Kidney transplantation halts cardiovascular disease progression in patients with end-stage renal disease

Cysteine as an Innovative Biomarker for Kidney Injury

BACKGROUND

Kidney transplantation is a widely used treatment for end-stage kidney disease. Nevertheless, the incidence of acute kidney injury (AKI) in deceased donors poses a potential hazard because it significantly increases the risk of delayed graft function and potentially exerts an influence on the kidney allograft outcome. It is crucial to develop a diagnostic model capable of assessing the existence and severity of AKI in renal grafts. However, no suitable kidney injury markers have been developed thus far.

METHODS

We evaluated the efficacy of the molecular probe NPO-B, which selectively responds to cysteine, as a new diagnostic tool for kidney injury. We used an in vitro model using ischemia/reperfusion injury human kidney-2 cells and an in vivo ischemia/reperfusion injury mouse model. Additionally, cysteine was investigated using urine samples from deceased donors and living donors to assess the applicability of detection techniques to humans.

RESULTS

This study confirmed that the NPO-B probe effectively identified and visualized the severity of kidney injury by detecting cysteine in both in vitro and in vivo models. We observed that the fluorescence intensity of urine samples measured using NPO-B from the deceased donors who are at a high risk of renal injury was significantly stronger than that of the living donors.

CONCLUSIONS

If implemented in clinical practice, this new diagnostic tool using NPO-B can potentially enhance the success rate of kidney transplantation by accurately determining the extent of AKI in renal grafts.

Syndecan-1 in the Serum of Deceased Kidney Donors as a Potential Biomarker of Kidney Function

BACKGROUND

The process of kidney transplantation remains the optimal treatment for end-stage renal disease, offering improved quality of life and increased survival rates compared to long-term dialysis. However, despite advances in surgical techniques, immunosuppression regimens, and post-operative care, there are still significant challenges in predicting the organ's status and long-term outcomes of transplantation. Among the many factors that influence graft survival, the quality of the donated organ plays a fundamental role. There is an ongoing need for accurate and reliable biomarkers. Syndecan-1 is found in the endothelial glycocalyx and shed at a higher rate into the blood during systemic pathological conditions. The aim of this study is to evaluate the potential of serum syndecan-1 levels as a biomarker for assessing donor kidney quality and to investigate its correlation with donor characteristics and short-term outcomes in kidney recipients.

MATERIAL AND METHODS

We investigated serum syndecan-1 levels in 80 deceased donors and correlated them with donor characteristics and short-term outcomes (defined as delayed graft function - defined as the need for dialysis within the first week post-transplantation and renal function at 3 months post-transplantation - assessed using serum creatinine levels) in 104 corresponding kidney recipients. This single-center retrospective observational cohort study was conducted from April to December 2021.

RESULTS

The donor pool consisted of 65% males with a median age of 53 years. Of these, 45 donors (56%) were classified as extended criteria donors. Higher syndecan-1 levels correlated with the last creatinine levels before organ procurement (R = 0.32, p = 0.01) and were marginally higher in donors with acute kidney injury (p = 0.07). However, syndecan-1 levels were not associated with short-term outcomes in kidney recipients (renal function at 3 months).

CONCLUSIONS

The data suggests syndecan-1 could be a potential biomarker for assessing donor kidney quality, although its implications on recipient outcomes require further study. This pilot investigation underscores the importance of syndecan-1 in evaluating organ quality but highlights the necessity for more extensive research to validate these findings and explore their implications in transplant success.

Paired Remote Ischemic Preconditioning in Recipients and Living Donors Can Mitigate Cardiovascular Stress in Recipients After Living-Donor Kidney Transplantation: A Propensity-Score-Matching Analysis

Background and Objectives: This study explored the effect of paired remote ischemic preconditioning (RIPC), involving both recipients and living donors, on cardiovascular stress in recipients after living-donor kidney transplantation (LDKT). The analysis included an assessment of the impact on cardiovascular biomarkers and post-transplant cardiovascular clinical events. Materials and Methods: A retrospective observational cohort study of 520 adult LDKT patients was conducted, employing propensity score matching (PSM) to analyze perioperative factors. The patients were allocated to no-RIPC (n = 260) and paired-RIPC (n = 260) groups. The two groups were compared with respect to high-sensitivity troponin I (hsTnI) and B-type natriuretic peptide (BNP) levels, corrected QT (QTc) intervals, the occurrence of arrhythmia, and the requirement for cardiovascular interventions. Results: After PSM, there were no significant differences in perioperative parameters between the no-RIPC and paired-RIPC groups. However, on postoperative day (POD) 1, higher hsTnI levels and QTc interval prolongation, as well as higher incidences of arrhythmia and the need for percutaneous coronary intervention (PCI), were determined in the no-RIPC group than in the paired-RIPC group. The associations between paired RIPC and improved cardiovascular outcomes were significant, including reduced odds of elevated hsTnI levels, QTc prolongation, and arrhythmia. The no-RIPC group also had longer intensive care unit (ICU) stays, and higher rates of rescue dialysis. Conclusions: Paired-RIPC involving recipients and donors effectively reduces cardiovascular stress markers and improves postoperative cardiovascular outcomes in LDKT recipients, underscoring its potential as a protective strategy against perioperative cardiovascular risks.

Unraveling the impact of abdominal arterial calcifications on kidney transplant waitlist mortality through ensemble machine learning

The scarcity of organ donors relative to the number of patients with End Stage Kidney Disease (ESKD) has led to prolonged waiting times for kidney transplants, contributing to elevated cardiovascular mortality risk. Transplant professionals are tasked with the complex allocation of limited organs to a vulnerable patient group facing heightened morbidity and mortality risk. The need for continuous re-evaluation of waitlisted patients is evident due to the significant number who perish while awaiting transplantation. Among individuals with ESKD, vascular calcification, particularly Abdominal Arterial Calcifications (AAC), holds predictive value for cardiovascular events and mortality. However, a standardized method to quantify AAC's prognostic potential remains lacking, especially for kidney transplant evaluations. This study presents an ensemble machine learning (ML) approach to study the relationship between AAC score and mortality in patients on the waitlist and triage patients needing transplantation. Using the AAC score, the proposed ML model can predict kidney transplant waitlist morality with an accuracy of 78% while its accuracy is 68% without using this score. This study leverages explainable ML to explore the relationship between predictors and mortality in waitlisted patients, aiming to improve patient triage accuracy.

Kidney Transplant Candidacy: Addressing Common Medical and Psychosocial Barriers to Transplant

Improving access to kidney transplants remains a priority for the transplant community. However, many medical, psychosocial, geographic, and socioeconomic barriers exist that prevent or delay transplantation for candidates with certain conditions. There is a lack of consensus regarding how to best approach many of these issues and barriers, leading to heterogeneity in transplant centers' management and acceptance practices for a variety of pretransplant candidate issues. In this review, we address several of the more common contemporary patient medical and psychosocial barriers frequently encountered by transplant programs. The barriers discussed here include kidney transplant candidates with obesity, older age, prior malignancy, cardiovascular disease, history of nonadherence, and cannabis use. Improving understanding of how to best address these specific issues can empower referring providers, transplant programs, and patients to address these issues as necessary to progress toward eventual successful transplantation.

Dialysis Duration, Time Interaction, and Visceral Fat Accumulation: A 6-Year Posttransplantation Study

BACKGROUND

Kidney transplantation (KT) leads to body composition change, particularly increasing the fat mass. However, limited researches have focused on the long-term follow-up of these changes and factors influencing body composition after KT.

METHODS

This study evaluated body composition in 31 adult KT recipients, measuring body mass index (BMI), the psoas muscle mass index (PMI) representing muscle mass, visceral and subcutaneous adipose tissue (VAT and SAT) representing fat mass, and skeletal muscle radiodensity (SMR) representing muscle quality before KT and at 2, 4, and 6 years posttransplantation using computed tomography. Linear mixed models (LMM) analyzed temporal changes and contributing factors, while growth curve models assessed influence of these factors on body composition changes posttransplantation.

RESULTS

Following KT, BMI, and PMI remained stable, while SAT increased significantly, revealing a 1.30-fold increase from baseline 2 years after transplantation. Similarly, a substantial increase in VAT was observed, with a 1.47-fold increase from baseline 2 years after transplantation with a further 1.75-fold increase 6 years after transplantation. In contrast, SMR decreased with a 0.86-fold decrease from baseline after 2 years. VAT increase was significantly influenced by the interaction between posttransplantation and dialysis duration. Growth curve models confirmed this interaction effect persistently influenced VAT increase posttransplantation.

CONCLUSIONS

The study revealed that KT promoted significant alterations in body composition characterized by increase in the VAT and SAT and a decline in SMR. Notably, dialysis duration and its interaction with posttransplantation duration emerged as significant factors influencing VAT increase.

Clinical Outcomes of Renal Transplant Recipients Undergoing Percutaneous Coronary Intervention

BACKGROUND

Clinical outcomes of patients with renal transplant (RT) undergoing percutaneous coronary intervention (PCI) remain poorly elucidated.

METHOD

Between 2014 and 2021, data were analysed for the following three groups of patients undergoing PCI enrolled in a multicentre Australian registry: (1) RT recipients (n=226), (2) patients on dialysis (n=992), and (3) chronic kidney disease (CKD) patients (estimated glomerular filtration rate [eGFR], 30‒60 mL/min per 1.73 m2) without previous RT (n=15,534). Primary outcome was 30-day major adverse cardiac and cerebrovascular events (MACCEs)-composite of mortality, myocardial infarction, stent thrombosis, target vessel revascularisation, and stroke.

