Quality assurance in surgical trials of arteriovenous grafts for haemodialysis: A systematic review, a narrative exploration and expert recommendations

BACKGROUND

Introducing new procedures and challenging established paradigms requires well-designed randomised controlled trials (RCT). However, RCT in surgery present unique challenges with much of treatment tailored to the individual patient circumstances, refined by experience and limited by organisational factors. There has been considerable debate over the outcomes of arteriovenous grafts (AVG) compared to AVF, but any differences may reflect differing practice and potential variability. It is essential, therefore, when considering an RCT of a novel surgical procedure or device that quality assurance (QA) is defined for both the new approach and the comparator. The aim of this systematic review was to evaluate the QA standards performed in RCT of AVG using a multi-national, multi-disciplinary approach and propose an approach for future RCT.

METHOD

The methods of this have been previously registered (PROSPERO: CRD420234284280) and published. In summary, a four-stage review was performed: identification of RCT of AVG, initial review, multidisciplinary appraisal of QA methods and reconciliation. QA measures were sought in four areas - generic, credentialing, standardisation and monitoring, with data abstracted by a multi-national, multi-speciality review body.

RESULTS

QA in RCT involving AVG in all four domains is highly variable, often sub-optimally described and has not improved over the past three decades. Few RCT established or defined a pre-RCT level of experience, none documented a pre-trial education programme, or had minimal standards of peri-operative management, no study had a defined pre-trial monitoring programme, and none assessed technical performance.

CONCLUSION

QA in RCT is a relatively new area that is expanding to ensure evidence is reliable and reproducible. This review demonstrates that QA has not previously been detailed, but can be measured in surgical RCT of vascular access, and that a four-domain approach can easily be implemented into future RCT.

Early-cannulation arteriovenous grafts: Multidisciplinary learning is essential to optimize outcomes

BACKGROUND

It is likely that there will be an increasing role for early-cannulation arteriovenous grafts (ecAVG) with a wider recognition of the need to tailor vascular access to avoid futile procedures and unnecessary TCVC. However, experience of these products is not common and limited to early surgical adopters, with little information on the systemic changes and multi-disciplinary care needed to optimize outcomes. The aim of this study was to report the impact of a multi-disciplinary approach on quantifiable outcomes.

METHODS

A retrospective analysis of a prospectively maintained database of 295 ecAVG implanted over an 8-year time-period was performed. Indicative outcomes were chosen to reflect nephrology (patient selection), nursing care (cannulation complications of infection and pseudoaneurysm) and radiology (thrombosis) on cumulative impact (functional patency) over three distinct time periods.

RESULTS

The incidence of ecAVG increased 10-fold over the three time periods. The use of ecAVG changed significantly from salvage tertiary access to TCVC avoidance and salvage of existing AVF. Nursing complications reduced markedly with significantly fewer over-cannulation episodes and pseudo-aneurysms. With an improved pro-active surveillance programme, the time to first thrombosis doubled and the risk of thrombosis halved. Ultimately this resulted in significantly improved functional patency with a risk of ecAVG loss less than one-third by the last time-period.

CONCLUSIONS

All aspects of ecAVG use require scrutiny and critical appraisal. Failure or success is not simply achieved by performing good technical surgery with an efficacious product, but by the care taken across a wide range of elements spanning case selection, implantation, use and maintenance.

Screening and surveillance of venous stenosis in AVG: Is it time to rethink our assumptions?

Guidelines make no firm recommendations about surveillance of arteriovenous grafts as several randomised trials (RCT) have not shown a clear benefit in patency. However a more thorough review of these RCT based on epidemiological principles reveals significant limitations. In particular a key weakness of these older studies is the interventions performed for venous stenosis detected that was largely angioplasty. However, the observational data of modern stent-grafts shows a clear benefit over angioplasty, and thus seems to suggest that a modern well considered RCT is now mandated.

A novel index for measuring the impact of devices on hypertension

A key limitation in assessing the therapeutic impact of non-pharmacological approaches to treating hypertension is the method of reporting outcomes. Reducing the medications required to achieve the same blood pressure may be reported separately to a reduction in the blood pressure without change in medication, and thus lessen the reported beneficial impact of treatment. This study aims to derive a novel scoring system to gauge the therapeutic impact of non-drug treatment of hypertension by utilising a combination of excessive blood pressure and the number of anti-hypertensives into a combined score-the hypertensive index (HTi). The hypertensive index was empirically derived based on the systolic blood pressure and number of antihypertensive drugs, and applied retrospectively to a cohort undergoing intervention for renovascular hypertension. Subgroup and receiver operating characteristic analyses were used to compare the HTi to traditional methods of reporting outcomes. Following intervention (99 patients), 46% had improvement in both medication load and blood pressure, 29% had benefit in blood pressure without reduction in medication load, 15% had reduction in medication load without significant change in blood pressure and 9% showed no benefit in either parameter. The HTi was superior in detecting benefit from intervention compared with measuring blood pressure or medication load alone (AUC 0.94 vs 0.85;0.84). The hypertensive index may be a more sensitive marker of treatment effect than assessing blood pressure measurements alone. The use of such scoring systems in future trial design may allow more accurate reporting of the effects of interventions for hypertension.

Quality assurance in surgical trials of arteriovenous grafts for haemodialysis: protocol for a systematic review

INTRODUCTION

Decisions regarding the optimal vascular access for haemodialysis patients are becoming increasingly complex, and the provision of vascular access is open to variations in systems of care as well as surgical experience and practice. Two main surgical options are recognised: arteriovenous fistula and arteriovenous graft (AVG). All recommendations regarding AVG are based on a limited number of randomised controlled trials (RCTs). It is essential that when considering an RCT of a surgical procedure, an appropriate definition of quality assurance (QA) is made for both the new approach and the comparator, otherwise replication of results or implementation into clinical practice may differ from published results. The aim of this systematic review will be to assess the methodological quality of RCT involving AVG, and the QA measures implemented in delivering interventions in these trials.

METHODS AND ANALYSIS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will be followed. A systematic search will be performed of the MEDLINE, Embase and Cochrane databases to identify relevant literature. Studies will be selected by title and abstract review, followed by a full-text review using inclusion and exclusion criteria. Data collected will pertain to generic measures of QA, credentialing of investigators, procedural standardisation and performance monitoring. Trial methodology will be compared against a standardised template developed by a multinational, multispecialty review body with experience in vascular access. A narrative approach will be taken to synthesise and report data.

ETHICS AND DISSEMINATION

Ethical approval is not required as it is a protocol for a systematic review. Findings will be disseminated through peer-reviewed publications and conference presentations, with the ultimate aim of providing recommendations for future RCT of AVG design.

Validation of a vascular access specific quality of life measure (VASQoL)

BACKGROUND

A self-administered 11 item vascular access specific quality of life measure (VASQoL) was previously derived from detailed qualitative interviews with adult patients with kidney failure who have experienced vascular access using the Capabilities Approach as a theoretical base. This study reports the psychometric validation of the VASQoL measure including its reliability, content validity and responsiveness to change.

