Transplanted Kidney Function Evaluation

Early and late assessment of renal allograft dysfunction using intravoxel incoherent motion (IVIM) and diffusion-weighted imaging (DWI): a prospective study

PURPOSE

To evaluate the ability of the Intravoxel Incoherent Motion (IVIM) and monoexponentially ADC in renal allograft function in the early and late phases of transplantation, and to predict their effectiveness in discrimination of the graft pathology.

METHODS

This is a prospective study included participants scanned with quantitative diffusion and perfusion sequences on a 3-T MR scanner (Philips, Ingenia); the ADC and IVIM parameters; were calculated. Correlations and regression analysis with the eGFR, transplantation periods, and pathology were assessed.

RESULTS

This study included 105 renal allograft recipients (85 males, and 20 females with mean age = 32.4 ± 11.9 years and age range = 22-61 years). There was a significant positive correlation between the whole parameters of the ADC and IVIM with eGFR however, the cortical parameters showed higher significant correlation coefficients (p < 0.001). Regression analysis revealed the most significant model can predict eGFR groups included cortical pseudo diffusion (D*) and cortical ADC (p < 0.001). In graft dysfunction eGFR was 61.5 ml/min and normal graft was 64 ml/min. This model demonstrates a high performance of an AUC 96% [0.93-0.97]. In the late transplantation, there is a higher correlation with D* compared to ADC, p-values = 0.001.

CONCLUSION

IVIM and ADC Values are significant biomarkers for renal allograft function assessment, cortical ADC, and D* had the highest performance even in situations with mild impairment that is not affect the eGFR yet as cases of proteinuria with normal eGFR. Furthermore, D* is superior to ADC in the late assessment of the renal transplant.

Management of an aneurysmal arteriovenous fistula in kidney transplant recipients

Aneurysms remain the most common complication of an arteriovenous fistula created for dialysis access. The management of an aneurysmal arteriovenous fistula (AAVF) in kidney transplant recipients remains contentious with a lack of clear clinical guidelines. Recipients of a functioning graft do not require the fistula for dialysis access, however risk of graft failure and needing the access at a future date must be considered. In this review we outline the current evidence in the assessment and management of a transplant recipient with an AAVF. We will describe our recommended five-step approach to assessing an AAVF in transplant patients; 1.) Define AAVF 2.) Risk assess AAVF 3.) Assess transplant graft function and future graft failure risk 4.) Consider future renal replacement therapy options 5.) Vascular mapping to assess future vascular access options. Then we will describe the current therapeutic options and when they would most appropriately be employed.

Exercise and Prediabetes After Renal Transplantation (EXPRED-I): A Prospective Study

BACKGROUND

Post-transplant diabetes mellitus (PTDM) beyond 12 months (late PTDM) is a severe complication after renal transplantation. Late PTDM develops mostly in subjects with prediabetes. Although exercise may have a potential role in preventing late PTDM, there are no previous data on the effect of exercise in patients with prediabetes.

MATERIAL AND METHODS

The design was a 12-month exploratory study to test the capacity of exercise in reverting prediabetes in order to prevent late-PTDM. The outcome was the reversibility of prediabetes, assessed every 3 months with oral glucose tolerance tests (OGTT). The protocol included an incremental plan of aerobic and/or strength training as well as an active plan for promoting adherence (telephone calls, digital technology, and visits). A priori, a sample size cannot be calculated which makes this an exploratory analysis. Based on previous studies, the spontaneous reversibility of prediabetes was 30% and the reversibility induced by exercise will account for another 30%, a total reversibility of 60% (p value < 0.05, assuming a potency of 85%). Ad interim analysis was performed during follow-up to test the certainty of this sample calculation. Patients beyond 12 months after renal transplantation with prediabetes were included.

RESULTS

The study was interrupted early due to efficacy after the evaluation of the follow-up of 27 patients. At the end of follow-up, 16 (60%) patients reverted to normal glucose levels at fasting (from 102.13 mg/dL ± 11 to 86.75 ± 6.9, p = 0.006) and at 120 min after the OGTTs (154.44 mg/dL ± 30 to 113.0 ± 13.1, p = 0.002) and 11 patients had persistent prediabetes (40%). Also, insulin sensitivity improved with the reversibility of prediabetes, compared to those with persistent prediabetes: 0.09 [0.08-0.11] versus 0.04 [0.01-0.07], p = 0.001 (Stumvoll index). Most needed at least one increment in the prescription of exercise and compliance. Finally, measures aimed at the improvement of compliance were successful in 22 (80%) patients.

