Screening and risk stratification of coronary artery disease in end-stage renal disease

Coronary Artery Disease Assessment and Cardiovascular Events in Middle-Aged Patients on Hemodialysis

OBJECTIVE

To explore whether, in younger patients on dialysis with longer life expectancy, assessment of coronary artery disease (CAD) could identify individuals at higher risk of events and revascularization might improve outcomes in selected patients contrary to what had been observed in elderly patients.

METHODS

From August 1997 to January 2019, 2265 patients with stage 5 chronic kidney disease were prospectively referred for cardiovascular assessment. For this study, we selected 1374 asymptomatic patients aged between 18 and 64 years. After clinical risk stratification and cardiac scintigraphy by single-photon emission computed tomography, 866 patients underwent coronary angiography. The primary end point was the composite incidence of nonfatal/fatal major adverse cardiovascular events during a follow-up period of 0.1 to 189.7 months (median, 26 months). The secondary end point was all-cause mortality.

RESULTS

The primary end point occurred in 327 (23.8%) patients. Clinically stratified high-risk patients had a 3-fold increased risk of the primary end point. The prevalence of abnormal findings on perfusion scans was 29.2% (n=375), and significant CAD was found in 449 (51.8%) of 866 patients who underwent coronary angiography. An abnormal finding on myocardial perfusion scan and the presence of CAD were significantly associated with a 74% and 22% increased risk of cardiovascular events, respectively. In patients undergoing percutaneous coronary intervention or coronary artery bypass grafting (n=99), there was an 18% reduction in the risk of all-cause death relative to patients receiving medical treatment (P=.03).

CONCLUSION

In this cohort of middle-aged, asymptomatic patients on dialysis, assessment of CAD identified individuals at higher risk of events, and coronary intervention was associated with reducing the risk of death in selected patients.

External validation of the SYNTAX score II 2020 in patients with chronic renal insufficiency

BACKGROUND

The SYNTAX score Ⅱ 2020 (SSⅡ-2020) was created as a customized decision-making tool for individuals diagnosed with complex coronary artery disease (CAD). Nevertheless, there has been a scarcity of research investigating the long-term predictive significance of SSⅡ-2020 for patients with both CAD and chronic renal insufficiency (CRI) who undergo percutaneous coronary intervention (PCI).

AIMS

We sought to showcase the prognostic capacity of SSII-2020 in evaluating long-term all-cause mortality (ACM) within this high-risk patient cohort.

METHODS

A retrospective cohort comprising 1156 individuals diagnosed with CRI and exhibiting left main CAD, three-vessel CAD or both was included in this investigation. We categorized participants into three groups based on the optimal SSII-2020 threshold for predicting long-term ACM, determined using the X-tile software.

RESULTS

At the median follow-up duration of 6.3 years, the ACM rates were determined to be 10% in the low, 17% in the moderate, and 28% in the high SSII-2020 groups (p < 0.001). Employing multivariate Cox regression analysis, it was observed that the high SSII-2020 group exhibited a 3.289-fold increased risk of ACM (95% confidence interval [CI]: 2.229-4.856, p < 0.001) compared with the low SSII-2020 group, whereas the high SSII-2020 group displayed a 1.757-fold (95% CI: 1.190-2.597, p = 0.005) in comparison to the median SSII-2020 groups. Compared with SSII, the SSII-2020 had an incremental value for predicting 7-year ACM (C-index: 0.662 vs. 0.534, p = 0.007; IDI: 0.016, p < 0.001).

CONCLUSIONS

SSII-2020 enhances long-term ACM prediction, facilitates improved risk stratification, and improves clinical utility for PCI patients with complex CAD and CRI.

HEART and TIMI Scores Predict Severe Coronary Atherosclerosis in Patients With End-Stage Renal Disease

Objectives History, EKG, age, risk factors, and troponin (HEART) and thrombolysis in myocardial infarction (TIMI) risk calculators have been validated to predict the risk of subsequent acute coronary syndromes and in some studies, severe coronary atherosclerosis in patients with a concerning clinical history. Their performance in patients with end-stage renal disease (ESRD), a population with a high pretest probability for the condition, is unknown. We aimed to determine whether HEART and TIMI scores can predict severe coronary atherosclerosis in patients with end-stage renal disease (ESRD). Methods A single-center retrospective cohort of admitted patients aged 18 years or older with ESRD on dialysis who underwent coronary angiography during admission (November 2010 to December 2017) was retrospectively reviewed. The outcome of coronary angiography was compared with the calculated HEART and TIMI scores at the time of presentation. Receiver operating characteristics and logistic regression models were used to determine optimal score cutoffs, score usefulness, and associations between outcomes, scores, and patient characteristics. Results Among 231 patient encounters, the mean HEART and TIMI scores were 6±2 and 3±1 points, respectively. Patients with diabetes mellitus, those 65 years old and older, and those reported to have angina pectoris were more likely to show severe coronary artery disease (CAD) lesions. Optimal score cutoffs for determining severe coronary lesions were between six and seven (area under the curve (AUC)=0.754, confidence interval (CI): 0.682-0.826) and between three and four (AUC=0.716, CI: 0.640-0.792) for the HEART and TIMI scores, respectively. Conclusion Similar to the general population, HEART and TIMI scores can predict severe coronary atherosclerosis in the complex ESRD population.

The prediction of in-hospital mortality in chronic kidney disease patients with coronary artery disease using machine learning models

OBJECTIVE

Chronic kidney disease (CKD) patients with coronary artery disease (CAD) in the intensive care unit (ICU) have higher in-hospital mortality and poorer prognosis than patients with either single condition. The objective of this study is to develop a novel model that can predict the in-hospital mortality of that kind of patient in the ICU using machine learning methods.

METHODS

Data of CKD patients with CAD were extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Boruta algorithm was conducted for the feature selection process. Eight machine learning algorithms, such as logistic regression (LR), random forest (RF), Decision Tree, K-nearest neighbors (KNN), Gradient Boosting Decision Tree Machine (GBDT), Support Vector Machine (SVM), Neural Network (NN), and Extreme Gradient Boosting (XGBoost), were conducted to construct the predictive model for in-hospital mortality and performance was evaluated by average precision (AP) and area under the receiver operating characteristic curve (AUC). Shapley Additive Explanations (SHAP) algorithm was applied to explain the model visually. Moreover, data from the Telehealth Intensive Care Unit Collaborative Research Database (eICU-CRD) were acquired as an external validation set.

RESULTS

3590 and 1657 CKD patients with CAD were acquired from MIMIC-IV and eICU-CRD databases, respectively. A total of 78 variables were selected for the machine learning model development process. Comparatively, GBDT had the highest predictive performance according to the results of AUC (0.946) and AP (0.778). The SHAP method reveals the top 20 factors based on the importance ranking. In addition, GBDT had good predictive value and a certain degree of clinical value in the external validation according to the AUC (0.865), AP (0.672), decision curve analysis, and calibration curve.

CONCLUSION

Machine learning algorithms, especially GBDT, can be reliable tools for accurately predicting the in-hospital mortality risk for CKD patients with CAD in the ICU. This contributed to providing optimal resource allocation and reducing in-hospital mortality by tailoring precise management and implementation of early interventions.

Quantitative plaque analysis with A.I.-augmented CCTA in end-stage renal disease and complex CAD

BACKGROUND

Adverse cardiovascular events are a significant cause of mortality in end-stage renal disease (ESRD) patients. High-risk plaque anatomy may be a significant contributor. However, their atherosclerotic phenotypes have not been described. We sought to define atherosclerotic plaque characteristics (APC) in dialysis patients using artificial-intelligence augmented CCTA.