METHODS

Cognitive interviews were conducted with 23 adult patients with kidney failure after completion of the VASQoL measure. Focus group discussion with a vascular access professional multidisciplinary team was undertaken (n = 8) and subsequently a further 101 adult kidney failure patients with vascular access (TCVC, AVF or AVG) completed the digital VASQoL measure, EQ-5D and SF-36 questionnaires in a longitudinal study with prospectively recorded vascular access events.

RESULTS

Transcript analysis of cognitive interviews after VASQoL completion indicated that the content was comprehensive and well understood by participants. Assessment of Internal reliability for the VASQoL measure was high (Cronbach's alpha 0.858). Test-retest reliability of the overall VASQoL measure was high (intra class correlation coefficient 0.916). In those patients who experienced a vascular access event, significant differences were observed in paired analysis of the VASQoL physical domain questions and vascular access function domain questions and in the EQ-5D usual activities, pain and anxiety domains. In those with no vascular access event, variation was observed in longitudinal analysis in VASQoL questions relating to worry about VA function and capability domains, whilst no variation was observed in the EQ5D measure.

CONCLUSION

The VASQoL measure has good internal consistency, test-retest reliability, convergent validity and responsiveness to change for clinically relevant vascular access outcomes. This provides a validated, vascular access specific quality of life measure that can be used in future trials of vascular access, evaluation of new technologies and routine use as a patient reported outcome measure (PROM).

Pre-emptive or reactive treatment, angioplasty or stent-graft? The outcome for interventions for venous stenosis in early-cannulation arteriovenous grafts

BACKGROUND

Early-cannulation arteriovenous grafts (ecAVG) have good initial patency, but frequent episodes of reintervention for venous stenosis (VS) and thrombosis limit their use. Stent grafts (SG) have shown promise in reducing re-interventions and improving functional patency for dysfunctional ecAVG and recurrent VS. There is little data on the impact of stent grafts as the first elective procedure for VS. The aim of this study was to determine firstly, if treating VS whilst asymptomatic has a better outcome than treating after presentation with thrombosis; and secondly, to determine the best initial treatment for asymptomatic VS: SG or angioplasty.

METHODS

A retrospective study was performed of 259 ecAVG with a sutured anastomosis. The case-mix and outcomes of 153 who presented with VS was analysed by presentation (elective at surveillance or emergency following thrombosis), and then for only elective patients, by treatment (SG vs angioplasty).

RESULTS

There was no significant difference in case-mix and time to presentation by mode of presentation (100 elective and 53 with thrombosis) other than a higher rate of pro-thrombotic disorders in thrombosed ecAVG. Thrombosed ecAVG had poorer outcomes with increased re-intervention rates and thrombosis in the following year, and reduced long-term functional patency. In patients presenting electively, primary SG rather than angioplasty led to significantly reduced thrombosis rates, a longer time to re-intervention in the following year, and superior long-term functional patency. The use of SG was the same in both groups. Both the mode of presentation and the type of intervention performed were independently predictive of a poorer subsequent functional patency.

CONCLUSIONS

Primary elective stent-grafting may be the optimal strategy to reducing maintenance costs with ecAVG.

The impact of stent-graft sizing on venous stenosis re-intervention and arteriovenous graft patency: Free-floating stent outflow is associated with improved outcomes

BACKGROUND

Early cannulation arteriovenous grafts (ecAVG) for dialysis access are limited by reintervention for venous stenosis (VS) despite their good initial patency. Whilst stent-grafts (SG) have shown promise, the optimal sizing is unclear. Therefore, this study aims to determine if outflow vein diameter, SG diameter or these relative to each other (V:Sr) alters outcomes, and if so, which is more important.

METHODS

Retrospective analysis was performed of Gore® Acuseal® ecAVGs with VS treated with Gore® Viabahn® SG over a 7-year period. Primary patency (PP), time to thrombosis and functional patency were analysed by SG length/diameter, vein diameter and V:Sr.

RESULTS

We identified 114 ecAVGs with median follow-up 492 days (IQR 189-770). SG length and diameter did not correlate with PP, however, there was a significant relationship between vein diameter and PP (RR = 0.901 (0.832-0.975), p = 0.01) and between V:Sr and PP (RR = 0.462 (0.255-0.838), x2 = 5.866, p = 0.0015). The optimal V:Sr was ⩾1.4 (i.e. vein diameter at least 40% greater than the stent-graft; or 'free-floating' stent outflow) (RR = 2.759 (1.670-4.558), p < 0.001), translating to a difference in median PP of 252 versus 496 days (IQR: 188-316; 322-670). On multivariate analysis, absolute vein diameter lost significance, whilst V:Sr remained an independently significant predictor of PP (RR = 3.247 (1.560-6.759), p = 0.02).

CONCLUSIONS

Placement of the SG outflow into a relatively larger segment of vein was associated with a significant increase in PP independent of the absolute vein diameter. This suggests that larger calibre SG which are apposed to the vein wall are not required for optimal primary patency, and indeed should be actively avoided. Instead, a 'free-floating' stent outflow which is undersized relative to the recipient vein (whilst maintaining a minimum anchoring calibre) is recommended where possible. This should be considered during intervention and may require selection of longer devices, where practical, to bring the stent outflow into a larger vein segment.

LEVEL OF EVIDENCE

Level 3a, Non-randomised controlled cohort/follow-up study.

Patient characteristics predict patency of early-cannulation arteriovenous grafts

There is a new emphasis on tailoring appropriate vascular access for hemodialysis to patients and their life-plans, but there is little known about the optimal use of newer devices such as early-cannulation arteriovenous grafts (ecAVG), with studies utilising them in a wide variety of situations. The aim of this study was to determine if the outcome of ecAVG can be predicted by patient characteristics known pre-operatively. This retrospective analysis of 278 consecutive ecAVG with minimum one-year follow-up correlated functional patency with demographic data, renal history, renal replacement and vascular access history. On univariate analysis, aetiology of renal disease, indication for an ecAVG, the number of previous tunnelled central venous catheters (TCVC) prior to insertion of an ecAVG, peripheral vascular disease, and BMI were significant associates with functional patency. On multivariate analysis the number of previous TCVC, the presence of peripheral vascular disease and indication were independently associated with outcome after allowing for age, sex and BMI. When selecting for vascular access, understanding the clinical circumstances such as indication and previous vascular access can identify patients with differing outcomes. Importantly, strategies that result in TCVC exposure have an independent and cumulative association with decreasing long-term patency for subsequent ecAVG. As such, TCVC exposure is best avoided or minimised particularly when ecAVG can be considered.