CONCLUSION

Exercise training was effective to improve glucose metabolism in renal transplant patients with prediabetes. Exercise prescription must be conducted considering both the clinical characteristics of the patients and pre-defined strategy to promote adherence. The trial registration number of the study was NCT04489043.

Intravoxel Incoherent Motion-Diffusion-Weighted MRI for Investigation of Delayed Graft Function Immediately after Kidney Transplantation

Purpose

A non-invasive way of assessing post-transplant renal graft function has been needed. This study aimed to assess the micro-structural and micro-functional status of graft kidneys by using intravoxel incoherent motion- (IVIM-) diffusion-weighted imaging (DWI) to investigate delayed graft function (DGF) immediately after transplantation.

Method

A prospective study was conducted on 37 patients, 14 with early graft function (EGF) and 23 with DGF (9 with complication, 14 without) who underwent IVIM-DWI, most often within 1-7 days after kidney transplantation. A total of 37 cases were collected and all the participants have been well-informed and signed their consents. In addition, the study conducted in this paper was approved by the Ethics Committee of Clinical Research, Taichung Veterans General Hospital (IRB number: CE14065). Using biexponential analysis of slow diffusion coefficient (D_slow), fast diffusion coefficient (D_fast), and perfusion fraction was performed. The apparent diffusion coefficient (ADC) was calculated by use of a monoexponential model. All parameters were measured from three different regions-of-interest (ROI), covering the entire renal parenchyma, cortex, and medulla.

Results

D_slow, perfusion fraction, and ADC were significantly higher in patients with EGF than DGF (all p values values <0.001). Especially, ADC measured from ROI covering the entire kidney parenchyma had the best cut-off value (1.93μm²/msec) with the highest area under the receiver operating characteristic curve (AUC 0.943) in differentiating EGF from DGF. For analysis of pair-wise differences, only the perfusion fraction values, measured from the ROI covering the renal cortex, were significantly higher in 14 DGF patients with no complications than in the 9 DGF patients with complications, with the best cut-off value of 12.3% and the AUC of 0.844.

Conclusion

Noninvasive IVIM-DWI reliably differentiates DGF from EGF after kidney transplantation, and it may aid in identifying posttransplant complications and indications for renal biopsy.

Two point Dixon-based chemical exchange saturation transfer (CEST) MRI in renal transplant patients on 3 T

PURPOSE

To assess the performance of two point (2-pt) Dixon-based chemical exchange saturation transfer (CEST) imaging for fat suppression in renal transplant patients.

METHODS

The 2-pt Dixon-based CEST MRI was validated in an egg-phantom and in fourteen renal transplant recipients (5 females and 9 males; age range: 23-78 years; mean age: 51 ± 16.8). All CEST experiments were performed on a 3 T clinical MRI scanner using a dual-echo CEST sequence. The 2-pt Dixon technique was applied to generate water-only CEST images at different frequency offsets, which were further used to calculate the z-spectra. The magnetization transfer ratio asymmetry (MTR_asym) values in the frequency ranges of hydroxyl, amine and amide protons were estimated in the renal cortex and medulla.

RESULTS

Results of the in vitro experiments suggest that the 2-pt Dixon technique enables effective fat peak removal and does not introduce additional asymmetries to the z-spectrum. Accordingly, our results in vivo show that the fat-corrected amide proton transfer (APT) effect in the kidney is significantly higher compared to that obtained from the CEST data acquired close to the in-phase condition both in the renal cortex (-0.1 [0.7] vs. -0.7 [1.2], P = 0.029) and medulla (0.3 [0.8] vs. 0.01 [1.3], P = 0.049), indicating that the 2-pt Dixon-based CEST method increases the specificity of the APT contrast by correcting the fat-induced artifacts.

