Survival of patients on the kidney transplant wait list: relationship to cardiac troponin T

Walking Ability and Brain Natriuretic Peptide Are Highly Predictive of Kidney Transplant Waiting List Removal

Kidney transplant waitlist management is complex because waiting time is long, and the patients have significant comorbidities. Identification of patients at highest risk for waiting list removal for death and medical complications could allow better outcomes and allocation of resources.

Methods

Demographics, functional and frailty assessment' and biochemical data were retrospectively analyzed on 313 consecutive patients listed for kidney transplant. Troponin, brain natriuretic peptide, components of the Fried frailty metrics, pedometer activity, and treadmill ability were measured at the time of transplant evaluation and at subsequent re-evaluations. Cox proportional hazards models were used to identify factors associated with death or waiting list removal for medical reasons. Multivariate models were created to identify significant predictor sets.

Results

Among 249 patients removed while waitlisted, 19 (6.1%) died and 51 (16.3%) were removed for medical reasons. Mean follow-up duration was 2.3 y (±1.5 y). 417 sets of measurements were collected. Significant (P < 0.05) non-time-dependent variables associated with the composite outcome identified on univariate analysis included N-terminal probrain natriuretic peptide (BNP), treadmill ability, pedometer activity, diagnosis of diabetes and the Center of Epidemiological Studies Depression Scale question asking how many days per week could you not get going. Significant time-dependent factors included BNP, treadmill ability, Up and Go, pedometer activity, handgrip, 30 s chair sit-stand test, and age. The optimal time-dependent predictor set included BNP, treadmill ability, and patient age.

Conclusions

Changes in functional and biochemical markers are predictive of kidney waitlist removal for death and medical reasons. BNP and measures of walking ability were of particular importance.

Physiological Age by Artificial Intelligence-Enhanced Electrocardiograms as a Novel Risk Factor of Mortality in Kidney Transplant Candidates

BACKGROUND

Mortality risk assessment before kidney transplantation (KT) is imperfect. An emerging risk factor for death in nontransplant populations is physiological age as determined by the application of artificial intelligence to the electrocardiogram (ECG). The aim of this study was to examine the relationship between ECG age and KT waitlist mortality.

METHODS

We applied a previously developed convolutional neural network to the ECGs of KT candidates evaluated 2014 to 2019 to determine ECG age. We used a Cox proportional hazard model to examine whether ECG age was associated with waitlist mortality.

RESULTS

Of the 2183 patients evaluated, 59.1% were male, 81.4% were white, and 11.4% died during follow-up. Mean ECG age was 59.0 ± 12.0 y and mean chronological age at ECG was 53.3 ± 13.6 y. After adjusting for chronological age, comorbidities, and other characteristics associated with mortality, each increase in ECG age of >10 y than the average ECG age for patients of a similar chronological age was associated with an increase in mortality risk (hazard ratio 3.59 per 10-y increase; 95% confidence interval, 2.06-5.72; P  < 0.0001).

CONCLUSIONS

ECG age is a risk factor for KT waitlist mortality. Determining ECG age through artificial intelligence may help guide risk-benefit assessment when evaluating candidates for KT.

Psychosocial characteristics of patients evaluated for kidney transplant and associations with functional and frailty metrics at a veterans affairs hospital

BACKGROUND

The effect of psychosocial problems on listing outcomes and potential interactions with functional metrics is not well-characterized among Veteran transplant candidates.

METHODS

The results from psychosocial evaluations, frailty metrics, and biochemical markers were collected on 375 consecutive Veteran kidney transplant candidates. Psychosocial diagnoses were compared between patients listed or denied for transplant. Functional abilities were compared among patients with or without psychosocial diagnoses and then evaluated based on reason for denial.

RESULTS

Eighty-four percent of patients had a psychosocial diagnosis. Common issues included substance or alcohol abuse (62%), psychiatric diagnoses (50%), and poor adherence (25%). Patients with psychiatric diagnoses, cognitive impairments, and poor adherence were more likely to be denied for transplant (P < .05). Patients with depression, PTSD, and anxiety did not have worse functional ability, but experienced more exhaustion than patients without these problems. Patients denied for medical but not purely psychosocial reasons had worse troponin and functional metrics compared with listed patients.

CONCLUSION

Over 80% of patients with a psychosocial diagnosis were listed; however, poor adherence was a particularly important reason for denial for purely psychosocial reasons. Patients with psychosocial diagnoses generally were not more functionally limited than their counterparts without psychosocial diagnoses or those listed for transplant.

The assessment of coronary artery disease in patients with end-stage renal disease

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality among patients with end-stage renal disease (ESRD). Clustering of traditional atherosclerotic and non-traditional risk factors drive the excess rates of coronary and non-coronary CVD in patients with ESRD. Coronary artery disease (CAD) is a key disease process, present in ∼50% of the haemodialysis population ≥65 years of age. Patients with ESRD are more likely to be asymptomatic, posing a challenge to the correct identification of CAD, which is essential for appropriate risk stratification and management. Given the lack of randomized clinical trial evidence in this population, current practice is informed by observational data with a significant potential for bias. For this reason, the most appropriate approach to the investigation of CAD is the subject of considerable discussion, with practice patterns largely varying between different centres. Traditional imaging modalities are limited in their diagnostic accuracy and prognostic value for cardiac events and survival in patients with ESRD, demonstrated by the large number of adverse cardiac outcomes among patients with negative test results. This review focuses on the current understanding of CAD screening in the ESRD population, discussing the available evidence for the use of various imaging techniques to refine risk prediction, with an emphasis on their strengths and limitations.