METHODS

We retrospectively analyzed ESRD patients referred for CCTA using an FDA approved artificial-intelligence augmented-CCTA program (Cleerly). Coronary lesions were evaluated for APCs by CCTA. APCs included percent atheroma volume(PAV), low-density non-calcified-plaque (LD-NCP), non-calcified-plaque (NCP), calcified-plaque (CP), length, and high-risk-plaque (HRP), defined by LD-NCP and positive arterial remodeling >1.10 (PR).

RESULTS

79 ESRD patients were enrolled, mean age 65.3 years, 32.9% female. Disease distribution was non-obstructive (65.8%), 1-vessel disease (21.5%), 2-vessel disease (7.6%), and 3-vessel disease (5.1%). Mean total plaque volume (TPV) was 810.0 mm³, LD-NCP 16.8 mm³, NCP 403.1 mm³, and CP 390.1 mm³. HRP was present in 81.0% patients. Patients with at least one >50% stenosis, or obstructive lesions, had significantly higher TPV, LD-NCP, NCP, and CP. Patients >65 years had more CP and higher PAV.

CONCLUSION

Our study provides novel insight into ESRD plaque phenotypes and demonstrates that artificial-intelligence augmented CCTA analysis is feasible for CAD characterization despite severe calcification. We demonstrate elevated plaque burden and stenosis caused by predominantly non-calcified-plaque. Furthermore, the quantity of calcified-plaques increased with age, with men exhibiting increased number of 2-feature plaques and higher plaque volumes. Artificial-intelligence augmented CCTA analysis of APCs may be a promising metric for cardiac risk stratification and warrants further prospective investigation.

Cardiac imaging for the assessment of patients being evaluated for kidney transplantation

Cardiac risk assessment before kidney transplantation has become widely accepted. However, the optimal patient selection and screening tool for cardiac assessment remain controversial. Clinicians face several challenges in this process, including the ever-growing pre-transplant population, aging transplant candidates, increasing prevalence of coronary artery disease, and scarcity of donor organs. Optimizing the cardiovascular risk profile in kidney transplant candidates is necessary to better appropriate limited donor organs and improve patient outcomes. Increasing waiting times from the initial evaluation for transplant candidacy to the actual transplant raises questions regarding re-testing and re-stratification of risk. In this review, we summarize and discuss the current literature on cardiac evaluation prior to kidney transplantation. We also propose simple evidence-based evaluation algorithms for initial and follow-up CAD surveillance in patients being wait-listed for kidney transplantation.

Cardiovascular risk stratification in the noncardiac solid organ transplant candidate

PURPOSE OF REVIEW

Solid organ transplantation (SOT) has become a widely accepted therapy for end-stage disease across the spectrum of thoracic and abdominal organs. With contemporary advances in medical and surgical therapies in transplantation, candidates for SOT are increasingly older with a larger burden of comorbidities, including cardiovascular disease (CVD). CVD, in particular, is a leading cause of morbidity and mortality in SOT candidates with end-stage disease of noncardiac organs [1].

RECENT FINDINGS

Identification of coronary artery disease (CAD), heart failure, and valvular disease are important in noncardiac SOT to ensure both appropriate peri-transplant management and equitable organ allocation. Although the American College of Cardiology (ACC) and the American Heart Association (AHA) have published guidelines and recommendations for the perioperative cardiovascular evaluation of patients undergoing noncardiac surgery, the implications of both symptomatic and asymptomatic CVD differ in patients with end-stage organ failure being considered for SOT when compared to the general population.

SUMMARY

Herein, we review the epidemiology, diagnosis, and evidence for the management of CVD in kidney and liver transplantation, combining current guidelines from the 2012 ACC/AHA scientific statement on cardiac disease evaluation in SOT with more contemporary evidenced-based algorithms.

Decreased B lymphocytes subpopulations are associated with higher atherosclerotic risk in elderly patients with moderate-to-severe chronic kidney diseases

Aim

Cardiovascular diseases (CVD) are the leading cause of death in patients with chronic kidney disease (CKD), and the risk of CVD increases with reductions in renal function. This study aims to investigate the potential roles of B lymphocyte populations in subclinical atherosclerosis (measured by intima-media thickness, IMT) and prognosis in elderly patients with moderate-to-severe CKD.

Methods

In this study, a total of 219 patients (143 moderate-to-severe CKD patients with stage 3–4 and 76 non-CKD controls) were recruited. B cell subsets: CD19(+)CD5(+) and CD19(+)CD5(−) B cells were analyzed by flow cytometry. Intima-media thickness (IMT) was measured by ultrasound. Correlations between the B cell subsets with IMT and clinical outcome was analyzed.

Results

CKD patients showed increased IMT (P = 0.006). The level of CD19(+)CD5(+) and CD19(+)CD5(−) B cells were decreased in CKD patients. Correlation analysis showed that IMT was positively correlated with systolic blood pressure, protein/creatinine ratio and diabetes (P < 0.05), and were negatively correlated with CD19(+)CD5(+) and CD19(+)CD5(−) B lymphocytes (P < 0.05). Stepwise multiple regression analysis showed that CD19(+)CD5(−) B cells had a significant independent association with IMT (P < 0.05). IMT was increased in lower level of total CD19(+) B cells (≤ 0.06 × 10⁹ /L) and CD19(+)CD5(−) B cells (≤ 0.05 × 10⁹ /L) (P < 0.05). Kaplan-Meier analysis showed that patients with lower levels of CD19(+)CD5(+) and CD19(+)CD5(−) B cells exhibited worse survival (P < 0.05). Cox regression analysis showed that patients with lower CD19(+)CD5(+) and CD19(+)CD5(−) B cells counts have a higher risk of all-cause mortality (P < 0.05).

Conclusions

Our results showed that decreased CD19(+)CD5(+) and CD19(+)CD5(−) B lymphocytes were correlated with atherosclerosis and worse survival, which indicates that B lymphocytes might involve in atherosclerosis and associated the prognosis of elderly patients with moderate-to-severe CKD.

Epicardial adipose tissue radiodensity is associated with all-cause mortality in patients undergoing hemodialysis

The radiodensity and volume of epicardial adipose tissue (EAT) on computed tomography angiography (CTA) may provide information regarding cardiovascular risk and long-term outcomes. EAT volume is associated with mortality in patients undergoing incident hemodialysis. However, the relationship between EAT radiodensity/volume and all-cause mortality in patients with end-stage renal disease (ESRD) undergoing maintenance hemodialysis remains elusive. In this retrospective study, EAT radiodensity (in Hounsfield units) and volume (in cm³) on coronary CTA were quantified for patients with ESRD using automatic, quantitative measurement software between January 2012 and December 2018. All-cause mortality data (up to December 2019) were obtained from the Korean National Statistical Office. The prognostic values of EAT radiodensity and volume for predicting long-term mortality were assessed using multivariable Cox regression models, which were adjusted for potential confounders. A total of 221 patients (mean age: 64.88 ± 11.09 years; 114 women and 107 men) with ESRD were included. The median follow-up duration (interquartile range) after coronary CTA was 29.63 (range 16.67–44.7) months. During follow-up, 82 (37.1%) deaths occurred. In the multivariable analysis, EAT radiodensity (hazard ratio [HR] 1.055; 95% confidence interval [CI] 1.015–1.095; p = 0.006) was an independent predictor of all-cause mortality in patients with ESRD. However, EAT volume was not associated with mortality. Higher EAT radiodensity on CTA is associated with higher long-term all-cause mortality in patients undergoing prevalent hemodialysis, highlighting its potential as a prognostic imaging biomarker in patients undergoing hemodialysis.

Pericoronary fat attenuation index in computed tomography angiography is associated with mortality in end-stage renal disease

Background

An increased pericoronary fat attenuation index (FAI) on computed tomography angiography (CTA) is associated with increased all-cause and cardiac mortality in the general population. However, the ability of pericoronary FAI to predict long-term outcomes in chronic kidney disease (CKD) patients is unknown.