CONCLUSION

Combination of the dual-echo CEST acquisition with Dixon post-processing provides effective water-fat separation, allowing more accurate quantification of the APT CEST effect in the transplanted kidney.

Exercise and Prediabetes after Renal Transplantation (EXPRED): Protocol Description

BACKGROUND

Post-transplant diabetes mellitus (PTDM) is a frequent and severe complication after renal transplantation. In fact, PTDM is a risk factor for both infection and cardiovascular diseases. The prevalence and incidence of PTDM have a bimodal evolution: early (up to 3 months) and late PTDM (beyond 12 months). The majority of late PTDM occurs in subjects with prediabetes after transplantation. So, treating patients with prediabetes, a potentially reversible condition, might help preventing PTDM. In the general population, exercise prevents the evolution from prediabetes to diabetes. However, in renal transplantation, not enough evidence is available in this field.

OBJECTIVES

We designed an exploratory analysis to evaluate the feasibility of exercise to reverse prediabetes as a first step in the design of a trial to prevent PTDM.

METHODS

Only patients with prediabetes beyond 12 months after transplantation with capacity to perform exercise will be included. Prediabetes will be diagnosed based on fasting glucose levels and oral glucose tolerance tests (OGTTs). Patients will be treated with a stepped training intervention, starting with aerobic exercise training (brisk walking, swimming, and cycling) 5 times per week and 30 min/day. Aerobic exercise training will be gradually increased to 60 min/day or eventually combined with anaerobic exercise training in case of persistent prediabetes. The reversibility/persistence of prediabetes will be measured with fasting glucose and OGTTs every 3 months. This study will last for 12 months.

Interleukin 8 Is Overexpressed in Acute Rejection in Kidney Transplant Patients

The main complication associated with renal graft loss is immune rejection. The gold standard for the diagnosis of renal graft rejection is percutaneous renal biopsy, which is expensive and can lead to complications. Inflammation is one of the main pathogenic pathways in allograft rejection, and urine samples seem to be efficient windows to explore the allograft condition with a high cost-benefit ratio. This study aimed to evaluate the messenger ribonucleic acid (mRNA) profile expression pattern for interleukin (IL) 2, IL-4, IL-6, IL-8, and IL-10; tumor necrosis factor alfa; gamma interferon; and transforming growth factor β1 in the urine renal cells of patients with a diagnosis of humoral rejection and patients with a diagnosis of normal biopsy. METHODS: An observational, cross-sectional analytical study was performed. All kidney transplants were performed at the Organ Transplant Department between 2018 and 2019. Also, a healthy control with a normal blood test and no apparent infection was included. mRNA from urine samples and biopsies was isolated, and the expression of interleukins was analyzed in PCR real time. Data were analyzed by Shapiro-Wilk and Kruskal-Wallis tests. RESULTS: The proinflammatory IL expression pattern in urine samples of kidney rejection group showed overexpression for IL-8 (P = .0001). No differences were observed in the rest of the interleukins analyzed. When we compared the results in the rejected versus not rejected transplanted patients with a group of apparently healthy subjects, the difference remains consistent. Thus, mRNA of IL-8 could function as a diagnostic tool in cases of chronic damage secondary to fibrosis.

Detecting impaired function of renal allografts at the early stage after transplantation using intravoxel incoherent motion imaging

Background

Detecting renal allografts with impaired function early after renal transplantation and timely intervention are important to ensure a successful outcome.

Purpose

To detect impaired function of renal allografts at the early stage after renal transplantation using intravoxel incoherent motion imaging (IVIM).

Material and Methods

Forty-six recipients with good allograft function and 32 recipients with impaired function were included in this study. All participants were scanned with IVIM using 11 b-values on a 3-T magnetic resonance (MR) scanner; the apparent diffusion coefficient (ADC), ADC of slow diffusion (ADCslow), pseudo-diffusion (ADCfast), and perfusion fraction (f) values were calculated using a full bi-exponential model. Correlations between estimated glomerular filtration rate (eGFR) and the IVIM parameters were assessed by using Spearman correlation analysis. Receiver operating characteristics were used to assess the diagnostic utilities for detecting allografts with impaired function.

