Kidney transplant recipients who die with functioning grafts: serum creatinine level and cause of death

DPYSL2/CRMP2 isoform B knockout in human iPSC-derived glutamatergic neurons confirms its role in mTOR signaling and neurodevelopmental disorders

The DPYSL2/CRMP2 gene encodes a microtubule-stabilizing protein crucial for neurogenesis and is associated with numerous psychiatric and neurodegenerative disorders including schizophrenia, bipolar disorder, and Alzheimer's disease. DPYSL2 generates multiple RNA and protein isoforms, but few studies have differentiated between them. We previously reported an association of a functional variant in the DPYSL2-B isoform with schizophrenia (SCZ) and demonstrated in HEK293 cells that this variant reduced the length of cellular projections and created transcriptomic changes that captured schizophrenia etiology by disrupting mTOR signaling-mediated regulation. In the present study, we follow up on these results by creating, to our knowledge, the first models of endogenous DPYSL2-B knockout in human induced pluripotent stem cells (iPSCs) and neurons. CRISPR/Cas9-faciliated knockout of DPYSL2-B in iPSCs followed by Ngn2-induced differentiation to glutamatergic neurons showed a reduction in DPYSL2-B/CRMP2-B RNA and protein with no observable impact on DPYSL2-A/CRMP2-A. The average length of dendrites in knockout neurons was reduced up to 58% compared to controls. Transcriptome analysis revealed disruptions in pathways highly relevant to psychiatric disease including mTOR signaling, cytoskeletal dynamics, immune function, calcium signaling, and cholesterol biosynthesis. We also observed a significant enrichment of the differentially expressed genes in SCZ-associated loci from genome-wide association studies (GWAS). Our findings expand our previous results to neuronal cells, clarify the functions of the human DPYSL2-B isoform and confirm its involvement in molecular pathologies shared between many psychiatric diseases.

New Approaches to Cardiovascular Disease and Its Management in Kidney Transplant Recipients

Cardiovascular events, including ischemic heart disease, heart failure, and arrhythmia, are common complications after kidney transplantation and continue to be leading causes of graft loss. Kidney transplant recipients have both traditional and transplant-specific risk factors for cardiovascular disease. In the general population, modification of cardiovascular risk factors is the best strategy to reduce cardiovascular events; however, studies evaluating the impact of risk modification strategies on cardiovascular outcomes among kidney transplant recipients are limited. Furthermore, there is only minimal guidance on appropriate cardiovascular screening and monitoring in this unique patient population. This review focuses on the limited scientific evidence that addresses cardiovascular events in kidney transplant recipients. Additionally, we focus on clinical management of specific cardiovascular entities that are more prevalent among kidney transplant recipients (ie, pulmonary hypertension, valvular diseases, diastolic dysfunction) and the use of newer evolving drug classes for treatment of heart failure within this cohort of patients. We note that there are no consensus documents describing optimal diagnostic, monitoring, or management strategies to reduce cardiovascular events after kidney transplantation; however, we outline quality initiatives and research recommendations for the assessment and management of cardiovascular-specific risk factors that could improve outcomes.

Retransplanting a previously transplanted kidney: A safe strategy in times of organ shortage?

BACKGROUND

The shortage of organs for transplantation remains a global problem. The retransplantation of a previously transplanted kidney might be a possibility to expand the pool of donors. We provide our experience with the successful reuse of transplanted kidneys in the Eurotransplant region.

METHODS

A query in the Eurotransplant database was performed between January 1, 1995 and December 31, 2015, to find kidney donors who themselves had previously received a kidney graft.

RESULTS

Nine out of a total of 68,554 allocated kidneys had previously been transplanted. Four of these kidneys were transplanted once again. The mean interval between the first transplant and retransplantation was 1689±1682 days (SD; range 55-5,333 days). At the time of the first transplantation the mean serum creatinine of the donors was 1.0 mg/dl (.6-1.3 mg/dl) and at the second transplantation 1.4 mg/dl (.8-1.5 mg/dl). The mean graft survival in the first recipient was 50 months (2-110 months) and in the second recipient 111 months (40-215 months).

CONCLUSION

Transplantation of a previously transplanted kidney may successfully be performed with well-preserved graft function and long-term graft survival, even if the first transplantation was performed a long time ago. Such organs should be considered even for younger recipients in carefully selected cases.

Late Graft Loss After Kidney Transplantation: Is "Death With Function" Really Death With a Functioning Allograft?

BACKGROUND

About half of late kidney allograft losses are attributed to death with function (DWF), a poorly characterized outcome. An ongoing question is whether DWF is a consequence of chronic allograft dysfunction. Using the prospective Long-term Deterioration of Kidney Allograft Function study database, we sought to better define the impact, phenotype, and clinical course of DWF in the current era.

METHODS

Three thousand five hundred eighty-seven kidney recipients with functional grafts at 90 days post-transplant were followed prospectively for a median of 5.2 years.

RESULTS

Characteristics at transplantation in those with DWF (N = 350, 9.8%) differed from those who otherwise lost their grafts (death-censored graft failure [DC-GF], N = 295, 8.2%) or maintained function (N = 2942, 82.0%); DWF patients were older, sicker, and had been on dialysis longer, with more preexisting cardiovascular disease, whereas DC-GF patients experienced more early rejection, more acute rejection after 90 days, and a clinically significant decrease in kidney function before graft failure. In contrast, the clinical course after transplantation in DWF patients did not differ before death from those who maintained function throughout.