Methods

In this single-center retrospective longitudinal cohort study, we assessed the utility of CTA-based pericoronary FAI measurement to predict mortality of CKD patients, including those with end-stage renal disease (ESRD). Mapping and analysis of pericoronary FAI involved three major proximal coronary arteries. The prognostic value of pericoronary FAI for long-term mortality was assessed with multivariable Cox regression models.

Results

Among 268 CKD participants who underwent coronary CTA, 209 participants with left anterior descending artery (LAD) FAI measurements were included. The pericoronary FAI measured at the LAD was not significantly associated with adjusted risk of all-cause mortality (hazard ratio [HR], 2.08; 95% confidence interval [CI], 0.94–3.51) in any CKD group. However, ESRD patients with elevated pericoronary FAI values had a greater adjusted risk of all-cause mortality compared with the low-FAI group (HR, 2.26; 95% CI, 1.11–4.61).

Conclusion

The pericoronary FAI measured at the LAD predicted long-term mortality in patients with ESRD, which could provide an opportunity for early primary intervention in ESRD patients.

Serum Sortilin Is Associated with Coronary Artery Calcification and Cardiovascular and Cerebrovascular Events in Maintenance Hemodialysis Patients

OBJECTIVE

To analyze the role of serum sortilin in coronary artery calcification (CAC) and cardiovascular and cerebrovascular events (CCE) in maintenance hemodialysis (MHD) patients.

METHODS

One hundred eleven patients with MHD ≥3 months were included in this study. The general data, clinical features, hematological data, and medication history of the patients were recorded. Eighty-five cases were examined by vascular color Doppler ultrasound, cardiac color Doppler ultrasound, lateral lumbar radiography, and coronary artery calcification score. The patients were followed up for a median time of 45 months. The primary endpoint was CCE or death from a vascular event, and the role of sortilin in this process was analyzed.

RESULTS

Among 85 MHD patients, 51 cases (60.00%) had different degrees of CAC. There were significant differences in diabetes, dialysis time, serum phosphorus, calcium-phosphorus product, medical history of phosphate binders, sortilin, and carotid artery plaque between 4 different degrees of calcification groups (p < 0.05). Logistic regression analysis showed that diabetes (OR = 5.475; 95% CI: 1.794-16.71, p = 0.003), calcium-phosphorus product (OR = 2.953; 95% CI: 1.198-7.279, p = 0.019), and sortilin (OR = 1.475 per 100 pg/mL; 95% CI: 1.170-1.858, p = 0.001) were independent risk factors for CAC. During the follow-up, 28 cases of 111 patients (25.23%) suffered from CCE. There were significant differences in CCE between mild, moderate, and severe CAC groups and noncalcification groups (p < 0.05). Cox regression analysis showed that diabetes mellitus (HR 3.424; 95% CI: 1.348-8.701, p = 0.010), CAC (HR 5.210; 95% CI: 1.093-24.83, p = 0.038), and serum sortilin (HR = 8.588; 95% CI: 1.919-38.43, p = 0.005) were independent risk factors for CCE. Besides, we proposed a cutoff value of 418 pg/mL for serum sortilin level, which was able to predict the occurrence of CCE with 75.0% sensitivity and 71.9% specificity. The area under the curve was 0.778 (95% CI: 0.673-0.883).

CONCLUSION

Sortilin is newly found to be independently associated with CAC and CCE in MHD patients.

The cardiovascular-dialysis nexus: the transition to dialysis is a treacherous time for the heart

Chronic kidney disease (CKD) patients require dialysis to manage the progressive complications of uraemia. Yet, many physicians and patients do not recognize that dialysis initiation, although often necessary, subjects patients to substantial risk for cardiovascular (CV) death. While most recognize CV mortality risk approximately doubles with CKD the new data presented here show that this risk spikes to >20 times higher than the US population average at the initiation of chronic renal replacement therapy, and this elevated CV risk continues through the first 4 months of dialysis. Moreover, this peak reflects how dialysis itself changes the pathophysiology of CV disease and transforms its presentation, progression, and prognosis. This article reviews how dialysis initiation modifies the interpretation of circulating biomarkers, alters the accuracy of CV imaging, and worsens prognosis. We advocate a multidisciplinary approach and outline the issues practitioners should consider to optimize CV care for this unique and vulnerable population during a perilous passage.

Incidence and predictors of vascular events following end-stage kidney disease in childhood

AIM

Cardiovascular death is a leading cause of mortality in paediatric end-stage kidney disease (ESKD). There is however little known about the clinically relevant vascular disease in this population. We aimed to describe the incidence of new onset vascular disease and vascular death in Australian children receiving renal replacement therapy (RRT). We also aimed to identify demographic or childhood risk factors for these endpoints, and whether vascular disease predicts mortality.

METHODS

Data on Australian patients who commenced RRT at <18 years of age from 1991 to 2017 were extracted from the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA). Multivariable competing risks regression was used to identify factors associated with vascular events.

RESULTS

A cohort of 1268 patients were followed up for a median of 10.31 years. Vascular disease was reported in 5.4%, and vascular death in 4.1%. The cumulative incidence of any vascular event, that is, disease or death, at 10 and 20 years was 5.5% and 12.8%, respectively. Childhood vascular events were associated with non-Caucasian, non-Indigenous ethnicity, and for the 804 patients followed up after 18 years of age, vascular events were associated with lack of childhood transplantation, longer childhood dialysis duration and Indigenous ethnicity. Vascular disease was only reported for 25.49% of patients who had a vascular death, and although a significant risk factor for mortality, it had limited ability to predict mortality.

CONCLUSION

Cumulative incidence of vascular events is significant after commencing RRT during childhood and is associated with ethnicity, longer childhood dialysis duration and lack of childhood transplantation.

Cardiovascular risk assessment and coronary artery calcification burden in asymptomatic patients in the initial years of hemodialysis

The specific tool for cardiovascular risk assessment in hemodialysis population has not yet been proposed, despite high prevalence of cardiovascular morbidity, and mortality in clinically asymptomatic patients. Coronary artery calcium score (CACS), as a reliable predictor of future cardiovascular events, might be a valuable approach. We sought to evaluate coronary artery calcification burden and its association with clinical and laboratory parameters in asymptomatic patients who recently initiated hemodialysis. The cross-sectional study included 60 asymptomatic patients receiving chronic hemodialysis for no longer than 48 months. CACS was assessed by cardiac computed tomography. Intima-media thickness (IMT) of both common carotid and femoral arteries were measured using ultrasonography. The mean total CACS was 160.50 (443). Patients' age correlated significantly with CACS (σ = 0.367; P = 0.004), carotid (σ = 0.375; P = 0.004) and femoral IMT (σ = 0.323; P = 0.013). Patients with CACS = 0 were significantly younger than patients with CACS >400: 52.4 ± 7.91 vs. 63.88 ± 8.37 years old, respectively (P = 0.034). In patients receiving dialysis for longer than 24 months CACS, femoral and carotid IMT were higher than in those dialyzed for less than 24 months; however, none has reached significance. There was a significant positive correlation between CACS and right (σ = 0.312; P = 0.018) and left (σ = 0.521; P < 0.001) femoral IMT, while not with carotid. CACS showed significant negative correlation with the serum iron (σ = -0.351; P = 0.007). Calcification burden varies significantly in asymptomatic patients in early years of dialysis. It correlates with patients' age and tends to increase with dialysis vintage. Femoral IMT might be useful for cardiovascular risk stratification in asymptomatic patients who recently initiated hemodialysis.