Results

The ADC, ADCslow, ADCfast, and f values of the renal cortex and the ADC and ADCslow values of the renal medulla were significantly higher in allografts with good function compared to those with impaired function (all P < 0.05). There was a significant corticomedullary difference in ADCslow, ADC, and f in all allografts. ADCfast values were higher in the cortex than in the medulla for allografts with good function but no differences were seen in allografts with impaired function ( P > 0.05). Combined use of all cortical IVIM parameters has higher efficacy in detecting renal allograft dysfunction than any single parameter (sensitivity = 90.62%; specificity = 78.26%).

Conclusion

IVIM technique may be useful for detecting renal allograft dysfunction, especially combined use of cortical parameters.

Risk factors for new-onset diabetes mellitus after kidney transplantation (NODAT): a Brazilian single center study

OBJECTIVES

This study aims to verify the new-onset diabetes after kidney transplant (NODAT) incidence in recipients within 1 year after kidney transplantation from a single center in Southern Brazil and to assess the associated conditions.

SUBJECTS AND METHODS

A retrospective study of 258 post-renal transplant patients was performed. Demographic (gender, age, ethnic background) and clinical (origin of graft, associated infections, body mass index (BMI) at transplant time and 6 and 12 months after, causes of renal failure, and comorbidities) data were analyzed. All patients were on tacrolimus, mycophenolate mofetil, and prednisone treatment. Patients with and without NODAT were compared.

RESULTS

A NODAT incidence of 31.2% was noted 1 year post transplantation. In the univariate analysis, patients with NODAT were older (p = 0.001), mostly had African-American ethnic background (p = 0.02), and had renal failure secondary to high blood pressure (HBP) (p = 0.001). The group of patients with NODAT also had more incidence of post-transplant HBP (p = 0.01), heart failure (p = 0.02), and dyslipidemia (p = 0.001). Logistic regression showed that African-American ethnic background, post-transplant HBP, and dyslipidemia were independently associated with NODAT.

CONCLUSION

This study shows a NODAT incidence that is greater in patients with African-American ethnic background and that is associated with HBP and dyslipidemia.

Using functional magnetic resonance imaging to evaluate an acute allograft rejection model in rats

PURPOSE

To assess the longitudinal changes of allograft pathophysiology by intravoxel incoherent motion (IVIM) and blood oxygen level-dependent (BOLD) MRI in a rat model of acute renal allograft rejection.

MATERIALS AND METHODS

Acute rejection (AR) was induced by transplantation of Dark Agouti donor kidneys into Lewis recipients (n = 18). A Lewis-Lewis rat syngeneically transplanted (sTX) model served as the control (n = 6). Acute tubular necrosis (n = 6) and acute calcineurin inhibitor toxicity (n = 6) groups were established using Lewis rats. MRI was performed on postoperative day (POD) 1, 4 and 7 in the allogeneically transplanted (aTX) group and on POD4 in the other groups. Histological evaluation and PCR were performed.

RESULTS

After the allogenic transplantation, all MRI parameters of allograft further decreased until POD7, and the D and ADC values in the cortex were significantly lower than that in the sTX group (1.03 ± 0.09 vs 1.52 ± 0.09 × 10^-3 mm²/s, P_adj < 0.05; 1.21 ± 0.03 vs 1.78 ± 0.07 × 10^-3 mm²/s, P_adj < 0.05). The D*, f and R2* values of the aTX group in the cortex and medulla were significantly lower than those in the sTX group on POD7 (cortex, D*: 25.60 ± 4.78 vs 69.32 ± 9.79 × 10^-3 mm²/s, P_adj < 0.05; f: 7.84 ± 1.83 vs 20.34 ± 3.08%, P_adj < 0.05; R2*: 16.61 ± 4.18 vs 31.48 ± 6.43 1/s, P_adj < 0.05; medulla, D*: 13.59 ± 6.08 vs 62.75 ± 9.20 × 10^-3 mm²/s, P_adj < 0.05; f: 7.46 ± 1.62 vs 14.68 ± 2.05%, P_adj < 0.05; R2*: 21.59 ± 3.45 vs 39.53 ± 4.34 1/s, P_adj < 0.05). AR grafts presented serve interstitial inflammation, tubulitis and infiltration of T-lymphocytes and macrophages. The MRI parameters, including D, ADC, D*, f and R2*, were significantly correlated with the histological changes, cell infiltration and inflammatory cytokine mRNA levels.