CONCLUSIONS

DWF and DC-GF in kidney transplant recipients represent differing clinical phenotypes occurring in distinct patient populations. Reducing the impact of DWF requires better definition of causes and clinical course and then trials of therapies to improve outcomes. Composite endpoints in clinical trials that group DWF and DC-GF together may obscure important clinical findings.

Cardiovascular disease in the kidney transplant recipient: epidemiology, diagnosis and management strategies

Kidney transplantation (KT) is the optimal therapy for end-stage kidney disease (ESKD), resulting in significant improvement in survival as well as quality of life when compared with maintenance dialysis. The burden of cardiovascular disease (CVD) in ESKD is reduced after KT; however, it still remains the leading cause of premature patient and allograft loss, as well as a source of significant morbidity and healthcare costs. All major phenotypes of CVD including coronary artery disease, heart failure, valvular heart disease, arrhythmias and pulmonary hypertension are represented in the KT recipient population. Pre-existing risk factors for CVD in the KT recipient are amplified by superimposed cardio-metabolic derangements after transplantation such as the metabolic effects of immunosuppressive regimens, obesity, posttransplant diabetes, hypertension, dyslipidemia and allograft dysfunction. This review summarizes the major risk factors for CVD in KT recipients and describes the individual phenotypes of overt CVD in this population. It highlights gaps in the existing literature to emphasize the need for future studies in those areas and optimize cardiovascular outcomes after KT. Finally, it outlines the need for a joint 'cardio-nephrology' clinical care model to ensure continuity, multidisciplinary collaboration and implementation of best clinical practices toward reducing CVD after KT.

Successful reuse of a transplanted kidney 9 years after initial transplantation: 4-year follow-up

Background

Kidney transplantation is the preferred renal replacement therapy for patients with end-stage renal disease, but the waiting list for kidneys continues to grow because of a shortage of donor organs. The reuse of transplanted kidneys would seem to be a good approach to expand the pool of available organs. Here, we describe the reuse of a kidney 9 years after the initial transplantation. At 4-year follow-up, the second recipient is showing good renal function.

Case presentation

In 2005, a kidney was transplanted from a 40-year-old man, who suffered brain death due to an intracranial hemorrhage, into a 45-year-old man. Nine years later, the recipient suffered a ruptured cerebral aneurysm, resulting in brain death. The kidney was re-transplanted into a 40-year-old man with diabetic nephropathy who had received hemodialysis for 5 years. During 4 years of follow-up, the graft has functioned well.

Conclusions

This case demonstrates the successful regrafting of a transplanted kidney. We believe this is the longest period for reuse of kidney after initial transplantation. The outcome suggests that a well-functioning transplanted kidney can be reused years after transplantation.

Pathophysiologic and treatment strategies for cardiovascular disease in end-stage renal disease and kidney transplantations

The inextricable link between the heart and the kidneys predestines that significant cardiovascular disease ensues in the face of end-stage renal disease (ESRD). As a point of fact, the leading cause of mortality of patients on dialysis is still from cardiovascular etiologies, albeit differing in particular types of disease from the general population. For example, sudden cardiac death outnumbers coronary artery disease in patients with ESRD, which is the reverse for the general population. In this review, we will focus on the pathophysiology and treatment options of important traditional and nontraditional risk factors for cardiovascular disease in ESRD patients such as hypertension, anemia, vascular calcification, hyperparathyroidism, uremia, and oxidative stress. The evidence of erythropoietin-stimulating agents, phosphate binders, calcimimetics, and dialysis modalities will be presented. We will then discuss how these risk factors may be changed and perhaps exacerbated after renal transplantation. This is largely due to the immunosuppressive agents that are both crucial yet potentially detrimental in the posttransplant state. Calcineurin inhibitors, corticosteroids, and mammalian target of rapamycin inhibitors, the mainstay of transplant immunosuppression, are all known to increase the risks of developing new onset diabetes as well as the metabolic syndrome. Thus, we need to carefully negotiate between patients' cardiovascular profile and their risks of rejection. Finally, we end by considering strategies by which we may minimize cardiovascular disease in the transplant population, as this modality still confers the highest chance of survival in patients with ESRD.

Reuse of a previously transplanted kidney from a deceased donor using Luminex virtual crossmatching: a case report

Kidney transplantation is the most desired modality of renal replacement therapy for patients with end-stage renal disease (ESRD). We have attempted to expand the organ donor pool through several methods, including the use of expanded donor criteria. Although previously transplanted kidneys are rarely reused, they can be suitable for transplantation into patients in need. We report a case of successful reuse of a previously transplanted kidney from a deceased donor by means of Luminex virtual crossmatching with the first donor and actual crossmatching with the second donor.