Kidney-Pancreas Transplant Recipients Experience Higher Risk of Complications Compared to the General Population after Undergoing Coronary Artery Bypass Grafting

This retrospective analysis aims to identify differences in surgical outcomes between pancreas and/or kidney transplant recipients compared with the general population undergoing coronary artery bypass grafting (CABG). Using Nationwide Inpatient Sample (NIS) data from 2005 to 2014, patients who underwent CABG were stratified by either no history of transplant, or history of pancreas and/or kidney transplant. Multivariate analysis was used to calculate odds ratio (OR) to evaluate in-hospital mortality, morbidity, length of stay (LOS), and total hospital charge in all centers. The analysis was performed for both nonemergency and emergency CABG. Overall, 2,678 KTx (kidney transplant alone), 184 PTx (pancreas transplant alone), 254 KPTx (kidney-pancreas transplant recipients), and 1,796,186 Non-Tx (nontransplant) met inclusion criteria. KPTx experienced higher complication rates compared with Non-Tx (78.3 vs. 47.8%, p  < 0.01). Those with PTx incurred greater total hospital charge and LOS. On weighted multivariate analysis, KPTx was associated with an increased risk for developing any complication following CABG (OR 3.512, p  < 0.01) and emergency CABG (3.707, p  < 0.01). This risk was even higher at transplant centers (CABG OR 4.302, p  < 0.01; emergency CABG OR 10.072, p  < 0.001). KTx was associated with increased in-hospital mortality following emergency CABG, while PTx and KPTx had no mortality to analyze. KPTx experienced a significantly higher risk of complications compared with the general population after undergoing CABG, in both transplant and nontransplant centers. These outcomes should be considered when providing perioperative care.

Coronary artery calcium progresses rapidly and discriminates incident cardiovascular events in chronic kidney disease regardless of diabetes: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND AND AIMS

Chronic kidney disease (CKD) is associated with high prevalence of cardiovascular disease (CVD) events. We sought to assess the prognostic utility of coronary artery calcium (CAC) scores in discriminating incident CVD events among subpopulations of CKD, particularly those without diabetes mellitus (DM).

METHODS

Using the Multi-Ethnic Study of Atherosclerosis, we identified 4 groups based on present/absent CKD/diabetes (CKD-/DM-, n = 5308; CKD-/DM+, n = 586, CKD+/DM-, n = 620; CKD+/DM+, n = 266). Baseline and follow-up CAC (Agatston units) measurements, and association between CAC and incident CVD events in median follow-up of 13 years were evaluated using proportional hazards regression adjusting for demographics, clinical, biomarker variables.

RESULTS

Prevalence of CKD and DM in the cohort was 13% and 12.5% respectively. Annual progression in adjusted median CAC score was 24.8%, 27.9%, 26.7%, 36.8% and unadjusted cumulative incident CVD rates were 12.6%, 22.3%, 23.1%, 39.8% for CKD-/DM-, CKD-/DM+, CKD+/DM-, CKD+/DM+, respectively. After full adjustment (CKD-/DM-referent), hazard ratios (HR, 95% CI) for incident CVD events were 1.25 (1.01-1.53) CKD-/DM+, 1.10 (0.90-1.33) CKD+/DM- and 2.18 (1.73-2.76) CKD+/DM+. Using CKD-/DM-/baseline CAC = 0 referent, adjusted HRs (95% CI) for incident CVD in CKD+/DM- were 1.30 (0.81-2.07), 2.05 (1.4-2.99), and 4.15 (2.94-5.86) for baseline CAC = 0, 1-100, and >300 Agatston units respectively while for CKD+/DM+, adjusted HRs were 3.15 (2.04-4.86), 3.56 (2.26-5.62), 7.90 (5.35-11.67), respectively.

CONCLUSIONS

CAC provides incremental prognostic information to predict incident CVD events in CKD regardless of DM. Moreover, baseline CAC categories discriminate incident CVD among CKD without DM, which may have implications in individualizing approach to primary prevention in this high-risk population.

Cardiovascular Functional Changes in Chronic Kidney Disease: Integrative Physiology, Pathophysiology and Applications of Cardiopulmonary Exercise Testing

The development of cardiovascular disease during renal impairment involves striking multi-tiered, multi-dimensional complex alterations encompassing the entire oxygen transport system. Complex interactions between target organ systems involving alterations of the heart, vascular, musculoskeletal and respiratory systems occur in Chronic Kidney Disease (CKD) and collectively contribute to impairment of cardiovascular function. These systemic changes have challenged our diagnostic and therapeutic efforts, particularly given that imaging cardiac structure at rest, rather than ascertainment under the stress of exercise, may not accurately reflect the risk of premature death in CKD. The multi-systemic nature of cardiovascular disease in CKD patients provides strong rationale for an integrated approach to the assessment of cardiovascular alterations in this population. State-of-the-art cardiopulmonary exercise testing (CPET) is a powerful, dynamic technology that enables the global assessment of cardiovascular functional alterations and reflects the integrative exercise response and complex machinery that form the oxygen transport system. CPET provides a wealth of data from a single assessment with mechanistic, physiological and prognostic utility. It is an underutilized technology in the care of patients with kidney disease with the potential to help advance the field of cardio-nephrology. This article reviews the integrative physiology and pathophysiology of cardio-renal impairment, critical new insights derived from CPET technology, and contemporary evidence for potential applications of CPET technology in patients with kidney disease.

Cardiac Imaging for Coronary Heart Disease Risk Stratification in Chronic Kidney Disease

Chronic kidney disease (CKD), defined as dysfunction of the glomerular filtration apparatus, is an independent risk factor for the development of coronary artery disease (CAD). Patients with CKD are at a substantially higher risk of cardiovascular mortality compared with the age- and sex-adjusted general population with normal kidney function. The risk of CAD and mortality in patients with CKD is correlated with the degree of renal dysfunction including presence of microalbuminuria. A greater cardiovascular risk, albeit lower than for patients receiving dialysis, persists even after kidney transplantation. Congestive heart failure, commonly caused by CAD, also accounts for a significant portion of the cardiovascular-related events observed in CKD. The optimal strategy for the evaluation of CAD in patients with CKD, particularly before renal transplantation, remains a topic of contention spanning over several decades. Although the evaluation of coexisting cardiac disease in patients with CKD is desirable, severe renal dysfunction limits the use of radiographic and magnetic resonance contrast agents due to concerns regarding contrast-induced nephropathy and nephrogenic systemic sclerosis, respectively. In addition, many patients with CKD have extensive and premature (often medial) calcification disproportionate to the severity of obstructive CAD, thereby limiting the diagnostic value of computed tomography angiography. As such, echocardiography, non-contrast-enhanced magnetic resonance, nuclear myocardial perfusion, and metabolic imaging offer a variety of approaches to assess obstructive CAD and cardiomyopathy of advanced CKD without the need for nephrotoxic contrast agents.

Coronary Artery Disease in patients with End-Stage Kidney Disease; Current perspective and gaps of knowledge

Coronary artery disease (CAD) is very common in dialysis patients. One third have preexisting CAD and another one third have significant occult disease at the time of starting dialysis. Symptoms are often absent or are atypical, emphasizing the need for vigorous screening, specifically in patients awaiting transplant. The lesions tend to be heavily calcified, diffuse, and involve multiple vessels, consequently, percutaneous coronary interventions are more complicated to perform, and are less successful in achieving and maintaining short- and long-term patency. Dialysis patients have been excluded from the randomized controlled trials on which the current standards for managing CAD have been established. Due to differences in pathobiology and risks and benefits, it is uncertain that the results of these clinical trials extrapolate to patients with advanced chronic kidney disease (CKD). Here we review the data from observational studies and identify special considerations concerning the diagnosis and management of CAD in dialysis patients, including the use of noninvasive functional testing vs anatomical testing, the management of acute coronary syndromes and of stable coronary artery disease, the role for percutaneous revascularization vs coronary artery bypass grafting, and of platelet inhibitor therapy after coronary stenting. We review the preliminary results of the recently published ISCHEMIA-CKD trial, the only trial to date to involve large numbers of dialysis patients. This is the first of, hopefully, many trials in the pipeline that will examine therapies for CAD specifically in patients with advanced CKD, a growing population that is at particularly high risk for poor outcomes.