Diagnosis and treatment of myocardial infarction in patient with end - stage renal disease on chronic hemodialysis

This review represents different aspects of myocardial infarction in patient with end - stage renal disease on chronic hemodialysis. We discuss difficulties in diagnosis, optimal method of coronary revascularization, timing of hemodialysis session, medical therapy, as well as epidemiology and prognosis. There are no unambiguous answers to these problems because patients with end - stage renal disease were excluded from most of the studies.

Risk Stratification and Treatment of Coronary Disease in Chronic Kidney Disease and End-Stage Kidney Disease

Patients with advanced chronic kidney disease have an enormous burden of cardiovascular morbidity and mortality, but, paradoxically, their representation in randomized trials for the evaluation and management of coronary artery disease has been limited. Clinicians therefore are faced with the conundrum of synergizing evidence from observational studies, expert opinion, and extrapolation from the general population to provide care to this complex and clinically distinct patient population. In this review, we address clinical risk stratification of patients with chronic kidney disease and end-stage kidney disease using traditional cardiovascular risk factors, noninvasive functional and structural cardiac imaging, invasive coronary angiography, and cardiovascular biomarkers. We highlight the unique characteristics of this population, including the high competing risk of all-cause mortality relative to the risk of major adverse cardiac events, likely owing to important contributions from nonatherosclerotic mechanisms. We further discuss the management of coronary artery disease in patients with chronic kidney disease and end-stage kidney disease, including evidence pertaining to medical management, coronary revascularization with percutaneous coronary intervention, and coronary artery bypass grafting. Our discussion includes considerations of drug-eluting versus bare metal stents for percutaneous coronary intervention and off-pump versus on-pump coronary artery bypass graft surgery. Finally, we address currently ongoing randomized trials, from which clinicians are optimistic about receiving guidance regarding the best strategies to incorporate into their practice for the evaluation and management of coronary artery disease in this high-risk population.

The Relationship Between Frailty and Decreased Physical Performance With Death on the Kidney Transplant Waiting List

INTRODUCTION

Frailty and decreased physical performance are associated with poor outcomes after kidney transplant. Less is known about their relationship with pretransplant outcomes. The aim of this study was to characterize associations between frailty and physical performance with death on the kidney transplant waiting list.

DESIGN

Since December 2014, high-risk kidney transplant candidates at our center (age > 59, diabetic and/or history of >3 years dialysis) have undergone frailty and physical performance testing using Fried Criteria and the Short Physical Performance Battery.

RESULTS

Between December 2014 and November 2016, 272 high-risk candidates underwent testing and were approved for transplant. Both frailty and physical performance score were significantly associated with death on the waiting list (hazard ratio [HR]: 6.7, confidence interval [CI]: 1.5-30.1; P = .01; HR: 0.8 per 1-point increase, CI: 0.7-1.0; P = .02, respectively). The relationship between frailty, physical performance score, and death on the waiting list appeared to be independent of age, diabetes, or duration of dialysis.

DISCUSSION

Frailty and decreased physical performance appear to be independently associated with increased mortality on the kidney transplant waiting list. Further studies are needed to determine whether improving frailty and physical performance prior to transplant can decrease waiting list mortality.

Co-Administration of Melatonin Effectively Enhances the Therapeutic Effects of Pioglitazone on Mesenchymal Stem Cells Undergoing Indoxyl Sulfate-Induced Senescence through Modulation of Cellular Prion Protein Expression

Background: Mesenchymal stem cells (MSCs) are a promising source for regenerative medicine. However, their therapeutic potential in patients with chronic kidney disease (CKD) is restricted by the presence of uremic toxins. To address this limitation, we explored the protective effect of melatonin and pioglitazone on MSCs undergoing senescence induced by the uremic toxin, indoxyl sulfate (IS). Methods: MSC senescence was induced by IS, and the therapeutic effects of melatonin and pioglitazone were identified. The expression of cellular prion protein (PrP^C) was suppressed by transfection of MSCs with prion protein gene (PRNP) siRNA. Subsequently, these cells were used to study the protective effects of melatonin and pioglitazone against IS-induced senescence; Results: The IS-induced senescence of MSCs was significantly reduced by co-treatment with melatonin and pioglitazone compared to treatment with melatonin or pioglitazone alone. In the presence of IS, the reduced MSC proliferation was rescued by co-treatment with melatonin and pioglitazone. Melatonin and pioglitazone enhanced the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) in MSCs, which resulted in the augmentation of PrP^C level. The inhibitory effect of the co-treatment with melatonin and pioglitazone on IS-induced senescence in MSCs was blocked by the knockdown of PRNP. In addition, the restorative effect of the co-treatment on the reduced MSC proliferation induced by IS was also blocked by the knockdown of PRNP. These findings indicate that co-treatment with melatonin and pioglitazone protected MSCs from uremic toxin-induced senescence through the regulation of the PPAR-γ-PrP^C axis. Conclusions: Our study suggests that co-treatment of MSCs with melatonin and pioglitazone may represent a novel strategy for the development of MSC-based therapies for patients with CKD.

Soluble ST2 does not change cardiovascular risk prediction compared to cardiac troponin T in kidney transplant candidates

BACKGROUND

Solubility of Tumorigenicity 2 (sST2) is a novel biomarker that better stratifies risk of cardiovascular events (CVE) compared to cardiac troponin T(cTnT) in heart failure. We assessed the association of sST2 with the composite outcome of CVE and/or mortality compared to cTnT in kidney transplant candidates.

METHODS

200 kidney transplant candidates between 2010 and 2013 were included. Elevated sST2 was defined as ≥30ng/ml, cTnT≥0.01 ng/ml.