Long-Term Impact of Different Immunosuppressive Drugs on QT and PR Intervals in Renal Transplant Patients

BACKGROUND

Sudden cardiac deaths due to arrhythmias are thought to be an important cause of mortality in patients with renal transplants. Exposure to immunosuppressive drugs may lead to QT or PR interval abnormalities which may consequently cause arrhythmias. Our study investigated the long term impact of four different immunosuppressive drugs on PR and corrected QT intervals (QTc) in renal transplant patients

METHODS

The study population consisted of 98 kidney transplant recipients. Study patients were receiving immunosuppressive management with tacrolimus, cyclosporine A, everolimus or azathioprine according to the local protocols. QTc and PR intervals obtained from the most recent post-transplant electrocardiograms were compared with the pre-transplant intervals dated before the transplantation procedure.

RESULTS

Post-transplant QTc intervals had prolonged significantly in comparison to the pre-transplant QTc intervals in all groups. However, there were no significant differences between the immunosuppressive agents with regard to post-transplant QTc interval prolongation (p > 0.05). There were no significant differences between the groups with regard to the pre and post-transplant PR interval changes (p > 0.05).

CONCLUSIONS

QT interval prolongation, a marker of risk for arrhythmias and sudden death, is highly prevalent among kidney transplant patients receiving different classes of immunosuppressive drugs.

Chronic graft loss and death in patients with post-transplant malignancy in living kidney transplantation: a competing risk analysis

Background:

Malignancy is a common complication after renal transplantation. Death with functioning graft and chronic graft loss are two competing outcomes in patients with post-transplant malignancies.

Objectives:

The purpose of our study was to evaluate the risk factors associated with cumulative incidence of these two outcomes.

Patients and Methods:

Fine-Gray model was used for 266 cases with post-transplant malignancy in Iran. These patients were followed-up from the diagnosis until the date of last visit, chronic graft loss, or death, subsequently.

Results:

At the end of the study, as competing events, chronic graft loss and death with functioning graft were seen in 27 (10.2%) and 53 cases (19.9%), respectively, while 186 cases (69.9%) were accounted as censored. The incidence rate of death was approximately two-time of the incidence rate of chronic graft loss (8.6 vs. 4.4 per 100 person-years). In multivariate analysis, significant risk factors associated with cumulative incidence of death included age (P < 0.007, subhazard ratio (SHR) = 1.03), type of cancer (P < 0.0001), and response to treatment (P < 0.0001, SHR = 0.027). The significant risk factors associated with cumulative incidence of chronic graft loss were gender (P = 0.05, SHR = 0.37), treatment modality (P < 0.0001), and response to treatment (P = 0.048, SHR = 0.47).

Conclusions:

Using these factors, nephrologists may predict the occurrence of graft loss or death. If the probability of graft loss was higher, physicians can decrease the immunosuppressive medications dosage to decrease the incidence of graft loss.

Cardiovascular risk estimated in renal transplant recipients with the Framingham score

BACKGROUND

Cardiovascular disease is responsible for much of the mortality and morbidity observed in the renal transplant population. Some studies have applied the Framingham score mainly to the chronic kidney disease (CKD) on renal replacement therapy in an attempt to predict cardiovascular events, but the results underestimated the risk. It became evident at the participation of so-called nontraditional factors, such as anemia and inflammatory markers among others, were important predictors of risk in this population.

OBJECTIVE

The aim of this study was to apply the Framingham score to a population of renal transplant subjects to assess its quality to predict cardiovascular events among a population without the theoretically nontraditional risk factors.

METHODS

We retrospectively evaluated the medical records of patients transplanted from 2005 to 2010 for the score as determined by sex, age, blood pressure, low-density lipoprotein cholesterol, smoking history, and presence of diabetes mellitus. The final results expressed the risk for absolute development of cardiovascular diseases at the end of 10 years.

RESULTS

Among 126 patients including 44 women and, 82 men of mean age 45 ± 16 years were 64 living-related and 62 deceased-donor grafts. The etiology of CKD was hypertension (58%), diabetes (37%), and other causes (5%). Fifty-nine percent of patients had a low risk of developing coronary artery diseases at the end of 10 years, 30% medium risk, and only 11% high risk when measured by the Framingham score.

CONCLUSIONS

The assessment of cardiovascular risk using the Framingham risk score did not reflect the observations in the literature of both high mortality and high morbidity. Therefore, this was not a good method to assess the risk of cardiovascular disease, probably because it does not include cardiovascular risk factors in addition to traditional ones that are important in this population.

Causes of death in renal transplant recipients with functioning allograft

The survival of transplant recipients is significantly lower than age-matched controls in the general population. The aim of this study was to analyze the trends in mortality of renal allograft recipients at our centre. We retrospectively analyzed data from all patients who were transplanted between October 1988 and June 2010 and were followed at our center. Patients were considered to have death with graft function (DWGF) if death was not preceded by return to dialysis or re-transplantation. The study included 98 renal allograft recipients (male : female – 7.99 : 1). The mean recipient and donor ages were 35.06 ± 11.84 (range: 15–69) and 41.17 ± 10.44 (range: 22–60) years, respectively. Basic kidney diseases were CGN (chronic glomerulonephritis) (60.20%), CIN (chronic interstitial nephritis) (15.31%), DN (diabetic nephropathy) (8.16%), ADPKD (autosomal dominant polycystic kidney disease) (2.04%) and others (14.29%). They were followed up for a mean 79.91 ± 60.05 patient-months. Mortality occurred in 25 (25.51%) patients (male : female – 4 : 1). Causes of death were sepsis/infection (36%), coronary artery disease (28%), CVA (8%), failed graft (4%), and rest unknown (24%). DWGF was 88% of total death and contributed to 78.57% of total graft loss. Overall patient survival at 1, 5, 10, and 15 years were 90.8%, 80.2%, 65.6%, and 59.1%, respectively (Kaplan–Meier analysis). Those who died exhibited significant differences in recipient's age (median 40 years vs 31 years, P=0.007), pretransplantation hypertension (HTN) (100% vs 65.75%, P<0.001), post-transplant infection (76% vs 42.47%, P=0.005), coronary artery disease (28% vs 1.37%, P<0.001), and serum creatinine at last follow up (median 2.3mg/dL vs 1.56mg/dL, P=0.003). Cardiovascular disease, in addition to infection, is an important cause of death during the first 15 years following renal transplantation even in nondiabetic recipients. Death with functioning graft is of concern.