Reduced myocardial blood flow reserve in kidney transplant candidates may hamper risk stratification

BACKGROUND

Vasodilator nuclear stress testing is frequently ordered for risk stratification prior to kidney transplantation. Since ⁸²Rb-positron emission tomography-computed tomography can measure myocardial blood flow (MBF), the response to vasodilator stress can be verified rendering the results of the scan more reliable.

METHODS

We reviewed the MBF response to dipyridamole infusion in 328 patients with end-stage kidney disease (ESKD) prior to transplant (188 hemodialysis-HD, 120 peritoneal dialysis-PD, and 20 pre-dialysis patients-CKD5) and in 100 controls with normal kidney function. A stress/rest MBF ratio ≥ 2 was considered an adequate response to dipyridamole. Coronary artery calcium (CAC) was measured on CT.

RESULTS

Inadequate MBF response was seen in 36%-HD, 21%-PD, 45%-CKD5 vs. 23%-controls (p = 0.006). Univariable predictors of poor MBF response in ESKD patients were age, diabetes mellitus, and CAC (all p < 0.03) while serum hemoglobin was borderline significant (p = 0.052). Multivariable predictors of a poor MBF response were age (p = 0.002) and lower serum hemoglobin (p = 0.014). Ischemia was identified in 8% of ESKD patients and 24% of controls (p < 0.001).

CONCLUSIONS

ESKD patients are less likely to respond appropriately to vasodilator stress compared to patients with normal renal function and had a lower incidence of ischemia despite a high pre-test probability of disease. Physicians performing vasodilator stress without MBF measurement should be aware of the high probability of a false negative response.

Heart Rate-Independent 3D Myocardial Blood Oxygen Level-Dependent MRI at 3.0 T with Simultaneous 13N-Ammonia PET Validation

Background Despite advances, blood oxygen level-dependent (BOLD) cardiac MRI for myocardial perfusion is limited by inadequate spatial coverage, imaging speed, multiple breath holds, and imaging artifacts, particularly at 3.0 T. Purpose To develop and validate a robust, contrast agent-unenhanced, free-breathing three-dimensional (3D) cardiac MRI approach for reliably examining changes in myocardial perfusion between rest and adenosine stress. Materials and Methods A heart rate-independent, free-breathing 3D T2 mapping technique at 3.0 T that can be completed within the period of adenosine stress (≤4 minutes) was developed by using computer simulations, ex vivo heart preparations, and dogs. Studies in dogs were performed with and without coronary stenosis and validated with simultaneously acquired nitrogen 13 (13N) ammonia PET perfusion in a clinical PET/MRI system. The MRI approach was also prospectively evaluated in healthy human volunteers (from January 2017 to September 2017). Myocardial BOLD responses (MBRs) between normal and ischemic myocardium were compared with mixed model analysis. Results Dogs (n = 10; weight range, 20-25 kg; mongrel dogs) and healthy human volunteers (n = 10; age range, 22-53 years; seven men) were evaluated. In healthy dogs, T2 MRI at adenosine stress was greater than at rest (mean rest vs stress, 38.7 msec ± 2.5 [standard deviation] vs 45.4 msec ± 3.3, respectively; MBR, 1.19 ± 0.08; both, P < .001). At the same conditions, mean rest versus stress PET perfusion was 1.1 mL/mg/min ± 0.11 versus 2.3 mL/mg/min ± 0.82, respectively (P < .001); myocardial perfusion reserve (MPR) was 2.4 ± 0.82 (P < .001). The BOLD response and PET MPR were positively correlated (R = 0.67; P < .001). In dogs with coronary stenosis, perfusion anomalies were detected on the basis of MBR (normal vs ischemic, 1.09 ± 0.05 vs 1.00 ± 0.04, respectively; P < .001) and MPR (normal vs ischemic, 2.7 ± 0.08 vs 1.7 ± 1.1, respectively; P < .001). Human volunteers showed increased myocardial T2 at stress (rest vs stress, 44.5 msec ± 2.6 vs 49.0 msec ± 5.5, respectively; P = .004; MBR, 1.1 msec ± 8.08). Conclusion This three-dimensional cardiac blood oxygen level-dependent (BOLD) MRI approach overcame key limitations associated with conventional cardiac BOLD MRI by enabling whole-heart coverage within the standard duration of adenosine infusion, and increased the magnitude and reliability of BOLD contrast, which may be performed without requiring breath holds. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Almeida in this issue.

MicroRNA-497/fibroblast growth factor-23 axis, a predictive indictor for decreased major adverse cardiac and cerebral event risk in end-stage renal disease patients who underwent continuous ambulatory peritoneal dialysis

OBJECTIVE

This study aimed at exploring the correlation of microRNA (miR)-497/fibroblast growth factor-23 (FGF-23) axis with major adverse cardiac and cerebral event (MACCE) occurrence in end-stage renal disease (ESRD) patients who underwent continuous ambulatory peritoneal dialysis (CAPD).

METHODS

Totally, 360 ESRD patients who underwent CAPD were enrolled. Their plasma samples were collected to detect miR-497 expression by real-time quantitative polymerase chain reaction, and FGF-23 level by enzyme-linked immunosorbent assay. All patients were followed up for 36 months, and the occurrence of MACCE during the follow-up was documented.

RESULTS

MiR-497 expression negatively correlated with FGF-23 level in ESRD patients who underwent CAPD (P < .001). The MACCE occurrence rate at 1, 2, and 3-year was 5.6%, 11.9%, and 15.0%, respectively. Furthermore, miR-497/FGF-23 axis high level (P < .001) and miR-497 high expression (P = .034) correlated with reduced accumulating MACCE occurrence, whereas FGF-23 high level (P = .008) correlated with increased accumulating MACCE occurrence. Forward stepwise multivariate Cox's regression disclosed that miR-497/FGF-23 axis high level (P = .008) was an independent predictive factor for lower accumulating MACCE occurrence, whereas age (≥55 years) (P < .001), body mass index (≥21.7 kg/m² ) (P = .006), peritoneal dialysis duration (≥61.0 months) (P < .001), C-reactive protein (≥4.7 mg/L) (P = .001), serum uric acid (≥409.4 μmol/L) (P = .009), β-fibrinogen (≥5.8 mmol/L) (P < .001), and low-density lipoprotein cholesterol (≥2.7 mmol/L) (P = .003) were independent factors for predicting higher accumulating MACCE occurrence.

CONCLUSION

MiR-497/FGF-23 axis holds clinical significance for predicting attenuated MACCE risk in ESRD patients who underwent CAPD.

Epicardial adipose tissue deposition in patients with diabetes and renal impairment: Analysis of the literature

Diabetes mellitus (DM) is defined as a chronic disease of disordered metabolism with an ongoing increase in prevalence and incidence rates. Renal disease in patients with diabetes is associated with increased morbidity and premature mortality, particularly attributed to their very high cardiovascular risk. Since this group of patients frequently lacks specific symptomatology prior to the adverse events, a screening tool for the identification of high-risk patients is necessary. The epicardial adipose tissue (EAT) is a biologically active organ having properties similar to visceral adipose tissue and has been associated with metabolic diseases and coronary artery disease. Superior to conventional cardiovascular risk factors and anthropometric measures, including body mass index and waist circumference, the EAT can early predict the development of coronary artery disease. Assessment of EAT can be performed by two-dimensional echocardiography, magnetic resonance imaging or computer tomography. However, its role and significance in patients with DM and nephropathy has not been thoroughly evaluated. The aim of the current editorial is to evaluate all available evidence regarding EAT in patients with DM and renal impairment. Systematic search of the literature revealed that patients with DM and nephropathy have increased EAT measurements, uncontrolled underlying disease, high body mass index and raised cardiovascular risk markers. Acknowledging the practical implications of this test, EAT assessment could serve as a novel and non-invasive biomarker to identify high-risk patients for cardiovascular adverse events.

