Prolonged cold ischaemic time (CIT) is associated with delayed initial graft function and may also have a negative impact on long-term graft outcome. We carried out a study comparing the long-term graft survival rates between those recipients who received the first of a pair of donor kidneys versus the recipient of the second graft. Adult kidney transplant recipients who received one of a pair of donor kidneys at our institution between 1989-1995 were included. All recipients received a cyclosporin based immunosupression regimen. Graft survival rates were compared between the 2 groups at 1-, 3-, 5- and 10-year intervals. A total of 520 renal transplant grafts were included in this study. Mean donor age was 35.4 years. Groups were similar for recipient age, gender, number of HLA mismatches, transplant number for that patient and percentage PRA. CIT was the only variable that was significantly different between the two groups; mean of 19.93 h in the first group compared to 25.65 h in the second group. Graft survival rates for the first kidney were significantly better than the second kidney-graft survival at 1 year 88.5% versus 84.7%, at 3 years 81.8% versus 76.7%, at 5 years 72.2% versus 64.9% and at 10 years 55.2% versus 40% (p = 0.012). Patient survival rates were similar in both groups. In our experience, the long-term graft survival rates are significantly better for the first kidney transplanted compared to the second kidney.

Pretransplant cardiac investigations in the Irish renal transplant population--the effectiveness of our current screening techniques in predicting cardiac events.

BACKGROUND: Coronary artery disease (CAD) is prevalent among endstage renal failure patients and remains the major cause of mortality following renal transplantation. Death with a functioning transplant institute remains the most common cause of kidney graft failure. In this study we attempt to evaluate the effectiveness of the clinical history and current screening techniques available in predicting posttransplant CAD and also assess the role of coronary angiography as a pretransplant screening technique. METHODS: Clinical data of 190 renal transplant patients was analyzed. Any clinical history of cardiac disease and all preoperative cardiac screening data was recorded for each patient. The study endpoints were the subsequent development of myocardial infarction (MI), undergoing coronary artery bypass graft (CABG) or death. RESULTS: Factors that were significantly associated with reaching a study endpoint included: age at transplant [Hazard Ratio (HR) 1.91, P<0.001], history of heart failure (HR 8.22, P<0.001), presence of CAD on coronary angiography (HR 5.55, P=0.033), anterior Q wave on electrocardiograph (ECG) (HR 8.6, P<0.001), carotid artery disease (HR 3.74, P=0.030) and history of a cerebrovascular accident (HR of 4.32, P=0.008). The screening techniques of exercise stress testing and echocardiography were not conclusive as predictive variables of outcome. CONCLUSION: Clinical history and ECG results are good, practical and low-cost screening methods. In our study exercise stress testing and echocardiography were found to be of limited value. Coronary angiography is appropriate in certain high-risk groups but not necessary as part of screening in all potential renal transplant recipients.

Acute interstitial nephritis: clinical features and response to corticosteroid therapy.

BACKGROUND: Acute interstitial nephritis (AIN) is a recognized cause of reversible acute renal failure characterized by the presence of an interstitial inflammatory cell infiltrate. METHODS: In order to evaluate the clinical characteristics and management of this disorder, we performed a retrospective study of all cases of AIN found by reviewing 2598 native renal biopsies received at our institution over a 12 year period. Presenting clinical, laboratory and histological features were identified, as was clinical outcome with specific regard to corticosteroid therapy response. RESULTS: AIN was found in 2.6% of native biopsies, and 10.3% of all biopsies performed in the setting of acute renal failure during the period analysed (n = 60). The incidence of AIN increased progressively over the period observed from 1 to 4% per annum. AIN was drug related in 92% of cases and appeared to be idiopathic in the remainder. The presenting symptoms included oliguria (51%), arthralgia (45%), fever (30%), rash (21%) and loin pain (21%). Median serum creatinine at presentation was 670 micromol/l [interquartile range (IQR) 431-1031] and 58% of cases required acute renal replacement therapy. Corticosteroid therapy was administered in 60% of cases. Serum creatinine at baseline was similar in the corticosteroid-treated and conservatively managed groups; 700 micromol/l (IQR 449-1031) vs 545 micromol/l (IQR 339-1110) P = 0.4. In this, the largest retrospective series to date, we did not detect a statistically significant difference in outcome, as determined by serum creatinine, between those patients who received corticosteroid therapy and those who did not, at 1, 6 and 12 months following presentation. CONCLUSION: The results of this study do not support the routine administration of corticosteroid therapy in the management of AIN.

Plasmapheresis as rescue therapy in accelerated acute humoral rejection.

Accelerated acute humoral rejection (AHR) continues to occur in renal transplantation despite improved crossmatching, with potentially devastating consequences. Between 1 June 1998 and 31 December 2000, 440 renal transplants were performed in our center. AHR was diagnosed by the demonstration of typical pathological features on renal histology and positive direct immunofluorescence or detection of anti-HLA antibodies in serum. AHR developed in 20 (4.5%) of our renal transplant recipients, nine male and eleven female at an average of 16.3 days post transplantation. All of these patients had a negative current cytotoxic crossmatch prior to transplantation. The median serum creatinine at diagnosis was 5.96 mg/dL, and 83% of these individuals developed oliguric renal failure requiring dialysis after having initially attained good graft function (median of best serum creatinine before AHR was 2.64 mg/dL). The 18 recipients who had not infarcted their grafts at the time of diagnosis of AHR received plasmapheresis in conjunction with intensification of their immunosuppressive regimen. This regimen was successful in reversing AHR in 78% of those treated with apheresis. In the 14 responders, graft survival at 6 months was 100% and at 12 months was 91%. Median serum creatinine at 6 and 12 months was 1.26 and 1.33 mg/dL, respectively. Patients received an average of 8.1 plasma exchanges. However, responders received a significantly higher frequency of plasmapheresis (P =.0053), despite undergoing a similar number of exchanges overall. Plasmapheresis appears to be an effective modality for reversing AHR and maintaining graft function.