Cardiac surgical outcomes in abdominal solid organ (renal and hepatic) transplant recipients: a case-matched study

OBJECTIVES

This study aims to investigate the outcomes of cardiac surgery in patients with abdominal solid organ transplants and to compare them with the case-matched population undergoing cardiac surgery.

METHODS

Data from all transplant recipients abdominal solid organ transplant (ASOT) N = 36 (30 renal and 6 hepatic) who underwent cardiac surgery in a single centre during the period from January 1997 to December 2010 were collected from hospital transplant registries and the cardiac database. The transplant recipients were case matched (CM) with 104 patients in terms of the variables of age, sex and the type of cardiac surgery. Follow-up data were obtained from medical records and by a set of questionnaire through telephonic interviews.

RESULTS

Follow-up times were 4.5 ± 3.2 and 3.9 ± 3.2 years in the transplant and CM groups, respectively. Follow-up in the transplant group was 100%. There was no 30-day mortality in the transplant group. Thirty-day combined major morbidities were 9% in the matched group vs 11% in the transplant patients (P = 0.6). Median length of stay was 6 days (inter-quartile range, IQR 5.9) for ASOT vs 5 days (IQR 4.6) for CM (P < 0.01). New dialysis was 8.3% in transplant patients compared with 0.96% in the matched population, while infection was 16.66 vs 0.42% in the CM cohort. There was no allograft failure/dysfunction at the time of death or latest follow-up. Late deaths were 8 of 36 (22%) in ASOT vs 6 of 104 (6%) in CM. Infection (63%) was the most frequent major cause of death in transplant patients. One-, 2-, 5- and 10-year survivals for ASOT vs CM were 94, 88, 80, 59 vs 99, 99, 91, 85%, respectively. Multivariate predictors of mortality were increasing age (hazard ratio, HR 1.1, 95% confidence interval, CI 1.04-1.18; P = 0.003) and solid organ transplantation (HR 3.44, CI 1.19-9.98; P = 0.023).

CONCLUSIONS

Cardiac surgery can be performed in patients with abdominal solid organ tranpslant recipients with acceptable early morbidity and mortality. However, long-term survival in transplant patients is poor. Infection remains the most common cause of death.

Delayed graft function and the risk of death with graft function in living donor kidney transplant recipients

BACKGROUND

The link between delayed graft function (DGF) and death with graft function (DWGF) in living donor kidney transplant recipients presently is unknown.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

44,630 adult living donor kidney recipients (first transplants only) in the US Renal Data System from January 1, 1994, to December 31, 2004.

PREDICTOR

DGF, defined as the need for dialysis therapy in the first week after transplant.

OUTCOME

Time to DWGF.

MEASUREMENTS

Kaplan-Meier curves were constructed to assess the impact of DGF on DWGF. Recipients with DGF were 1:1 propensity score matched to those without DGF, and time-dependent Cox proportional hazards models were used to examine factors associated with DWGF. Subgroup and sensitivity analyses also were conducted.

RESULTS

DWGF occurred in 3,878 patients during 3.9 years' (median) follow-up. In patients with DGF, survival with graft function at 1, 3, 5, and 10 years was 91.9%, 86.8%, 81.6%, and 61.7%, respectively (in patients without DGF, these values were 98.0%, 95.2%, 91.6%, and 80.1%, respectively; P < 0.001 compared with the DGF group). In a fully adjusted time-dependent Cox model, HRs for DWGF in patients with DGF (vs without DGF) were 6.55 (95% CI, 4.78-8.97), 3.55 (95% CI, 2.46-5.11), 2.07 (95% CI, 1.53-2.81), and 1.48 (95% CI, 1.26-1.73) at 0-1, 1-3, 3-12, and longer than 12 months posttransplant, respectively. Propensity score analysis showed similar results. Inferences were unchanged after adjustment for kidney function and acute rejection at 6 months and 1 year posttransplant. Cardiovascular and infectious causes of DWGF were more prevalent in patients with DGF. The association was more marked in female recipients and robust to various sensitivity analyses.

LIMITATIONS

The impact of lesser decreases in early graft function could not be evaluated.

CONCLUSIONS

DGF is associated with an increased risk of DWGF in living donor kidney recipients. The mechanisms underlying this relation require further study.