RESULTS

RT recipients were younger than dialysis and patients with CKD (61±10 vs 68±12 vs 78±8.2 years, p<0.001). Patients with RT less frequently had severe left ventricular dysfunction compared with dialysis and CKD groups (6.7% vs 14% and 8.5%); however more, often presented with acute coronary syndrome (58% vs 52% and 48%), especially STEMI (all p<0.001). Patients with RT and CKD had lower rates of 30-day MACCE (4.4% and 6.8% vs 11.6%, p<0.001) than the dialysis group. Three-year survival was similar between RT and CKD groups, however was lower in the dialysis group (80% and 83% vs 60%, p<0.001). After adjustment, dialysis was an independent predictor of 30-day MACCE (odds ratio [OR] 1.90, 95% confidence interval [CI] 1.44‒2.50, p<0.001), however RT was not (OR 0.91, CI 0.42‒1.96, p=0.802). Both RT (hazard ratio [HR] 2.07, CI 1.46‒2.95, p<0.001) and dialysis (HR 1.35, CI 1.02‒1.80, p=0.036) heightened the hazard of long-term mortality.

CONCLUSIONS

RT recipients have more favourable clinical outcomes following PCI compared with patients on dialysis. However, despite having similar short-term outcomes to patients with CKD, the hazard of long-term mortality is significantly greater for RT recipients.

Arteriovenous fistula for haemodialysis as a predictor of de novo heart failure in kidney transplant recipients

Background

The haemodynamic effects of a functioning haemodialysis arteriovenous fistula (AVF) can cause or exacerbate heart failure (HF). We investigated whether the presence of an AVF at the time of kidney transplant (KT) is associated with de novo HF.

Methods

This was an observational cohort study including adult patients who received a KT in the West of Scotland between 2010 and 2020. We evaluated the risk and associations of pretransplant factors with de novo HF, alone and as a composite cardiovascular (CV) outcome (including non-fatal myocardial infarction, non-fatal stroke, de novo HF and CV death). Multivariable proportional hazards regression and sensitivity analyses were used to identify independent correlates of the outcomes.

Results

Among 1330 included patients, the incident rate of de novo HF after transplantation was 58/1000 person-years [95% confidence interval (CI) 50-67] in AVF patients (n = 716) compared with 33/1000 person-years (95% CI 27-41) in non-AVF patients (n = 614). De novo HF was associated with the presence of an AVF [adjusted hazard ratio (aHR) 2.14 (95% CI 1.40-3.26)], duration of dialysis [aHR 1.03/year increase (95% CI 1.01-1.04)], age at transplant [aHR 1.03/year increase (95% CI 1.02-1.05)], female sex [aHR 1.93 (95% CI 1.40-2.65)] and pretransplant diabetes [aHR 2.43 (95% CI 1.48-4.01)]. The presence of an AVF was also associated with the composite CV outcome [aHR 1.91 (95% CI 1.31-2.78)].

Conclusions

The presence of an AVF may be an underrecognized modifiable predictor of de novo HF posttransplantation.

Kidney replacement therapy: trends in incidence, treatment, and outcomes of myocardial infarction and stroke in a nationwide Scottish study

BACKGROUND AND AIMS

Patients with kidney failure have a higher risk of cardiovascular disease compared with the general population. Whilst temporal trends of myocardial infarction and stroke are declining in the general population, these have not been evaluated in patients with kidney failure. This study aimed to describe national trends in the incidence, treatment, and outcomes of myocardial infarction and stroke in patients with kidney failure (i.e. on dialysis or with a kidney transplant) over a 20-year period, stratified by age and sex.

METHODS

In this retrospective national data linkage study, all patients with kidney failure in Scotland (UK) receiving kidney replacement therapy between January 1996 and December 2016 were linked to national hospitalization, prescribing, and death records. The primary outcomes were the incidence of myocardial infarction and stroke, and subsequent cardiovascular death. Generalized additive models were constructed to estimate age-standardized, sex-stratified incidence rates and trends in cardiovascular and all-cause death.

RESULTS

Amongst 16 050 patients with kidney failure [52 (SD 15) years; 41.5% women], there were 1992 [66 (SD 12) years; 34.8% women] and 996 [65 (SD 13) years; 45.1% women] incident myocardial infarctions and strokes, respectively, between January 1996 and December 2016. During this period, the age-standardized incidence of myocardial infarction per 100 000 decreased in men {from 4376 [95% confidence interval (CI) 3998-4785] to 1835 (95% CI 1692-1988)} and women [from 3268 (95% CI 2982-3593) to 1369 (95% CI 1257-1491)]. Similarly, the age-standardized incidence of stroke per 100 000 also decreased in men [from 1978 (95% CI 1795-2175) to 799 (95% CI 729-875)] and women [from 2234 (95% CI 2031-2468) to 903 (95% CI 824-990)]. Compared with the general population, the incidence of myocardial infarction was four- to eight-fold higher in patients with kidney failure, whilst for stroke it was two- to four-fold higher. The use of evidence-based cardioprotective treatment increased over the study period, and the predicted probability of cardiovascular death within 1 year of myocardial infarction for a 66-year-old patient with kidney failure (mean age of the cohort) fell in men (76.6% to 38.6%) and women (76.8% to 38.8%), and also decreased in both sexes following stroke (men, from 63.5% to 41.4%; women, from 67.6% to 45.8%).

CONCLUSIONS

The incidence of myocardial infarction and stroke has halved in patients with kidney failure over the past 20 years but remains significantly higher than in the general population. Despite improvements in treatment and outcomes, the prognosis of these patients following myocardial infarction and stroke remains poor.

Predicting Cellular Rejection of Renal Allograft Based on the Serum Proteomic Fingerprint

Kidney transplantation is an essential medical procedure that significantly enhances the survival rates and quality of life for patients with end-stage kidney disease. However, despite advancements in immunosuppressive therapies, allograft rejection remains a leading cause of organ loss. Notably, predictions of cellular rejection processes primarily rely on biopsy analysis, which is not routinely performed due to its invasive nature. The present work evaluates if the serum proteomic fingerprint, as acquired by Fourier Transform Infrared (FTIR) spectroscopy, can predict cellular rejection processes. We analyzed 28 serum samples, corresponding to 17 without cellular rejection processes and 11 associated with cellular rejection processes, as based on biopsy analyses. The leave-one-out-cross validation procedure of a Naïve Bayes model enabled the prediction of cellular rejection processes with high sensitivity and specificity (AUC > 0.984). The serum proteomic profile was obtained in a high-throughput mode and based on a simple, rapid, and economical procedure, making it suitable for routine analyses and large-scale studies. Consequently, the current method presents a high potential to predict cellular rejection processes translatable to clinical scenarios, and that should continue to be explored.

Improvement in Echocardiographic Indexes of Systolic Heart Failure Post-Kidney Transplantation: A Retrospective Analysis

INTRODUCTION

End-stage renal disease is a major risk factor for cardiovascular morbidity and mortality, which can be partially eliminated by kidney transplantation. Systolic heart failure might be considered contraindication for kidney transplant, although some patients demonstrate myocardial recovery post-transplant. We aimed to identify and characterize the phenomenon of reverse myocardial remodeling in kidney transplanted patients.

METHODS

The study is a retrospective cohort of patients undergoing kidney transplants between 2016 and 2019 (n = 604) at Rabin Medical Center. Patients were assessed according to availability of two echocardiographic examinations: pre- and post-kidney transplant. The change in estimated ejection fraction (EF) and possible predictors of myocardial recovery were examined.

RESULTS

Data of 293 patients was available for the final analysis. Eighty-one (28%) patients had a LVEF improvement equal to or above 5%, whereas 36 (12%) patients had a LVEF improvement of 10% or more post-transplantation. Twenty-five patients (8.5%) had moderate or severe systolic heart failure with LVEF reduced to 40% or less at baseline. 13 of them (52%) had a LVEF improvement of ≥5%, and 10 patients (40%) had an improvement of ≥10% in their EF. Cox regression analyses identified female gender as the only independent variable associated with LVEF improvement of at least 10%.

CONCLUSION

Renal transplantation might lead to improved LV systolic function in some patients.

Sex disparities in mortality and cardiovascular outcomes in chronic kidney disease

Sex (biologically determined) and gender (socially constructed) modulate manifestations and prognosis of a vast number of diseases, including cardiovascular disease (CVD) and chronic kidney disease (CKD). CVD remains the leading cause of death in CKD patients. Population-based studies indicate that women present a higher prevalence of CKD and experience less CVD than men in all CKD stages, although this is not as clear in patients on dialysis or transplantation. When compared to the general population of the same sex, CKD has a more negative impact on women on kidney replacement therapy. European women on dialysis or recipients of kidney transplants have life expectancy up to 44.8 and 19.8 years lower, respectively, than their counterparts of similar age in the general population. For men, these figures stand at 37.1 and 16.5 years, representing a 21% to 20% difference, respectively. Hormonal, genetic, societal, and cultural influences may contribute to these sex-based disparities. To gain a more comprehensive understanding of these differences and their implications for patient care, well-designed clinical trials that involve a larger representation of women and focus on sex-related variables are urgently needed. This narrative review emphasizes the importance of acknowledging the epidemiology and prognosis of sex disparities in CVD among CKD patients. Such insights can guide research into the underlying pathophysiological mechanisms, leading to optimized treatment strategies and ultimately, improved clinical outcomes.

Long-term cardiovascular events, graft failure, and mortality in kidney transplant recipients

BACKGROUND

Kidney transplant recipients are at increased risks of cardiovascular events, but contemporary risk estimates are sparse. Using the Danish nationwide administrative databases, we quantified 1- and 5-year risks of cardiovascular disease and kidney failure among all first-time kidney transplant recipients (2005-2018) and age- and sex-matched controls (1:10 ratio).

