Cardiovascular Assessment of Diabetic End-Stage Renal Disease Patients Before Renal Transplantation

Diagnostic accuracy of myocardial perfusion imaging in patients evaluated for kidney transplantation: A systematic review and meta-analysis

BACKGROUND

Cardiovascular disease is the most common cause of death after kidney transplantation. Coronary artery disease (CAD) assessment is therefore mandatory in patients evaluated for transplantation. We aimed to assess the diagnostic accuracy for CAD of single-photon emission computed tomography (SPECT) compared to the standards invasive coronary angiography (ICA) and coronary computed tomography angiography (CCTA) in patients evaluated for kidney transplantation.

METHODS

We performed a systematic literature search in PubMed, EMBASE, Web of Science, OvidSP (Medline), The Cochrane Library and Google Scholar. Studies investigating the diagnostic accuracy of myocardial perfusion imaging (MPI) SPECT in patients evaluated for kidney transplantation were retrieved. After a risk of bias assessment using QUADAS-2, a meta-analysis was conducted.

RESULTS

Out of 1459 records, 13 MPI SPECT studies were included in the meta-analysis with a total of 1245 MPI SPECT scans. There were no studies available with CCTA as reference. Pooled sensitivity of MPI SPECT for CAD was 0.66 (95% CI 0.53 to 0.77), pooled specificity was 0.75 (95% CI 0.63 to 0.84) and the area under the curve (AUC) was 0.76. Positive likelihood ratio was 2.50 (95% CI 1.78 to 3.51) and negative likelihood ratio was 0.41 (95% CI 0.28 to 0.61). Pooled positive predictive value was 64.9% and pooled negative predictive value was 74.1%. Significant heterogeneity existed across the included studies.

CONCLUSIONS

MPI SPECT had a moderate diagnostic accuracy in patients evaluated for kidney transplantation, with a high rate of false-negative findings. The use of an anatomical gold standard against a functional imaging test in the included studies is however suboptimal.

Cardiac Imaging and Management of Cardiac Disease in Asymptomatic Renal Transplant Candidates: A Current Update

Given the high cardiovascular risk accompanying end-stage kidney disease, it would be of paramount importance for the clinical nephrologist to know which screening method(s) identify high-risk patients and whether screening asymptomatic transplant candidates effectively reduces cardiovascular risk in the perioperative setting as well as in the longer term. Within this review, key studies concerning the above questions are reported and critically analyzed. The lack of unified screening criteria and of a prognostically sufficient screening cardiovascular effect for renal transplant candidates sets the foundation for a personalized patient approach in the near future and highlights the need for well-designed studies to produce robust evidence which will address the above questions.

Glucose as a modifiable cause of atherosclerotic cardiovascular disease: Insights from type 1 diabetes and transplantation

Diabetes is a major risk factor for cardiovascular (CV) disease. In contrast to the clear benefits from treatments which reduce blood pressure and lipids, clinical trials targeting blood glucose have not shown clear CV benefits. Interventions to intensify glycemic control early in the course of diabetes may have benefits in long term observational studies (DCCT-EDIC/UKPDS), but may not be helpful if introduced late in the course of type 2 diabetes (ACCORD, ADVANCE, VA-DT). More recent CVOT in high risk subjects suggest that the benefits of SGLT2 and GLP1-RA are glucose-independent. Type 1 diabetes provides a "cleaner" model to study the links between glucose and cardiovascular disease. Abnormalities of glucose regulation in type 1 diabetes is not restricted to hyperglycemia, but includes glycemic variability and hypoglycemia. Increasingly the mechanisms linking glycemic variability and hypoglycemia as key mediators of cardiovascular complications are being understood. Furthermore, data from pancreas and islet transplantation showing reduced cardiovascular mortality and regression of intima-media thickness supports a causal role for glucose in the pathogenesis of atherosclerosis, but suggests that restoration of normal glucose regulation may be required to demonstrate substantial impact on CV risk accrued over decades of type 1 diabetes. Considering the limited organ supply and risks of immunosuppression, advances in biology (stem cell derived beta cells) or technology (automated insulin delivery systems) will be required to provide a scalable solution to deliver optimal glucose control and reduce CV risk for people with type 1 diabetes.