Ventricular arrhythmia in incident kidney transplant recipients: prevalence and associated factors

Cardiovascular mortality in kidney transplant recipients has shown to be substantially elevated particularly in the first year of transplantation. Complex ventricular arrhythmia (VA) has been pointed as one of the etiologies of sudden death. The aim of this study was to evaluate the prevalence of VA and to investigate the factors associated with their occurrence in incident kidney transplant recipients. A total of 100 incident kidney transplant recipients were included in the study (39.7 ± 10.1 years, 55% male, 43.6 ± 10.1 days of transplantation, 66% living donors). All the patients underwent 24 h electrocardiogram, echocardiogram and multi-slice computed tomography. Thirty percent of the patients had VA. Left ventricular hypertrophy was observed in 57% of the patients while heart failure was found in 5%. Coronary artery calcification (CAC) was observed in 26 patients, from which 31% had severe calcification. The group of patients with VA was predominantly male, had been on dialysis therapy for a longer time and had more coronary calcification. In the multiple logistic regression analysis, male gender and CAC score were independently associated with the presence of VA. In conclusion, kidney transplant recipients exhibited a high prevalence of VA and the factors associated with its occurrence were the male gender and the presence of CAC.

Delayed graft function and the risk for death with a functioning graft

Delayed graft function (DGF) associates with an increased risk for graft failure, but its link with death with graft function (DWGF) is unknown. We used the US Renal Data System to assemble a cohort of all first, adult, deceased-donor kidney transplant recipients from January 1, 1998, through December 31, 2004. In total, 11,542 (23%) of 50,246 recipients required at least one dialysis session in the first week after transplantation. Compared with patients without DGF, patients with DGF were significantly more likely to die with a functioning graft (relative hazard 1.83 [95% confidence interval 1.73 to 1.93] and 1.53 [95% CI 1.45 to 1.63] for unadjusted and fully adjusted models, respectively). The risk for DWGF was slightly higher among women with DGF than among men. There was no significant heterogeneity among other subgroups, and the results were robust to sensitivity analyses. Acute rejection within the first year attenuated the DGF-DWGF association. Cardiovascular and infectious deaths were slightly more prevalent in the DGF group, but the relative hazards of cause-specific death were similar between DWGF and deaths during total follow-up. In summary, DGF associates with an increased risk for DWGF; the mechanisms underlying the negative impact of DGF require further study.

Why hasn't eliminating acute rejection improved graft survival?

Although patients with end-stage renal disease can be maintained with dialysis therapy, the superiority of patient survival with renal transplantation makes transplantation the preferred method of renal replacement. Potent immunosuppressive therapies, particularly calcineurin inhibitors, have greatly reduced the incidence of acute rejection. However, long-term allograft survival remains limited. We discuss the impact of acute rejection on long-term allograft survival and discuss other factors leading to late allograft loss, including calcineurin inhibitor toxicity, chronic allograft nephropathy, and BK virus nephropathy, as well as donor and recipient factors associated with long-term allograft loss.

Predictors of cardiovascular events and associated mortality within two years of kidney transplantation

BACKGROUND

Cardiovascular disease is the most common cause of death after renal transplantation. Furthermore, acute coronary syndrome (ACS) attributable to coronary artery disease (CAD) accounts for the majority of deaths due to cardiovascular disease posttransplant. While renal transplantation is the treatment of choice for end-stage renal disease, understanding the causes of graft and patient loss is exceedingly important to improve outcomes.

METHODS

This observational case-controlled study included 780 patients who underwent a kidney transplant between 1989 and 2001 who experienced early ACS (within 2 years). Patients were compared with controls matched for gender, year of transplant, and age. The primary outcome was the occurrence of an ACS event within 2 years after renal transplantation.

RESULTS

Cardiovascular disease was the most common cause of death, with all 13 cardiovascular deaths due to CAD. An additional 15 episodes of nonfatal ACS episodes occurred. Thirty-seven percent of early ACS occurred perioperatively, the majority in the first 3 posttransplant months. On multivariate analysis, diabetes (OR [odds ratio] 5.56; P = .0007), smoking (OR 3.56; P = .034), and prior transplant (OR 2.81; P = .047) were associated with early ACS.

CONCLUSIONS

Diabetes, smoking, and prior transplant were significantly associated with early ACS. The majority of events occurred perioperatively or within 3 months of transplant, highlighting the importance of improved screening and perioperative management.

Conversion from cyclosporine to azathioprine at three months reduces the incidence of chronic allograft nephropathy

BACKGROUND

Conversion from cyclosporine to azathioprine after renal transplantation has been shown to be beneficial in terms of allograft function, cardiovascular risk factor profile, and the incidence of gout. A higher incidence of acute rejection, however, has also been reported and uncertainty still exists about the long-term outcome after conversion. We report on the extended follow-up of an open-label, randomized trial that examined conversion to azathioprine as early as three months after transplantation.

METHODS

One hundred twenty-eight patients were enrolled in this single-center study. Three months after transplantation they were randomly assigned to continue cyclosporine treatment (N = 68), or they were converted to azathioprine (N = 60). The steroid dose was temporarily increased in the patients who were converted.