RESULTS

Median age 53 (interquartile range (IQR) 42-61) years, 59.7% male and 82.0% white. 33.5% had history of CVE, 42.5% left ventricular hypertrophy (LVH) and 15.6% positive cardiac stress test. Elevated sST2 correlated with male gender, history of prior-transplants, CVE, positive stress test, LVH, elevated cTnT, anemia, hyperphosphatemia, increased CRP and non-transplanted status. Male gender, history of CVE and LVH were independent determinants of sST2. During 28 months (IQR 25.3-30), 7.5% died, 13.0% developed CVE and 19.0% developed the composite outcome. Elevated sST2 was associated with the composite outcome (hazard ratio = 1.76, CI 1.06-2.73, p = 0.029) on univariate analysis but not after adjusting for age, diabetes and cTnT (p = 0.068). sST2 did not change the risk prediction model for composite outcome after including age, diabetes, prior history of CVE and elevated cTnT.

CONCLUSIONS

Increased sST2 level is significantly associated with variables associated with CVE in kidney transplant candidates. sST2 was associated with increased risk of the composite outcome of CVE and/or death but not independent of cTnT. Larger studies are needed to confirm these findings and determine whether sST2 has added value in CV risk stratification in this cohort of patients.

Predictors of Cardiovascular Events After Liver Transplantation

Indications for liver transplant have been extended, and older and sicker patients are undergoing transplantation. Infectious, malignant, and cardiovascular diseases account for the most posttransplant deaths. Cirrhotic patients can develop heart disease through systemic diseases affecting the heart and the liver, cirrhosis-specific heart disease, or common cardiovascular. No single factor can predict posttransplant cardiovascular complications. Patients with history of cardiovascular disease, and specific abnormalities on echocardiography, electrocardiography, or serum markers of heart disease seem to be at increased risk of complications. Pretransplant cardiovascular evaluation is essential to detecting these risk factors so their effects can be mitigated through appropriate intervention.

Relationship between pre-transplant physical function and outcomes after kidney transplant

BACKGROUND

Performance-based measures of physical function predict morbidity following non-transplant surgery. Study objectives were to determine whether physical function predicts outcomes after kidney transplant and assess how physical function changes post-transplant.

METHODS

We conducted a prospective study involving living donor kidney transplants recipients at our center from May 2012 to February 2014. Physical function was measured using the Short Physical Performance Battery (SPPB [balance, chair stands, gait speed]) and grip strength testing. Initial length of stay (LOS), 30- day rehospitalizations, allograft function, and quality of life (QOL) were assessed.

RESULTS

The majority of the 140 patients in our cohort had excellent pre-transplant physical function. In general, balance scores were more predictive of post-transplant outcomes than the SPPB. Decreased pre-transplant balance was independently associated with longer LOS and increased rehospitalizations but not with post-transplant QOL; 35% of patients experienced a clinically meaningful (≥ 1.0 m/s) improvement in gait speed 4 months post-transplant.

CONCLUSIONS

Decreased physical function may be associated with longer LOS and rehospitalizations following kidney transplant. Further studies are needed to confirm this association. The lack of relationship between pre-transplant gait speed and outcomes in our cohort may represent a ceiling effect. More comprehensive measures, including balance testing, may be required for risk stratification.

Utility of Ecological Risk Factors for Evaluation of Transplant Center Performance

There is substantial evidence across different healthcare contexts that social determinants of health are strongly associated with morbidity and mortality in the United States. These factors, including socioeconomic status, behavior and environmental risks, education, social support, healthy food, and access to healthcare also vary widely by region and individual communities. One of the implications of heterogeneity in these risks is the potential impact on measured quality of healthcare providers. In particular, there is concern that providers treating disproportionally vulnerable communities may be disadvantaged by lack of risk adjustment for these factors that affect health but not indicators of quality of care. Recently, the National Quality Forum has endorsed risk adjustment for sociodemographic characteristics based on these concerns. These issues are salient to transplant programs since social determinants of health impact transplant patient outcomes and vary by region. In this viewpoint, we argue that integration of ecological (area-level) factors in risk adjustment models used to assess transplant center quality should be strongly considered. We believe this reform could be accomplished rapidly, would attenuate disparities in access to care by reducing disincentives to treat patients from vulnerable communities, and improve risk adjustment and calibration of models used for center evaluations.

Abdominal lean muscle is associated with lower mortality among kidney waitlist candidates

Morphometric assessments, such as muscle density and body fat distribution, have emerged as strong predictors of cardiovascular risk and postoperative morbidity and mortality. To date, no study has examined morphometric mortality risk prediction among kidney transplant (KT) candidates. KT candidates, waitlisted 2008-2009, were identified (n=96) and followed to the earliest of transplant, death, or administrative end of study. Morphometric measures, including abdominal adipose tissue, paraspinous and psoas muscle composition, and aortic calcification, were measured from CTs. Risk of waitlist mortality was examined using Cox proportional hazard regression. On adjusted analyses, radiologic measures remained independently and significantly associated with lower waitlist mortality; the addition of radiologic measures significantly improved model predictive ability over models containing traditional risk factors alone (net reclassification index: 0.56, 95% CI: 0.31-0.75). Higher psoas muscle attenuation (indicative of leaner muscle) was associated with decreased risk of death (aHR: 0.93, 95% CI: 0.91-0.96, P<.001), and for each unit increase in lean paraspinous volume, there was an associated 2% decreased risk for death (aHR: 0.98, 95% CI: 0.96-0.99, P=.03). Radiologic measures of lean muscle mass, such as psoas muscle attenuation and paraspinous lean volume, may improve waitlist mortality risk prediction and candidate selection.