Early-Cannulation Arteriovenous Grafts Are Safe and Effective in Avoiding Recurrent Tunneled Central Catheter Infection

OBJECTIVES

Tunneled central venous catheter infection (TCVCi) is a common complication that often necessitates removal of the TCVC and replacement by a further TCVC. Theoretically, insertion of an early - cannulation graft (ecAVG) early after TCVC infection is possible but not widely practiced with concerns over safety and infection in the ecAVG. With 8 years of ecAVG experience, the aim of this study was to compare the outcomes following TCVC infection, comparing replacement with TCVC (TCVCr) versus immediate ecAVG (ecAVGr).

DESIGN

Retrospective comparison of 2 cohorts, who underwent replacement of an infected TCVC either by an early cannulation graft (n = 18) or by a further central catheter (n = 39).

METHODS

Data were abstracted from a prospectively completed electronic patient record and collected on patient demographics, TCVC insertion, duration and infection, including culture proven bacteriaemia and subsequent access interventions.

RESULTS

Eighteen of 299 patients identified from 2012 to 2020 had an ecAVG implanted as treatment for a TCVCi. In a 1-year time-period (January 1, 2015-December 31, 2015) out of 222 TCVC inserted, 39 were as a replacement following a TCVCi. No patient with an ecAVGr developed an immediate infection, nor complication from the procedure. The rate of subsequent vascular access infection was significantly more frequent for those with a TCVCr than with an ecAVGr (0.6 vs. 0.1/patient/1000 HD days, P< 0.000). The number of further TCVC required was significantly higher in the TCVCr group (7.1 vs. 0.4/patient/1000 HD days, P= 0.000).

CONCLUSIONS

An ecAVG early following a TCVC infection is safe, reduces the incidence of subsequent infectious complications and reduces the number of TCVC required, with a better functional patency.

Epidemiology of bloodstream infections in a Scottish haemodialysis population with focus on vascular access method

BACKGROUND

Infection is the second highest cause of mortality in end-stage renal disease, with a significant proportion relating to haemodialysis (HD) vascular access-related infection (VARI).

AIM

To report the rate and antimicrobial resistance (AMR) of all-source bloodstream infections (BSIs) by vascular access type in a Scottish HD cohort.

METHODS

Retrospective analysis was undertaken of data on adult patients attending seven HD units during 2017. Total HD days for each vascular access type were calculated. BSIs were analysed with rates expressed per 1000 HD days. AMR was verified using health board microbiology databases.

FINDINGS

Excluding contaminant organisms, there was an overall BSI rate of 0.57 per 1000 HD days. The highest all-source and vascular access-related infection (VARI) BSI rates per 1000 HD days were in the non-tunnelled central venous catheter (CVC) group (3.11 and 2.07 respectively), followed by tunnelled CVC (1.10 and 0.67), arteriovenous graft (0.51 and 0.31), and finally arteriovenous fistula (0.29 and 0.02). The non-VARI BSI rates were lowest in the arteriovenous graft group. Staphylococci comprised the majority of events, with Staphylococcus aureus implicated in 29%. Gram-negative BSIs were prevalent, particularly in CVC groups, and associated with higher mortality. Multidrug-resistant (MDR) S. aureus and carbapenem resistance were relatively low. MDR Gram-negatives were high compared with the Scottish population.

CONCLUSION

Arteriovenous fistula access is confirmed as having lowest all-source and VARI BSI rates, and arteriovenous graft access the lowest non-VARI BSI rates. Staphylococci remain the prevailing genus; however, the contributions of Gram-negative BSIs, the higher mortality, and proportion of MDR organisms in this group are notable.

Ferumoxytol MR Angiography versus Duplex US for Vascular Mapping before Arteriovenous Fistula Surgery for Hemodialysis

Background Duplex US is performed routinely for vascular mapping prior to arteriovenous fistula (AVF) creation for hemodialysis but cannot demonstrate the central vasculature. Ferumoxytol, an iron oxide nanoparticle, provides an alternative to gadolinium contrast material for MR angiography for safe use in chronic kidney disease (CKD). Purpose To assess the clinical utility of ferumoxytol-enhanced MR angiography compared with duplex US for vascular mapping before upper limb AVF creation in participants with CKD. Materials and Methods In a prospective comparative study (ClinicalTrials.gov: NCT02997046) from December 2016 to August 2018, participants with CKD underwent ferumoxytol-enhanced MR angiography and duplex US. Two independent readers evaluated vessels for diameter, stenosis or occlusion, arterial disease, and central stenosis. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to assess intra- and interreader variability. On the basis of accepted standards for AVF creation, an algorithm was developed to predict AVF outcome based on imaging findings. Multivariable regression models used AVF success as the dependent variable and age, sex, and duplex US or ferumoxytol-enhanced MR angiography findings as independent variables. Results Fifty-nine participants with CKD (mean age, 59 years ± 13 [standard deviation]; 30 women) were evaluated. A total of 51 fistulas were created, of which 24 (47%) were successful. Ferumoxytol-enhanced MR angiography showed excellent inter- and intrareader repeatability (ICC, 0.84-0.99) for all variables assessed. In addition to revealing 15 central vasculature stenoses, ferumoxytol-enhanced MR angiography resulted in characterization of 88 of 236 (37%) of the arterial sections examined as unsuitable for AVF creation compared with 61 of 236 (26%) sections with duplex US (P = .01). Ferumoxytol-enhanced MR angiography independently predicted AVF success in models including (odds ratio, 6.5; 95% confidence interval: 1.7, 25; P = .006) and those excluding (odds ratio, 4.6; 95% confidence interval: 1.3, 17; P = .02) the central vasculature. Conclusion In addition to enabling identification of central vessel pathologic features, ferumoxytol-enhanced MR angiography revealed peripheral arterial disease not recognized with duplex US and was more predictive than duplex US of the outcome of arteriovenous fistula surgery. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Finn in this issue.

The management of lower limb arteriovenous grafts in the perioperative period following renal transplantation

BACKGROUND

The presence of a lower limb arteriovenous graft (LL-AVG) is indicative of a group of complex hemodialysis patients who have precarious long-term vascular access. The aim of this study is to describe our experience of the clinical decisions and interactions between LL-AVG and renal transplantation.

METHODS

The records of 23 patients who received a transplant in the presence of a LL-AVG between 2010 and 2018 were analyzed: firstly, to determine whether patients with a LL-AVG received extended criteria transplants, the implantation procedure, and the management of the LL-AVG in the post-operative period.

RESULTS

Seventeen patients (74%) had "end-stage access" and were thus considered for all offer stratified by the kidney donor profile index (KDPI) and donor type (DBD or DCD). In eleven patients (48%), a kidney with a high risk of delayed graft function was transplanted. Same-sided renal transplantation occurred in only 35% of cases, and of these, only one LL-AVG was ligated immediately to improve transplant perfusion.

CONCLUSION

A patient-based approach applied in decision-making on management of the LL-AVG post-transplantation should include (a) the likelihood of delayed graft function, (b) the need for post-operative hemodialysis, (c) the side of proposed transplant compared to the LL-AVG, and (d) local complications.