METHODS

Cumulative 1- and 5-year incidence of cardiovascular events (myocardial infarction, stroke, or heart failure), kidney failure (re-transplantation or need for dialysis >30 days post-transplant), and mortality following transplantation were calculated until maximally Dec 31, 2018.

RESULTS

A total of 2,565 kidney transplant recipients (median age 50.5 [25-75th percentile 40.2-60.7] years, 37 % females) and 25,650 controls were included. 1-year cumulative incidence of myocardial infarction, stroke, or heart failure was 2.6 % (95 % confidence interval 1.9 %-3.2 %) among kidney transplant recipients versus 0.5 % (0.4 %-0.5 %) in controls. Cumulative 5-year risk estimates for the same endpoints were 8.3 % (7.1 %-9.5 %) for the transplant patients, and 2.6 % (2.3 %-2.8 %) among controls, respectively. For the kidney transplant cohort, cumulative mortality was 2.2 % (1.7 %-2.8 %) and 10.3 % (9.0 %-11.6 %) at 1- and 5 years, respectively, versus 0.5 % (0.4 %-0.6 %) and 3.0 % (2.7 %-3.2 %) for controls. The cumulative incidence of dialysis and re-transplantation was 6.1 % (5.2 %-7.1 %) at 1 year and 16.3 % (14.7 %-17.9 %) at 5 years, respectively.

CONCLUSIONS

Despite the benefits of transplantation, kidney transplant recipients continue to have significant long-term cardiovascular disease, end-stage kidney disease, and mortality risks even with contemporary medical management. Better cardiovascular preventive strategies are warranted to improve prognosis in this segment of patients.

Old for young kidney transplantation: a responsible option for our patients to reduce waiting time?

PURPOSE

The Eurotransplant Senior program allocating grafts from donors ≥ 65 years to recipients aged ≥ 65 years has proven good results within the last 20 years. However, "old" grafts are also allocated to younger recipients < 65 years, and this outcome of "old for young" kidney transplantations (KT) still lacks detailed investigations.

METHODS

All "old for young" KT performed at four tertiary referral centers were retrospectively compared including a recent follow-up, stratifying for "old for young" (donor ≥ 65 years to recipient < 65 years) vs. "very old for young" KT (donor ≥ 70 years to recipient < 65 years).

RESULTS

Overall, 99 patients were included with 56 (56.6%) "old for young" and 43 (43.4%) "very old for young" KT. The median waiting time did not differ (60.7 vs. 45.8 months, respectively) at comparable living donation rates (57.1% vs. 44.2%) as well as intra- and postoperative results. At a median follow-up of 44 months (range 1; 133), the 3-year graft survival of 91% vs. 87% did not significantly vary. In subgroup analyses assessing living donation or donation after brain death (DBD) KT only, the graft survival was significantly longer for "old for young" KT within the living donation subgroup. In multivariate Cox regression analyses, the presence of panel-reactive antibodies was the only significant impact factor on graft survival (HR 8.32, p = 0.001).

CONCLUSION

This analysis clearly demonstrates the effectiveness of the "old for young" approach, enabling favorable perioperative results as well as comparable data of graft- and overall survival, while reducing waiting time for eligible patients.

Intramuscular and abdominal fat measured by computed tomography and mortality of hemodialysis patients

BACKGROUND

In hemodialysis patients, high body mass index is associated with low mortality while abdominal obesity relates to increased mortality. We aimed to investigate the association between muscle mass, intramuscular fat and abdominal fat measured by abdominal computed tomography (CT), and mortality in this patients population.

METHODS

This two-center retrospective cohort study included hemodialysis patients who underwent abdominal CT between January 2013 and December 2018. Skeletal muscle mass index (SMI), muscle radiation attenuation (MRA) as an index of intramuscular fat, and visceral fat to subcutaneous fat ratio (VSR) were calculated using CT images at the third lumbar vertebral level. Multivariate Cox proportional hazards model was used to determine the independent predictors of all-cause, cardiovascular and non-cardiovascular mortalities.

RESULTS

The study included 344 patients (median age 71.0 years; female 33.7%), among whom 145 died during a median follow-up of 4.9 years-46 and 99 from cardiovascular and non-cardiovascular causes, respectively. Lower MRA [hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.58-0.87, P = .001] and higher VSR (HR 1.17, 95% CI 1.01-1.37, P = .04) were independently associated with higher all-cause mortality but not with lower SMI (HR 0.87, 95% CI 0.68-1.11, P = .26). Lower MRA (HR 0.51, 95% CI 0.35-0.73, P < .001) and higher VSR (HR 1.29, 95% CI 1.09-1.54, P = .003) were also associated with cardiovascular and non-cardiovascular mortality, respectively.

CONCLUSIONS

Intramuscular fat and abdominal fat as measured using abdominal CT in hemodialysis patients are stronger independent predictors of mortality than muscle mass.

Benefits of statin therapy within a year after kidney transplantation

Cardiovascular disease remains a leading cause of morbidity and mortality after kidney transplantation (KT). Although statins reduce cardiovascular risk and have renal benefits in the general population, their effects on KT recipients are not well-established. We studied the effects of early statin use (within 1-year post-transplantation) on long-term outcomes in 714 KT recipients from the Korean cohort study for outcome in patients with KT. Compared with the control group, statin group recipients were significantly older, had a higher body mass index, and had a higher prevalence of diabetes mellitus. During a median follow-up of 85 months, 74 graft losses occurred (54 death-censored graft losses and 20 deaths). Early statin use was independently associated with lower mortality (hazard ratio, 0.280; 95% confidence interval 0.111-0.703) and lower death-censored graft loss (hazard ratio, 0.350; 95% confidence interval 0.198-0.616). Statin therapy significantly reduced low-density lipoprotein cholesterol levels but did not decrease the risk of major adverse cardiovascular events. Biopsy-proven rejection and graft renal function were not significantly different between statin and control groups. Our findings suggest that early statin use is an effective strategy for reducing low-density lipoprotein cholesterol and improving patient and graft survival after KT.

Comparative Effectiveness of PET and SPECT MPI for Predicting Cardiovascular Events After Kidney Transplant

BACKGROUND

Advanced chronic kidney disease is associated with high cardiovascular risk, even after kidney transplant. Pretransplant cardiac testing may identify patients who require additional assessment before transplant or would benefit from risk optimization. The objective of the current study was to determine the relative prognostic utility of pretransplant positron emission tomography (PET) and single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for posttransplant major adverse cardiovascular events (MACEs).

METHODS

We retrospectively followed patients who underwent MPI before kidney transplant for the occurrence of MACE after transplant including myocardial infarction, stroke, heart failure, and cardiac death. An abnormal MPI result was defined as a total perfusion deficit >5% of the myocardium. To determine associations of MPI results with MACE, we utilized Cox hazard regression with propensity weighting for PET versus SPECT with model factors, including demographics and cardiovascular risk factors.

RESULTS

A total of 393 patients underwent MPI (208 PET and 185 SPECT) and were followed for a median of 5.9 years post-transplant. Most were male (58%), median age was 58 years, and there was a high burden of hypertension (88%) and diabetes (33%). A minority had abnormal MPI (n=58, 15%). In propensity-weighted hazard regression, abnormal PET result was associated with posttransplant MACE (hazard ratio, 3.02 [95% CI, 1.78-5.11]; P<0.001), while there was insufficient evidence of an association of abnormal SPECT result with MACE (1.39 [95% CI, 0.72-2.66]; P=0.33). The explained relative risk of the PET result was higher than the SPECT result (R2 0.086 versus 0.007). Normal PET was associated with the lowest risk of MACE (2.2%/year versus 3.6%/year for normal SPECT; P<0.001).

CONCLUSIONS

Kidney transplant recipients are at high cardiovascular risk, despite a minority having obstructive coronary artery disease on MPI. PET MPI findings predict posttransplant MACE. Normal PET may better discriminate lower risk patients compared with normal SPECT, which should be confirmed in a larger prospective study.

Dialysis Modality, Transplant Characteristics, and Incident Atrial Fibrillation After Kidney Transplant: An Observational Study Using USRDS Data

Rationale & Objective

Atrial fibrillation is the most common arrhythmia and is increasing in prevalence. The prevalence of atrial fibrillation is high among patients receiving dialysis, affecting ∼21.3% of the patients receiving hemodialysis and 15.5% of those receiving peritoneal dialysis. The association of previous dialysis modality with incident atrial fibrillation in patients after receiving their first kidney transplant has not been studied.

Study Design

We used the United States Renal Data System to retrospectively identify adult, Medicare-insured patients who received their first kidney transplant between January 1, 2005, and September 30, 2012 and who had not previously been diagnosed with atrial fibrillation.

Setting & Participants

The study included 43,621 patients who were aged 18 years older when receiving a first kidney transplant between January 1, 2005, and September 30, 2012 and whose primary payer was Medicare (parts A and B) at the time of transplantation and the 6 months preceding it.

Exposure

Dialysis modality used before transplant.

Outcome

Time to incidence of atrial fibrillation up to 3 years posttransplant.

Analytical Approach

Multivariable Cox regression was used to estimate HRs.

Results

Of 43,621 patients, 84.9% received hemodialysis and 15.1% received peritoneal dialysis before transplant. The mean ± SD age was 51 ± 13.6 years; 60.8% were male, 55.6% White, and 35.8% Black race. The mean dialysis vintage was 4.3 ± 2.8 years. Newly diagnosed atrial fibrillation after kidney transplant occurred in 286 patients (during 15,363 person-years) who had received peritoneal dialysis and in 2,315 patients (during 83,536 person-years) who had received hemodialysis. After multivariable adjustment, atrial fibrillation was 20% (95% CI, 4%-38%) more likely in those who had been receiving hemodialysis versus peritoneal dialysis, regardless of whether death was considered a competing risk or a censoring event. Each year of pretransplant dialysis vintage increased the risk of posttransplant atrial fibrillation by 6% (95% CI, 3%-9%).

