Cardiovascular complications after renal transplantation and their prevention

Primary care of the renal transplant patient

There has been a remarkable rise in the number of kidney transplant recipients (KTR) in the US over the last decade. Increasing use of potent immunosuppressants, which are also potentially diabetogenic and atherogenic, can result in worsening of pre-existing medical conditions as well as development of post-transplant disease. This, coupled with improving long-term survival, is putting tremendous pressure on transplant centers that were not designed to deliver primary care to KTR. Thus, increasing numbers of KTR will present to their primary care physicians (PCP) post-transplant for routine medical care. Similar to native chronic kidney disease patients, KTRs are vulnerable to cardiovascular disease as well as a host of other problems including bone disease, infections and malignancies. Deaths related to complications of cardiovascular disease and malignancies account for 60-65% of long-term mortality among KTRs. Guidelines from the National Kidney Foundation and the European Best Practice Guidelines Expert Group on the management of hypertension, dyslipidemia, smoking, diabetes and bone disease should be incorporated into the long-term care plan of the KTR to improve outcomes. A number of transplant centers do not supply PCPs with protocols and guidelines, making the task of the PCP more difficult. Despite this, PCPs are expected to continue to provide general preventive medicine, vaccinations and management of chronic medical problems. In this narrative review, we examine the common medical problems seen in KTR from the PCP's perspective. Medical management issues related to immunosuppressive medications are also briefly discussed.

Management of Hypertension in Renal Transplant Patients: A Comprehensive Review of Nonpharmacologic and Pharmacologic Treatment Strategies

Objective:

To review the guidelines and literature for the treatment of hypertension in renal transplant patients and to provide guidance to practitioners in the selection of appropriate nonpharmacologic and pharmacologic treatment options.

Data Sources:

A PubMed search (January 1948–March 2010) was performed using the search terms hypertension, antihypertensive agents, blood pressure, and cardiovascular disease, in combination with renal transplant and kidney transplant. The search was limited to articles published in English. All relevant peer-reviewed original studies, meta-analyses, guidelines, consensus statements, and review articles were examined. In addition, reference citations from publications identified were reviewed.

Study Selection and Data Extraction:

All literature found was evaluated for inclusion. Review articles as well as prospective and retrospective original research articles were reviewed.

Data Synthesis:

Hypertension after solid organ transplantation is a problem commonly encountered in patients during their posttransplantation clinic visits. Effective management of these patients' hypertension is crucial, as hypertension left untreated may lead to increased morbidity and mortality as well as graft loss. The unique, multifactorial etiology of hypertension in this population makes treatment choices more challenging compared to treatment of a nontransplant patient. Therefore, to guide practitioners in this process, we developed a hypertension management protocol, taking into account the unique considerations faced in the adult renal transplant population. The review guides practitioners from the initial assessment of patients' hypertension through the evaluation and selection of nonpharmacologic and pharmacologic treatment options and provides information about the discontinuation of certain antihypertensive medications. It also provides a concise, but comprehensive review of the major antihypertensive drug classes and economic considerations.

Conclusions:

The management of hypertension in posttransplantation patients is challenging and complicated, yet necessary to prevent morbidity, mortality, and graft loss for these patients. Therapy should be individualized based on patient assessment, response to previous therapy, and economic considerations.

Cyclosporin A and atherosclerosis--cellular pathways in atherogenesis

Cyclosporin A (CsA) is an immunosuppressant drug widely used in organ transplant recipients and people with autoimmune disorders. Long term treatment with CsA is associated with many side effects including hyperlipidemia and an increased risk of atherosclerosis. While its immunosuppressive effects are closely linked to its effects on T cell activation via the inhibition of the nuclear factor of activated T cells (NFAT) pathway, the precise mechanisms underlying its cardiovascular effects appear to involve multiple pathways additional to those relevant for immunosuppression. These include inhibition of calcineurin activity and intracellular cyclophilin peptidylprolyl isomerase and chaperone activities, inhibition of pro-inflammatory extracellular cyclophilin A, and NFAT-independent transcriptional effects. CsA demonstrates complex effects on lipoprotein metabolism and bile acid production, and affects endothelial cells, smooth muscle cells and macrophages, all of which are critical to the atherosclerotic process. Interpretation of the available data is hampered as many experimental models are used to study the effects of CsA in vivo and in vitro, leading to diverse and often contradictory findings. In this review we will describe the cellular mechanisms related to CsA-induced hyperlipidemia and atherosclerosis, with a focus on identifying pro-atherogenic pathways that are distinct from those relevant to its immunosuppressant effects. The potential of CsA analogues to avoid such sequelae will be discussed.

Cardiovascular disease in kidney transplant recipients: the prognostic value of inflammatory cytokine genotypes

BACKGROUND

Cardiovascular disease (CVD) represents the main cause of morbidity and mortality after renal transplantation. In view of the modern paradigm of atherosclerosis as an inflammatory disease, this study investigated the impact of inflammatory cytokine polymorphisms on posttransplant CVD.

METHODS

The association between cytokine polymorphisms and CVD was assessed in a case-control study to identify the differences in genotype distributions between kidney allografts with or without posttransplant CVD. To validate our results in two independent groups, we divided a cohort of 798 renal transplant recipients according to geographic area: an evaluation cohort of 478 patients from Emilia-Romagna and a validation cohort of 320 patients from the rest of Italy. Tumor necrosis factor (TNF)-alpha, transforming growth factor-beta1, interleukin (IL)-10, IL-6, interferon-gamma, and IL-8 polymorphisms were analyzed, and thereafter, the cytokine production genotype was assigned.