A propensity score-matched analysis indicates screening for asymptomatic coronary artery disease does not predict cardiac events in kidney transplant recipients

Screening for asymptomatic coronary artery disease prior to kidney transplantation aims to reduce peri- and post-operative cardiac events. It is uncertain if this is achieved. Here, we investigated whether pre-transplant screening with a stress test or coronary angiogram associated with any difference in major adverse cardiac events (MACE) up to five years post-transplantation. We examined a national prospective cohort recruited to the Access to Transplant and Transplant Outcome Measures study who received a kidney transplant between 2011-2017, and linked patient demographics and details of cardiac screening investigations to outcome data extracted from the Hospital Episode Statistics dataset and United Kingdom Renal Registry. Propensity score matched groups were analyzed using Kaplan-Meier and Cox survival analyses. Overall, 2572 individuals were transplanted in 18 centers; 51% underwent screening and the proportion undergoing screening by center ranged from 5-100%. The incidence of MACE at 90 days, one and five years was 0.9%, 2.1% and 9.4% respectively. After propensity score matching based on the presence or absence of screening, 1760 individuals were examined (880 each in screened and unscreened groups). There was no statistically significant association between screening and MACE at 90 days (hazard ratio 0.80, 95% Confidence Interval 0.31-2.05), one year (1.12, 0.51-2.47) or five years (1.31, 0.86-1.99). Age, male sex and history of ischemic heart disease were associated with MACE. Thus, there is no association between screening for asymptomatic coronary artery disease and MACE up to five years post-transplant. Practices involving unselected screening of transplant recipients should be reviewed.

Non-invasive cardiac stress studies may not offer significant benefit in pre-kidney transplant evaluation: A retrospective cohort study

Background

Screening with cardiac non-invasive stress studies (NISS) prior to listing for kidney transplantation can help in identifying treatable coronary disease and is considered an integral part of pre-kidney transplant evaluation. However, few studies assessed their effectiveness in all patients evaluated for transplantation in clinical practice. To evaluate the role of NISS in pre-kidney transplant evaluation we analyzed their impact prior to waitlisting in 1053 adult CKD-5 patients consecutively evaluated in Greater Manchester, UK during a 6-year period.

Methods

918 waitlisted patients were grouped based on presence or absence of Diabetes or Cardio-Vascular Disease (CVD): Group-1 (255 DM-/CVD-/NISS-), Group-2 (368 DM-/CVD-/NISS+) and Group-3 (295 with DM or CVD).

Results

Group-2 patients had longer ‘time-to-listing’ (5.5months in Group-1 vs 6.9months in ‘Normal-NISS’ vs 9.9months in ‘Abnormal-NISS’, p<0.01) but none with ‘Abnormal-NISS’ needed coronary revascularization before listing. NISS was followed by revascularization in 8 Group-3 patients (3%). In multi-variate analyses, there was no association of NISS on death or MACE in listed patients. During follow up, Transplantation was the most significant factor associated with improved outcomes in all subgroups (HR:0.97, p<0.001). 135 patients were considered unsuitable for waitlisting, with NISS influencing management in 11 of these patients (8%).

Conclusions

Pre-kidney transplant evaluation with NISS influenced clinical management in 19 of 1053 (2%) patients. Screening with NISS added limited benefit but contributes to significant delays in listing and adding resource implications. Further studies are needed to assess clinical and cost effectiveness of NISS in pretransplant evaluation to optimize outcomes and resources.

Current practices in coronary artery disease evaluation of renal transplant candidates prior to renal transplantation

Cardiovascular disease is the leading cause of morbidity and mortality in renal transplant recipients and candidates awaiting transplant. Pre-transplant coronary artery disease evaluation can aid in determining transplant candidacy, identifying patients who may benefit from pre-operative cardiac intervention, and implementing measures to reduce perioperative and post-transplant cardiovascular events. However, the choice of investigations and approach in evaluation has yet to be well defined. This article aims to review the evidence for the use of non-invasive investigations and coronary angiography in prognostication, as well as the evidence for revascularization in reducing future cardiac events. The article will also summarize international recommendations and describe the local practice in coronary artery disease evaluation prior to transplant.