The first 365 days on haemodialysis: variation in the haemodialysis access journey and its associated burden

Background

The modality by which haemodialysis (HD) is delivered [arteriovenous fistula (AVF), arteriovenous graft (AVG) or central venous catheter (CVC)] varies widely and is influenced by clinical evidence, patient factors and the prevailing service configuration. The aim of this study was to determine the outcome and impact of access strategy on patient outcome by mapping out the HD journey in a cohort of incident patients.

Methods

A 2-year cohort of consecutive incident HD patients from the point of referral for first dialysis access to completion of the first 365 days of HD was prospectively reviewed. Data were sought on access type; radiological, surgical and other access-related activity; bacteraemic events; admission rates and cumulative financial cost.

Results

A total of 144 patients started RRT for the first time with HD over the 2-year period. All were followed up to 1 year after starting HD, generating a total of 47 753 observed HD days.  Activity prior to starting HD for the full cohort was found to average 0.92 arteriovenous (AV) access creation procedures, 0.40 CVC insertions, 0.14 interventional radiology procedures and 0.41 ultrasound examinations per patient. The small number of patients who started on an AVG had a tendency towards higher pre-HD surgical and imaging activity than those who started on an AVF or CVC.  Activity after starting HD varied greatly with the access type used at the start of HD, with AVF patients experiencing less hospitalization, procedure and imaging activity and financial costs compared with those who start HD with a CVC. Patients who started on an AVG had a tendency towards lower surgical activity rates and financial costs than those who started on a CVC.

Conclusions

Providing, maintaining and dealing with the complications of HD vascular access places a significant burden of activity that is shared across nephrology, surgery and imaging services. A well-functioning AVF is associated with the lowest burden, whereas a failed AVF or CVC access is associated with the highest burden. Patient journeys are shaped by the vascular access that they use and we suggest that the contemporary pursuit of HD access should focus on delivering personalized access solutions.

Has the Expansion in Extended Criteria Deceased Donors Led to a Different Type of Delayed Graft Function and Poorer Outcomes?

OBJECTIVES

There has been considerable change in the practice of deceased kidney transplantation in the past 15 years, with more extreme phenotypes implanted. The aim of this study was to determine whether increased use of expanded criteria donors (extended criteria donors and donors after circulatory death) affected clinical outcomes, including the incidence and pattern of delayed graft function.

METHODS AND MATERIALS

A retrospective analysis of 1359 renal transplants was performed over 15 years. The first 10 years of data (group 1) were compared with the subsequent 5 years (group 2). Outcomes were analyzed at 6 months and 12 months in addition to serum creatinine and patterns of delayed graft function (posttransplant times: on hemodialysis, to peak creatinine, for creatinine to half, and for creatinine to fall within 10% of baseline).

RESULTS

There was a significant increase in the percentage of expanded criteria donor allografts used in group 2 with a significant increase in the incidence of delayed graft function. Despite this, serum creatinine and the incidence of biopsy-proven acute rejection had both improved in group 2. Group 2 expanded criteria donor kidneys had a significantly lower incidence of type 1 delayed graft function and a significantly higher incidence of types 3 and 4 delayed graft function. Time for creatinine to half in both groups was the best predictor of a serum creatinine <180 μmol/L at 1 year.

CONCLUSION

The increased use of expanded criteria donor kidneys has led to a higher incidence of delayed graft function, but the pattern has shown that the requirement for hemodialysis has significantly reduced.

A molecular signature for delayed graft function

Chronic kidney disease and associated comorbidities (diabetes, cardiovascular diseases) manifest with an accelerated ageing phenotype, leading ultimately to organ failure and renal replacement therapy. This process can be modulated by epigenetic and environmental factors which promote loss of physiological function and resilience to stress earlier, linking biological age with adverse outcomes post-transplantation including delayed graft function (DGF). The molecular features underpinning this have yet to be fully elucidated. We have determined a molecular signature for loss of resilience and impaired physiological function, via a synchronous genome, transcriptome and proteome snapshot, using human renal allografts as a source of healthy tissue as an in vivo model of ageing in humans. This comprises 42 specific transcripts, related through IFNγ signalling, which in allografts displaying clinically impaired physiological function (DGF) exhibited a greater magnitude of change in transcriptional amplitude and elevated expression of noncoding RNAs and pseudogenes, consistent with increased allostatic load. This was accompanied by increased DNA methylation within the promoter and intragenic regions of the DGF panel in preperfusion allografts with immediate graft function. Pathway analysis indicated that an inability to sufficiently resolve inflammatory responses was enabled by decreased resilience to stress and resulted in impaired physiological function in biologically older allografts. Cross-comparison with publically available data sets for renal pathologies identified significant transcriptional commonality for over 20 DGF transcripts. Our data are clinically relevant and important, as they provide a clear molecular signature for the burden of "wear and tear" within the kidney and thus age-related physiological capability and resilience.

Ferumoxytol-enhanced magnetic resonance angiography for the assessment of potential kidney transplant recipients

Objectives

Traditional contrast-enhanced methods for scanning blood vessels using magnetic resonance imaging (MRI) or CT carry potential risks for patients with advanced kidney disease. Ferumoxytol is a superparamagnetic iron oxide nanoparticle preparation that has potential as an MRI contrast agent in assessing the vasculature.

Methods

Twenty patients with advanced kidney disease requiring aorto-iliac vascular imaging as part of pre-operative kidney transplant candidacy assessment underwent ferumoxytol-enhanced magnetic resonance angiography (FeMRA) between December 2015 and August 2016. All scans were performed for clinical indications where standard imaging techniques were deemed potentially harmful or inconclusive. Image quality was evaluated for both arterial and venous compartments.

Results

First-pass and steady-state FeMRA using incremental doses of up to 4 mg/kg body weight of ferumoxytol as intravenous contrast agent for vascular enhancement was performed. Good arterial and venous enhancements were achieved, and FeMRA was not limited by calcification in assessing the arterial lumen. The scans were diagnostic and all patients completed their studies without adverse events.

Conclusions

Our preliminary experience supports the feasibility and utility of FeMRA for vascular imaging in patients with advanced kidney disease due for transplant listing, which has the advantages of obtaining both arteriography and venography using a single test without nephrotoxicity.

Key Points

• Evaluation of vascular disease is important in planning kidney transplantation.

• Standard vascular imaging methods are often problematic in kidney disease patients.

• FeMRA has the advantage of arteriography and venography in a single test.

• FeMRA is safe and non-nephrotoxic.

• FeMRA is not limited by arterial calcification.

Changes in the demographics of intravenous drug users with mycotic common femoral artery pseudoaneurysm as a consequence of self-injection does not influence outcome following emergency ligation

Objectives

The reported annual incidence of mycotic pseudoaneurysm of the common femoral artery in intravenous drug users has been estimated at 0.03%. Over the past 5 years in Scotland, the proportion of people receiving specialist attention for heroin use over the age of 40 years has increased from 15 to 22%. Although routinely managed with arterial ligation (without reconstruction), some series have reported rates of major limb amputation of up to 10%. We sought to define whether this management strategy was still acceptable in an older population.