RESULTS

In the evaluation cohort, the patients in the CVD and no-CVD groups differed significantly in TNF-alpha and IL-10 genotype frequencies. Using multivariate analyses to test the association with CVD, the TNF-alpha high-producer genotype was associated with a significantly increased cardiovascular risk (odds ratio [OR]=4.41, 95% confidence interval (CI)=2.53-7.67). Conversely, the IL-10 high-producer genotype resulted protective against CVD (OR=0.07, 95% CI=0.02-0.29). These findings were confirmed in the validation cohort where the carriers of the TNF-alpha high-producer genotype proved to be at 2.45-fold increased cardiovascular risk (OR=2.45, 95% CI=1.29-4.63), whereas the IL-10 high-producer genotype was associated with a 0.08-fold reduced risk (OR=0.08, 95% CI=0.02-0.36).

CONCLUSIONS

This work suggests a prognostic value of TNF-alpha and IL-10 genotypes, which might represent cardiovascular risk markers in renal transplant.

New-onset diabetes mellitus after kidney transplantation in Denmark

BACKGROUND AND OBJECTIVES

This study aimed to investigate the development of new-onset diabetes mellitus (NODM) in a prospective study of 97 nondiabetic uremic patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Included were 57 kidney recipients (Tx group, age 39 +/- 13 years) and 40 uremic patients remaining on the waiting list for kidney transplantation (uremic controls, age 47 +/- 11 years). All were examined at baseline before possible transplantation and after 12 months. The prevalence of diabetes, prediabetes, insulin sensitivity index (ISI), and insulin secretion index (Isecr) were estimated using an oral glucose tolerance test with measurements of plasma glucose and plasma insulin.

RESULTS

One year after transplantation NODM was present in 14% (8 of 57) compared with 5% (2 of 40) in the uremic control group (P = 0.01). ISI in the Tx group deteriorated from 6.8 +/- 3.9 before transplantation to 4.9 +/- 2.8 at 12 months after transplantation (P = 0.005), and a slight increase in Isecr from 37 +/- 19 to 46 +/- 22 (P = 0.02) was seen. No significant changes occurred in the uremic controls (ISI was 7.9 +/- 5 and 8.5 +/- 5, and Isecr was 31 +/- 17 and 28 +/- 15). Using multivariate ordinal logistic regression, pre-Tx ISI and age predicted NODM (odds ratios: 0.82, P = 0.01 and 1.06, P = 0.02, respectively).

CONCLUSIONS

One year after kidney transplantation, NODM was present in 14% of patients. This was mainly caused by an increase in insulin resistance and was observed despite improvement in insulin secretion.

Transplantation in diabetic kidney failure patients: modalities, outcomes, and clinical management

Diabetes mellitus (DM) is a common and devastating disease, affecting up to 19.3 million Americans. It is the leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in the United States. Diabetic patients with ESRD have a high incidence of cardiovascular disease and death. For those kidney transplant patients with no history of DM prior to transplantation, the development of new onset diabetes after transplantation (NODAT) also poses a serious threat to both graft and patient survival. Kidney transplantation is the best renal replacement option for diabetic ESRD and has the potential to halt the progression of cardiovascular diseases. Early referral for transplant evaluation is essential for pre-emptive or early kidney transplantation in this cohort of patients. In type 1 DM patients with ESRD, simultaneous pancreas and kidney transplantation (SPK) should be encouraged; and in patients facing prolonged waiting time for SPK transplantation but with an available living donor, living donor kidney transplantation followed by pancreas after kidney transplantation (PAK) is a suitable alternative. Islet transplantation in type 1 diabetics is deemed experimental by Medicare, and easy access to this modality remains restricted to qualified patients enrolled in clinical trials or with private insurance. The optimal management of kidney transplant patients with pre-existent DM or NODAT involves a multi-pronged approach consisting of pharmacological and nonpharmacological intervention to address all potential cardiovascular risk factors such as glycemic and lipid control, blood pressure control, weight loss, and smoking cessation. Finally, re-transplantation should be recommended in suitable kidney transplant patients when the kidney allograft demonstrates continuous and progressive decline in function.

Measuring vs estimating glomerular filtration rate in kidney transplantation

Evaluation of kidney function is crucial in the care of kidney transplant recipients and in the design and interpretation of clinical trials in transplantation. Kidney function is most commonly assessed in both instances using serum creatinine concentration or an estimate of glomerular filtration rate (GFR) based on serum creatinine. These are inexpensive, widely available, and easily administered. Both have significant drawbacks, notably with respect to their inability to accurately identify changes in GFR. Novel markers of GFR such as cystatin C and beta-trace protein show promise as accurate and sensitive markers of GFR but have not yet been adequately evaluated in kidney transplantation. In addition, they are relatively expensive compared to creatinine and their assays are not available in most clinical laboratories. Glomerular filtration rate measurement using a variety of different available tracers and techniques is infrequently used in either clinical care or research protocols because of its cost and cumbersomeness. This review will discuss the merits and pitfalls of the various tools available to evaluate GFR in kidney transplantation.

A phase III study of belatacept versus cyclosporine in kidney transplants from extended criteria donors (BENEFIT-EXT study)