Creatinine-Based and Cystatin C-Based GFR Estimating Equations and Their Non-GFR Determinants in Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

eGFR equations have been evaluated in kidney transplant recipients with variable performance. We assessed the performance of the Modification of Diet in Renal Disease equation and the Chronic Kidney Disease Epidemiology Collaboration equations on the basis of creatinine, cystatin C, and both (eGFR creatinine-cystatin C) compared with measured GFR by iothalamate clearance and evaluated their non-GFR determinants and associations across 15 cardiovascular risk factors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A cross-sectional cohort of 1139 kidney transplant recipients >1 year after transplant was analyzed. eGFR bias, precision, and accuracy (percentage of estimates within 30% of measured GFR) were assessed. Interaction of each cardiovascular risk factor with eGFR relative to measured GFR was determined.

RESULTS

Median measured GFR was 55.0 ml/min per 1.73 m(2). eGFR creatinine overestimated measured GFR by 3.1% (percentage of estimates within 30% of measured GFR of 80.4%), and eGFR Modification of Diet in Renal Disease underestimated measured GFR by 2.2% (percentage of estimates within 30% of measured GFR of 80.4%). eGFR cystatin C underestimated measured GFR by -13.7% (percentage of estimates within 30% of measured GFR of 77.1%), and eGFR creatinine-cystatin C underestimated measured GFR by -8.1% (percentage of estimates within 30% of measured GFR of 86.5%). Lower measured GFR associated with older age, women, obesity, longer time after transplant, lower HDL, lower hemoglobin, lower albumin, higher triglycerides, higher proteinuria, and an elevated cardiac troponin T level but did not associate with diabetes, smoking, cardiovascular events, pretransplant dialysis, or hemoglobin A1c. These risk factor associations differed for five risk factors with eGFR creatinine, six risk factors for eGFR Modification of Diet in Renal Disease, ten risk factors for eGFR cystatin C, and four risk factors for eGFR creatinine-cystatin C.

CONCLUSIONS

Thus, eGFR creatinine and eGFR creatinine-cystatin C are preferred over eGFR cystatin C in kidney transplant recipients because they are less biased, more accurate, and more consistently reflect the same risk factor associations seen with measured GFR.

Echocardiography Criteria for Structural Heart Disease in Patients With End-Stage Renal Disease Initiating Hemodialysis

BACKGROUND

Cardiovascular disease among hemodialysis (HD) patients is linked to poor outcomes. The Acute Dialysis Quality Initiative Workgroup proposed echocardiographic (ECHO) criteria for structural heart disease (SHD) in dialysis patients. The association of SHD with important patient outcomes is not well defined.

OBJECTIVES

This study sought to determine prevalence of ECHO-determined SHD and its association with survival among incident HD patients.

METHODS

We analyzed patients who began chronic HD from 2001 to 2013 who underwent ECHO ≤1 month prior to or ≤3 months following initiation of HD (n = 654).

RESULTS

Mean patient age was 66 ± 16 years, and 60% of patients were male. ECHO findings that met 1 or more and ≥3 of the new criteria were discovered in 87% and 54% of patients, respectively. Over a median of 2.4 years, 415 patients died: 108 (26%) died within 6 months. Five-year mortality was 62%. Age- and sex-adjusted structural heart disease variables associated with death were left ventricular ejection fraction (LVEF) ≤45% (hazard ratio [HR]: 1.48; confidence interval [CI]: 1.20 to 1.83) and right ventricular (RV) systolic dysfunction (HR: 1.68; CI: 1.35 to 2.07). An additive of higher death risk included LVEF ≤45% and RV systolic dysfunction rather than neither (HR: 2.04; CI: 1.57 to 2.67; p = 0.53 for test for interaction). Following adjustment for age, sex, race, diabetic kidney disease, and dialysis access, RV dysfunction was independently associated with death (HR: 1.66; CI 1.34 to 2.06; p < 0.001).

CONCLUSIONS

SHD was common in our HD study population, and RV systolic dysfunction independently predicted mortality.

Challenges and opportunities for stem cell therapy in patients with chronic kidney disease

Chronic kidney disease (CKD) is a global health care burden affecting billions of individuals worldwide. The kidney has limited regenerative capacity from chronic insults, and for the most common causes of CKD, no effective treatment exists to prevent progression to end-stage kidney failure. Therefore, novel interventions, such as regenerative cell-based therapies, need to be developed for CKD. Given the risk of allosensitization, autologous transplantation of cells to boost regenerative potential is preferred. Therefore, verification of cell function and vitality in CKD patients is imperative. Two cell types have been most commonly applied in regenerative medicine. Endothelial progenitor cells contribute to neovasculogenesis primarily through paracrine angiogenic activity and partly by differentiation into mature endothelial cells in situ. Mesenchymal stem cells also exert paracrine effects, including proangiogenic, anti-inflammatory, and antifibrotic activity. However, in CKD, multiple factors may contribute to reduced cell function, including older age, coexisting cardiovascular disease, diabetes, chronic inflammatory states, and uremia, which may limit the effectiveness of an autologous cell-based therapy approach. This Review highlights current knowledge on stem and progenitor cell function and vitality, aspects of the uremic milieu that may serve as a barrier to therapy, and novel methods to improve stem cell function for potential transplantation.

Troponin T as a Predictor of End-Stage Renal Disease and All-Cause Death in African Americans and Whites From Hypertensive Families

OBJECTIVE

To evaluate cardiac troponin T (cTnT) as a predictor of end-stage renal disease (ESRD) and death in a cohort of African American and white community-dwelling adults with hypertensive families.