Epicardial Adipose Tissue and Renal Disease

Epicardial adipose tissue (EAT) is derived from splanchnic mesoderm, localized anatomically between the myocardium and pericardial visceral layer, and surrounds the coronary arteries. Being a metabolically active organ, EAT secretes numerous cytokines, which moderate cardiovascular morphology and function. Through its paracrine and vasocrine secretions, EAT may play a prominent role in modulating cardiac function. EAT protects the heart in normal physiological conditions by secreting a variety of adipokines with anti-atherosclerotic properties, and in contrast, secretes inflammatory molecules in pathologic conditions that may play a dynamic role in the pathogenesis of cardiovascular diseases by promoting atherosclerosis. Considerable research has been focused on comparing the anatomical and biochemical features of EAT in healthy people, and a variety of disease conditions such as cardiovascular diseases and renal diseases. The global cardiovascular morbidity and mortality in renal disease are high, and there is a paucity of concrete evidence and societal guidelines to detect early cardiovascular disease (CVD) in this group of patients. Here we performed a clinical review on the existing evidence and knowledge on EAT in patients with renal disease, to evaluate its application as a reliable, early, noninvasive biomarker and indicator for CVD, and to assess its significance in cardiovascular risk stratification.

Screening coronary angiography in patients with long-standing diabetes mellitus undergoing kidney transplant evaluation

BACKGROUND

The utility of coronary angiography in patients with diabetes mellitus undergoing kidney transplant evaluation is unclear. Predictors of critical angiography lesions in these patients will aid in appropriate use of angiography.

METHODS

Single-center study of 80 patients with ≥15 years of diabetes mellitus who underwent a screening coronary angiography despite a negative cardiac stress test. Risk factors for needing coronary intervention (CI) (percutaneous or bypass grafting) were analyzed.

RESULTS

Eighteen patients (23%) had a ≥70% occlusion in one or more major coronary vessel(s), with right coronary artery being the most commonly involved (71%). Fifteen patients (19%) underwent coronary intervention: ten percutaneously and five with bypass surgery. Risk factors for needing CI were not being on statin (OR 3.54, P = 0.047) and history of stroke or peripheral vascular disease (PVD; OR 3.5, P = 0.034). A model that included statin use, stroke/PVD history, and glycosylated hemoglobin had a receiver operating characteristic curve area under the curve of 0.8 to predict CI.

CONCLUSION

Despite a negative stress test, the prevalence of critical coronary lesions was high among kidney transplant candidates with long-standing diabetes. Risk factors for needing coronary intervention were absence of statin use and a history of stroke or peripheral vascular disease.

Association between circulating proprotein convertase subtilisin/kexin type 9 levels and prognosis in patients with severe chronic kidney disease

Background

Chronic kidney disease is a risk factor for premature development of coronary atherosclerosis and mortality. A high level of proprotein convertase subtilisin/kexin type 9 (PCSK9) is a recently recognized cardiovascular risk factor and has become the target of effective inhibitory treatment. In 167 kidney transplantation candidates, we aimed to: (i) compare levels of PCSK9 with those of healthy controls, (ii) examine the association between levels of PCSK9 and low-density lipoprotein cholesterol (LDL-c) and the degree of coronary artery disease (CAD) and (iii) evaluate if levels of PCSK9 predict major adverse cardiac events (MACE) and mortality.

Methods

Kidney transplant candidates (n = 167) underwent coronary computed tomography angiography (CCTA) and invasive coronary angiography (ICA) before transplantation. MACE and mortality data were extracted from the Western Denmark Heart Registry, a review of patient records and patient interviews. A group of 79 healthy subjects were used as controls.

Results

Mean PCSK9 levels did not differ between healthy controls and kidney transplant candidates. In patients not receiving lipid-lowering therapy, PCSK9 correlated positively with LDL-c (rho = 0.24, P &lt; 0.05). Mean PCSK9 was similar in patients with and without obstructive CAD at both CCTA and ICA. In a multiple regression analysis, PCSK9 was associated with neither LDL-c (β=−6.45, P = 0.44) nor coronary artery calcium score (β=2.17, P = 0.84). During a follow-up of 3.7 years, PCSK9 levels were not associated with either MACE or mortality.

Conclusions

The ability of PCSK9 levels to predict cardiovascular disease and prognosis does not seem to apply to a cohort of kidney transplant candidates.

Prevalence and risk factors for vascular calcification in Chinese patients receiving dialysis: baseline results from a prospective cohort study

OBJECTIVE

With limited data available on calcification prevalence in chronic kidney disease (CKD) patients on dialysis, the China Dialysis Calcification Study (CDCS) determined the prevalence of vascular/valvular calcification (VC) and association of risk factors in Chinese patients with prevalent hemodialysis (HD) or peritoneal dialysis (PD).

METHODS

CKD patients undergoing HD/PD for ≥6 months were enrolled. Prevalence data for calcification and medical history were documented at baseline. Coronary artery calcification (CAC) was assessed by electron beam or multi-slice computed tomography (EBCT/MSCT), abdominal aortic calcification (AAC) by lateral lumbar radiography, and cardiac valvular calcification (ValvC) by echocardiography. Serum phosphorus, calcium, intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D and FGF-23 were evaluated. A logistic regression model was used to evaluate the association between risk factors and VC.

RESULTS

Of 1,497 patients, 1,493 (78.3% HD, 21.7% PD) had ≥1 baseline calcification image (final analysis cohort, FAC) and 1,423 (78.8% HD, 21.2% PD) had baseline calcification data complete (BCDC). Prevalence of VC was 77.4% in FAC (80.8% HD, 65.1% PD, p < .001) and 77.5% in BCDC (80.7% HD, 65.8% PD). The proportion of BCDC patients with single-site calcification were 20% for CAC, 4.3% for AAC, and 4.3% for cardiac valvular calcification (ValvC), respectively. Double site calcifications were 23.4% for CAC and AAC, 6.5% for CAC and ValvC, and 1.1% for AAC and ValvC, respectively. In total, 17.9% patients had calcification at all three sites.

CONCLUSIONS

High prevalence of total VC in Chinese CKD patients will supplement current knowledge, which is mostly limited, contributing in creating awareness and optimizing VC management.

Dioscin protects against coronary heart disease by reducing oxidative stress and inflammation via Sirt1/Nrf2 and p38 MAPK pathways

Cardiovascular diseases are common diseases in Sweden as in most countries. In 2016, 25,700 persons suffered from coronary heart disease (CHD) and 25% of these died within 28 days. The present study investigated whether dioscin may exert protective effects against CHD‑induced heart apoptosis, oxidative stress and inflammation in a pig model and the potential underlying mechanisms. Adult pigs were used to establish a CHD model group and 80 mg/kg dioscin was administered for 4 weeks. Histological analysis and measurement of serum levels of heart injury markers demonstrated that 80 mg/kg dioscin markedly alleviated CHD, while left ventricular ejection fraction and left ventricular systolic internal diameter measurements indicated that 80 mg/kg dioscin also increased heart function in the CHD pig model. Furthermore, western blotting demonstrated that 80 mg/kg dioscin significantly reduced protein levels of apoptosis markers in the heart of CHD model pigs, including Bcl‑2‑associated X and caspase‑3, potentially via the suppression of poly (ADP‑ribose) polymerase 1 (PARP)/p53 expression. Additionally, the results of ELISA and western blotting demonstrated that 80 mg/kg dioscin may reduce oxidative stress and inflammation in CHD model pigs through the promotion of sirtuin 1 (Sirt1)/nuclear factor erythroid 2‑related factor 2 (Nrf2) protein expression and the suppression of PARP/p53 and p38 mitogen‑activated protein kinase (MAPK) expression. The results of the current study indicate that dioscin may protect against CHD by regulating oxidative stress and inflammation via Sirt1/Nrf2 and p38 MAPK pathways.