Recipients of extended criteria donor (ECD) kidneys are at increased risk for graft dysfunction/loss, and may benefit from immunosuppression that avoids calcineurin inhibitor (CNI) nephrotoxicity. Belatacept, a selective costimulation blocker, may preserve renal function and improve long-term outcomes versus CNIs. BENEFIT-EXT (Belatacept Evaluation of Nephroprotection and Efficacy as First-line Immunosuppression Trial-EXTended criteria donors) is a 3-year, Phase III study that assessed a more (MI) or less intensive (LI) regimen of belatacept versus cyclosporine in adult ECD kidney transplant recipients. The co-primary endpoints at 12 months were composite patient/graft survival and a composite renal impairment endpoint. Patient/graft survival with belatacept was similar to cyclosporine (86% MI, 89% LI, 85% cyclosporine) at 12 months. Fewer belatacept patients reached the composite renal impairment endpoint versus cyclosporine (71% MI, 77% LI, 85% cyclosporine; p = 0.002 MI vs. cyclosporine; p = 0.06 LI vs. cyclosporine). The mean measured glomerular filtration rate was 4-7 mL/min higher on belatacept versus cyclosporine (p = 0.008 MI vs. cyclosporine; p = 0.1039 LI vs. cyclosporine), and the overall cardiovascular/metabolic profile was better on belatacept versus cyclosporine. The incidence of acute rejection was similar across groups (18% MI; 18% LI; 14% cyclosporine). Overall rates of infection and malignancy were similar between groups; however, more cases of posttransplant lymphoproliferative disorder (PTLD) occurred in the CNS on belatacept. ECD kidney transplant recipients treated with belatacept-based immunosuppression achieved similar patient/graft survival, better renal function, had an increased incidence of PTLD, and exhibited improvement in the cardiovascular/metabolic risk profile versus cyclosporine-treated patients.

Cardiovascular risk profile of patients with acute liver failure after liver transplantation when compared with the general population

BACKGROUND

As opposed to most solid-organ transplant recipients, patients with acute liver failure exhibit a pretransplant health status more comparable with the general population, and any posttransplant cardiovascular risk excess should thus be more attributable to transplantation-related factors alone.

METHODS

This study compared the cardiovascular risk of 77 consecutive patients with acute liver failure at 5 years after liver transplantation with that of the general population using age, sex, and residence area-standardized prevalence ratios (SPR).

RESULTS

At least one cardiovascular risk factor developed in 92% of patients. Treated hypertension, observed in 71% of patients at 5 years, was more common among patients than controls (SPR, 2.73; 95% confidence interval [CI], 2.06-3.55), whereas the 61% prevalence of dyslipidemia and 3% prevalence of impaired fasting glucose were significantly less frequent among patients (SPR, 0.69; 95% CI, 0.51-0.92 and SPR, 0.29; 95% CI, 0.04-1.00). The 5-year prevalence of diabetes (10%), overweight (32%), and obesity (13%) deviated nonsignificantly from controls (SPR 1.90, 0.85, and 0.58). Antibody therapy associated with a 1.49-fold increase in the risk of hypertension (95% CI, 1.15-1.94) and a 6.43-fold increase in the risk of diabetes (95% CI, 1.18-34.9). Immunosuppression-type, steroids, acute rejection, retransplantation, or graft steatosis revealed nonsignificant risk alterations.

CONCLUSIONS

Liver transplantation and associated immunosuppression evidently cause hypertension, and possibly elicit diabetes in susceptible individuals. Conversely, the often reported transplantation-associated increased burden of overweight/obesity and dyslipidemia might relate mostly to other factors.

Prevalence evolution and impact of cardiovascular risk factors on allograft and renal transplant patient survival

OBJECTIVE

The prevalence of traditional cardiovascular risk factors in renal transplantation is high. Studying the evolution of cardiovascular risk factors over time may help us to design better strategies to control them. The relative impact of traditional cardiovascular risk factors on allograft survival and mortality in transplant recipients is not clear. This study was performed to determine the incidence and risk factors for allograft survival and mortality among renal transplant patients.

PATIENTS AND METHODS

We enrolled 250 patients who had undergone transplantation between 1980 and 2004. They were followed for various periods, and we analyzed the impact of traditional and nontraditional risk factors on renal allograft survival.

RESULTS

The prevalence of hypertension was >80% during all the follow-up periods. Blood pressure diminished, antihypertensive drug prescription increased, and 15% of patients had adequate blood pressure control during follow-up. The prevalence of pretransplant diabetes mellitus was 6.8%; the incidence of posttransplant diabetes mellitus (PTDM) was 14.2%. The prevalence of PTDM increased over the course of patient evolution. The prevalence of dyslipidemia was in all cases >70%; total cholesterol and low-density lipoprotein (LDL)-cholesterol decreased; prescription of statins increased; and the percentage of patients with good lipid control also increased. The 25% prevalence of active smoking at the time of transplantation decreased to 13.6% at 10 years posttransplantation. The mean patient follow-up was 8 +/- 4.6 years. Sixty-five patients (26%) lost their grafts and 40 (16%) died during follow-up. Donor age, exercise, diastolic blood pressure, renal function, and albumin levels were independent risk factors for graft loss. Charlson comorbidity index at transplantation, recipient and donor ages, exercise, diastolic blood pressure, and LDL-cholesterol posttransplantation were independent risk factors for mortality among renal transplant recipients.

CONCLUSION

Blood pressure and lipid control improved during follow-up, however, insufficiently among renal transplant patients. The prevalence of diabetes gradually increased, and the incidence of smoking cessation was low. Diastolic blood pressure, exercise, and albuminemia were the most significant modifiable cardiovascular risk factors for renal allograft survival. Diastolic blood pressure, LDL-cholesterol level, and exercise were the most relevant modifiable cardiovascular risk factors for the survival of renal transplant patients.

Markers of the hepatic component of the metabolic syndrome as predictors of mortality in renal transplant recipients

Cardiovascular disease (CVD) is a leading cause of mortality in renal transplant recipients (RTRs). Metabolic syndrome (MS) is highly prevalent in RTRs. Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic component of MS. We investigated associations of NAFLD markers with MS and mortality. RTRs were investigated between 2001 and 2003. NAFLD markers, alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and alkaline phosphatase (AP) were measured. Bone and nonbone fractions of AP were also determined. Death was recorded until August 2007. Six hundred and two RTRs were studied (age 52+/-12 years, 55% men). At baseline 388 RTRs had MS. Prevalence of MS was positively associated with liver enzymes. During follow-up for 5.3[4.5-5.7] years, 95 recipients died (49 cardiovascular). In univariate Cox regression analyses, GGT (HR=1.43[1.21-1.69], p<0.001) and AP (HR=1.34[1.11-1.63], p=0.003) were associated with mortality, whereas ALT was not. Similar associations were found for cardiovascular mortality. Adjustment for potential confounders, including MS, diabetes and traditional risk factors did not materially change these associations. Results for nonbone AP mirrored that for total AP. ALT, GGT and AP are associated with MS. Of these three enzymes, GGT and AP are associated with mortality, independent of MS. These findings suggest that GGT and AP are independently related to mortality in RTRs.