Limitations

Residual confounding; data from billing claims does not specify the duration of atrial fibrillation or whether it is valvular.

Conclusions

Pretransplant hemodialysis, as compared with peritoneal dialysis, was associated with higher risk of newly diagnosed atrial fibrillation after a first kidney transplant.

Plain-Language Summary

New-onset atrial fibrillation (AF) occurs in 7% of kidney transplant recipients in the first 3 years posttransplantation. We conducted this study to determine whether pretransplant dialysis modality was associated with posttransplant AF. We identified 43,621 patients; 84.9% used hemodialysis and 15.1% used peritoneal dialysis pretransplant. Multivariable Cox regression was used to estimate hazard ratios. We found that patients receiving hemodialysis pretransplant were at 20% increased risk of developing posttransplant AF as compared with patients receiving peritoneal dialysis. As our understanding of transplant-specific risk factors for AF increases, we may be able to better risk-stratify transplant patients and develop monitoring and management strategies that can improve outcomes.

External Validation of Proposed American Heart Association Algorithm for Cardiovascular Screening Before Kidney Transplantation

BACKGROUND

Screening for cardiovascular disease is currently recommended before kidney transplantation. The present study aimed to validate the proposed algorithm by the American Heart Association (AHA-2022) considering cardiovascular findings and outcomes in kidney transplant candidates, and to compare AHA-2022 with the previous recommendation (AHA-2012).

METHODS AND RESULTS

We applied the 2 screening algorithms to an observational cohort of kidney transplant candidates (n=529) who were already extensively screened for coronary heart disease by referral to cardiac computed tomography between 2014 and 2019. The cohort was divided into 3 groups as per the AHA-2022 algorithm, or into 2 groups as per AHA-2012. Outcomes were degree of coronary heart disease, revascularization rate following screening, major adverse cardiovascular events, and all-cause death. Using the AHA-2022 algorithm, 69 (13%) patients were recommended for cardiology referral, 315 (60%) for cardiac screening, and 145 (27%) no further screening. More patients were recommended cardiology referral or screening compared with the AHA-2012 (73% versus 53%; P<0.0001). Patients recommended cardiology referral or cardiac screening had a higher risk of major adverse cardiovascular events (hazard ratio [HR], 5.5 [95% CI, 2.8-10.8]; and HR, 2.1 [95% CI, 1.2-3.9]) and all-cause death (HR, 12.0 [95% [CI, 4.6-31.4]; and HR, 5.3 [95% CI, 2.1-13.3]) compared with patients recommended no further screening, and were more often revascularized following initial screening (20% versus 7% versus 0.7%; P<0.001).

CONCLUSIONS

The AHA-2022 algorithm allocates more patients for cardiac referral and screening compared with AHA-2012. Furthermore, the AHA-2022 algorithm effectively discriminates between kidney transplant candidates at high, intermediate, and low risk with respect to major adverse cardiovascular events and all-cause death.

The value of pre-transplant coronary angiography findings in kidney transplant candidates at high risk for cardiovascular disease

Introduction

Cardiovascular disease is a significant cause of mortality after kidney transplantation. Whether pre-transplant screening for coronary artery disease (CAD) in asymptomatic kidney transplant candidates (KTCs) is beneficial is unclear.

Methods

We conducted a retrospective cohort study evaluating post-transplant cardiovascular events in 192 high-risk KTCs who underwent pre-transplant CAD evaluation. The study aimed to identify risk factors associated with finding severe CAD on pre-transplant angiography, and to assess the relationship between screening strategies and post-transplant cardiovascular events.

Results

At five years post-transplant, cardiovascular events occurred in 23.9% of subjects. Prior CAD history and left ventricular ejection fraction (LVEF) < 50% were associated with higher odds of finding severe CAD on pre-transplant angiography. Severe CAD on angiography was associated with a higher risk of early cardiovascular events within six months of transplantation. However, coronary intervention in KTCs with severe CAD was not associated with lower rates of post-transplant cardiovascular events.

Conclusion

Pre-transplant coronary angiography to identify severe CAD is of highest yield in KTCs with a history of CAD or an LVEF < 50%. Our findings indicate that the identification of severe CAD in KTCs has prognostic significance for the early post-transplant period. Optimization of medical therapy in these high-risk KTCs may improve post-transplant cardiovascular outcomes.

MCP1 Inverts the Correlation between FGF23 and Omega 6/3 Ratio: Is It Also True in Renal Transplantation?

During chronic kidney disease (CKD) progression, an increase in fibroblast growth factor (FGF23) is present. In stage 5, a positive correlation between FGF23 and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) emerges. Hypothesizing that the rising positive correlation between monocyte chemoattractant protein 1 (MCP1) and n-6 in stage 4 could be the cause, we previously explored FGF23 and MCP1's roles in dyslipidemia and cardiovascular risk in CKD. In the present paper, we retraced the study evaluating 40 kidney transplant patients (KTx), a cohort where several factors might modify the previous relationships found. An ELISA and gas chromatography assessed the MCP1, FGF23, and PUFA levels. Despite the FGF23 increase (p < 0.0001), low MCP1 levels were found. A decrease in the n-6/n-3 ratio (p = 0.042 CKD stage 4 vs. 5) lowered by the increase in both n-3 αlinolenic (p = 0.012) and docosapentaenoic acid (p = 0.049) was observed. A negative correlation between FGF23 and the n-6/n-3 ratio in CKD stage 4 (r2 -0.3 p = 0.043) and none with MCP1 appeared. According to our findings, different mechanisms in the relationship between FGF23, PUFAs, and MCP1 in CKD and KTx patients might be present, which is possibly related to the immunosuppressive status of the last. Future research will further clarify our hypothesis.

Pyelovesicostomy as an Alternative Surgical Treatment for Complex Ureteral Lesions After Kidney Transplant

OBJECTIVES

We evaluated the feasibility, safety, and long-term outcomes of pyelovesicostomy as an alternative surgical treatment for complex ureteral lesions after kidney transplant.

MATERIALS AND METHODS

A single-center, retrospective, observational cohort study was conducted on 5 adult kidney transplant recipients who underwent pyelovesicostomy between January 2000 and June 2023. The collected data included patient demographics, surgery indication, time from transplant to pyelovesicostomy, procedure details, and kidney function at various time points after surgery. Primary outcomes were allograft function and complications.

RESULTS

The 5 patients (4 female, 1 male) had a mean age of 65.8 years and mean body mass index of 26.8. Indications were complex ureteral lesions. The time between transplant and reoperation ranged from 4 days to 12 years. Renal function improved for all patients, with a progressive decrease in mean serum creatinine concentration. The mean follow-up period extended to 7 years. One patient died with the graft still functional at 20 years after the operation, whereas the remaining 4 patients continue to live with functional grafts.

CONCLUSIONS

Our study suggests that pyelovesicostomy may provide a potent alternative for the management of complex ureteral lesions after kidney transplant. We have observed good short-term and long-term outcomes in specific patients, pointing toward a promising avenue oftreatment worth further exploration. This reaffirms the importance of a personalized approach in medicine, to consider each patient's unique conditions and characteristics during therapeutic decisions.

In a real-life setting, risk factors, coronary artery calcium score, and coronary stenosis at computed tomography angiography are associated with major adverse cardiovascular events and all-cause mortality among kidney transplant candidates

Kidney failure is associated with an increased risk of cardiovascular disease and death. This single-center, a retrospective study evaluated the association between risk factors, coronary artery calcium score (CACS), coronary computed tomography angiography (CTA), major adverse cardiovascular events (MACEs), and all-cause mortality in kidney transplant candidates. Data on clinical risk factors, MACE, and all-cause mortality were collected from patient records. A total of 529 kidney transplant candidates were included (median follow-up of 4.7 years). CACS was evaluated in 437 patients and CTA in 411. Both the presence of ≥3 risk factors, CACS of ≥400, as well as multiple-vessel stenoses or left main artery disease predicted MACE (hazard ratio, 2.09; [95% confidence interval, 1.35-3.23]; 4.65 [2.20-9.82]; 3.70 [1.81-7.57]; 4.90 [2.40-10.01]) and all-cause mortality (harad ratio, 4.44; [95% confidence interval, 2.54-7.76]; 4.47 [2.22-9.02]; 2.82 [1.34-5.94]; 5.41 [2.81-10.41]) in univariate analyses. Among patients eligible for CACS and CTA (n = 376), only CACS and CTA were associated with both MACE and all-cause mortality. In conclusion, risk factors, CACS, and CTA provide information on the risk of MACE and mortality in kidney transplant candidates. An additional value of CACS and CTA compared with risk factors was observed for the prediction of MACE in a subpopulation undergoing both CACS and CTA.