CONCLUSIONS

IVIM coupled with BOLD MRI allows longitudinal assessment of allograft diffusion, perfusion and oxygen consumption impairment caused by acute renal allograft rejection in rat model.

Two Different Causes of Decreased Activity on Ipsilateral Iliac Artery in Renal Transplant Scintigraphy

In 2 patients, perfusion images of renal transplant scintigraphy showed similarly decreased activity on ipsilateral iliac artery. One's graft was photopenic because of arterial thrombosis. However, the other's graft had sufficient perfusion and no abnormality in iliac arteries, but he had femoral arteriovenous graft for hemodialysis on the contralateral side. So, in this patient, decreased activity on ipsilateral iliac artery was probably related to increased arterial flow of the contralateral side. It should be considered that decreased activity on ipsilateral iliac artery in perfusion images is not only due to ipsilateral problem; the cause could be on the contralateral side.

ACR Appropriateness Criteria® Renal Transplant Dysfunction

Renal transplantation is the treatment of choice in patients with end-stage renal disease because the 5-year survival rates range from 72% to 99%. Although graft survival has improved secondary to the introduction of newer immunosuppression drugs and the advancements in surgical technique, various complications still occur. Ultrasound is the first-line imaging modality for the evaluation of renal transplants in the immediate postoperative period and for long-term follow-up. In addition to depicting many of the potential complications of renal transplantation, ultrasound can also guide therapeutic interventions. Nuclear medicine studies, CT, and MRI are often helpful as complementary examinations for specific indications. Angiography remains the reference standard for vascular complications and is utilized to guide nonsurgical intervention. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Functional Evaluation of Transplanted Kidneys with Reduced Field-of-View Diffusion-Weighted Imaging at 3T

Objective

To determine the feasibility of reduced field-of-view diffusion-weighted imaging (rFOV DWI) with multi-b values to detect functional variability in transplanted kidneys.

Materials and Methods

Using a 3T MRI scanner, multi-b rFOV DWI of transplanted kidney or native kidney was performed in 40 renal transplantation recipients and 18 healthy volunteers. The patients were stratified, according to an estimated glomerular filtration rate (eGFR): Group 1, eGFR ≥ 60 mL/min/1.73 m²; Group 2, eGFR ≥ 30 mL/min/1.73 m² and < 60 mL/min/1.73 m²; Group 3, eGFR < 30 mL/min/1.73 m². Total apparent diffusion coefficient (ADC_T), perfusion-free ADC (ADC_D) and perfusion fraction (F_P) of kidneys were calculated and compared among the four groups. Correlations between the imaging results and eGFR were assessed.

Results

All volunteers had eGFR ≥ 60 mL/min/1.73 m², while 16, 16, and 8 patients were included in Groups 1, 2, and 3, respectively. In the renal cortex, ADCT was higher in Group 1 ([1.65 ± 0.13] × 10^-3 mm²/s) than Group 3 ([1.44 ± 0.11] × 10^-3 mm²/s) (p < 0.05), and the inter-group differences of F_P values were significant (all p < 0.05) (0.330 ± 0.024, 0.309 ± 0.019, 0.278 ± 0.033, and 0.250 ± 0.028 for control group, Groups 1, 2, and 3, respectively). Renal cortical ADC_T, ADC_D, F_P, and renal medullary ADC_T and F_P correlated positively with eGFR (r = 0.596, 0.403, 0.711, 0.341, and 0.323, respectively; all p < 0.05). When using 0.278 as the cutoff value, renal cortical F_P had a sensitivity of 97.1% and a specificity of 66.7% for predicting decreased renal function.

Conclusion

Multi-b rFOV DWI presents transplanted kidneys with high resolution, which is a promising functional tool for non-invasively monitoring function of transplanted kidneys.

Scintigraphic texture analysis for assessment of renal allograft function

Purpose

Early detection and monitoring of kidney function during the post-transplantation period is one of the most important issues for improving the accuracy of an initial diagnosis. The aim of this study was to evaluate texture analysis (TA) in scintigraphic imaging to detect changes in kidney status after transplantation.