PATIENTS AND METHODS

A total of 3050 participants (whites from Rochester, Minnesota; African Americans from Jackson, Mississippi) of the Genetic Epidemiology Network of Arteriopathy study were followed from baseline examination (June 1, 1996, through August 31, 2000) through January 22, 2010. Cox proportional hazards regression models were used to examine the association of cTnT with ESRD and death after adjusting for traditional risk factors.

RESULTS

Cohort demographic characteristics and measurements included 1395 whites (45.7%), 2174 hypertensive (71.3%), 992 estimated glomerular filtration rate of less than 60 mL/min per 1.73 m(2) (32.5%), 1574 high-sensitivity C-reactive protein level of greater than 3 mg/L (51.6%), and 66 abnormal cTnT level of 0.01 ng/mL or higher (2.2%). The estimated cumulative incidence of ESRD at 10 years was 27.4% among those with abnormal cTnT levels compared with 1.3% for those with normal levels. Similarly, the estimated cumulative incidence of death at 10 years was 47% among those with abnormal cTnT compared with 7.3% among those with normal cTnT. Abnormal cTnT levels were strongly associated with ESRD and death. This effect was attenuated but was still highly significant after adjustment for demographic characteristics, estimated glomerular filtration rate, and traditional risk factors for ESRD (unadjusted hazard ratio [HR], 23.91; 95% CI, 12.9-44.2; adjusted HR, 2.81; 95% CI, 1.3-5.9) and death (unadjusted HR, 8.43; 95% CI, 6.0-11.9; adjusted HR, 3.46; 95% CI, 2.3-5.1).

CONCLUSION

Cardiac troponin T makes an independent contribution to the prediction of ESRD and all-cause death in community-dwelling individuals beyond traditional risk markers. Further studies may be needed to determine whether cTnT screening in individuals with hypertension or in a subset of hypertensive individuals would help identify those at risk of ESRD and all-cause death.

Cardiovascular risk assessment in kidney transplantation

Cardiovascular disease (CVD) remains the most common cause of death after kidney transplantation worldwide, with the highest event rate in the early postoperative period. In an attempt to address this issue, screening for CVD prior to transplant is common, but the clinical utility of screening asymptomatic transplant candidates remains unclear. A large degree of variation exists among both transplant center practice patterns and clinical practice guidelines regarding who should be screened, and opinions are based on mixed observational data with great potential for bias. In this review, we discuss the potential risks, benefits, and evidence for screening for CVD in kidney transplant candidates, and also the next steps to better evaluate and treat asymptomatic kidney transplant candidates.

Evaluation of solid organ transplant candidates for coronary artery disease

Solid organ transplantation has increased in frequency in the United States, having evolved from an area of experimentation into accepted therapy for end-organ failure. As organ transplantation has become more common, the average age of transplant recipients has increased, thus increasing the potential for multiple comorbidities including coronary artery disease (CAD). CAD has been shown to be a major cause of morbidity and mortality in kidney, lung and liver transplant recipients. Identification of CAD in solid organ transplant candidates allows for stratification of short- and long-term risk, ensuring proper use of valuable allograft resources while guiding further patient management. Assessment of asymptomatic transplant candidates for CAD is difficult. Many patients undergo stress echocardiography or nuclear imaging, which have demonstrated inconsistent rates of sensitivity and specificity for the detection of CAD in these patient populations. Cardiac computed tomography is a potential tool for detecting CAD in these populations, but has questionable utility at this time. Coronary angiography has an important role in detecting CAD in high-risk transplant candidates, affecting their long-term management and risk.

Patient selection and preoperative evaluation for transplant surgery

Candidates for abdominal transplant undergo a pretransplant evaluation to identify associated conditions that may require intervention or that may influence a patient's candidacy for transplant. Coronary artery disease is prevalent in candidates for abdominal organ transplantation. The optimal approach to identify and manage coronary artery disease in the peri-transplant period is currently unclear. In liver transplant candidates portopulmonary hypertension and hepatopulmonary syndrome should be screened for. Identification of the patient who is too sick to benefit from transplant is problematic; with no good evidence available decisions should be individualized and made after multidisciplinary discussion.

Small changes in troponin T levels are common in patients with non-ST-segment elevation myocardial infarction and are linked to higher mortality

OBJECTIVES

The purpose of this study was to examine the extent of change in troponin T levels in patients with non-ST-segment elevation myocardial infarction (NSTEMI).

BACKGROUND

Changes in cardiac troponin T (cTnT) levels are required for the diagnosis of NSTEMI, according to the new universal definition of acute myocardial infarction. A relative change of 20% to 230% and an absolute change of 7 to 9 ng/l have been suggested as cutoff points.

METHODS

In a clinical setting, where a change in cTnT was not mandatory for the diagnosis of NSTEMI, serial samples of cTnT were measured with a high-sensitivity cTnT (hs-cTnT) assay, and 37 clinical parameters were evaluated in 1,178 patients with a final diagnosis of NSTEMI presenting <24 h after symptom onset.

RESULTS

After 6 h of observation, the relative change in the hs-cTnT level remained <20% in 26% and the absolute change <9 ng/l in 12% of the NSTEMI patients. A relative hs-cTnT change <20% was linked to higher long-term mortality across quartiles (p = 0.002) and in multivariate analyses (hazard ratio: 1.61 [95% confidence interval: 1.17 to 2.21], p = 0.004), whereas 30-day mortality was similar across quartiles of relative hs-cTnT change.

CONCLUSIONS

Because stable hs-TnT levels are common in patients with a clinical diagnosis of NSTEMI in our hospital, a small hs-cTnT change may not be useful to exclude NSTEMI, particularly as these patients show both short-term and long-term mortality at least as high as patients with large changes in hs-cTnT.