Methods

Retrospective review of patients presenting to a tertiary vascular service with mycotic pseudoaneurysm of the common femoral artery due to arterial injection by intravenous drug users between October 2010 and March 2016. Variables of interest included patient demographics and requirement for major amputation.

Results

There were 55 patients identified. The annual incidence of mycotic pseudoaneurysm of the common femoral artery in intravenous drug users was 2.1%. It was more common in men (3:1) and the mean age at presentation was 41 years (standard deviation ± 8 years). Three patients underwent major limb amputation during the index admission for severe limb ischaemia (two transfemoral amputations; one hip-disarticulation). Following discharge two patients were readmitted (134 and 200 days, respectively, following primary ligation) for major limb amputation due to of critical limb ischaemia.

Conclusions

Despite the increasing age of intravenous drug users presenting with mycotic pseudoaneurysm of the common femoral artery primary ligation of pseudoaneurysm would seem to remain an appropriate therapeutic intervention.

Wedge Versus Core Biopsy at Time Zero: Which Provides Better Predictive Value for Delayed Graft Function With the Remuzzi Histological Scoring System?

BACKGROUND

Histopathological features on time-zero renal biopsies correlate with graft outcome after renal transplantation. With increasing numbers of marginal donors, assessment of pre-implantation graft quality is essential. The clinician's choice of wedge or core biopsy is performed without evidence of efficacy or safety. This study aims to compare the information derived from wedge biopsy versus core biopsy.

METHODS

Prospective evaluation of 37 wedge biopsies and 30 core biopsies was performed. Histopathological data were collected on number of glomeruli and arterioles observed, and Remuzzi scoring for glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arteriolar narrowing was performed. Clinical data on delayed graft function (DGF) were also collated. Sensitivity, specificity, and positive and negative predictive values for DGF were compared.

RESULTS

Patient demographics between the two cohorts were comparable. No complications of biopsies occurred; 81% of wedge biopsies versus 50% of core biopsies had >10 glomeruli (P = .01), whereas 32% of wedge biopsies and 57% of core biopsies had >2 arterioles (P = .02). Wedge biopsies were more likely to identify pathology with more glomerulosclerosis, tubular atrophy (P < .01), and interstitial fibrosis (P < .01). There was a non-significant trend toward high Remuzzi scores in wedge biopsy (22% versus 7% with Remuzzi ≥ 4; P = .12). The sensitivity and positive predictive value of Remuzzi ≥ 4 for predicting DGF was better on wedge biopsy (45.5% versus 0%; P < .01 and 62.5% versus 0%; P < .01, respectively).

CONCLUSIONS

Wedge biopsies were safe and superior to core biopsies for identifying clinically significant histopathological findings on pre-implantation renal biopsy. We believe that the wedge biopsy is the method of choice for time-zero biopsies.

Identification of Molecular Markers of Delayed Graft Function Based on the Regulation of Biological Ageing

Introduction

Delayed graft function is a prevalent clinical problem in renal transplantation for which there is no objective system to predict occurrence in advance. It can result in a significant increase in the necessity for hospitalisation post-transplant and is a significant risk factor for other post-transplant complications.

Methodology

The importance of microRNAs (miRNAs), a specific subclass of small RNA, have been clearly demonstrated to influence many pathways in health and disease. To investigate the influence of miRNAs on renal allograft performance post-transplant, the expression of a panel of miRNAs in pre-transplant renal biopsies was measured using qPCR. Expression was then related to clinical parameters and outcomes in two independent renal transplant cohorts.

Results

Here we demonstrate, in two independent cohorts of pre-implantation human renal allograft biopsies, that a novel pre-transplant renal performance scoring system (GRPSS), can determine the occurrence of DGF with a high sensitivity (>90%) and specificity (>60%) for donor allografts pre-transplant, using just three senescence associated microRNAs combined with donor age and type of organ donation.

Conclusion

These results demonstrate a relationship between pre-transplant microRNA expression levels, cellular biological ageing pathways and clinical outcomes for renal transplantation. They provide for a simple, rapid quantitative molecular pre-transplant assay to determine post-transplant allograft function and scope for future intervention. Furthermore, these results demonstrate the involvement of senescence pathways in ischaemic injury during the organ transplantation process and an indication of accelerated bio-ageing as a consequence of both warm and cold ischaemia.

Predictors of sustained arteriovenous access use for haemodialysis

BACKGROUND

Guidelines encourage early arteriovenous (AV) fistula (AVF) planning for haemodialysis (HD). The aim of this study was to estimate the likelihood of sustained AV access use taking into account age, sex, comorbidity, anatomical site of first AVF and, for pre-dialysis patients, eGFR and proteinuria.

METHODS

1,092 patients attending our centre who had AVF as their first AV access procedure between January 1, 2000 and August 23, 2012 were identified from the electronic patient record. The primary end-point was time to first sustained AV access use, defined as use of any AV access for a minimum of 30 consecutive HD sessions.

RESULTS

52.9% (n = 578) of the patients ultimately achieved sustained AV access use. The main reasons for AV access non-use were AVF failure to mature and death. The 3-year Kaplan-Meier probability of sustained AV access use was 68.8% for those not on renal replacement therapy (RRT) (n = 688) and 74.2% for those already on RRT (n = 404) at the time of first AVF. By multivariate analysis in patients not on RRT, male sex (HR 2.22; p < 0.001), uPCR (HR 1.03; p = 0.03) and eGFR (hazard ratio, HR 0.85; p < 0.001) were independent predictors of AV access use. In patients already on RRT, age (HR 0.98; p < 0.001) and peripheral vascular disease (HR 0.48; p = 0.02) were independent predictors of AV access use.

CONCLUSION

Our data suggest that refinement of the current guideline for timing of AV access creation in planning RRT is justified to take into account individual factors that contribute to the likelihood of technical success and clinical need.

Pharmacotherapy to improve outcomes in vascular access surgery: a review of current treatment strategies

BACKGROUND

Renal failure is a major cause of morbidity in western Europe, with rising prevalence. Vascular access complications are the leading cause of morbidity among patients on haemodialysis. Considering the health care burden of vascular access failure, there is limited research dedicated to the topic.

METHODS

Randomised control trials of medications aimed at improving vascular access patency were identified using a medline search between January 1950 and January 2011.

RESULTS

Thirteen randomised trials were identified, investigating antiplatelets, anticoagulants and fish oil in preserving vascular access patency. Outcomes are presented and reviewed in conjunction with the underlying pathophysiological mechanisms of failure of vascular access.

DISCUSSION

Vascular access failure is a complex process. Most clinical trials so far have involved medications primarily aimed at preventing thrombosis. Other contributing pathways such as neointimal hyperplasia have not been investigated clinically. Improved outcomes may be seen by linking future therapies to these pathways.