Material and methods

Scintigraphic images were used for TA from a total of 94 kidney allografts (39 rejected and 55 non-rejected). Images corresponding to the frames at the 2^nd, 5^th, and 20^th minute of the study were used to determine the optimum time point for analysis of differences in texture features between the rejected and non-rejected allografts.

Results

Linear discriminant analysis indicated the best performance at the fifth minute frame for classification of the rejected and non-rejected allografts with receiver operating characteristic curve (A_z) of 0.982, corresponding to 91.89% sensitivity, 96.49% specificity, and 94.68% accuracy. Also, TA can differentiate acute tubular necrosis from acute rejection with A_z of 0.953 corresponding to 88% sensitivity, 92.31% specificity, and 90.62% accuracy at the 5^th minute frame. The best correlation between texture feature and kidney function was achieved at the 20^th minute frame (r = -0.396) for glomerular filtration rate.

Conclusions

TA has good potential for the characterisation of kidney failure after transplantation and can improve clinical diagnosis.

Essential role of microRNA-650 in the regulation of B-cell CLL/lymphoma 11B gene expression following transplantation: A novel mechanism behind the acute rejection of renal allografts

Kidney transplantation is an effective final therapeutic procedure for patients with end-stage kidney failure. Although advanced immunosuppressive therapy is administered following transplantation, certain patients still suffer from acute allograft rejection. MicroRNAs (miRs) have a potential diagnostic and therapeutic value for acute renal allograft rejection; however, their underlying mechanism of action is largely unknown. In the present study, an increased level of miR-650 was identified to be associated with the downregulation of B-cell CLL/lymphoma 11B (BCL11B) expression in acute renal allograft rejection. Furthermore, in vitro study using human renal glomerular endothelial cells (HRGECs) transfected with a miR-650 mimic revealed that key characteristics of acute renal allograft rejection were observed, including apoptosis, the release of cytokines and the chemotaxis of macrophages, while the effects were reduced in HRGECs transfected with a miR-650 inhibitor. The existence of a conserved miR-650 binding site on the 3'-untranslated region of BCL11B mRNA was predicted by computational algorithms and confirmed by a luciferase reporter assay. Knockdown of BCL11B with small interfering RNA (siRNA) significantly increased the apoptotic rate and significantly decreased the proliferation ability of HRGECs compared with the negative control group. HRGECs transfected with a combination of BCL11B siRNA and the miR-650 mimic demonstrated a significant increase in the rate of apoptosis compared with the control. These results suggest that the upregulation of miR-650 contributes to the development of acute renal allograft rejection by suppression of BCL11B, which leads to apoptosis and inflammatory responses. Thus, miR-650 and BCL11B may represent potential therapeutic targets for the prevention of acute renal allograft rejection.

Peri- and Postsurgical Evaluations of Renal Transplant

Renal transplantation is the best treatment of choice for patient with chronic renal insufficiency because it provides better quality of life and longer survival. Survival rates for grafts and patients have improved over the recent decades because of significant evolution of surgical techniques and immunosuppressive treatment. However, renal transplantation is still associated with several complications, which may result in poor outcome. Cause of allograft dysfunction, which occurs in the early or late post-transplantation period, should be recognized immediately, so that it can be managed correctly. Surgical complications are rare and include renal artery stenosis, vascular thrombosis, hematoma, ureteral obstruction, urinary leak, hematoma, lymphocele, and perinephric fluid collections. Parenchymal complications, which are histopathologically categorized according to Banff classification, include antibody-mediated rejection, T-cell mediated rejection, interstitial fibrosis and tubular atrophy, calcineurin inhibitors, acute tubular injury, and others. Detection of changes in the allograft function is an important task in the appropriate management of complications. Although first-line imaging tool in the recognition of complications is ultrasonography, radionuclide imaging is a modality capable of assessing graft function qualitatively and quantitatively. Sequential renal scintigraphy is of particular importance in the differential diagnosis of complications, which need prompt and accurate management. Renal scintigraphy within 24-48 hours of transplantation surgery is recommended to serve as a baseline for comparison when functional impairment develops. In addition, studies have shown that early renal scintigraphy has a predictive value for the short-term and long-term graft outcomes. This article focuses in the main complications after renal transplantation, their imaging findings, and the role of renal scintigraphy.