KDIGO clinical practice guideline for the care of kidney transplant recipients

The 2009 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline on the monitoring, management, and treatment of kidney transplant recipients is intended to assist the practitioner caring for adults and children after kidney transplantation. The guideline development process followed an evidence-based approach, and management recommendations are based on systematic reviews of relevant treatment trials. Critical appraisal of the quality of the evidence and the strength of recommendations followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. The guideline makes recommendations for immunosuppression, graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy, and other complications that are common in kidney transplant recipients, including hematological and bone disorders. Limitations of the evidence, especially on the lack of definitive clinical outcome trials, are discussed and suggestions are provided for future research.

Fasting plasma glucose and glycosylated hemoglobin in the screening for diabetes mellitus after renal transplantation

BACKGROUND

Fasting plasma glucose (fPG) is recommended to identify new-onset posttransplant diabetes mellitus (PTDM), but an oral glucose tolerance test (OGTT) has higher diagnostic sensitivity. We aimed to assess the accuracy of fPG and glycosylated hemoglobin (HbA1c) for the selection of patients who should undergo a diagnostic OGTT 10 weeks after renal transplantation.

METHODS

A total of 1571 renal transplant recipients without prior diabetes underwent an OGTT 10 weeks after transplantation. Receiver operating characteristic analyses were used to identify optimal thresholds to incite further diagnostic tests. A sensitivity level of 80% was chosen for screening purpose.

RESULTS

We diagnosed PTDM in 213 (14%) patients of whom 109 (51%) were identified by 2-hr plasma glucose more than or equal to 11.1 mmol/L alone, 35 (17%) by fPG alone, and 69 (32%) by both criteria. Receiver operating characteristic analysis revealed an area under the curve of 0.761 (95% confidence interval 0.714-0.809) for fPG and 0.817 (95% confidence interval 0.758-0.876) for HbA1c. Performing an OGTT on patients with an fPG more than or equal to 5.3 mmol/L or HbA1c more than or equal to 5.8% predicted diabetes with 81% and 83% sensitivity, requiring 49% and 41% of the patients to be tested, respectively. The combined criterion fPG more than or equal to 5.0 mmol/L and HbA1c more than or equal to 5.7%, provided a similar sensitivity (79%) from testing only 29% of the population.

CONCLUSION

We conclude that patients with an fPG between 5.3 and 6.9 mmol/L or HbA1c more than or equal to 5.8%, alternatively an fPG more than or equal to 5.0 mmol/L combined with HbA1c more than or equal to 5.7% in the early posttransplant period should undergo an OGTT for diagnostic verification of PTDM.

Steroid-free maintenance immunosuppression in kidney transplantation: is it time to consider it as a standard therapy?

Steroid-free immunosuppression in kidney transplantation has been gaining popularity over the past decade, as documented by a continuous and steady rise in the number of kidney transplant patients discharged on steroid-free regimens. This increased interest in steroid-free immunosuppression is fueled by the recognition that half of transplant loss is related to patient death due to cardiovascular disease and/or infectious complications and that the long-term use of steroids contributes to such elevated cardiovascular morbidity and mortality. The availability of newer and more potent immunosuppressive agents has furthered such interest. Many clinical trials over the past two decades have demonstrated the feasibility of steroid-free regimens, at the expense of a slight increase in the rate of acute rejection, which is an important end point in any clinical trial of relatively short duration. The largest epidemiological study to date has reassured the transplant community that the selective use of steroid-free immunosuppression in kidney transplant patients provides no inferior outcome in patient and graft survival at intermediate term. Steroid-free regimens have the potential to improve cardiovascular risk profile. The challenges that remain are to identify the subset of kidney transplant patients who may not benefit from steroid-free immunosuppression and to demonstrate the survival advantage of steroid-free immunosuppresion in suitable kidney transplant candidates.

The scope of coronary heart disease in patients with chronic kidney disease

Chronic kidney disease (CKD) affects approximately 13% of the U.S. population and is associated with increased risk of cardiovascular complications. Once renal replacement therapy became available, it became apparent that the mode of death of patients with advanced CKD was more likely than not related to cardiovascular compromise. Further observation revealed that such compromise was related to myocardial disease (related to hypertension, stiff vessels, coronary heart disease, or uremic toxins). Early on, the excess of cardiovascular events was attributed to accelerated atherosclerosis, inadequate control of blood pressure, lipids, or inflammatory cytokines, or perhaps poor glycemia control. In more recent times, outcome research has given us further information that relates even lesser degrees of renal compromise to an excess of cardiovascular events in the general population and in those with already present atherosclerotic disease. As renal function deteriorates, certain physiologic changes occur (perhaps due to hemodynamic, inflammatory, or metabolic changes) that decrease oxygen-carrying capacity of the blood by virtue of anemia, make blood vessels stiffer by altering collagen or through medial calcinosis, raise the blood pressure, increase shearing stresses, or alter the constituents of atherosclerotic plaque or the balance of thrombogenesis and thrombolysis. At further levels of renal dysfunction, tangible metabolic perturbations are recognized as requiring specific therapy to reduce complications (such as for anemia and hyperparathyroidism), although outcome research to support some of our current guidelines is sorely lacking. Understanding the process by which renal dysfunction alters the prognosis of cardiac disease might lead to further methods of treatment. This review will outline the relationship of CKD to coronary heart disease with respect to the current understanding of the traditional and nontraditional risk factors, the role of various imaging modalities, and the impact of coronary revascularization on outcome.