Cardiac troponin T before and after kidney transplantation: determinants and implications for posttransplant survival

Pretransplant cardiac troponin T(cTnT(pre) ) is a significant predictor of survival postkidney transplantation. We assessed correlates of cTnT levels pre- and posttransplantation and their relationship with recipient survival. A total of 1206 adult recipients of kidney grafts between 2000 and 2010 were included. Pretransplant cTnT was elevated (≥0.01 ng/mL) in 56.4%. Higher cTnT(pre) was associated with increased risk of posttransplant death/cardiac events independent of cardiovascular risk factors. Elevated cTnT(pre) declined rapidly posttransplant and was normal in 75% of recipients at 3 weeks and 88.6% at 1 year. Elevated posttransplant cTnT was associated with reduced patient survival (cTnT(3wks) : HR = 5.575, CI 3.207-9.692, p < 0.0001; cTnT(1year) : 3.664, 2.129-6.305, p < 0.0001) independent of age, diabetes, pretransplant dialysis, heart disease and allograft function. Negative/positive predictive values for high cTnT(3wks) were 91.4%/50% respectively. Normalization of cTnT posttransplant was associated with reduced risk. Variables related to elevated cTnT posttransplant included pretransplant diabetes, older age, time on dialysis, high cTnT(pre) and lower graft function. Patients with delayed graft function and those with GFR < 30 mL/min at 3 weeks were more likely to have an elevated cTnT(3wks) and remained at high risk. When allografts restore sufficient kidney function cTnT normalizes and patient survival improves. Lack of normalization of cTnT posttransplant identifies a group of individuals with high risk of death/cardiac events.

Is cardiac biomarkers and left ventricular function affected by chronic kidney disease?

BACKGROUND

Cardiovascular disease is the leading cause of death in patients with chronic kidney disease (CKD). These patients may have high level of cardiac troponins in their serum irrelevant to acute coronary syndrome (ACS) that could have profound impact on patient's morbidity and mortality.

OBJECTIVES

The aim of this study was to assess the relation between level of serum creatinine (Cr) and cardiac troponins T and I, and left ventricular (LV) function (as defined by LV ejection fraction) in non-dialysis and non-acute coronary syndrome CKD patients.

MATERIALS AND METHODS

This is a prospective cross sectional study that includes 150 non-dialysis CKD patients without history of ACS in at least 1 month before the beginning of the study. Patients with history of CKD (serum Cr ≥1.5 mg/dl) of more than 6 months were selected. Patients with advanced multi-organ disease (lung disease, liver disease, cerebrovascular disease and peripheral vascular disease) and history of dialysis were excluded from the study. In each patient blood sample was obtained for analyzing serum Cr and cardiac troponin T and I (cTnT and cTnI). Also LV ejection fraction (LVEF) was measured by echocardiography in the same session.

RESULT

There was a positive non-parametric relation between serum Cr and cTnT (p = 0.028). However there were no relation between serum Cr, cTnI (p = 0.57) and LVEF (p = 0.188).

CONCLUSION

In patients with CKD, serum Cr level has an impact on cTnT, but has no impact on cTnI and LVEF.

Optimal fluid control can normalize cardiovascular risk markers and limit left ventricular hypertrophy in thrice weekly dialysis patients

Increased hemodialysis frequency can make fluid overload easier to treat, although most patients are still treated thrice weekly. Chronic fluid overload is associated with left ventricular hypertrophy and elevated serum cardiac biomarkers, recognized as mortality risk factors. Serum cardiac troponin T (cTnT), N-terminal prohormone brain natriuretic peptide (NT-proBNP), left ventricular mass index by cardiac magnetic imaging, and ambulatory blood pressure was measured in 30 thrice weekly hemodiafiltration patients. Time-averaged fluid overload (TAFO) was quantified by bioimpedance spectroscopy. In the study group, left ventricular hypertrophy was found to be 26% by cardiac magnetic resonance. Ambulatory blood pressure was 130 mmHg (112-151) requiring a low equivalent dose of medication of 0.25 units (0-1). Significantly, lower levels of left ventricular mass index (P < 0.05) were associated in those patients with TAFO <1 L or NT-proBNP <1200 pg/mL or cTnT <0.1 ug/L. In the subgroups, 16 patients had normal cTnT (<0.03 ug/L), 16 patients had NT-proBNP <400 pg/mL, and 20 patients had TAFO <1 L. Nine patients had both cTnT <0.03 ug/L and NT-proBNP <400 pg/mL. Normally hydrated thrice-weekly hemodiafiltration patients can have cardiac biomarker and TAFO levels indistinguishable from the normal healthy population. Obtaining TAFO by bioimpedance monitoring can offer a practical alternative to serum cardiac biomarkers.

Troponin I levels and postoperative myocardial infarction following renal transplantation

BACKGROUND

The relationship of routine postoperative troponin I (TnI) monitoring in kidney transplant recipients and in-hospital myocardial infarction (MI) is not known.

METHODS

This observational study evaluated the prevalence of abnormal postoperative TnI (Ortho Clinical Diagnostics assay) in 376 consecutive kidney or kidney/pancreas transplant recipients. In-hospital MI was adjudicated using the universal definition. Rates of death and coronary revascularizations at 1 year were studied. Logistic regression analysis was performed to identify independent predictors of abnormal TnI.