Protective effects of resveratrol improve cardiovascular function in rats with diabetes

Resveratrol is a flavonoid with a stilbene structure that is able to suppress acute pulmonary thromboembolism-induced pulmonary artery hypertension. Furthermore, it possesses anti-cancer and antioxidant properties, is able to regulate blood lipids and increase life expectancy. In the present study, it was evaluated whether the protective effect of resveratrol was able to improve cardiovascular function in rats with diabetes. The effects of resveratrol on blood glucose, body weight, heart/body weight ratio, plasma triglyceride levels, heart rate, aspartate transaminase (AST)/alanine transaminase (ALT) ratio and total plasma insulin were evaluated. Levels of inflammation and oxidative stress were also evaluated using ELISA kits, and the expressions of endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF) and phosphorylated (p)-p38 protein were evaluated via western blot analysis. The results demonstrated that administration of resveratrol in rats with diabetes-related myocardial infarction (DRMI) significantly reduced blood glucose, body weight, plasma triglyceride levels, heart rate and AST/ALT ratio (all P<0.01) and significantly increased total plasma insulin (P<0.01). Furthermore, resveratrol significantly reduced levels of inflammation factors (P<0.01) and malondialdehyde, a marker for oxidative stress, in rats with DRMI (P<0.01). Resveratrol significantly increased the expression of eNOS (P<0.01) and suppressed the expression of VEGF and p-p38 (both P<0.01) in rats with DRMI. These results suggest that treatment with resveratrol is able to improve cardiovascular function via inhibition of eNOS and VEGF, and suppression of p38 phosphorylation in rats with DRMI.

Evaluation of the coronary circulation and calcification in children on regular hemodialysis

BACKGROUND

The objective of this study was to evaluate the coronary circulation and calcification in children with end-stage renal disease (ESRD) on hemodialysis.

METHODS

A total of 50 children with ESRD and 50 healthy controls were enrolled in the study. Cardiac functions and coronary blood flow were evaluated with conventional and tissue Doppler echocardiography. Coronary artery calcification (CAC) was evaluated using high-resolution multidetector computed tomography (CT).

RESULTS

The hyperemic coronary flow volume (CFV) and coronary flow reserve were significantly lower in the patient group than in the controls, while there was no significant difference in the baseline CFV between the two groups. Hypertension was present in 60% and CAC was observed in 20% of the children in the patient group. CAC was present in 30% of the children in the hypertensive subgroup. The left ventricle myocardial performance index (LV MPI), CAC score, duration of hypertension and level of diastolic blood pressure were independent predictors of the coronary blood flow, and LV MPI, serum parathyroid hormone, duration of dialysis and E'/A' mitral valve were independent predictors of coronary calcification.

CONCLUSION

High diastolic blood pressure, long duration of hypertension, high LV MPI and increased CAC scores are independent risk factors for impaired coronary blood flow in children with ESRD.

Prognostic value of silent myocardial infarction in patients with chronic kidney disease being evaluated for kidney transplantation

BACKGROUND

Patients with advanced chronic kidney disease (CKD) have increased risk of myocardial infarction (MI). Silent MIs (SMIs) are common in CKD patients and carry increased mortality risk. The prevalence and prognostic value of SMI in advanced CKD has not been evaluated.

METHODS

We identified consecutive patients with advanced CKD who were evaluated for renal transplantation at the University of Alabama at Birmingham between June 2004 and January 2006. Clinical MI (CMI) was determined by review of medical records. SMI was defined as ECG evidence of MI without clinical history of MI. The primary end-point was a composite of death, MI, or coronary revascularization censored at time of renal transplantation.

RESULTS

The cohort included 1007 patients with advanced CKD aged 48±12years (58% men, 43% diabetes, 75% on dialysis). The prevalence of SMI and CMI was 10.7% and 6.7%, respectively. The only independent predictor of SMI was older age (odds ratio for age ≥50yrs. 2.32, p<0.001). During a median follow-up of 28months, 376 (37%) patients experienced the primary outcome (33% death, 2% MI, 5% coronary revascularization). In a multivariable adjusted Cox-regression model, both SMI (adjusted HR 1.58, [1.13-2.20], p=0.007) and CMI (adjusted HR 1.67 [1.15-2.43], p=0.007) were independently associated with the primary outcome. Further, both SMI (HR 2.37 [1.15-4.88], p=0.02) and CMI (HR 4.02 [1.80-8.98], p=0.001) were associated with increased risk after renal transplantation.

CONCLUSIONS

SMI is more common than CMI in patients with advanced CKD. Both SMI and CMI are associated with increased risk of future cardiovascular events.

Prognostic Value of Risk Factors, Calcium Score, Coronary CTA, Myocardial Perfusion Imaging, and Invasive Coronary Angiography in Kidney Transplantation Candidates

OBJECTIVES

This study sought to perform a prospective head-to-head comparison of the predictive value of clinical risk factors and a variety of cardiac imaging modalities including coronary artery calcium score (CACS), coronary computed tomography angiography (CTA), single-photon emission computed tomography (SPECT), and invasive coronary angiography (ICA) on major adverse cardiac events (MACE) and all-cause mortality in kidney transplantation candidates.

BACKGROUND

Current guidelines recommend screening for coronary artery disease in kidney transplantation candidates. Furthermore, noninvasive stress imaging is recommended in current guidelines, despite its low diagnostic accuracy and uncertain prognostic value.

METHODS

The study prospectively evaluated 154 patients referred for kidney transplantation. All patients underwent CACS, coronary CTA, SPECT, and ICA testing. The clinical endpoints were extracted from patients' interviews, patients' records, and registries.

RESULTS

The mean follow-up time was 3.7 years. In total, 27 (17.5%) patients experienced MACE, and 31 (20.1%) patients died during follow-up. In a time-to-event analysis, both risk factors and CACS significantly predicted death, but only CACS predicted MACE. Combining risk factors with CACS identified a very-low-risk cohort with a MACE event rate of 2.1%, and a 1.0% mortality rate per year. Of the diagnostic modalities, coronary CTA and ICA significantly predicted MACE, but only coronary CTA predicted death. In contrast, SPECT predicted neither MACE nor death.

CONCLUSIONS

Compared with traditional risk factors and other cardiac imaging modalities, CACS and coronary CTA seem superior for risk stratification in kidney transplant candidates. Applying a combination of risk factors and CACS and subsequently coronary CTA seems to be the most appropriate strategy. (Angiographic CT of Renal Transplantation Candidate Study [ACToR]; NCT01344434).

Atrial function, atrial volume and cardiovascular clinical outcomes in patients with end-stage renal disease - A study of cardiac computed tomography

BACKGROUND

Patients with chronic kidney disease (CKD) have an increased risk of cardiovascular events. Previous studies using 2-dimensional echocardiography show that left atrial end-diastolic volume (LAEDV) predicts cardiovascular outcomes and mortality in patients with CKD. However, contrast-enhanced cardiac CT may offers a more precise measure of atrial dimensions and function than 2-dimensional echocardiography and may provide improved predictionof patient outcome.

AIM

The aim of the present study was to examine the association of LAEDV and left atrial ejection fraction (LAEF) assessed by CT with left ventricle end-diastolic volume (LVEDV), left ventricular mass, left ventricular ejection fraction and N-terminal plasma-pro-brain natriuretic peptide (NT-PRO-BNP). Furthermore, we examined LAEDV and LAEF as predictors of major adverse cardiac events (MACE) and mortality.

METHODS

Kidney transplant candidates (n = 117) underwent contrast-enhanced CT screening for coronary artery disease as part of the work-up prior to kidney transplantation before being accepted on the transplantation waiting list. Left atrial (LA) and left ventricular (LV) volume and function were determined by cardiac CT. MACE and mortality data were extracted from the Western Denmark Heart Registry, a review of patient records and patient interviews.