Incidence, risk factors, and outcomes of stroke post-transplantation in patients receiving a steroid sparing immunosuppression protocol

Corticosteroid use after transplantation is associated with an increased incidence of cardiovascular events and death. Cerebrovascular disease is a common cause of morbidity and mortality post-renal transplantation; however, a dedicated analysis of cerebrovascular disease in recipients of a steroid sparing protocol has not been reported. The aim of this study was to examine the incidence, risk factors, and outcomes of CVA in transplant recipients receiving a steroid sparing protocol. We retrospectively analyzed 1237 patients who received a kidney alone or a simultaneous pancreas and kidney (SPK) transplant. Fifty-six of 1237 (4.53%) patients had a CVA post-transplant. All-cause mortality was significantly higher in the CVA group compared with the non-CVA group, OR: 3.4 (1.7-7.0), p < 0.001. Factors found to be associated with increased risk of CVA by multivariate analysis were older age, HR: 1.07 (1.04-1.09), p < 0.001; diabetes at the time of transplantation, HR: 2.83 (1.42-5.64), p = 0.003; corticosteroid use pre-transplant, HR: 3.27 (1.29-8.27), p = 0.013 and recipients of a SPK, HR: 4.03 (1.85-8.79), p < 0.001. This study has identified subgroups of patients who are at increased risk of CVA post-transplant in patients otherwise receiving a steroid sparing immunosuppression protocol.

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.

Diabetes and kidney transplantation: past, present, and future

Diabetes mellitus is the most common etiology for end stage renal disease (ESRD) worldwide and in the United States. The incidence of morbidity and mortality is higher in diabetic patients with ESRD due to increased cardiovascular events. Patients with type 2 diabetes who receive a renal allograft have a higher survival rate compared with patients who are maintained on chronic hemodialysis therapy, but there is scarcity of data on long-term graft outcomes. Most recently the development of new onset diabetes after transplantation (NODAT) poses a serious threat to patient and allograft survival. Pre-emptive transplantation and the use of living donors have improved overall survival. In addition, critical management of glucose, blood pressure, and cholesterol are some of the factors that can help minimize adverse outcomes in both patients with pre-existing diabetes and patients who develop NODAT. Future clinical trials are warranted to improve therapeutic medical management of these patients thus influencing graft attrition.

Should we screen for coronary artery disease in asymptomatic chronic dialysis patients?

The hemodialysis population is characterized by a high prevalence of 'asymptomatic' coronary artery disease (CAD), which should be interpreted differently from asymptomatic disease in the general population. A hemodynamically significant stenosis may not become clinically apparent owing to impaired exercise tolerance and autonomic neuropathy. The continuous presence of silent ischemia may cause heart failure, arrhythmias, and sudden death. Whether revascularization of an asymptomatic dialysis patient improves outcome remains a moot point, although several observational studies and one small RCT suggest a benefit. It can therefore be defended to screen asymptomatic dialysis patients for CAD. A number of noninvasive screening tests are available, but none has proved equally practical and reliable in the dialysis population as in the general population. Myocardial perfusion scintigraphy (MPS) before and after a pharmacological stress such as dipyridamole can reveal both ischemia and myocardial scarring. When compared with coronary angiography, low sensitivities were reported and attributed to impaired vasodilation to dipyridamole in dialysis patients. A more likely explanation is that not every anatomical stenosis will lead to impaired coronary blood flow on MPS. Numerous studies have shown an incremental prognostic value of dipyridamole-MPS over clinical data for prediction of adverse cardiac events, in some studies even over coronary angiography. Pending the availability of high-quality evidence, in our opinion asymptomatic dialysis patients could undergo dipyridamole-MPS, followed by coronary angiography in case of an abnormal scan. This combined physiological and anatomical evaluation of the coronary circulation allows us to determine which coronary stenosis is clinically relevant and therefore should be revascularized.