RESULTS

Patient survival was not different in the two groups. Graft survival tended to be lower (64.7% vs. 76.5% at 15 years) in the cyclosporine continuation group (P = 0.14) when data were analyzed on an intention to treat basis. The graft survival of the patients that stayed on their assigned treatment was significantly higher in the azathioprine arm, starting at two years' post-transplantation. The glomerular filtration rate was significantly higher in the patients who were converted to azathioprine. More allograft biopsies were taken from patients remaining on cyclosporine for suspicion of cyclosporine-related nephrotoxicity and prompted a high rate of late conversions (19%). The relative risk of chronic allograft nephropathy was significantly higher in the group that continued cyclosporine [relative risk, 4.3 (95% CI, 1.4 to 12.9); P = 0.009]. Conversion to azathioprine reduced the need of blood pressure and lipid-lowering drugs.

CONCLUSION

Conversion to a calcineurin inhibitor-free immunosuppressive regiment three months after renal transplantation improved allograft function, reduced the need of cardiovascular risk factor-controlling medication, and reduced the incidence of chronic allograft nephropathy.

Improving estimates of event incidence over time in populations exposed to other events: application to three large databases

The Kaplan-Meier (KM) method is commonly used to estimate the incidence of an event over time. It assumes independence between the event of interest and any competing event that precludes the event of interest to occur. However, when the competing event is death without the event of interest, censoring these patients will affect the incidence of the event of interest by modifying the number of exposed patients, so that KM results will be misleading. Three prospective cohorts were studied: (1) 657 renal transplant recipients, (2) 262 children with acute leukemia who received bone marrow transplants, and (3) 8,353 intensive care patients. The main outcome measures were kidney graft loss, leukemia relapse, and ICU-acquired infection, respectively, with death before the main outcome as the competing event. The incidence of each main outcome was overestimated by the KM method. The magnitude of overestimation ranged from 3% to 30%, and varied with baseline patient characteristics and follow-up duration, with most of this variation being related to the rate of the competing event. A competing-risk approach must be used to analyze the risk of events other than death in cohort studies, particularly when mortality rates are high.

Cardiovascular autonomic dysfunction in uremia

Cardiovascular morbidity and mortality is common in chronic renal failure patients, and may be explained in part by abnormalities in cardiovascular autonomic regulation. This review discusses the results of cardiovascular autonomic function studies in chronic renal failure patients. While covering most methods of assessing autonomic function, we focus particularly on power spectral analysis methods. These newer techniques are non-invasive, reproducible, and allow the rapid assessment of the integrity of cardiovascular autonomic reflexes at the bedside. The abnormalities of parasympathetic, sympathetic and cardiac baroreceptor function seen in dialysis-dependent patients are highlighted, and their significance in intra-dialytic hypotension and cardiovascular mortality as well as the effects of dialysis and transplantation on these parameters examined. Importantly, studies of cardiovascular autonomic dysfunction in pre-dialysis chronic renal failure patients, when abnormalities may be amenable to intervention to prevent progression and premature cardiovascular morbidity and mortality, are reviewed.

Four causes of cadaveric kidney transplant failure: a competing risk analysis

Multiple pathological processes are responsible for renal transplant loss. Development of effective prophylactic regimens requires that risks associated with different outcomes be assessed when several processes act together. A multistate competing risk model that derived multiple endpoint probabilities without averaging impacts of covariates over different outcomes or overestimating fractions of survivors was used to estimate the influence of 16 factors simultaneously on four failure types (acute rejection, chronic rejection, death with a functioning graft and all other causes combined). We analyzed 12,413 non-Black and 5,121 Black patients undergoing primary cadaveric kidney transplantation reported to UNOS during 1994-96. Black recipients generally demonstrated higher rates of failure, but the method provided joint probabilities for each failure type and covariate level. To illustrate, a middle-aged Black recipient had probabilities of 6.5%, 5.9%, 2.6% and 6.6% to experience acute rejection failure, chronic rejection failure, death with a functioning graft and other failures, respectively, within 3 years. The corresponding non-Black's chances were 2.9%, 2.5%, 2.7% and 3.6%. The overall 3-year survival equaled 78.4% [100%-(6.5% + 5.9% + 2.6% + 6.6%)] and 88.3% for Blacks and non-Blacks, respectively. The growing complexity of transplantation will benefit from new analytic approaches that accommodate multiple transitions along diverse paths to eventual graft loss or death.

Long-term survival in renal transplant recipients with graft function

Long-term survival in renal transplant recipients with graft function.

BACKGROUND

Death with graft function (DWGF) is a common cause of graft loss. The risks and determinants of DWGF have not been studied in a recent cohort of renal transplant recipients. We performed a population-based survival analysis of U.S. patients with end-stage renal disease (ESRD) transplanted between 1988 and 1997.

METHODS

Registry data were used to evaluate long-term patient survival and cause-specific risks of DWGF in 86,502 adult (>/=18 years) renal transplant recipients.

RESULTS

Out of 18,482 deaths, 38% (N = 7040) were deaths with graft function. This accounts for 42. 5% of all graft loss. Patient survival with graft function was 97, 91, and 86% at 1, 5, and 10 years, respectively. The risk of DWGF decreased by 67% (RR = 0.33, P < 0.001) between 1988 and 1997. The adjusted rate of DWGF was 4.6, 0.8, 2.2, and 1.4 deaths per 1000 person-years for cardiovascular disease, stroke, infections, and malignancy, respectively. The suicide rate was 15.7 versus 9.0 deaths per 100,000 person-years in the general population (P < 0. 001). In multivariate analysis, the following factors were independently and significantly predictive of DWGF: white recipient, age at transplantation, ESRD caused by hypertension or diabetes mellitus, length of pretransplant dialysis, delayed graft function, acute rejection, panel reactive antibody> 30%, African American donor race, age> 45 years, and donor death caused by cerebrovascular disease.