Home-Based Exercise Training and Cardiac Autonomic Neuropathy in Kidney Transplant Recipients with Type-II Diabetes Mellitus

This randomized clinical trial aimed to examine the effects of a 6-month home-based, combined exercise training program on Cardiac Autonomic Neuropathy (CAN) in kidney transplant recipients (KTRs) with diabetes. Twenty-five KTRs (19 men (76.0%), with a mean age of 54.4 ± 11.3 years old, CAN and type II Diabetes Mellitus (DM-II)), were randomly assigned into two groups: A (n1 = 13 KTRs), who underwent a home-based exercise training program for 6 months, and B (n2 = 12 KTRs), who were assessed at the end of the study. A cardiopulmonary exercise testing (CPET), sit-to-stand test in 30 s (30-s STS), isokinetic muscle strength dynamometry, and 24-h electrocardiographic monitoring were applied to all participants, both at the baseline and at the end of the clinical trial. At first, there were no statistically significant differences between groups. After 6 months, group A showed higher values in exercise time by 8.7% (p = 0.02), VO2peak by 7.3% (p < 0.05), 30-s STS by 12.0% (p < 0.05), upper limb strength by 46.1% (p < 0.05), and lower limb strength by 24.6% (p = 0.02), respectively, compared to the B group. Furthermore, inter-group changes at the end of the 6-month study indicated that group A statistically increased the standard deviation of R-R intervals (SDNN) by 30.3% (p = 0.01), root mean square of successive differences between normal heartbeats (rMSSD) by 32.0% (p = 0.03), number of pairs of successive NN (R-R) intervals that differ by more than 50 ms (pNN50) by 29.0% (p = 0.04), high frequency (HF (ms2)) by 21.6% (p < 0.05), HF (n.u.) by 48.5% (p = 0.01), and turbulence slope (TS) by 22.5% (p = 0.02), and decreased the low frequency (LF (ms2)) by 13.2% (p = 0.01), LF (n.u.) by 24.9% (p = 0.04), and LF/HF ratio by 24% (p = 0.01), compared to group B. Linear regression analysis after the 6-month study showed that there was a strong positive correlation between VO2peak and SDNN (r = 0.701, p < 0.05) in group A. Moreover, multiple regression analysis showed that KTRs' participation in the exercise program showed favorable modifications to sympathovagal balance and aerobic capacity, as measured with SDNN and VO2peak, respectively. To summarize, diabetic KTRs' cardiac autonomic function and functional capacity can be improved after a home-based long-term exercise training program.

Variations in Risk of Cancer and Death From Cancer According to Kidney Allograft Function, Graft Loss, and Return to Dialysis

BACKGROUND

Cancer incidence and mortality may change with varying kidney allograft function and after graft loss. We aimed to quantify cancer incidence and mortality during periods with a functioning graft and after graft loss.

METHODS

We included all adult Australians aged 20 and above who commenced kidney replacement therapy between 1982 and 2014 using data from Australia and New Zealand Dialysis and Transplant Registry. We calculated the standardized incidence ratios and standardized mortality ratios (standardized against the Australian general population) for dialysis patients and transplant recipients during periods with a functioning graft and after graft loss.

RESULTS

A total of 44 765 dialysis patients without transplants, 13 443 with first kidney transplants, 2951 after first graft loss, 1010 with second transplants, and 279 after second graft loss were followed for 274 660 patient-years. Cancer incidence and mortality (per 100 000 patient-years) were 1564 and 760 in dialysis patients, 1564 and 689 in recipients of first transplants, 1188 and 390 after first graft loss, 1525 and 693 after second transplants, and 1645 and 779 after second graft loss. Cancer standardized incidence ratios and standardized mortality ratios (95% confidence intervals) were 1.15 (1.11-1.20) and 1.29 (1.21-1.36) for dialysis patients, 2.03 (1.94-2.13) and 2.50 (2.33-2.69) for recipients following their first transplant, 1.55 (1.29-1.85) and 1.40 (1.00-1.90) after first graft loss, 2.18 (1.79-2.63) and 3.00 (2.23-3.96) for second transplants, 2.59 (1.56-4.04) and 3.82 (1.75-7.25) after second graft loss.

CONCLUSIONS

In kidney transplant recipients, cancer incidence and mortality are highest during periods with a functioning graft and remained higher than in the general population even after graft loss.

The Importance Of Avoiding Time-Dependent Bias When Testing The Prognostic Value Of An Intervening Event - Two Acute Cellular Rejection Examples In Intestinal Transplantation

In testing the prognostic value of the occurrence of an intervening event (clinical event that occurs post-transplant), 3 proper statistical methodologies for testing its prognostic value exist (time dependent covariate, landmark, and semi-Markov modelling methods). However, time-dependent bias has appeared in many clinical reports, whereby the intervening event is statistically treated as a baseline variable (as if it occurred at transplant). Using a single-center cohort of 445 intestinal transplant cases to test the prognostic value of 1^st acute cellular rejection (ACR) and severe (grade of) ACR on the hazard rate of developing graft loss, we demonstrate how the inclusion of such time-dependent bias can lead to severe underestimation of the true hazard ratio (HR). The (statistically more powerful) time dependent covariate method in Cox's multivariable model yielded significantly unfavorable effects of 1^st ACR (P<.0001; HR=2.492) and severe ACR (P<.0001; HR=4.531). In contrast, when using the time-dependent biased approach, multivariable analysis yielded an incorrect conclusion for the prognostic value of 1^st ACR (P=.31, HR=0.877, 35.2% of 2.492) and a much smaller estimated effect of severe ACR (P=.0008; HR=1.589; 35.1% of 4.531). In conclusion, this study demonstrates the importance of avoiding time-dependent bias when testing the prognostic value of an intervening event.

Incidence of cardiovascular disease and mortality in childhood solid organ transplant recipients: a population-based study

BACKGROUND

With improved survival among children after transplantation, our understanding of the risk for developing other comorbidities is improving, yet little is known about the long-term risk of cardiovascular events and mortality after solid organ transplantation.

METHODS

In a cohort study using health administrative data, we compared cardiovascular events in children (n = 615) with liver, lung, kidney, small bowel, or multi-organ transplant at the Hospital for Sick Children, Toronto, Canada, with asthmatic children (n = 481,697) between 1996 and 2014. Outcomes included non-fatal cardiovascular events, cardiovascular death, all-cause mortality, and a composite of non-fatal and fatal cardiovascular events. Time-stratified Cox proportional hazards models were used.

RESULTS

Among 615 children, 317 (52%) were recipients of kidneys, 253 (41%) of livers, and the remaining 45 (7%) had lung, small bowel, or multi-organ transplants. Median follow-up was 12.1 [7.2, 16.7] years. Non-fatal incident cardiovascular events were 34 times higher among solid organ transplant recipients than non-transplanted children (incidence rate ratio (IRR) 34.4, 95% CI: 25.5, 46.4). Among transplant recipients, the cumulative incidence of non-fatal and fatal cardiovascular events was 2.3% and 13.0%, 5 and 15 years after transplantation, respectively.

CONCLUSIONS

Increased rate of cardiovascular events in children after transplantation highlights the need for surveillance during transition into adulthood and beyond. A higher resolution version of the Graphical abstract is available as Supplementary information.

Revisiting maintenance immunosuppression in patients with renal transplant failure: early weaning of immunosuppression versus prolonged maintenance-systematic review and meta-analysis

INTRODUCTION

Prolonged immunosuppression after dialysis start has been assumed to reduce sensitization, need for graft nephrectomy, and to favor re-transplantation. In contrast, immunosuppression is considered to increase the risk of mortality, infection, and malignancy. We aimed to assess the evidence regarding superiority of early or late withdrawal of maintenance immunosuppression post renal transplant failure.

METHODS

A literature search of the PubMed, WOS, Ovid, and Scopus databases was conducted. Combined relative risks, (RRs), mean differences, and 95% confidence intervals (CIs) were calculated by using a random-effect model.

RESULTS

Ten studies involving 1187 patients with kidney transplant failure were included. No difference could be detected between patients with early withdrawal of  immunosuppressive drugs (≤ 3 months) or prolonged immunosuppressive treatment (> 3 months) regarding mortality (95% CI 0.91-2.28), panel reactive antibodies (PRAs) (95% CI - 0.75-30.10), re-transplantation rate (95% CI 0.55-1.35), infectious episodes (95% CI 0.67, 1.17), cancer (95% CI 0.26-1.54), and graft nephrectomy (95% CI 0.82-1.63). Similarly, no difference was found between immunosuppressive drug withdrawal over < 6 or ≥ 6 months regarding mortality (95% CI 0.16, 2.89), re-transplantation rate (95% CI 0.85-1.55), cancer (95% CI 0.37-1.63), and allograft nephrectomy (95% CI 0.87-4.33).

CONCLUSION

Prolonged maintenance immunosuppression post kidney transplant failure is not associated with increased risk of mortality, infection, or malignancy, or reduced risk of sensitization or allograft nephrectomy compared with early withdrawal.

Serological and histopathological assessment of galactose-deficient immunoglobulin A1 deposition in kidney allografts: A multicenter prospective observational study

BACKGROUND

Recurrent immunoglobulin A (IgA) nephropathy is an important risk factor for kidney allograft loss. However, there is no classification system for IgA deposition in kidney allografts based on serological and histopathological evaluation of galactose-deficient IgA1 (Gd-IgA1). This study aimed to establish a classification system for IgA deposition in kidney allografts based on serological and histological evaluation of Gd-IgA1.

METHODS

This multicenter prospective study included 106 adult kidney transplant recipients in whom an allograft biopsy was performed. Serum and urinary Gd-IgA1 levels were investigated in 46 transplant recipients who were IgA-positive and classified into four subgroups according to the presence or absence of mesangial Gd-IgA1 (KM55 antibody) deposits and C3.

RESULTS

Minor histological changes without an acute lesion were observed in recipients with IgA deposition. Fourteen (30%) of the 46 IgA-positive recipients were KM55-positive and 18 (39%) were C3-positive. The C3 positivity rate was higher in the KM55-positive group. Serum and urinary Gd-IgA1 levels were significantly higher in KM55-positive/C3-positive recipients than in the other three groups with IgA deposition. Disappearance of IgA deposits was confirmed in 10 of 15 IgA-positive recipients in whom a further allograft biopsy was performed. The serum Gd-IgA1 level at the time of enrollment was significantly higher in recipients in whom IgA deposition continued than in those in whom it disappeared (p = 0.02).