The incidence of new onset diabetes after transplantation and related factors: Single center experience

AIM

New-onset diabetes after transplantation (NODAT) is a frequent metabolic complication and is considered a risk factor for patients undergoing renal transplant. The aim of this study was to evaluate the incidence and developing duration of new-onset diabetes after transplant (NODAT) and influencing factors.

METHODS

All patients' data was investigated retrospectively. Diabetics, follow-up period<6 months, age<18years were excluded. Demographic, clinical and laboratory data was recorded. Patients were divided into two groups: with/without NODAT. NODAT group was divided into four subgroups according to the time of developing NODAT, which were 0-3, 3-6, 6-12 and 12 months later. Two groups were compared, to investigate the incidence of NODAT and risk factors associated with the occurrence of NODAT.

RESULTS

We retrospectively analyzed the records of 570 patients, of which 420 patients were included. Seventy (16.6%) patients had NODAT (36 female, mean age 51.7±8.2 years, mean follow-up 41.6±21.5 months), 52.8% of patients developed NODAT within the first three months of being diagnosed. 350 patients (116 female, mean age 43.2±12.5 years, mean follow-up 41.6±21.5 months) were without NODAT. The incidence of impaired fasting glucose (IFG) during the first week after transplant was found to be higher in the patients with NODAT (p<0.001). There was positive correlation between NODAT and older age, obesity, family history of diabetes, presence of IFG, fasting plasma glucose, total and LDL-cholesterol, triglycerides, parathormone. Old age, obesity, presence of IFG, pretransplant hypertriglyceridemia and hyperparathyroidism were predictors of development of NODAT.

CONCLUSION

Incidence of NODAT, especially the first six months, was high. All patients should be screened for IFG within the first week. Patients with dyslipidemia, elderly and obese patients should be closely monitored for the risk of development of NODAT.

New-Onset Diabetes After Kidney Transplantation and Pretransplant Hypomagnesemia

AIM

Hypomagnesemia is a frequent finding in kidney transplant patients and plays a causal role in insulin resistance and diabetes. The aim of this study was to investigate whether the pretransplant magnesium (Mg) level is a risk factor for the development of new-onset diabetes after kidney transplantation (NODAT) and the presence of relationship between pretransplant hypomagnesemia and the development period of NODAT.

METHODS

Four hundred and nineteen nondiabetic renal transplant recipients were evaluated retrospectively. The patients were divided into NODAT and non-NODAT groups. The time of diagnosis of patients with NODAT was divided into 0 to 3, 3 to 6, 6 to 12 months, and after 12 months. Patients' characteristics and pretransplant Mg levels in NODAT were compared with non-NODAT, and it was investigated whether pretransplant hypomagnesemia was a risk factor for the development of NODAT.

RESULTS

Totally 70 (16.6%) patients (36 female [F], mean age 51.7 ± 8.2 years) were diagnosed with NODAT. Three hundred and forty-nine patients (115 F, mean age 43.2 ± 12.5 years) did not have NODAT. Pretransplant mean Mg level was 1.97 ± 0.40 mg/dL in patients with NODAT, while it was 2.5 ± 0.45 mg/dL in non-NODAT patients (P < .001). Serum Mg level was found to be similar in subgroups according to the development period of NODAT (P = .07). When patients were stratified according to quartiles of Mg level, the frequency of NODAT was significantly higher in patients in the lower quartile (Mg < 2.1 mg/dL; P < .001). Older age, high body mass index, and low pretransplant serum Mg levels were established as risk factors for developing NODAT. According to the quartile of Mg level, the risk of developing NODAT was highest in the lowest quartile.

CONCLUSION

Pretransplant hypomagnesemia is an independent risk factor of NODAT. Therefore, it is necessary to closely monitor the Mg levels in the posttransplant period.