CONCLUSIONS

Patients with graft function have a high long-term survival. Although DWGF is a major cause of graft loss, the risk has declined substantially since 1990. Cardiovascular disease was the predominant reported cause of DWGF. Other causes vary by post-transplant time period. Attention to atherosclerotic risk factors may be the most important challenge to further improve the longevity of patients with successful renal transplants.

Changes in patterns of 24-hr heart rate variability after kidney and kidney-pancreas transplant

BACKGROUND

Transplantation has been shown to improve cardiorespiratory reflex measures of autonomic function. However, there are limited data on how kidney or kidney-pancreas transplantation influence continuous autonomic modulation of heart rate and the clinical utility of 24-hr heart rate variability (HRV) monitoring.

METHODS

Ninety nondiabetic kidney and 30 diabetic kidney-pancreas transplant recipients underwent 24-hr Holter monitoring before and again at 6 and 12 months posttransplantation. Tapes were submitted for determination of HRV including interbeat variability (the proportion of adjacent R-R intervals having a difference <50 msec, the SD of all R-R intervals for the entire recording, and the SD of the averages of R-R intervals calculated over 5-min blocks for the entire recording) which is associated with vagal function, sudden death, and circadian function, respectively. Power spectral analysis quantified total neural, sympathetic, and parasympathetic modulation of the heart in ln(msec2).

RESULTS

Nondiabetic kidney recipients showed improvement (P< or =0.05) in the SD of the averages of R-R intervals calculated over 5-min blocks (83.2 vs. 95.7 msec) and the SD of all R-R intervals (94.5 vs. 104.4 msec) by 6 months and all groups showed improvement by 12 months. Kidney-pancreas recipients also showed improved total neural (4.35 vs. 4.64) and sympathetic modulation (2.70 vs. 3.13). Kidney-pancreas recipients had significantly poorer values for each measure (P< or =0.05) at all time points.

CONCLUSIONS

Cardiac autonomic neuropathy arises in the presence of uremia and diabetes, with severe dysfunction seen when these conditions occur concomitantly. Improvement in cardiac autonomic function follows both kidney and kidney-pancreas transplantation with more pronounced improvement in the circadian measures. Therefore, circadian measures of 24-hr HRV could be used to monitor the restoration of cardiac autonomic function.

Decreased acute rejection in kidney transplant recipients is associated with decreased chronic rejection

OBJECTIVE

To determine whether a recent decrease in the rate of acute rejection after kidney transplantation was associated with a decrease in the rate of chronic rejection.

SUMMARY BACKGROUND DATA

Single-institution and multicenter retrospective analyses have identified acute rejection episodes as the major risk factor for chronic rejection after kidney transplantation. However, to date, no study has shown that a decrease in the rate of acute rejection leads to a decrease in the rate of chronic rejection.

METHODS

The authors studied patient populations who underwent transplants at a single center during two eras (1984-1987 and 1991-1994) to determine the rate of biopsy-proven acute rejection, the rate of biopsy-proven chronic rejection, and the graft half-life.

RESULTS

Recipients who underwent transplantation in era 2 had a decreased rate of biopsy-proven acute rejection compared with era 1 (p < 0.05). This decrease was associated with a decreased rate of biopsy-proven chronic rejection for both cadaver (p = 0.0001) and living donor (p = 0.08) recipients. A trend was observed toward increased graft half-life in era 2 (p = NS).

CONCLUSIONS

Development of immunosuppressive protocols that decrease the rate of acute rejection should lower the rate of chronic rejection and improve long-term graft survival.

Clostridium difficile colitis after kidney and kidney-pancreas transplantation

OBJECTIVE

To determine the timing and risk factors involved in the development of Clostridium difficile (CD) colitis in kidney and kidney-pancreas transplant recipients.

BACKGROUND DATA

The incidence of CD colitis after kidney and kidney-pancreas transplantation has not been studied in detail. The question of whether the immunosuppressed transplant recipient is more prone to CD colitis and its complications (i.e., megacolon, perforations) and the risk factors involved have not been determined.

METHODS

We retrospectively reviewed our experience in kidney and kidney-pancreas recipients who received transplants between January 1, 1985 and December 31, 1994. We divided these recipients into three groups: pediatric kidney recipients, adult kidney recipients, and kidney-pancreas recipients. For each group, we assessed the timing of infection, primary disease, colitis treatment, and any concurrent complications or risk factors.