B-type natriuretic peptide predicts long-term survival after major non-cardiac surgery

BACKGROUND

The prediction of long-term survival after surgery is complex. Natriuretic peptides can predict short-term postoperative cardiac morbidity and mortality. This study aims to determine the long-term prognostic significance of preoperative B-type natriuretic peptide (BNP) concentration after major non-cardiac surgery.

METHODS

We conducted a prospective single-centre observational cohort study in a West of Scotland teaching hospital. Three hundred and forty-five patients undergoing major non-cardiac surgery were included. The primary endpoint was long-term all-cause mortality.

RESULTS

Overall survival was 67.8% (234/345), with 27 postoperative deaths (within 42 days) and 84 deaths at subsequent follow-up (median follow-up 953 days). A BNP concentration of >87.5 pg ml(-1) best predicted mortality, and the mean survival of patients with an elevated BNP (>87.5 pg ml(-1)) was 731.9 (95% CI 613.6-850.2) days compared with 1284.6 days [(95% CI 1219.3-1350.0), P<0.001] in patients with a BNP<87.5 pg ml(-1). BNP was an independent predictor of survival.

CONCLUSIONS

BNP is an independent predictor of long-term survival after major non-cardiac surgery. A simple preoperative blood test can provide predictive information on future risk of death, and potentially has a role in preoperative risk assessment.

Are routine microbiological investigations indicated in the management of non-perianal cutaneous abscesses?

BACKGROUND

It is common practice to take a specimen of pus for microscopy and bacterial culture during drainage of abscesses. The aim of this study was to determine if routine culture and sensitivity had any therapeutic value in the care of patients with non-perianal cutaneous abscesses.

PATIENTS AND METHODS

A retrospective analysis ofall patients undergoing drainage ofa cutaneous abscess during a two year period (June 2003 - June 2005) was performed. Patients were identified from the hospital database and theatre records, and those with perianal, pilonidal or surgical wound sepsis were excluded. Notes were reviewed for clinical details, culture results, subsequent admissions and attendance at follow-up.

RESULTS

Of the 239 patients treated during this period, 74 patients had 77 operations to drain abscesses that matched the inclusion criteria. Specimens were sent from 52 (67.5%) procedures. Only 65.4% had an organism identified, of which methicillin-sensitive Staphylococcus aureus (MSSA) was the most commonly isolated organism (36.5%). Forty-one point six per cent of patients received antibiotics as part of their treatment. The results of the bacterial culture and antibiotic sensitivities were not known prior to discharge of any patient.

CONCLUSION

This study shows that bacteriology swabs are frequently taken during incision and drainage of non-perianal cutaneous abscesses and had little impact on the subsequent treatment, though these results may not be applicable to immune-compromised patients.

Prognostic value of cardiovascular screening in potential renal transplant recipients: a single-center prospective observational study

We assessed the outcome of pretransplant cardiac assessment in a single center. Three hundred patients with end-stage renal disease underwent electrocardiogram, Bruce exercise testing (ETT) and ventricular assessment by cardiac MRI. Patients with high index of suspicion of coronary artery disease (CAD) underwent coronary angiography and percutaneous coronary intervention (PCI) if indicated. Two hundred and twenty-two patients were accepted onto the renal transplant waiting list; 80 patients were transplanted during the follow-up period and 60 died (7 following transplantation). Successful transplantation was associated with improved survival (mean survival 4.5 +/- 0.6 years vs. listed not transplanted 4.1 +/- 1.4 years vs. not listed 3.1 +/- 1.7 years; p < 0.001). Ninety-nine patients underwent coronary angiography; 65 had normal or low-grade CAD and 34 obstructive CAD. Seventeen patients (5.6%) were treated by PCI. There was no apparent survival difference between patients who underwent PCI or coronary artery bypass graft compared to those who underwent angiography without intervention or no angiography (p = 0.67). Factors associated with nonlisting for renal transplantation included burden of preexisting cardiovascular disease, poor exercise tolerance and severity of CAD. Pretransplant cardiovascular screening provides prognostic information and information that can be used to restrict access to transplantation. However, if the aim is to identify and treat CAD, the benefits are far from clear.

Prognostic value of cardiovascular screening in potential renal transplant recipients: a single-center prospective observational study

We assessed the outcome of pretransplant cardiac assessment in a single center. Three hundred patients with end-stage renal disease underwent electrocardiogram, Bruce exercise testing (ETT) and ventricular assessment by cardiac MRI. Patients with high index of suspicion of coronary artery disease (CAD) underwent coronary angiography and percutaneous coronary intervention (PCI) if indicated. Two hundred and twenty-two patients were accepted onto the renal transplant waiting list; 80 patients were transplanted during the follow-up period and 60 died (7 following transplantation). Successful transplantation was associated with improved survival (mean survival 4.5 +/- 0.6 years vs. listed not transplanted 4.1 +/- 1.4 years vs. not listed 3.1 +/- 1.7 years; p < 0.001). Ninety-nine patients underwent coronary angiography; 65 had normal or low-grade CAD and 34 obstructive CAD. Seventeen patients (5.6%) were treated by PCI. There was no apparent survival difference between patients who underwent PCI or coronary artery bypass graft compared to those who underwent angiography without intervention or no angiography (p = 0.67). Factors associated with nonlisting for renal transplantation included burden of preexisting cardiovascular disease, poor exercise tolerance and severity of CAD. Pretransplant cardiovascular screening provides prognostic information and information that can be used to restrict access to transplantation. However, if the aim is to identify and treat CAD, the benefits are far from clear.

Measurement of process as quality control in the management of acute surgical emergencies

BACKGROUND

Quality of care measured by adverse events cannot address errors of process that have no adverse outcomes. The aim of this study was to determine whether process could be used to assess quality of care and whether process analysis could be used to assess interventions designed to improve quality.

METHODS

A single-centre prospective cohort study was performed over 12 weeks in an acute surgical admission unit. Data were collected prospectively for the first 24 h of admission on three aspects of process: documentation, general management and presentation-specific criteria. After a period of observation, the impact of three interventions (active observation, increasing awareness and issuing a job description) on the mean number of process errors per patient (process score) was compared.

RESULTS

The analysis was based on 566 patients admitted with general surgical pathology. Awareness of being observed failed to improve the process score. Interventions that increased awareness of process reduced the overall process score from 4.79 to 2.38 errors per person (P < 0.001). The mean overall process score in patients with an adverse event was twice that of patients who did not have an adverse event (5.74 (95 per cent confidence interval 4.03 to 7.45) versus 3.43 (3.19 to 3.66)).

CONCLUSION

Process can be measured objectively and used as a measure of quality of care. Interventions to increase awareness reduced process error rates and adverse events.

Comparison of breast cancer mortality rates with those of ovarian and colorectal carcinoma

Background

Traditional survival curves cannot easily be used to predict outcome for an individual patient on a year-to-year basis. This difficulty is partly overcome by yearly mortality analysis. This method was employed to analyse long-term follow-up of three cancers: colorectal, ovarian and breast cancer.