Metabolic syndrome and coronary artery calcification in renal transplant recipients

BACKGROUND

Coronary artery calcification (CAC) and metabolic syndrome (MS) have been associated with increased cardiovascular risk. The study objective was to examine the association of MS with CAC presence and progression in renal transplant recipients.

METHODS

We measured the CAC progression in asymptomatic recipients who had no prior history of coronary artery disease.

RESULTS

MS was common (55.4%). Median CAC scores were 0, 33.1, 98, and 261.9 for patients with one, two, three, and four or more positive components of the MS, respectively. Severe CAC scores were more common in recipients with MS (P=0.04). Although recipients with MS had higher mean CAC scores at baseline and significant CAC progression (483 [590.6] vs. 619 [813.8], P=0.01), MS was not an independent predictor of annualized rate of CAC change in a multivariate model.

CONCLUSION

Future studies to evaluate if MS treatment improves cardiovascular outcomes are imperative.

The impact of new-onset diabetes on arterial stiffness after renal transplantation

New-onset diabetes after renal transplantation (NODAT) is known to be a potent risk factor for cardiovascular events. We therefore investigated the incidence and risk factors for NODAT, and evaluated surrogate endpoints of atherosclerosis in Japanese patients with stable renal function after renal transplantation. Seventy-nine patients were enrolled in the study, and a 75 g oral glucose tolerance test (OGTT) was performed in subjects excluding patients with known NODAT. We evaluated the risk factors for NODAT and the degree of atherosclerosis, determined by brachial-ankle pulse wave velocity (baPWV), ankle-brachial blood pressure index (ABPI) and intima-media thickness (IMT) of the carotid artery. Eleven patients diagnosed as NODAT had significantly higher fasting plasma glucose before transplantation, blood pressure, and incidence of hepatitis C virus (HCV) infection than patients without NODAT. Multivariate regression analysis revealed that the independent determinant of NODAT was fasting plasma glucose pre-transplantation, HCV infection and systolic blood pressure. The baPWV in patients with NODAT was significantly higher compared to that in patients without NODAT. In addition, the independent determinant of baPWV evaluated by multivariate regression analysis was an increase in systolic blood pressure and age, and a decrease of adiponectin levels. In conclusion, we found that high fasting plasma glucose prior to transplantation, HCV infection and high blood pressure are risk factors for NODAT in Japanese patients after renal transplantation. Since NODAT patients have advanced arterial stiffness probably due to high blood pressure, strict control of blood pressure will be important for preventing the development of cardiovascular disease in NODAT.

Dyslipidemia can be controlled in diabetic as well as nondiabetic recipients after kidney transplant

BACKGROUND

Patients with diabetes have been reported to have greater dyslipidemia after kidney transplant (KTX). Because postKTX management of diabetes has changed markedly since those reports, we hypothesized that lipids can be controlled as well in diabetic as in nondiabetic recipients.

METHODS

We compared lipid levels up to 2 years after KTX (n=192) between diabetic and nondiabetic recipients. The cohort was subdivided into nondiabetic (nonDM-K; n=123), type 2 (DM2-K; n=33), or type 1 diabetes after KTX (DM1-K; n=14), or type 1 after kidney-pancreas transplant (DM1-KP; n=22).

RESULTS

Mean age and body mass index of DM2-K were greater than the others (P<0.01), and diabetes groups had a higher pretransplant A1C than nonDM-K (P<0.001). After KTX, lipid levels were not higher in diabetic than in nondiabetic recipients, and did not increase in any group. Total and low-density lipoprotein cholesterol levels decreased in DM1-K (P<0.001), high-density lipoprotein levels decreased in DM1-KP (P=0.02), and triglyceride levels were unchanged after KTX for all groups. A1C improved in DM1-K and DM1-KP (P<0.0001). There was less improvement in lipid levels with tacrolimus-sirolimus immunosuppression than with other steroid-containing regimens (P<0.05).

CONCLUSIONS

Multiple mechanisms may contribute to better lipid levels in both groups as well as the lack of difference between diabetic and nondiabetic recipients compared with what has been reported previously: greater use of and more effective lipid-lowering agents, no significant weight gain, no difference in renal function between groups, and better control of glucose in the diabetic group. Thus, overall, lipids can be controlled as well in diabetic as in nondiabetic KTX recipients.

Cyclosporine A and Rapamycin induce in vitro cholesteryl ester transfer protein activity, and suppress lipoprotein lipase activity in human plasma

PURPOSE

Cyclosporine A (CsA), Rapamycin (RAPA), Tacrolimus (FK-506) and Mycophenolate mofetil (MMF) are immunosuppressants that are widely used in solid organ transplant patients. However, some of these drugs have been reported to cause dyslipidemia in patients. Our aim was to determine the effects of these drugs on in vitro cholesteryl ester transfer protein (CETP), hepatic lipase (HL) and lipoprotein lipase (LPL) activity within human plasma.

METHODS

We measured CETP activity in human normolipidemic plasma with and without drug treatment, by measuring the incorporation of labeled cholesteryl ester into lipoproteins. To further confirm the result, we also measured recombinant CETP (rCETP) activity with and without drug treatment. We measured HL and LPL activity in post-heparin normal human plasma in the presence and absence of the drugs by measuring the release of fatty acids from radiolabeled triolein.

RESULTS

We found an increase in CETP activity in human normolipidemic plasma and rCETP treated with CsA and RAPA. By contrast, CETP activity was not altered significantly in the presence of FK-506 and MMF. LPL activity in post-heparin normal human plasma was suppressed following the co-incubation with CsA, RAPA, FK-506 or MMF whereas HL activity remained unaffected.