RESULTS

Of 1932 transplants, 159 recipients developed post-transplant CD colitis. 132 charts were available for review. Forty-three pediatric kidney recipients developed CD colitis. Their mean age was 3.2 yr; 74% (n = 37) of them developed their colitis during their initial hospital stay, with the mean timing of infection being 33 d. Forty-one (95%) had undergone intra-abdominal placement of the graft, with renal artery anastomoses to the aorta. Fifty adult kidney recipients developed CD colitis. Thirteen (26%) developed colitis during their initial hospital stay, with the mean timing of infection (for all adult kidney recipients) being 15 months. Thirty-nine kidney-pancreas recipients developed CD colitis. Mean timing of infection was 6 months. The overall incidence of CD colitis was 8%, with 16% in the pediatric kidney group, 15.5% in the kidney-pancreas group, and 3.5% in the adult kidney group. The difference in mean timing of infection was significant between the three groups (p < 0.001 for pediatric versus adult kidney recipients, p = 0.002 for pediatric kidney versus kidney-pancreas recipients, and p = 0.2846 for adult kidney versus kidney-pancreas recipients).

CONCLUSION

The incidence of CD colitis is increased in pediatric kidney and kidney-pancreas recipients. Young recipient age ( < 5 yr), female gender, treatment of rejection with monoclonal antibodies, antibiotic use, and intra-abdominal graft placement have been shown to increase the incidence of this disease. Further studies concerning prevention in the high-risk groups are needed.

Metabolism and drug interactions of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors in transplant patients: are the statins mechanistically similar?

3-Hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.88) inhibitors are the most effective drugs to lower cholesterol in transplant patients. However, immunosuppressants and several other drugs used after organ transplantation are cytochrome P4503A (CYP3A, EC 1.14.14.1) substrates. Pharmacokinetic interaction with some of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, specifically lovastatin and simvastatin, leads to an increased incidence of muscle skeletal toxicity in transplant patients. It is our objective to review the role of drug metabolism and drug interactions of lovastatin, simvastatin, pravastatin, fluvastatin, atorvastatin, and cerivastatin. In the treatment of transplant patients, from a drug interaction perspective, pravastatin, which is not significantly metabolized by CYP enzymes, and fluvastatin, presumably a CYP2C9 substrate, compare favorably with the other statins for which the major metabolic pathways are catalyzed by CYP3A.

Effect of long-term immunosuppression in kidney-graft recipients on cancer incidence: randomised comparison of two cyclosporin regimens

BACKGROUND

Long-term administration of cyclosporin carries a risk of renal toxicity, and immunosuppressants are associated with an increased rate of malignant disorders. We undertook an open randomised study of the risks and benefits of two long-term maintenance regimens of cyclosporin in kidney-allograft recipients. The primary endpoint was graft function; secondary endpoints were survival and occurrence of cancer and rejection.

METHODS

231 recipients of a first allograft with at most one previous rejection episode were randomised 1 year after transplantation. Most were receiving cyclosporin and azathioprine. One group received cyclosporin doses adjusted to yield trough blood concentrations of 75-125 ng/mL (low-dose group); the second received doses that yielded trough concentrations of 150-250 ng/mL (normal-dose group). Analysis was by intention to treat.

FINDINGS

At 66 months' follow-up, the low-dose and normal-dose groups were similar in mean serum creatinine (182 [SD 160] vs 184 [157] micromol/L; p=0.9) and mean creatinine clearance (47.5 [25.1] vs 45.3 (22.5] mL/min; p=0.6). Nine of 116 patients in the low-dose group and one of 115 in the normal-dose group had symptoms of rejection (p<0.02). There was no difference between the low-dose and normal-dose groups in survival (95 vs 92%; p=0.7) or graft survival (89 vs 82%; p=0.17) at 6 years. 60 patients developed cancers, 37 in the normal-dose group and 23 in the low-dose group (p<0.034); 66% were skin cancers (26 vs 17; p<0.05).

INTERPRETATION

We found no evidence that halving of trough blood cyclosporin concentrations significantly changes graft function or graft survival. The low-dose regimen was associated with fewer malignant disorders but more frequent rejection. The design of long-term maintenance protocols for transplant recipients based on powerful immunosuppressant combinations should take these potential risks into account.

Impact of cytomegalovirus serology on graft survival in living related kidney transplantation: implications for donor selection

BACKGROUND

The impact of cytomegalovirus in living related kidney transplantation remains controversial. This study considers the implications of donor and recipient cytomegalovirus (CMV) serology for the selection of living related donor.

METHODS

Graft survival was estimated by using the bivariate Kaplan-Meier method and multivariate Cox proportional hazards analysis for 7659 living related first transplantations performed in the United States between 1989 and 1994. The effects of donor CMV serology were estimated with respect to recipient CMV serology and compared with human leukocyte antigen (HLA) matching, transplantation, donor, and recipient characteristics. The implications of these estimates for the selection of living related donors were considered.

RESULTS

From Kaplan-Meier estimates, donor CMV-seropositive kidneys were associated with significantly reduced graft survival for CMV-seronegative recipients (p = 0.0002) but not CMV-seropositive recipients (p = 0.1623). These findings were verified by use of Cox proportional hazards analysis accounting for covariate factors. The impact of donor CMV-seropositive kidneys on CMV-seronegative recipients was similar to one HLA-DR match, greater than one HLA-B match, and significantly greater than one HLA-A match (p = 0.0331).

CONCLUSIONS

Results identify donor CMV serology as an important determinant of transplantation outcome for living related first kidney transplant recipients who are themselves CMV seronegative. Consideration should be given to donor and recipient CMV serology when selecting an appropriate donor for living related kidney transplantation.