Methods

The study used prospectively collected cancer registry data from geographically defined regions in Scotland. Cohort sizes were 7196 patients with breast cancer, 3200 with colorectal cancer and 1866 with ovarian cancer. Follow-up extended to 23 years.

Results

Two distinct patterns of mortality emerged. Mortality rates for ovarian and colorectal cancer were initially high (41 and 21 per cent) but decreased rapidly; by 10 years patients had either died or were cured. The influence of stage diminished with follow-up. Breast cancer mortality was lower than that of colorectal or ovarian cancer, but remained raised in comparison to the general population throughout follow-up. The influence of breast cancer size reduced with follow-up, whereas that of nodal status persisted.

Conclusion

Patients with breast cancer live at increased risk of death to the end of follow-up, supporting the concept of dormancy in breast cancer biology. This was not observed with colorectal or ovarian cancer.

B-type natriuretic peptide predicts cardiac morbidity and mortality after major surgery

Background

The objective of this study was to determine whether measurement of B-type natriuretic peptide (BNP) concentration before operation could be used to predict perioperative cardiac morbidity.

Methods

A prospective derivation study was performed in high-risk patients undergoing major non-cardiac surgery, with a subsequent validation study. A venous blood sample was taken the day before surgery for measurement of plasma BNP concentration. Screening for cardiac events (non-fatal myocardial infarction and cardiac death) was performed using clinical criteria, cardiac troponin I analysis and serial electrocardiography.

Results

Forty-one patients were recruited to the derivation cohort and 149 to the validation cohort. In the derivation cohort, the median (interquartile range) BNP concentration in the 11 patients who had a postoperative cardiac event was 210 (165–380) pg/ml, compared with 34·5 (14–70) pg/ml in those with no cardiac complications (P &lt; 0·001). In the validation cohort, the median BNP concentration in the 15 patients who had a cardiac event was 351 (127–1034) pg/ml, compared with 30·5 (11–79·5) pg/ml in the remainder (P &lt; 0·001). BNP concentration remained a significant outcome predictor in multivariable analysis (P &lt; 0·001). Using receiver–operator curve analysis it was calculated that a BNP concentration of 108·5 pg/ml best predicted the likelihood of cardiac events, with a sensitivity and specificity of 87 per cent each.

Conclusion

Preoperative serum BNP concentration predicted postoperative cardiac events in patients undergoing major non-cardiac surgery independently of other risk factors.

Prognostic Scoring in Patients With Melanoma After Adjuvant Isolated Limb Perfusion

BACKGROUND

The clinical course in melanoma is variable. The aim of the present study was to assess adjuvant isolated limb perfusion (ILP) efficacy using a surrogate comparison of observed survival versus Cochran-predicted survival.

MATERIALS AND METHODS

All patients in a single university hospital with primary, non-ulcerated limb melanoma who had undergone adjuvant ILP over 10 years (1986-1995) were studied. Clinical and pathological details including follow-up and survival were prospectively recorded in a national database. All patients were risk scored, as described by Cochran et al., to yield individual survival probability at the end of 3, 5 and 10 years and this was compared with observed survival at corresponding intervals.

RESULTS

There were 85 patients who had adjuvant ILP for primary non-ulcerated limb melanoma. Of these, 14 deaths were observed (O) within the 10-year follow-up period. The Cochran score predicted (E) 20 deaths within 10 years (O/E ratio 0.7). The O/E ratios for deaths in the 0 to 3, 3 to 5, and 5 to 10 year intervals were 8/7.4, 5/6.0, and 1/6.5, respectively; prediction of late deaths tended to be overestimated. When patients were grouped by predicted 10-year mortality (<20%, 20-40%, >40%) the overestimation was found to occur mainly in the highest risk group: O/E ratios were 6/5.9, 6/8.4, and 2/5.6, respectively (P = 0.10, Hosmer-Lemeshow test).

CONCLUSION

The observed and expected survival in patients receiving adjuvant ILP at the end of 3 and 5 years are comparable. The Cochran scoring system overestimated deaths during the 5 to 10 year interval. It is not clear whether this observation is a consequence of ILP efficacy or inaccuracy of the Cochran score.

Should Pre-operative Troponin be a Standard Requirement in Patients Undergoing Major Lower Extremity Amputation?

OBJECTIVES

The objective of this study was to ascertain the benefit of routine pre-operative cardiac troponin I (cTnI) measurement in patients undergoing major lower extremity amputation for critical limb ischaemia.

DESIGN

This was a prospective, blinded observational study.

METHODS

All patients scheduled for lower extremity amputation, without evidence of unstable coronary artery disease were recruited prospectively over a period of 1 year. In addition to routine pre-operative evaluation, a blood sample was taken for measurement of serum cTnI. Post-operative screening was conducted for cardiac events with patients followed up to 6 weeks.

RESULTS

Ten of the 44 patients included suffered a non-fatal myocardial infarction or died from a cardiac cause post-operatively. A rise in pre-operative cTnI was associated with a very poor outcome (two cardiac deaths and one post-operative myocardial infarction) and was the only significant predictor of post-operative cardiac events.

CONCLUSION

Routine pre-operative cTnI measurement may be of use to identify patients at high risk of cardiac complication who would benefit from optimization of cardiac status or in whom surgery could be deferred.

Axillary recurrence in breast cancer

AIM

To determine whether axillary recurrence reflects inadequate axillary treatment or adverse pathological features.

METHODS

The case-records were reviewed of 2122 women aged under 75 years, treated for invasive breast cancer during the time-period 1/1/86-31/12/91 in a geographically defined area. Data were abstracted on operations performed, pathological features, post-operative treatments and details of axillary recurrence. The risk of axillary recurrence was examined by pathological, treatment and patient factors.

RESULTS

Axillary recurrence was more than twice as likely after inadequate compared to adequate treatment of the axilla (adequate staging or axillary radiotherapy or clearance). Delayed treatment of the axilla was not as successful as adequate primary treatment: multiple axillary recurrences were twice as common, one third of which were uncontrolled at time of death. Inadequate surgical treatment was associated with increased rates of recurrence despite endocrine therapy, chemotherapy or radiotherapy. Lymphoedema was twice as common if axillary radiotherapy was combined with any axillary surgical procedure.

CONCLUSIONS

Axillary recurrence is more common in tumours with adverse pathology but may also result from inadequate axillary treatment. In order to minimise axillary recurrence, optimal treatment of the axilla entails adequate staging (sampling of four or more nodes) and treatment (axillary clearance or radiotherapy and endocrine therapy) in all women.

Inadequate treatment of symptomatic breast cancer

Background

Early trials that compared breast and axillary treatments showed differing recurrence rates without significant differences in survival. Consequently, there was a wide range of opinion and practice in the management of breast cancer. The present study explored this variability in surgical management to determine the impact of breast and axillary treatment on recurrence and survival.