CONCLUSIONS

The population with IgA deposition after kidney transplantation is serologically and pathologically heterogeneous. Serological and histological assessment of Gd-IgA1 is useful for identifying cases that should be carefully observed.

De novo major cardiovascular events in kidney transplant recipients: a comparative matched cohort study

BACKGROUND

Although cardiovascular disease is known to be one of the leading causes of death after kidney transplantation (KT), evidence on the risk difference of de novo major adverse cardiovascular events (MACEs) in kidney transplant recipients (KTRs) compared with that in dialysis patients or the general population (GP) remains rare.

METHODS

We identified KTRs using the nationwide health insurance database in South Korea and then 1:1 matched them with the dialysis and GP controls without a pre-existing MACE. The primary endpoint was defined as de novo MACEs consisting of myocardial infarction, coronary revascularization and ischemic stroke. The secondary endpoints were all-cause mortality and death-censored graft failure (DCGF) in KTRs.

RESULTS

We included 4156 individuals in each of the three groups and followed them up for 4.7 years. De novo MACEs occurred in 3.7, 21.7 and 2.5 individuals per 1000 person-years in the KTRs, dialysis controls and GP controls, respectively. KTRs showed a lower MACE risk {adjusted hazard ratio (aHR) 0.16 [95% confidence interval (CI) 0.12-0.20], P < .001} than dialysis controls, whereas a similar MACE risk to GP controls [aHR 0.81 (95% CI 0.52-1.27), P = .365]. In addition, KTRs showed a similar MACE risk compared with the GP group, regardless of age, sex and the presence of comorbidities, including hypertension, diabetes and dyslipidemia. Among KTRs, de novo MACEs were associated with an increased risk of all-cause mortality, but not with DCGF.

CONCLUSIONS

De novo MACEs in KTRs were much lower than that in dialysis patients and had a similar risk to the GP, but once it occurred it caused elevated mortality risk in KTRs.

Effect of kidney transplantation on indices of cardiorespiratory fitness assessed with cardiopulmonary exercise testing: a systematic review and meta-analysis

BACKGROUND

Patients with kidney failure often present with reduced cardiovascular reserve. Kidney transplantation (KT) is the optimal treatment for patients with end-stage kidney disease as it is associated with longer survival and improved quality of life compared to dialysis.

METHODS

This is a systematic review and meta-analysis of studies using cardiopulmonary-exercise-testing to examine the cardiorespiratory fitness of patients with kidney failure before and after KT. The primary outcome was difference in pre- and post-transplantation values of peak oxygen uptake (VO2peak). Literature search involved three databases (PubMed-Web of Science-Scopus), manual search, and grey literature.

RESULTS

From 379 records initially retrieved, six studies were included in final meta-analysis. A marginal, but not significant, improvement was observed in VO2peak after KT compared to pre-transplantation values (SMD: 0.32, 95%CI -0.02; 0.67). Oxygen consumption at anaerobic threshold was significantly improved after KT (WMD: 2.30 ml/kg/min, 95%CI 0.50; 4.09). Consistent results were shown between preemptive and after-dialysis-initiation transplantation and a trend for improvement in VO2peak was observed at least 3 months post-transplantation, but not earlier.

CONCLUSION

Several major indices of cardiorespiratory fitness tend to improve after KT. This finding may represent another modifiable factor contributing to better survival rates of kidney transplant recipients compared to patients undergoing dialysis.

Echocardiogram screening in pediatric dialysis and transplantation

Transthoracic echocardiography is commonly used to identify structural and functional cardiac abnormalities that can be prevalent in childhood chronic kidney failure (KF). Left ventricular mass (LVM) increase is most frequently reported and may persist post-kidney transplant especially with hypertension and obesity. While systolic dysfunction is infrequently seen in childhood chronic KF, systolic strain identified by speckle tracking echocardiography has been frequently identified in dialysis and it can also persist post-transplant. Echocardiogram association with long-term outcomes has not been studied in childhood KF but there are many adult studies demonstrating associations between increased LVM, systolic dysfunction, strain, diastolic dysfunction, and cardiovascular events and mortality. There has been limited study of interventions to improve echocardiogram status. In childhood, improved blood pressure has been associated with better LVM, and conversion from hemodialysis to hemodiafiltration has been associated with better diastolic and systolic function. Whether long-term cardiac outcomes are also improved with these interventions is unclear. Echocardiography is a well-established technique, and regular use in childhood chronic KF seems justified. A case can be made to extend screening to include speckle tracking echocardiography and intradialytic studies in high-risk populations. Further longitudinal studies including these newer echocardiogram modalities, interventions, and long-term outcomes would help clarify recommendations for optimal use as a screening tool.

RETRACTED:Predictive Factors of Surgical Complications in the First Year Following Kidney Transplantation

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( https://www.elsevier.com/locate/withdrawalpolicy ). The article has been retracted at the request of the last author, Sebastien Deglise, due to significant violations of research standards during the course of the study which do not ensure the reliability of the published data and of which the author has informed the journal that he was unaware at the time of the publication.

A population cohort analysis of English transplant centers indicates major adverse cardiovascular events after kidney transplantation

Major adverse cardiovascular event (MACE) rates immediately after kidney transplantation remain uncertain due to heterogeneous reporting in the literature. To clarify this, we retrospectively studied every eligible kidney transplant procedure performed in England between April 1, 2002 and March 31. 2018 with follow-up through August 31, 2019. The primary outcome of interest was MACE broadly defined as any hospital admission with myocardial infarction, stroke, unstable angina, heart failure, any coronary revascularisation procedure and/or any cardiovascular death. Among 30,325 kidney transplant recipients, MACE occurred in 781 within the first year after transplantation (2.6% of all kidney transplant procedures). Of these 781 events, 201 occurred during the index admission for kidney transplantation surgery representing 25.7% of all first-year MACE and 0.7% of all kidney transplant procedures. Kidney transplant recipients who suffered a non-fatal MACE within the first year had significantly decreased 1-, 3-, 5- and 10-year patient survival of 80.5%, 70.2%, 59.5% and 38.6% respectively, compared to 97.4%, 94.4%, 90.7% and 78.4% for kidney transplant recipients not developing MACE.. In an adjusted Cox proportional hazard model, non-fatal MACE within the first-year post-transplant was associated with significant long-term mortality risk (hazard ratio 2.59; 95% confidence interval 2.34-2.88). Kidney transplant recipients experiencing MACE during the index admission compared to subsequent admissions were differentiated by age, sex and previous cardiac history but had similar patient survival. These rates are significantly lower than those reported in North America. Thus, our data confirms MACE is not a benign post-transplant event and has a strong association with long-term mortality risk.

Scoring of medial arterial calcification predicts cardiovascular events and mortality after kidney transplantation

BACKGROUND

Progression of vascular calcification causes cardiovascular disease, which is the most common cause of death in chronic kidney failure and after kidney transplantation (KT). The prognostic impact of the extent of medial vascular calcification at KT is unknown.

METHODS

In this prospective cohort study, we investigated the impact of medial calcification compared to a mix of intimal and medial calcification represented by coronary artery calcification (CAC score) and aortic valve calcification in 342 patients starting on kidney failure replacement therapy. The primary outcomes were cardiovascular events (CVE) and death. The median follow-up time was 6.4 years (interquartile range 3.7-9.6 years). Exposure was CAC score and arteria epigastrica medial calcification scored as none, mild, moderate, or severe by a pathologist at time of KT (n = 200). We divided the patients according to kidney failure replacement therapy during follow-up, that is, living donor KT, deceased donor KT, or dialysis.

RESULTS

Moderate to severe medial calcification in the arteria epigastrica was associated with higher mortality (p = 0.001), and the hazard ratio for CVE was 3.1 (95% confidence interval [CI] 1.12-9.02, p < 0.05) compared to no or mild medial calcification. The hazard ratio for 10-year mortality in the dialysis group was 33.6 (95% CI, 10.0-113.0, p < 0.001) compared to living donor recipients, independent of Framingham risk score and prevalent CAC.

CONCLUSION

Scoring of medial calcification in the arteria epigastrica identified living donor recipients as having 3.1 times higher risk of CVE, independent of traditional risk factors. The medial calcification score could be a reliable method to identify patients with high and low risk of CVE and mortality following KT.

Time-dependent cardiac structural and functional changes after kidney transplantation: a multi-parametric cardiac magnetic resonance study

OBJECTIVES

To map time-dependent cardiac structural and functional change patterns after renal transplantation (KT) using cardiac magnetic resonance (CMR).

METHODS

Fifty-three patients with pre-KT and post-KT CMR exams were retrospectively analyzed. Patients were divided into three groups according to the time of post-KT CMR: group 1 (3 months post-KT, n = 16), group 2 (6 months post-KT, n = 21), and group 3 (over 9 months post-KT, n = 16). Twenty-one age- and sex-matched healthy controls (HC) were recruited for the study. CMR-derived left ventricular (LV) volumes, LV mass index (LVMi), LV ejection fraction (LVEF), global radial strain (GRS), global circumferential strain (GCS), global longitudinal strain (GLS), and native T1 value were compared. The association between the changes of CMR parameters was assessed.

RESULTS

LVMi post-KT decreased in groups 2 (p < 0.001) and 3 (p = 0.004) but both groups had higher LVMi values compared to HC (both p < 0.001). GLS post-KT was decreased in group 1 (p = 0.021), but slightly increased in group 2 (p = 0.728) and group 3 (p = 0.100) without significant difference. GLS post-KT in group 3 was not different from HC (p = 0.104). LVEF, GRS, and GCS post-KT in groups 2 and 3 significantly increased and showed no significant difference from HC. The post-KT native T1 value in all three groups significantly decreased; however, no group showed any significant difference from HC. The change of LVEF was associated with the change of GCS, GRS, and GLS.