CONCLUSIONS

The increase in CETP activity and suppression in LPL activity following CsA and RAPA treatment observed in the present study may be associated with elevated LDL cholesterol levels and hypertriglyceridemia seen in patients administered these drugs.

Management of cardiovascular disease in renal transplant recipients

Cardiovascular disease is a major cause of graft loss and the leading cause of death in renal transplant recipients. Although there are robust data on the frequency of risk factors and their contributions to cardiovascular disease in this population, few trials have demonstrated the benefit of modifying these risk factors to reduce cardiovascular events. Nevertheless, it is widely accepted that the clinical acumen filtered through the best available studies in the general population be used to treat individual renal transplant recipients given their high cardiovascular mortality. Transplant task forces and the Kidney Disease Outcomes Quality Initiative have created guidelines for this purpose. This review examines the data available for prevention and treatment of major risk factors contributing to cardiovascular disease in renal transplant recipients. The contribution of immunosuppressive agents to each risk factor and the evidence to support lifestyle modification as well as drug therapy are examined. Reducing cardiovascular risk factors requires an integrative approach that is best accomplished by a team of health care professionals. It creates a significant challenge but one that must be met if allograft survival is to improve.

Aortic stiffness of kidney transplant recipients correlates with donor age

Increased aortic stiffness is a major factor responsible for the high cardiovascular mortality in patients with end-stage renal disease, but the impact of kidney transplantation on recipient aortic stiffness remains poorly defined. The use of expanded-criteria kidney donors is associated with decreased recipient survival compared with the use of standard-criteria donors, although the underlying mechanisms are incompletely understood. It was hypothesized that donor characteristics may affect recipient aortic stiffness, which may contribute to cardiovascular mortality in these patients. Aortic stiffness was evaluated by measurement of carotid-femoral pulse wave velocity in 74 cadaveric kidney recipients at 3 and 12 mo after transplantation. At 3 mo, aortic stiffness was associated exclusively with recipient-related factors: Age, gender, and mean BP. At 12 mo, age of the donor kidney emerged as an additional determinant. The change in aortic stiffness between 3 and 12 mo strongly correlated with donor age; stiffness improved in recipients of young kidneys (first tertile of donor age) and worsened in recipients of older kidneys (upper tertile of donor age). At 12 mo, the carotid-femoral pulse wave velocity was >1 m/s higher in recipients of the oldest kidneys than in the recipients of younger kidneys. The association between donor age and aortic stiffness was independent of recipient age, gender, mean BP, pretransplantation dialysis duration, conventional cardiovascular risk factors, medication, posttransplantation events, and GFR. These results demonstrate that the impact of kidney transplantation on recipient aortic stiffness is dependent on donor age and suggest that ongoing damage to large arteries might contribute to the mechanism underlying the association of old-donor kidneys and increased cardiovascular mortality.

Assessment and management of a patient with a renal transplant

Renal transplant recipients admitted on the medical take can be challenging for the clinician. Immunosuppressant medications, reduced renal functional reserve, increased vascular risk, and propensity to uncommon infections and malignancies all contribute to make management more complex than in other patients. This article reviews salient points in the management of such patients by the non-specialist.

New onset diabetes mellitus after solid organ transplantation

This article presents an overview of the literature on the current diagnostic criteria for new onset diabetes mellitus after transplantation (NODAT) and discusses suggested risk factors for the development of NODAT, its potential pathogenic mechanisms, and its impact on post-transplant outcomes after solid organ transplantation. Suggested guidelines for early identification and management of NODAT are also discussed.

Subclinical inflammation in renal transplant recipients: impact of cyclosporine microemulsion versus tacrolimus

BACKGROUND

Renal insufficiency and renal transplant (RT) provoke a microinflammatory state that leads to increased atherosclerosis. It is not fully known whether calcineurin inhibitors (CNIs) play a role in the inflammation observed in these patients or whether any differences exist between CNIs.

OBJECTIVES

The study aimed to establish differences in the inflammatory state of two groups treated with cyclosporine microemulsion (CyA) or tacrolimus (TC).

PATIENTS AND METHODS

This prospective study included 81 RT patients divided into two groups according to the CNI: CyA group, n = 35 versus TC group, n = 46. The markers of inflammation (MIF) were determined preRT and at 3 and 12 months' postRT: C-reactive protein (CRP), serum amyloid protein A (SAA), interleukin-6 (IL-6), soluble interleukin-2 receptor (sIL-2R), tumor necrosis factor-alpha (TNF-alpha), and pregnancy-associated plasma protein A (PAPP-A). Samples were collected in stable patients in the absence of rejection, active infection, or inflammatory processes.

RESULTS

No significant differences existed between the markers of inflammation in the two treatment groups prior to transplantation. At 3 months' posttransplant, patients treated with CyA showed significantly higher levels of IL-6 (P = .05), SAA (P = .03), and sIL-2R (P = .008) compared with patients treated with TC. These differences were maintained for IL-6 (P = .03) and sIL-2R (P = .027) at 12 months' posttransplant. A multivariate analysis at 3 months showed that only age [OR 10.1; CI (95% 2.6-38.4); P = .001], SAA [OR 4.8; IC (95% 1.4-16.5); P = .015], and sIL-2R [OR 4.9; IC (95% 1.5-16.2); P = .009] were independent predictors of the CNI used. At 12 months, age [OR 3.7; IC (95% 0.9-14.2] and sIL-2R [OR 6.04; IC (95% 1.5-23); P = .006] continued to be independent predictors.

CONCLUSIONS

Patients treated with CyA displayed significantly higher levels of inflammatory markers (IL-6, SAA, sIL-2R) at 3 and 12 months' posttransplantation, independent of age, gender, time on dialysis, diabetes mellitus (preRT and de novo postRT), and renal function measured by serum creatinine.