RESULTS

Baseline patient characteristics did not differ between LAEDV tertiles. LAEDV was positively associated with measures of LV function - both LVEDV (β = 0.36, p < 0.05) and LV mass (β = 0.30, p < 0.05). LAEF was not associated with measures of LV function. LAEDV was positively and LAEF negatively associated with NT-PRO-BNP (LAEDV: β = 10.28, p < 0.05. LAEF: β = -0.06, p < 0.05). During a median follow-up of 3.7-years, 19 (16.2%) patients died and 19 (16.2%) patients suffered MACE. MACE and survival analysis showed no relation to LAEDV or LAEF.

CONCLUSIONS

Using contrast-enhanced CT, we demonstrated a correlation between atrial and ventricular functional parameters. However, we found no association with either LAEF or LAEDV or MACE and mortality in this cohort of kidney transplant candidates.

The immunology of atherosclerosis

Cardiovascular disease is the leading cause of death worldwide, both in the general population and among patients with chronic kidney disease (CKD). In most cases, the underlying cause of the cardiovascular event is atherosclerosis - a chronic inflammatory disease. CKD accelerates atherosclerosis via augmentation of inflammation, perturbation of lipid metabolism, and other mechanisms. In the artery wall, subendothelial retention of plasma lipoproteins triggers monocyte-derived macrophages and T helper type 1 (T_H1) cells to form atherosclerotic plaques. Inflammation is initiated by innate immune reactions to modified lipoproteins and is perpetuated by T_H1 cells that react to autoantigens from the apolipoprotein B100 protein of LDL. Other T cells are also active in atherosclerotic lesions; regulatory T cells inhibit pathological inflammation, whereas T_H17 cells can promote plaque fibrosis. The slow build-up of atherosclerotic plaques is asymptomatic, but plaque rupture or endothelial erosion can induce thrombus formation, leading to myocardial infarction or ischaemic stroke. Targeting risk factors for atherosclerosis has reduced mortality, but a need exists for novel therapies to stabilize plaques and to treat arterial inflammation. Patients with CKD would likely benefit from such preventive measures.

Cardiac Imaging in Chronic Kidney Disease Patients

Cardiovascular disease is highly prevalent and it is associated with high morbidity and mortality rates in patients with chronic kidney disease (CKD). The implementation of various imaging modalities may help to risk stratify these patients with a potential ease on the burden of complications and the rising costs of care. In this article we review some of the modern imaging techniques to diagnose cardiac disease in patients affected by CKD.

Stress SPECT Myocardial Perfusion Imaging in End-Stage Renal Disease

PURPOSE OF REVIEW

Patients with end-stage renal disease (ESRD) have an increased risk of cardiovascular morbidity and mortality. Cardiac risk assessment, though challenging, is critical in these high-risk patients, particularly in the pre-transplant population. In this review, we discuss the burden of coronary artery disease in the ESRD population and review the literature on the diagnostic and prognostic performance, clinical value, and future directions of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in ESRD patients.

RECENT FINDINGS

Stress myocardial perfusion imaging provides incremental prognostic value to clinical data. The AHA/ACCF consensus statement on the cardiac assessment of kidney transplant candidates provides some guidance on the selection of asymptomatic patients for further non-invasive risk stratification. Additionally, the novel selective A_2A receptor agonist vasodilator stress agent, regadenoson, is safe and effective in ESRD and has recently been approved by the Food and Drug Administration for use in this population. Ancillary stress MPI findings, namely heart rate response to vasodilator stress, can provide incremental risk stratification.

SUMMARY

While myocardial perfusion imaging is widely used as a risk assessment tool, its utilization and clinical implications in the ESRD population are controversial. Though stress SPECT-MPI has imperfect diagnostic accuracy in this specific patient population, it is still a valuable non-invasive modality in cardiovascular risk assessment.

Coronary Revascularization in Patients with CKD Stage 5D: Pragmatic Considerations

Coronary revascularization decisions for patients with CKD stage 5D present a dilemma for clinicians because of high baseline risks of mortality and future cardiovascular events. This population differs from the general population regarding characteristics of coronary plaque composition and behavior, accuracy of noninvasive testing, and response to surgical and percutaneous revascularization, such that findings from the general population cannot be automatically extrapolated. However, this high-risk population has been excluded from all randomized trials evaluating outcomes of revascularization. Observational studies have attempted to address long-term outcomes after surgical versus percutaneous revascularization strategies, but inherent selection bias may limit accuracy. Compared with percutaneous strategies, surgical revascularization seems to have long-term survival benefit on the basis of observational data but associates with substantially higher short-term mortality rates. Percutaneous revascularization with drug-eluting and bare metal stents associates with a high risk of in-stent restenosis and need for future revascularization, perhaps contributing to the higher long-term mortality hazard. Off-pump coronary bypass surgery and the newest generation of drug-eluting stent platforms offer no definitive benefits. In this review, we address the nuances, complexities, and tradeoffs that clinicians face in determining the optimal method of coronary revascularization for this high-risk population.

Rs10887800 renalase gene polymorphism is associated with an increased risk of coronary artery disease in hemodialyzed patients

Purpose

Coronary artery disease (CAD) is common in patients with end-stage renal disease (ESRD). Recent studies have suggested that renalase, a novel FAD-dependent amine oxidase, may play an important role in the pathogenesis of cardiovascular complications in ESRD patients. The aim of the study was to investigate the association between renalase gene polymorphisms and a risk of CAD in patients on hemodialysis.

Methods

In a case–control study, a total of 309 hemodialyzed patients (107 with and 202 without CAD) were genotyped for two SNPs in the renalase gene (rs10887800 and rs2576178) using the PCR–RFLP method.

Results

By multivariate logistic regression analysis, we found that rs10887800GG genotype was associated with an increased risk of CAD under the codominant model [GG vs AA; adjusted OR 2.66 (95 % CI, 1.19–5.94), p = .017] and under the recessive model [GG vs AG + AA; adjusted OR 2.10 (95 % CI, 1.10–4.02), p = .025]. The rs2576178 polymorphism did not influence the risk of CAD.

Conclusion

The study suggested for the first time that the rs10887800 renalase gene polymorphism may be involved in the pathogenesis of CAD in hemodialyzed patients and thus could be considered a new genetic risk factor for CAD in this population.

Repeated Contrast Administration Is Associated With Low Risk of Postcontrast Acute Kidney Injury and Long-Term Complications in Patients With Severe Chronic Kidney Disease

Patients with chronic kidney disease (CKD) frequently require radiographic examinations. We investigated the impact of repeated contrast administrations on short- and long-term kidney function and mortality in kidney transplantation candidates. In a prospective study, 81 predialysis transplantation candidates underwent computed tomography angiography (CTA) and invasive coronary angiography (ICA) as part of a pretransplant cardiovascular evaluation. Postcontrast plasma creatinine (P-creatinine) changes were compared with a precontrast control period. We identified postcontrast acute kidney injury (AKI) in 10 patients (13%) after CTA and in two patients (3%) after ICA. Compared with the control period, relative changes in P-creatinine were significantly higher after CTA (p < 0.001) and ICA (p < 0.01). Diabetic kidney failure (p < 0.05) and contrast dose >0.8 mL/kg (p < 0.001) were associated with increases in P-creatinine. All cases of postcontrast AKI were reversible, and we found no differences between the progression rates of the kidney failure during 12 months before and after contrast exposure (p = 0.56). In a Cox regression analysis, creatinine changes after CTA or ICA were not associated with increased need for dialysis treatment or mortality. Contrast exposure and transient postcontrast AKI did not increase the risk of accelerated CKD progression or the time to initiation of dialysis or death.