Methods

The records of 2776 women with histologically confirmed invasive breast cancer diagnosed between 1986 and 1991 were reviewed. The relationship between adequacy of breast and axillary treatment, recurrence and survival was examined in 2122 women who had surgery with curative intent. A Cox proportional hazards model that included tumour size, node status, grade, socioeconomic status and use of adjuvant therapy was used.

Results

Inadequate treatment was associated with a significantly higher risk of local recurrence after breast-conserving surgery (relative hazard ratio (RHR) 4·19 (95 per cent confidence interval (c.i.) 2·73 to 6·43); P &lt; 0·001). Inadequate axillary treatment was associated with a significantly higher risk of regional recurrence (RHR 2·29 (95 per cent c.i. 1·65 to 3·16); P &lt; 0·001). The risk of death from breast cancer was significantly higher if locoregional treatment was inadequate (RHR 1·29 (95 per cent c.i. 1·07 to 1·55); P = 0·008).

Conclusion

Adequate surgery is fundamental to the optimal treatment of breast cancer. Inadequate surgery resulted in higher recurrence rates despite adjuvant treatments.

Increased mortality from breast cancer and inadequate axillary treatment

BACKGROUND

The assessment of axillary nodal status remains divisive: inaccurate staging may result in untreated axillary disease, and appropriate adjuvant therapy not being delivered. The impact of inadequate axillary treatment on survival remains controversial. We analyse the impact of failure to adequately assess the axillary nodal status on survival.

METHODS

All women with confirmed breast cancer in a 15-year period were identified, and the original pathology reports examined, and details of radiotherapy obtained. The survival of women by axillary sample size was compared to a reference group of women and corrected for nodal status, tumour size, age, deprivation category and speciality of treating surgeon.

FINDINGS

Sampling less than four nodes is associated with a significantly increased risk of death. This cannot be due to understaging the extent of axillary disease nor is fully explainable by differential prescription of adjuvant therapies. We conclude that the survival of the women studied may have been adversely effected by inadequate axillary treatment.

The impact of late acute rejection after cadaveric kidney transplantation

BACKGROUND

Acute graft rejection (AR) following renal transplantation results in reduced graft survival. However, there is uncertainty regarding the definition, aetiology and long-term graft and patient outcome of AR occurring late in the post-transplant period.

AIM

To determine if rejection episodes can be classified by time from transplantation by their impact on graft survival into early acute rejection (EAR) and late acute rejection (LAR).

MATERIALS AND METHODS

687 consecutive adult renal transplant recipients who received their first cadaveric renal transplant at a single centre. All received cyclosporine (CyA)-based immunosuppression, from 1984 to 1996, with a median follow-up of 6.9 yr. Details were abstracted from clinical records, with emphasis on age, sex, co-morbid conditions, HLA matching, rejection episodes, patient and graft survival.

ANALYSIS

Patients were classified by the presence and time to AR from the date of transplantation. Using those patients who had no AR (NAR) as a baseline, we determined the relative risk of graft failure by time to rejection. The characteristics of patients who had no rejection, EAR and LAR were compared.

RESULTS

Compared with NAR, the risk of graft failure was higher for those patients who suffered a rejection episode. A much higher risk of graft failure was seen when the first rejection episode occurred after 90 d. Thus, a period of 90 d was taken to separate EAR and LAR (relative risk of 3.06 and 5.27 compared with NAR as baseline, p<0.001). Seventy-eight patients (11.4%) had LAR, 271 (39.4%) had EAR and 338 (49.2%) had NAR. The mean age for each of these groups differed (LAR 39.6 yr, EAR 40.8 yr compared with NAR 44 yr, p<0.003). The 5-yr graft survival for those who had LAR was 45% and 10-yr survival was 28%. HLA mismatches were more frequent in those with EAR vs. NAR (zero mismatches in HLA-A: 36 vs. 24%, HLA-B: 35 vs. 23% and HLA-DR: 63 vs. 41%, p<0.003). There was no difference in mismatching frequency between NAR and LAR.

CONCLUSIONS

AR had a deleterious impact on graft survival, particularly if occurring after 90 d. AR episodes should therefore be divided into early and late phases. In view of the very poor graft survival associated with LAR, it is important to gain further insight into the main aetiological factors. Those such as suboptimal CyA blood levels and non-compliance with medication should be further investigated with the aim of developing more effective immunosuppressive regimens in order to reduce the incidence of LAR.

Influence of diabetes mellitus on patient and graft survival in recipients of kidney transplantation

AIMS

To investigate the outcomes in patients who have pre-existing diabetes and those who develop post-transplant diabetes mellitus (PTDM).

METHODS

We retrospectively reviewed the charts of 939 patients who received a first functioning renal transplant in the cyclosporine (CyA) era between 1984 and 1999.

RESULTS

Sixty-six (7%) patients had renal failure due to insulin-dependent diabetes mellitus (IDDM) and 7 (0.8%) patients due to non-insulin-dependent diabetes mellitus (NIDDM). Ten (1.1%) patients had coexistent diabetes and 48 (5.1%) recipients developed PTDM. The mean graft survival for the patients with PTDM was 9.7 yr versus 11.3 yr for the non-diabetic patients, while mean graft survival was 10.1 yr for patients with IDDM and 2.9 yr with NIDDM and 8.3 yr for those with coexistent diabetes (p=ns). However, there was a statistically significant difference in patient survival between patients who developed PTDM and in those who did not develop this complication. The mean survivals of patients with IDDM, NIDDM, coexistent diabetics and PTDM were 8.4, 3.7, 8.6 and 10.3 yr, respectively. The mean survival of the patients without pre-existing diabetes or PTDM was 12.8 yr (p<0.001). The survival of patients older than 55 yr with PTDM was no different to the control group. However, in those younger than 55 yr, PTDM was associated with a higher risk of death (relative risk of 2.54, p<0.001). Fifty percent of patients with IDDM developed acute rejection episodes, whereas rejection rate was 57.1% in NIDDM group, 50.0% in the PTDM group, 20.0% in the coexistent diabetes group and 44.3% in the control group (p=ns).

CONCLUSION

Patient survival, but not graft survival, was adversely affected by both pre-existing diabetes and by PTDM, particularly in those with an age less than 55 yr.

Cooccurrence of collagenous colitis with seronegative spondyloarthropathy: report of a case and literature review

Collagenous colitis is an uncommon cause of chronic watery diarrhea, characterized by colonic deposition of collagen. Nonerosive, oligoarticular, peripheral arthritis has previously been noted in about 7% of patients with collagenous colitis. We describe a patient with collagenous colitis who concurrently developed erosive, seronegative spondyloarthropathy affecting peripheral and axial joints. Synovial histology was characterized by a conspicuous inflammatory infiltrate comprised of histiocytes, lymphocytes and plasma cells. Collagenous colitis is suggested to be a systemic autoimmune disorder, with extraintestinal features such as thyroiditis and arthritis.