Risk factors and prognosis for proteinuria in renal transplant recipients

INTRODUCTION

Proteinuria in renal transplant recipients has been recognized as a risk factor of progression of chronic allograft nephropathy and for cardiovascular disease, the main causes of transplant failure.

PATIENTS AND METHODS

We analyzed the risk factors for persistent proteinuria (>0.5 g/day) among 337 kidney allograft recipients with a minimum follow-up of 6 months, among a series of 375 transplants performed during a decade, as well as their association with allograft and patient survivals. Patients with proteinuria greater than 0.5 g/d were treated with angiotensin-converting enzyme inhibitors (ACEI) and/or angiotensin-receptor blockers.

RESULTS

After a mean follow-up of 53.35 +/- 52.63 months, 68 patients (20.17%) had persistent proteinuria greater than 0.5 g/d. Female patients (P = .012), body mass index (BMI) >25 (P = .008), pretransplant HLA sensitization (P = .039), and delayed graft function (DGF; P = .001) were associated with proteinuria. Induction treatment with antithymocyte globulin (P = .030) and treatment with tacrolimus instead of cyclosporine (P = .046) were associated with an increased risk of proteinuria. Multivariate analysis confirmed the independent value of DGF (RR = 2.23; 95% confidence interval [CI] 1.22 to 4.07; P = .009) and BMI >25 (RR = 1.968; 95% CI 1.05 to 3.68; P = .035) to predict postransplant proteinuria. The mean values of serum creatinine (P = .000) and systolic blood pressure (P < .05) were persistently higher from the early stages after transplantation in the proteinuric group. Graft survival at 5 years was 69% among patients who developed proteinuria and 93% in those without proteinuria (P = .000), with no differences in patient survival (P = .062).

CONCLUSION

Proteinuria in renal transplant recipients was related to immunological and nonimmunological factors, some of which, such as hypertension and obesity could be modifiable. Proteinuria in renal transplant recipients predicted a worse allograft survival despite of intensive treatment of hypertension including ACEI/angiotensin-receptor blockers.

Effect of apolipoprotein E polymorphism on renal transplantation

INTRODUCTION

Dyslipidemia is an important cardiovascular risk factor and is implicated in the pathogenesis of chronic graft failure in renal transplant recipients. Apolipoprotein E (apoE), a hepatic glycoprotein involved in lipid metabolism, has been associated with hypercholesterolemia and premature coronary disease.

AIM

This study assessed the impact of apoE polymorphism on the evolution of renal transplant recipients.

METHODS

A total of 517 patients (age, 47 +/- 14 years; 62% men), who had undergone renal transplantation at least 12 months before enrollment, were assessed (mean follow-up, 5.4 +/- 2.2 years). ApoE polymorphisms (E2, E3, and E4 alleles) were analyzed using polymerase chain reaction (PCR) using genomic DNA. Donor-recipient clinical variables were assessed using univariate methods and Cox multivariate regression model.

RESULTS

Genotype frequency was as follows: E2/E2 <1%, E2/E3 10%, E3/E3 71%, E2/E4 2%, E3/E4 16%, and E4/E4 1%, with no differences between sexes. In the univariate study, E2/E4, E3/E4, and E4/E4 genotypes were related with poorer patient survival (P = .0045). In the multivariate study, the E4 allele was associated with a higher independent risk of graft loss (odds ratio [OR], 3.23; 95% confidence interval [CI], 1.44-7.21; P < .0001) and death of the patient (OR, 16.03; 95% CI, 3.28-75.18; P < .0001), but only in patients older than 60 years of age. In patients with the E4 allele, 45% of deaths were due to cardiovascular causes.

CONCLUSIONS

The genetic polymorphism of apoE (E4 allele) has an independent negative impact on patient and graft survival in the long term, particularly in older patients.

Decreased Serum Retinol Is Associated with Increased Mortality in Renal Transplant Recipients

Background: Vitamin A plays a central role in epithelial integrity and immune function. Given the risk of infection after transplantation, adequate vitamin A concentrations may be important in patients with a transplant. We assessed whether there was an association between retinol concentration and all-cause mortality in renal transplant recipients.

Methods: We recruited 379 asymptomatic renal transplant recipients between June 2000 and December 2002. We measured serum retinol at baseline and collected prospective follow-up data at a median of 1739 days.

Results: Retinol was significantly decreased in those renal transplant recipients who had died at follow-up compared with those who were still alive at follow-up. Kaplan–Meier analysis showed that retinol concentration was a significant predictor of mortality. In multivariate Cox regression analysis, decreased retinol concentration remained a statistically significant predictor of all-cause mortality after adjustment for traditional cardiovascular risk factors, high-sensitivity C-reactive protein, and estimated glomerular filtration rate.

Conclusions: Serum retinol concentration is a significant independent predictor of all-cause mortality in renal transplantation patients. Higher retinol concentration might impart a survival advantage via an antiinflammatory or anti-infective mechanism.

Quality of life after kidney transplantation: the bright side of life?

This review describes the state-of-the-art on quality of life (QOL) in kidney transplant (KTx) recipients. More specifically, posttransplant QOL is compared with the pretransplant evaluation, with other chronically ill patient populations, and with healthy subjects. Determinants, consequences, and potential interventions to improve QOL are also summarized. However, because of the methodological diversity of published articles, this review starts with addressing some conceptual and methodological concerns surrounding research on QOL in general and in KTx recipients specifically. The ultimate goal of this review was to identify the gaps in the state-of-the-art evidence and to provide some guidelines for conduct of research in the future.