CONCLUSIONS

Although GRS, GCS, GLS, and native T1 values reversed to normal level, LVMi remained impaired in median 14 months after KT.

KEY POINTS

• Kidney transplantation has favorable effects on cardiac structure and function. • In a median 14 months of follow-up after KT, left ventricle strain and native T1 value reversed to normal level while LV mass index (LVMi) did not. Left ventricular hypertrophy may help to explain why KT recipients are still at increased cardiovascular risk. • The reason for the decrease of native T1 value after KT may be more than myocardial fibrosis and needs to be further studied.

Influence of Belatacept- vs. CNI-Based Immunosuppression on Vascular Stiffness and Body Composition

Background: Arterial stiffness and phase angle (PhA) have gained importance as a diagnostic and prognostic parameter in the management of cardiovascular disease. There are few studies regarding the differences in arterial stiffness and body composition between renal transplant recipients (RTRs) receiving belatacept (BELA) vs. calcineurin inhibitors (CNI). Therefore, we investigated the differences in arterial stiffness and body composition between RTRs treated with different immunosuppressants, including BELA. Methods: In total, 325 RTRs were enrolled in the study (mean age 52.2 years, M −62.7%). Arterial stiffness was determined with an automated oscillometric device. All body composition parameters were assessed, based on bioelectrical impedance analysis (BIA), and laboratory parameters were obtained from the medical files of the patients. Results: We did not detect any significant difference in terms of arterial stiffness and PhA in RTRs undergoing different immunosuppressive regimens, based on CsA, Tac, or BELA. Age was an essential risk factor for greater arterial stiffness. The PhA was associated with age, BMI, time of dialysis before transplantation, and kidney graft function. Conclusion: No significant differences in arterial stiffness and PhA were observed in RTRs under different immunosuppressive regimens. While our data provide additional evidence for arterial stiffness and PhA in RTRs, more research is needed to fully explore these cardiovascular risk factors and the impact of different immunosuppressive regimens.

Kidney transplant program specific reporting and transplant metrics

PURPOSE OF REVIEW

Kidney transplantation is a heavily regulated medical procedure with the Secretary of HHS ultimately responsible for oversight and authority derived from the NOTA and the Final Rule. Transplant Programs undergo publicly reported evaluations every 6 months based on outcomes from a 2-and-a-half-year period. The current Bayesian metrics for kidney transplant programs were created such that over ten percentage of programs are deemed underperformers, or 'flag', every 6 months. Newly suggested transplant metrics have been released for public comment in Summer 2021. In addition to graft outcomes, waiting list mortality and organ acceptance rate ratios are proposed.

RECENT FINDINGS

Under the newly proposed kidney transplant metrics, over 10% of programs are expected to be deemed underperformers or 'flagged'. Transplant Center flagging is well correlated with decreased transplantation due to the transplant centres move to more conservative organ and patient acceptance. Death on the waiting list is a proposed metric over which transplant centres have little influence.

SUMMARY

In the USA, the harsh regulation continued by Health Resources and Services Administration (HRSA) through the national organ procurement and transplant network (OPTN) and Scientific Registry for Transplant Recipients (SRTR) leads directly to high organ discard rates and limitations to transplanting patients with perceived unadjusted risks. Instead of loosening regulation in a highly functioning industry that achieves remarkable outcomes in end stage kidney patients, the OPTN with the SRTR persist in increasing potential penalties through more proposed metrics that continue to deem 10% of US kidney transplant programs as underperformers. HRSA must establish a reasonable regulatory environment that allows for innovation and increased transplant opportunities for US end-stage renal disease patients.

Prevalence and factors associated with hyperkalaemia in stable kidney transplant recipients

Background

Hyperkalaemia is a frequent and potentially life-threatening condition in patients with chronic kidney disease (CKD). Even after successful kidney transplantation (KTx), KTx recipients have mild to severe CKD. Moreover, they share comorbid conditions and frequently use medications that predispose to hyperkalaemia. This study aimed to examine the prevalence and factors associated with hyperkalaemia in this population.

Methods

Over a pre-specified period of 6 months (1 September 2019 to 31 March 2020), we recorded in cross-sectional fashion information on serum potassium (K⁺) and relevant demographics, comorbidities, medications, laboratory and transplant-associated variables in clinically stable KTx recipients attending the Transplant Outpatient Clinic of our Department. Ηyperkalaemia was classified as follows: serum K⁺ level >5.0 mEq/L; and further as >5.0 mEq/L with concomitant use of sodium (Na⁺) polystyrene sulphonate; serum K⁺ ≥5.2 mEq/L; serum K⁺ ≥5.5 mEq/L. Univariate and multiple logistic regression analyses were used to identify factors associated with serum K⁺ >5.0 mEq/L.

Results

The study population consisted of 582 stable KTx recipients, 369 (63.4%) males, aged 52.4 ± 13.5 years, with estimated glomerular filtration rate (eGFR) of 55.8 ± 20.1 mL/min/1.73 m² transplanted for >1 year. The prevalence of hyperkalaemia defined as K⁺ >5.0 mEq/L; >5.0 mEq/L and use of Na⁺ polystyrene sulphonate; K⁺ ≥5.2; or K⁺ ≥5.5 mEq/L, was: 22.7, 22.7, 14.4 and 4.1% (132, 132, 84 and 24 patients), respectively. In multivariate analysis, male gender [odds ratio (OR) = 2.020, 95% confidence interval (CI) 1.264–3.227] and use of renin–angiotensin–aldosterone system (RAAS) blockers (OR = 1.628, 95% CI 1.045–2.536) were independently associated with hyperkalaemia, while higher eGFR (OR = 0.967, 95% CI 0.955–0.979) and use of non-K⁺-sparing diuretics (OR = 0.140, 95% CI 0.046–0.430) were associated with lower odds of the disorder.

Conclusions

The prevalence of mild hyperkalaemia in stable KTx recipients is relatively high but that of moderate or severe hyperkalaemia is low. Among a wide range of factors studied, only male gender and RAAS blockade were associated with increased odds of hyperkalaemia, while higher eGFR and diuretics were associated with decreased odds of hyperkalaemia.

The Increase in Paraoxonase 1 Is Associated With Decrease in Left Ventricular Volume in Kidney Transplant Recipients

Background: Patients on dialysis have impaired cardiac function, in part due to increased fluid volume and ventricular stress. Restored kidney function through transplantation reduces left ventricular volume in both systole and diastole. We previously reported that the decrease in NT-proB-type natriuretic peptide (NT-proBNP) was associated with a decrease in adiponectin. Paraoxonase 1 (PON1) has been inversely associated with cardiovascular outcomes. We now report the association of changes in PON1 with changes in left ventricular volume and left ventricular mass after kidney transplantation.

Design: Patients on dialysis were assessed at baseline and 12 months after kidney transplantation (n = 38). A comparison group of patients on dialysis who were not expected to receive a transplant in the next 24 months were studied (n = 43) to determine if the change of PON1 with kidney transplantation achieved a significance greater than that due to biologic variation. Left ventricular volume and mass were determined by cardiac magnetic resonance imaging. PON1 was measured by arylesterase activity and by mass.

Results: PON1 mass and activity were not different between the groups at baseline. Both PON1 mass and activity were increased post-kidney transplantation (p < 0.0001 for change). The change in PON1 mass (p = 0.0062) and PON1 arylesterase activity (p = 0.0254) were inversely correlated with the change in NT-proBNP for patients receiving a kidney transplant. However, only the change in the PON1 mass, and not the change in PON1 arylesterase, was inversely correlated with the change in left ventricular volume (ml/m2.7) (p = 0.0146 and 0.0114 for diastolic and systolic, respectively) and with the change in hemoglobin (p = 0.0042).

Conclusion: Both PON1 mass and arylesterase activity are increased by kidney transplantation. The increase in PON1 mass is consistent with a novel relationship to the increase in hemoglobin and decrease in left ventricular volume and NT-proBNP seen when kidney function is restored.

Outcomes at 3 years posttransplant in imlifidase-desensitized kidney transplant patients

Imlifidase is a cysteine proteinase which specifically cleaves IgG, inhibiting Fc-mediated effector function within hours of administration. Imlifidase converts a positive crossmatch to a potential donor (T cell, B cell, or both), to negative, enabling transplantation to occur between previously HLA incompatible donor-recipient pairs. To date, 39 crossmatch positive patients received imlifidase prior to a kidney transplant in four single-arm, open-label, phase 2 studies. At 3 years, for patients who were AMR+ compared to AMR-, death-censored allograft survival was 93% vs 77%, patient survival was 85% vs 94%, and mean eGFR was 49 ml/min/1.73 m² vs 61 ml/min/1.73 m² , respectively. The incidence of AMR was 38% with most episodes occurring within the first month post-transplantation. Sub-analysis of patients deemed highly sensitized with cPRA ≥ 99.9%, and unlikely to be transplanted who received crossmatch-positive, deceased donor transplants had similar rates of patient survival, graft survival, and eGFR but a higher rate of AMR. These data demonstrate that outcomes and safety up to 3 years in recipients of imlifidase-enabled allografts is comparable to outcomes in other highly sensitized patients undergoing HLA-incompatible transplantation. Thus, imlifidase is a potent option to facilitate transplantation among patients who have a significant immunologic barrier to successful kidney transplantation. Clinical Trial: ClinicalTrials.gov (NCT02790437), EudraCT Number: 2016-002064-13.