RESULTS

Ninety-five (25%) recipients had abnormal TnI (>0.04 ng/ml) following transplantation. Abnormal TnI levels were more common in older (mean age: 52.2 ± 13.4 vs. 48.3 ± 13.2 years, p = 0.01), diabetic (57.9 vs. 45.6%, p = 0.04), and prior coronary artery disease (31.6 vs. 20.3%, p = 0.02) patients. In-hospital MI occurred in 6 patients (1.6%). All subsequent in-hospital cardiovascular events occurred in the abnormal postoperative TnI group; most in those with TnI levels >1 ng/ml. Previous coronary artery disease was the only independent predictor of a postoperative TnI level >1 ng/ml in multivariate analysis (odds ratio 4.61, 95% confidence interval 1.49-14.32). At 1 year there was no significant difference in death (3.2 vs. 1.8%, p = 0.42) and borderline significant difference in coronary revascularization (5.3 vs. 1.4%, p = 0.049) in abnormal versus normal TnI groups.

CONCLUSIONS

In-hospital MI was infrequent, but abnormal TnI highly prevalent following renal transplantation. Normal TnI levels following renal transplantation had a high negative predictive value in excluding patients likely to develop subsequent postoperative MI. The role of a higher TnI cut-off for screening for postoperative MI in high-risk subgroups deserves future prospective evaluation.

Coronary artery disease in a large renal transplant population: implications for management

Coronary artery disease (CAD) accounts for approximately one-half of the sizable mortality in patients with end-stage renal disease who have undergone transplantation. The study was a retrospective review of 1460 patients who underwent renal transplantation at the Mount Sinai Medical Center from January 1, 2000 to October 31, 2009. Noninvasive stress testing was performed in 848 patients (88.1%) with 278 patients (32.8%) having abnormal results. Cardiac catheterization was performed in 357 patients (37.1%) and of these, 212 patients had obstructive disease (59.4%). At 5 years posttransplant, there was no statistically significant difference between those with nonobstructive CAD and those who required percutaneous or surgical interventions (adjusted hazard ratio [aHR], 1.243; CI 95%, 0.513-3.010; p = 0.630). Those with medically managed obstructive CAD had significantly higher rates of death at the 5-year period when compared to those who received percutaneous intervention (aHR, 3.792; CI 95%, 1.320-10.895; p = 0.013) or those who received coronary artery bypass grafting (aHR, 6.691; CI 95%, 1.200-37.323). Because noninvasive imaging is poorly predictive of coronary disease in this high-risk population, an anatomic diagnosis is recommended. Revascularization may result in improved long-term outcomes.

Evaluation of adult kidney transplant candidates

Important advances in immunosuppressive therapy and refinement in surgical techniques have allowed renal transplantation to become the treatment of choice for virtually all suitable candidates with end-stage renal disease. Compared to dialysis, kidney transplantation improves both patient survival and quality of life and, over time, can reduce the total cost of medical care. It must be noted, however, that although the risk of death in the first year after transplantation is <5%, not all patients qualify for the surgery because of their unacceptable risks for complications. The transplant evaluation process requires a comprehensive assessment of each patient's medical, surgical, and psychosocial histories. Selection of the suitable transplant candidate remains a challenge for transplant physicians owing, predominantly, to the presence of complex medical issues in the potential candidates and nonstandardized criteria for acceptance or rejection among transplant centers. Furthermore, with the ever-increasing disparity between donor organ supply and demand and resultant increased wait-list times, the transplant physicians must further consider the optimal management and re-evaluation of wait-list patients during the waiting period. This article describes a systematic approach for the evaluation of a potential renal transplant candidate. Various medical issues that arise during the evaluation process are discussed.

[Evaluation of patients' readiness for surgery when called from the waiting list for kidney transplantation: experience of the Budapest Centre]

The aim of this study was to assess the impact of the establishment of waiting list committee on recipient evaluation for kidney transplantation. Studies on this issue have not been previously reported.

METHODS

Data of 714 patients were collected between September 1, 2007 and April 20, 2010. Of the 714 patients 354 were transplanted. Data from the first 16 months period were compared to those obtained during the second 16 months period.

RESULTS

During the first period 171 patients (47.9%) were unfit for transplantation [129 patients (36.1%) were refused after telephone information and 42 patients (11.8%) after clinical investigation]. During the second period 141 (39.5%) patients were found to be unsuitable [80 patients (22.4%) after telephone information and 61 patients (17.1)] after clinical examination. During the two periods of the study 44% of patients were unfit for transplantation. A considerable number of patients were refused because of cardiologic reasons. The percent of fit patients was 52.1% in the first period and 60.5% in the second period. In addition, the percent of unfit patients who were unsuitable for kidney transplantation after telephone information decreased from 36.1% to 22.4%, while the percent of unfit patients after clinical evaluation increased from 11.% to 17.1%.

CONCLUSIONS

Authors conclude that waiting list committee made an effective work.

Marked variation of the association of ESRD duration before and after wait listing on kidney transplant outcomes

Numerous studies report a strong association between pretransplant end-stage renal disease (ESRD) duration and diminished transplant outcomes. However, cumulative waiting time may reflect distinct phases and processes related to patients' physiological condition as well as pre-existing morbidity and access to care. The relative impact of pre- and postlisting ESRD durations on transplant outcomes is unknown. We examined the impact of these intervals from a national cohort of kidney transplant recipients from 1999 to 2008 (n = 112,249). Primary factors explaining prelisting ESRD duration were insurance and race, while primary factors explaining postlisting ESRD duration were blood type, PRA% and variation between centers. Extended time from ESRD to waitlisting had significant dose-response association with overall graft loss (AHR = 1.26 for deceased donors [DD], AHR = 1.32 for living donors [LD], p values < 0.001). Contrarily, time from waitlisting (after ESRD) to transplantation had negligible effects (p = 0.10[DD], p = 0.57[LD]). There were significant associations between pre- and postlisting ESRD time with posttransplant patient survival, however prelisting time had over sixfold greater effect. Prelisting ESRD time predominately explains the association of waiting time with transplant outcomes suggesting that factors associated with this interval should be prioritized for interventions and allocation policy. The degree to which the effect of prelisting ESRD time is a proxy for comorbid conditions, socioeconomic status or access to care requires further study.