Role of nuclear medicine imaging in evaluation of complications following renal transplant

Evaluation of a failing renal allograft is a complex and challenging diagnostic problem. While ultrasonography with colour Doppler is usually the first approach for evaluation of graft dysfunction, radionuclide imaging is an excellent modality which provides complementary information regarding the perfusion and function of the allograft without any deleterious effect on the precious allograft. In this article, we review the imaging techniques of the nuclear medicine studies most commonly performed after renal transplant, discuss their roles and limitations in different clinical settings and illustrate with cases from our institution. Lastly, we will explore future development in the arena of nuclear imaging for renal transplant related complications.

Results of cataract surgery in renal transplantation and hemodialysis patients

AIM

To compare the effect of cataract surgery in renal transplantation and hemodialysis patients.

METHODS

We evaluated 51 eyes of 31 renal transplantation patients, 41 eyes of 29 hemodialysis patients and 45 eyes of 32 normal control patients who received phacoemulsification and intraocular lens (IOL) implantation from January, 2000 to August, 2014 in the Beijing Friendship Hospital. Each individual underwent a blood routine and a kidney function examination. Routine ophthalmologic examination included best-corrected visual acuity (BCVA), a slit-lamp examination to detect cataract type, determination of intraocular pressure, a corneal endothelial count, and fundus examination. All patients received phacoemulsification and an IOL implantation.

RESULTS

For the types of cataract in the three groups, transplantation group was significantly different from normal control group (P=0.04), the most kind is posterior subcapsular cataract (PSC) in transplantation group 33 (64.7%), hemodialysis group had no significantly difference from normal control group (P=0.43), and the difference between transplantation group and hemodialysis group also had significantly difference (P=0.02). For postoperative BCVA in the three groups, transplantation group had significantly difference from normal control group (P=0.03), hemodialysis group was significantly different from normal control group (P=0.00), and the difference between transplantation group and hemodialysis group also had significantly difference (P=0.00). The multiple linear regression equation is Y=0.007 hemoglobin (Hb)-0.000233 serum creatinine (Cr), R(2)=0.898. Postoperative fundus examination showed that hemorrhage, exudation, and macular degeneration were greater in the hemodialysis group.

CONCLUSION

This study showed that the PSC was more in the renal transplantation patients. BCVA was better and fundus lesions were less frequent in the renal transplantation group than in the hemodialysis group after cataract surgery. The multiple linear regression was showed that the Hb was positively correlated with postoperative BCVA, while Cr was negatively correlated with postoperative BCVA. These results may act as indicators in predicting visual acuity for the renal transplantation and hemodialysis patients.

Influencing factors of new-onset diabetes after a renal transplant and their effects on complications and survival rate

OBJECTIVE

To discuss the onset of and relevant risk factors for new-onset diabetes after a transplant (NODAT) in patients who survive more than 1 year after undergoing a renal transplant and the influence of these risk factors on complications and long-term survival.

METHOD

A total of 428 patients who underwent a renal transplant between January 1993 and December 2008 and were not diabetic before surgery were studied. The prevalence rate of and relevant risk factors for postoperative NODAT were analyzed on the basis of fasting plasma glucose (FPG) levels, and differences in postoperative complications and survival rates between patients with and without NODAT were compared.

RESULTS

The patients in this study were followed up for a mean of 5.65 ± 3.68 years. In total, 87 patients (20.3%) developed NODAT. Patients who converted from treatment with CSA to FK506 had increased prevalence rates of NODAT (P <0.05). Multi-factor analysis indicated that preoperative FPG level (odds ratio [OR]  =  1.48), age (OR  =  1.10), body mass index (OR  =  1.05), hepatitis C virus infection (OR  =  2.72), and cadaveric donor kidney (OR  =  1.18) were independent risk factors for NODAT (All P <0.05). Compared with the N-NODAT group, the NODAT group had higher prevalence rates (P < 0.05) of postoperative infection, hypertension, and dyslipidemia; in addition, the survival rate and survival time of the 2 groups did not significantly differ.

CONCLUSION

Among the patients who survived more than 1 year after a renal transplant, the prevalence rate of NODAT was 20.32%. Preoperative FPG level, age, body mass index, hepatitis C virus infection, and cadaveric donor kidney were independent risk factors for NODAT. Patients who converted from treatment with CSA to FK506 after a renal transplant had aggravated impairments in glycometabolism. Patients with NODAT were also more vulnerable to postoperative complications such as infection, hypertension, and hyperlipidemia.