Cardiovascular disease posttransplant

Renal transplantation is currently the preferred treatment modality for virtually all suitable candidates with end-stage renal disease. Compared with dialysis, kidney transplantation improves both patient survival and quality of life. Nonetheless, posttransplant cardiac complications are associated with increased morbidity and mortality after renal transplantation. When compared with the general population, cardiovascular mortality in transplant recipients is increased by nearly 10-fold among patients within the age range of 35 and 44 and at least doubled among those between the ages of 55 and 64. Although renal transplantation ameliorates cardiovascular disease risk factors by restoring renal function, it introduces new cardiovascular risks derived, in part, from immunosuppressive medications. We provide an overview of the literature on conventional and unconventional cardiovascular disease risk factors after renal transplantation, and discuss an approach to their medical management.

Impact of Carotid Atherosclerosis as Assessed by B-Mode Ultrasonography on the Evolution of Kidney Transplantation

Carotid arteriosclerosis is a marker of cardiovascular risk in the general population. Cardiovascular disease is highly prevalent in kidney transplant recipients. This study analyzed the impact of arteriosclerotic carotid lesions on the evolution of renal transplant recipients.

METHODS

This prospective study was performed in 70 patients with renal transplantations (mean age 52 +/- 12 years; 67% men (n = 47). High-resolution B-mode ultrasonography (7.5 MHz) of both carotid arteries was performed at baseline to assess carotid caliber, mean and maximum intima-media thickness (IMT), presence of arteriosclerotic plaques (number and maximum height), and percentage stenosis. We analyzed the impact of carotid arteriosclerosis and various donor-recipient clinical covariables on long-term patient and graft survival.

RESULTS

Mean follow-up was 9.7 +/- 2.5 years (2-14). Atheroma plaques were detected in 74% of patients (n = 52). The mean number of plaques was 3.96 +/- 2.88 and maximum plaque height was 2.49 +/- 0.97 mm. IMT was 0.71 +/- 0.21 mm (0.4-1.5) with 27% of patients (n = 19) having an IMT value greater than 0.8 mm. Sonographic signs of occlusion were evident in 13% (n = 9) and the mean occlusion was 33 +/- 11% (range 20%-45%). The presence of plaques was significantly associated with age (P = .002), hypertension and diabetes (P = .016), and hypercholesterolemia (P = .01). There was an association between age and arterial wall thickness (P = .042). Acute rejection was an independent risk factor for graft loss (OR 8.14, P = .003). The multivariate study identified carotid wall thickness as an independent risk factor for patient death (OR 12.7, P = .017).

CONCLUSION

Carotid arteriosclerosis is highly prevalent among renal transplant recipients. Carotid lesions were an independent risk factor for long-term patient death. High-resolution ultrasound imaging of the carotid arteries was a useful, noninvasive diagnostic technique for accurate assessment of cardiovascular risk in renal transplant recipients.

Sirolimus Monotherapy as Maintenance Immunosuppression: Single-Center Experience in 50 Kidney Transplant Patients

INTRODUCTION

Chronic allograft nephropathy, cardiovascular mortality, and posttransplant malignancy are complications of conventional immunosuppression after kidney transplantation. We reported the feasibility of maintenance monotherapy with sirolimus (SRL) in a pilot experience. The aim was to study safety and feasibility of SRL maintenance monotherapy in 50 kidney transplant patients.

METHODS

All patients from our center with at least 6 months follow-up on SRL monotherapy were included. During the first month after start of SRL monotherapy, follow-up visits were performed weekly, then each month for the following 2 months. Each follow-up visit included a physical exam and laboratory screening.

RESULTS

Mean follow-up on SRL monotherapy was 34.7 +/- 14.9 months. The time between transplantation until start of monotherapy was 7.7 +/- 3.3 years. No rejections occurred. During follow-up, two patients died of cardiovascular disease (already diagnosed before monotherapy); one, of previously diagnosed posttransplant malignancy and one, of hepatitis C-related liver failure. Glomerular filtration rate (GFR) was 53 mL/min x 1.73 m2 at start of monotherapy and 50 mL/min x 1.73 m2 after 4 years. Proteinuria was 632 +/- 562 mg/24 hours at 4 years. During the follow-up, no significant changes in the lipid profile, glycemia, or hemoglobin occurred.

CONCLUSIONS

Sirolimus monotherapy is safe in a selected group of immunological low-risk patients without increasing the risk of rejection.

Prevalence of Risk Factors for Cardiovascular Disease in Brazilian Renal Transplant Recipients

OBJECTIVE

Cardiovascular disease (CVD) is the major cause of death in renal transplant recipients. The aim of this study was to assess the prevalence of CVD risk factors among Brazilian adult renal transplant recipients.

METHODS

This cross-sectional study included 192 cases in which the evaluated CVD risk factors were hypertension, diabetes mellitus, impaired fasting glucose, obesity, overweight, abdominal obesity, metabolic syndrome, and dyslipidemia.

RESULTS

Hypertension, abdominal obesity, and hypercholesterolemia were the highest prevalent risk factors among the total population with prevalences of approximately 60%. The prevalence of obesity was significantly higher (P < .001) in recipients with normal graft function (28%) than in those with impaired graft function (7%). Abdominal obesity was also higher (P = .02) in the normal graft function group (77%) than in recipients with creatinine clearance (CrCl) values <60 mL/min (61%). There were positive, significant correlations between CrCl and body mass index (BMI) (r = 0.47; P < .001) and between CrCl and waist circumference (WC) (r = 0.44; P < .001). BMI (r = 0.31; P < .001) and WC (r = 0.27; P < .001) were also positively associated with triglyceride levels. There were negative associations of high-density lipoprotein (HDL)-cholesterol (HDL-c) with BMI (r = -0.28; P < .01) and WC (r = -0.32; P < .01).

CONCLUSIONS

The high prevalence of CVD risk factors among renal transplant recipients emphasizes the importance of taking appropriate therapeutic measures to reduce modifiable risk factors, reducing CVD and its consequences.