The right kidney for the right recipient: the status of deceased donor kidney allocation reform

How best to allocate the limited number of deceased donor kidneys has been the subject of intense debate over past several months in the United States. Most of the major stakeholders have expressed their viewpoints in a series of recent publications. This manuscript aims to examine some of the most important issues in this discussion and to outline a possible path forward.

Troponin I is a predictor of acute cardiac events in the immediate postoperative renal transplant period

BACKGROUND

Patients on the renal transplant waiting list and renal transplant recipients have an increased risk of premature cardiovascular (CV) disease and death.

METHODS

We performed a prospective observational study in 331 kidney or kidney-pancreas transplant recipients to test whether Troponin I (TnI), determined at time of engraftment, can help to identify patients at risk for a major adverse cardiac event (MACE) in the immediate postoperative period. Logistic regression analysis was used to test if pretransplant TnI is a predictor of MACE within 3 months after transplantation.

RESULTS

Eleven patients (3.3%) developed a MACE during the first 2 weeks after transplantation. In patients with a CV history (23.6%), the incidence of MACE increased to 13.4%. In univariate analysis, age (odds ratio [OR] 1.062, P=0.04), TnI (OR 1.12, P=0.0042), HbA1c (OR 1.879, P=0.0076), and CV history (absent vs. present OR 0.027, P=0.0006) were associated with MACE. TnI remained an independent predictor after adjusting for every other significant variable. When we restricted the analysis to patients with a CV history, TnI was the only statistically significant variable associated with MACE.

CONCLUSION

Elevated TnI, immediately pretransplant, is an independent predictor of MACE in the immediate posttransplant period, particularly in patients with CV history.

Cardiovascular risk assessment among potential kidney transplant candidates: approaches and controversies

Cardiovascular disease is the most common cause of death after kidney transplantation. However, uncertainties regarding the optimal assessment of cardiovascular risk in potential transplant candidates have produced controversy and inconsistency in pretransplantation cardiac evaluation practices. In this review, we consider the evidence supporting cardiac evaluation in kidney transplant candidates, generally focused on coronary artery disease, according to the World Health Organization principles for screening. The importance of pretransplant cardiac evaluation is supported by the high prevalence of coronary artery disease and the incidence and adverse consequences of acute coronary syndromes in this population. Testing for coronary artery disease may be performed noninvasively by using modalities that include nuclear myocardial perfusion studies and dobutamine stress echocardiography. These tests have prognostic value for mortality, but imperfect sensitivity and specificity for detecting angiographically defined coronary artery disease in patients with end-stage renal disease. Associations of angiographically-defined coronary artery disease with subsequent survival also are inconsistent, likely because plaque instability is more critical for infarction risk than angiographic stenosis. The efficacy and best methods of myocardial revascularization have not been examined in large contemporary clinical trials in patients with end-stage renal disease. Biomarkers, such as cardiac troponin, have prognostic value in end-stage renal disease, but require further study to determine clinical applications in directing more expensive and invasive cardiac evaluation.

Patient survival after kidney transplantation: relationship to pretransplant cardiac troponin T levels

Assessing cardiovascular (CV) risk pretransplant is imprecise. We sought to determine whether cardiac troponin T (cTnT) relates to patient survival posttransplant. The study includes 603 adults, recipients of kidney transplants. In addition to cTnT dobutamine stress echography and coronary angiography were done in 45% and 19% of the candidates respectively. During 28.4 +/- 12.9 months 5.6% of patients died or had a major cardiac event. cTnT levels were elevated (>0.01 ng/ml) in 56.2% of patients. Elevated cTnT related to reduced event-free survival (hazard ratio (HR) = 1.81, CI 1.33-2.45, p < 0.0001) whether those events occurred during the first year or beyond. This relationship was statistically independent of all other variables tested, including older age, reduced left ventricular ejection fraction (EF) and delayed graft function. cTnT levels allowed better definition of risk in patients with other CV risk factors. Thus, event-free survival was excellent in older individuals, patients with diabetes, low EF and those with preexisting heart disease if their cTnT levels were normal. However, elevated cTnT together with another CV risk factor(s) identified patient with very poor survival posttransplant. Pretransplant cTnT levels are strong and independent predictors of posttransplant survival. These results suggest that cTnT is quite helpful in CV risk stratification of kidney transplant recipients.

Can cardiac troponin T level be used to predict survival of patients awaiting renal transplantation?

Cardiac troponin T (cTnT) levels are often elevated in chronic kidney disease and correlate with survival of patients receiving dialysis. This commentary discusses a recent paper by Hickson et al. that investigated whether a single cTnT measurement can predict survival of patients on the waiting list for renal transplantation. Elevated cTnT levels (>0.01 ng/ml) were associated with left ventricular hypertrophy, reduced left ventricular ejection fraction and ischemia or resting ventricular wall motion abnormalities on dobutamine stress echocardiography, and also predicted mortality independently of age, diabetes or history of heart disease. Although the authors recommend intensive cardiac evaluation in patients with high cTnT levels on transplantation waiting lists, predicting who is at highest risk of dying on the waiting list has no practical utility unless an intervention can reliably lower that risk. Until then, the time patients spend on dialysis should be minimized by rapid referral for transplantation, prompt and appropriate waitlisting and widespread encouragement of living donation.