Declining trend of preemptive kidney transplantation and impact of pretransplant dialysis: a Korean nationwide prospective cohort study

We evaluated the temporal trend of preemptive kidney transplantation (KT) and the effect of pretransplant dialysis duration on post-transplant outcomes. This was a nationwide cohort study of the first-time 3392 living donor KT (LDKT) recipients (2014-2019). The annual changes in proportion of preemptive KT, factors associated with preemptive KT, and post-transplant outcomes were analyzed. Preemptive KT was performed in 816 (24.1%) patients. Annual trend analysis revealed gradual decrease in preemptive KT over time (P = 0.042). Among the underlying causes of preemptive KT, the proportion of diabetes increased and that of glomerulonephritis decreased during the study period. Glomerulonephritis as the primary renal disease was a predictor of preemptive KT. Patients with pretransplant dialysis >6 months showed increased graft failure risk than preemptive KT in the subdistribution of hazard model for competing risk (adjusted hazard ratio [aHR], 2.53; 95% confidence interval [CI], 1.09-5.87; P = 0.031) and in propensity score-matched analysis (aHR, 2.45; 95% CI, 1.02-5.92; P = 0.034); however, pretransplant dialysis ≤6 months showed comparable graft survival with preemptive KT in both analyses. Preemptive KT declined over successive years, associated with an increase in diabetes and a decrease in glomerulonephritis as underlying causes of KT. Short period of dialysis less than 6 months does not affect graft survival compared with preemptive KT; however, longer dialysis decreases graft survival.

The impact of location and patency of the arteriovenous fistula on quality of life of kidney transplant recipients

Background

Arteriovenous fistulae (AVFs) may remain patent after kidney transplantation (KTx), contributing to maladaptive cardiac remodeling. The flow in AVFs is associated with the diameter of its vessels and thus with the AVF location. The main objective of this study is to assess the influence of AVF location and its patency on the self-reported quality of life (QOL) of kidney transplant recipients (KTRs) with past history of hemodialysis.

Methods

To gain clinical data, during a scheduled visit, 353 KTRs were asked to fill out an anonymous questionnaire. From this group, 284 respondents were found eligible for analysis. The outcome was defined as prevalence of symptoms and health status, measured with the Left Ventricular Dysfunction-36 (LVD-36) Questionnaire in symptomatic patients.

Results

The hemodialysis patients (n = 243) were divided into two groups according to AVF location, i.e., DAVF – distally located AVF – (n = 174) and PAVF – proximally located AVF – (n = 69). The proportion of patients with heart failure (HF) was higher in PAVF group (24% vs. 12%, p = 0.0482). In the multivariable regression, PAVF, serum creatinine levels, and the presence of HF or coronary artery disease (CAD) remained independent predictors of lower functional capacity. Among patients with heart disease, the presence of active AVF was independently associated with worse functional outcome (higher LVD-36 scores).

Conclusions

The influence of persistent PAVF in KTRs seems to be unfavorable, especially when coexisting with CAD or HF. Abbreviations: AVF arteriovenous fistula; BMI body mass index; CAD coronary artery disease; D-AVF distally-located arteriovenous fistula; EC exercise capacity; HD hemodialysis; HF heart failure; KTx kidney transplantation; KTR kidney transplant recipient; LVD-36 Left Ventricle Disfunction – 36; LVEF left ventricle ejection fraction; LVH left ventricle hypertrophy; NYHA New York Heart Association; P-AVF proximally located arteriovenous fistula; PD peritoneal dialysis; PRO patient-reported outcomes; QOL quality of life.

Cohort study: "Outcomes of kidney transplantation in patients with prosthetic heart valves"

The number of kidney transplant candidates with prosthetic heart valves (PHVs) is increasing. Yet, outcomes of kidney transplantation in these patients are still unclear. This is the first report of post-transplant outcomes in patients with PHVs at time of kidney transplantation. We conducted a matched cohort study among recipients from the multicentric and prospective DIVAT cohort to compare the outcomes in patients with left-sided PHVs at time of transplantation and a group of recipients without PHV matched according to age, dialysis time, initial disease, pretransplant DSA, diabetes, and cardiovascular events. Of 23 018 patients, 92 patients with PHVs were included and compared to 276 patients without PHV. Delayed graft function and postoperative bleeding occurred more frequently in patients with PHVs. Kidney graft survival was similar between groups. 5-year overall survival was 68.5% in patients with PHV vs. 87.9% in patients without PHV [HR, 2.72 (1.57-4.70), P = 0.0004]. Deaths from infection, endocarditis, and bleeding were more frequent in patients with PHV. Mechanical valves, but not bioprosthetic valves, were independent risk factors for mortality [HR, 2.89 (1.68-4.97), P = 0.0001]. Patients with PHV have high mortality rates after kidney transplantation. These data suggest that mechanical valves, but not biological valves, increase risks of post-transplant mortality.

Human CD16+ monocytes promote a pro-atherosclerotic endothelial cell phenotype via CX3CR1-CX3CL1 interaction

AIMS

Monocytes are central for atherosclerotic vascular inflammation. The human non-classical, patrolling subtype, which expresses high levels of CD16 and fractalkine receptor CX3CR1, strongly associates with cardiovascular events. This is most marked in renal failure, a condition with excess atherosclerosis morbidity. The underlying mechanism is not understood. This study investigated how human CD16+ monocytes modulate endothelial cell function.

METHODS AND RESULTS

In patients with kidney failure, CD16+ monocyte counts were elevated and dynamically decreased within a year after transplantation, chiefly due to a drop in CD14+CD16+ cells. The CX3CR1 ligand CX3CL1 was similarly elevated in the circulation of humans and mice with renal impairment. CX3CL1 up-regulation was also observed close to macrophage rich human coronary artery plaques. To investigate a mechanistic basis of this association, CD16+CX3CR1HIGH monocytes were co-incubated with primary human endothelium in vitro. Compared to classical CD14+ monocytes or transwell cocultures, CD16+ monocytes enhanced endothelial STAT1 and NF-κB p65 phosphorylation, up-regulated expression of CX3CL1 and interleukin-1β, numerous CCL and CXCL chemokines and molecules promoting leucocyte patrolling and adhesion such as ICAM1 and VCAM1. Genes required for vasodilatation including endothelial nitric oxide synthase decreased while endothelial collagen production increased. Uraemic patients' monocytes enhanced endothelial CX3CL1 even more markedly. Their receptor CX3CR1 was required for enhanced aortic endothelial stiffness in murine atherosclerosis with renal impairment. CX3CR1 dose-dependently modulated monocyte-contact-dependent gene expression in human endothelium.

CONCLUSION

By demonstrating endothelial proatherosclerotic gene regulation in direct contact with CD16+ monocytes, in part via cellular CX3CR1-CX3CL1 interaction, our data delineate a mechanism how this celltype can increase cardiovascular risk.

Development and validation of a risk score for the prediction of cardiovascular disease in living donor kidney transplant recipients

BACKGROUND

Cardiovascular disease (CVD) is a major cause of death in kidney transplant (KT) recipients. To improve their long-term survival, it is clinically important to estimate the risk of CVD after living donor KT via adequate pre-transplant CVD screening.

METHODS

A derivation cohort containing 331 KT recipients underwent living donor KT at Kyushu University Hospital from January 2006 to December 2012. A prediction model was retrospectively developed and risk scores were investigated via a Cox proportional hazards regression model. The discrimination and calibration capacities of the prediction model were estimated via the c-statistic and the Hosmer-Lemeshow goodness of fit test. External validation was estimated via the same statistical methods by applying the model to a validation cohort of 300 KT recipients who underwent living donor KT at Tokyo Women's Medical University Hospital.

RESULTS

In the derivation cohort, 28 patients (8.5%) had CVD events during the observation period. Recipient age, CVD history, diabetic nephropathy, dialysis vintage, serum albumin and proteinuria at 12 months after KT were significant predictors of CVD. A prediction model consisting of integer risk scores demonstrated good discrimination (c-statistic 0.88) and goodness of fit (Hosmer-Lemeshow test P = 0.18). In a validation cohort, the model demonstrated moderate discrimination (c-statistic 0.77) and goodness of fit (Hosmer-Lemeshow test P = 0.15), suggesting external validity.

CONCLUSIONS

The above-described simple model for predicting CVD after living donor KT was accurate and useful in clinical situations.

Predicting operation time and creating a difficulty scoring system in donor nephrectomy

BACKGROUND

To determine predictive formulas for operation time and surgical difficulty in laparoscopic living-donor kidney transplantation.

METHODS

We retrospectively analyzed data for 222 living donors aged > 20 years and recorded factors affecting operation time from patients' computed tomography images and medical records. We used the factors significantly affecting operation time to create a formula to predict operation time and designed a model to predict surgical difficulty based on the standardized partial regression coefficient, β. We also analyzed the relationship between surgical difficulty (high vs low) and operation time.

RESULTS

This study involved 111 pure retroperitoneal donor nephrectomies (PRDN) and 111 hand-assisted laparoscopic donor nephrectomies (HALDN). Patients' mean age was 55.7 years, and 59.5% were women; 5.0% underwent right nephrectomy, and 77.0% vs. 23.0% had single- vs. multiple renal arteries. The average estimated kidney graft weight was 160.0 g; actual average graft weight was 155.3 g. The following factors were significantly correlated with operation time in the regression analysis: number of renal arteries, Mayo adhesive probability (MAP) score, estimated kidney graft weight, right nephrectomy, and operation type (PRDN). These five factors were used to create the operation time prediction equation and difficulty scoring system. The multiple r2 value was 0.40 for the operation time prediction equation. Receiver operating characteristic curve analysis of the difficulty scoring system revealed the following: sensitivity: 78.0%, specificity: 64.9%, and c-statistic: 0.76 (95% confidence interval: 0.70-0.83).

CONCLUSIONS

The equation to predict operation time and the surgical difficulty prediction model created in this study are easy to calculate and are accurate. Both may help in selecting an appropriately-skilled surgeon and in improving safety in living-donor kidney transplantation.