A preoperative echocardiographic predictive model for assessment of cardiovascular outcome after renal transplantation

Cardiovascular and All-Cause Mortality Is Affected by Serum Magnesium and Diet Pattern in a Cohort of Dialysis Patients

Background: Hypomagnesaemia is associated with an increased overall mortality in patients with chronic kidney disease on dialysis (CKD-5D). Mediterranean-style diet (MD), having a high magnesium content, can serve as a form of dietary magnesium supplementation. We examined whether there is a potential link between increased Mediterranean Diet score (MDS) and elevated serum magnesium (sMg) to assess its impact on reducing mortality risk in CKD-5D patients. Methods: In this multi-center prospective observational study, 117 CKD-5D patients (66 on hemodialysis and 51 on peritoneal dialysis) with a mean age of 62 ± 15 years were studied for a median follow-up period of 68 months. After baseline assessment, including measurement of sMg and MDS, all patients were followed up for cardiovascular (CV) and all-cause mortality. Results: Forty deaths occurred, 58% of which were cardiovascular. Patients who were above the median value of sMg (2.2 mg/dL) had a 66% reduction in CV (crude HR, 0.34; 95% CI, 0.11-0.70), and 49% reduction in all-cause (crude HR, 0.51; 95% CI, 0.27-0.96) mortality, even after adjustment for age, malnutrition inflammation score, left ventricular mass index, peripheral vascular disease and diabetes. Similar results were obtained when sMg was analyzed as a continuous variable. sMg was associated directly with MDS (r = 0.230; p = 0.012). Conclusions: Higher sMg levels are strongly and independently associated with reduced CV and all-cause mortality in CKD-5D patients. A strong correlation exists between MDS and sMg. Elevated sMg levels, achieved through MD adherence, can significantly reduce CV mortality, implicating MD as a mediator of the association between sMg and CV mortality.

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.

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.

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.

Aortic Valve Sclerosis Adds to Prediction of Short-Term Mortality in Patients with Documented Coronary Atherosclerosis

Aims: Aortic valve sclerosis (AVSc), a non-uniform thickening of leaflets with an unrestricted opening, is characterized by inflammation, lipoprotein deposition, and matrix degradation. In the general population, AVSc predicts long-term cardiovascular mortality (+50%) even after adjustment for vascular risk factors and clinical atherosclerosis. We have hypothesized that AVSc is a risk-multiplier able to predict even short-term mortality. To address this issue, we retrospectively analyzed 90-day mortality of all patients who underwent isolated coronary artery bypass grafting (CABG) at Centro Cardiologico Monzino over a ten-year period (2006–2016). Methods: We analyzed 2246 patients and 90-day all-cause mortality was 1.5% (31 deaths). We selected only patients deceased from cardiac causes (n = 29) and compared to alive patients (n = 2215). A cardiologist classified the aortic valve as no-AVSc (n = 1352) or AVSc (n = 892). Cox linear regression and integrated discrimination improvement (IDI) analyses were used to evaluate AVSc in predicting 90-day mortality. Results: AVSc 90-day survival (97.6%) was lower than in no-AVSc (99.4%; p < 0.0001) with a hazard ratio (HR) of 4.0 (95%CI: 1.78, 9.05; p < 0.0001). The HR for AVSc, adjusted for propensity score, was 2.7 (95%CI: 1.17, 6.23; p = 0.02) and IDI statistics confirmed that AVSc significantly adds (p < 0.001) to the identification of high-risk patients than EuroSCORE II alone. Conclusion: Our data supports the hypothesis that a risk stratification strategy based on AVSc, added to ESII, may allow better recognition of patients at high-risk of short-term mortality after isolated surgical myocardial revascularization. Results from this study warrant further confirmation.

Pre-Transplant Left Ventricular Geometry and Major Adverse Cardiovascular Events After Kidney Transplantation

Background

Preventing major adverse cardiovascular events (MACE) after kidney transplantation motivates pre-transplant cardiac evaluation that includes two-dimensional transthoracic echocardiography (TTE). The relationship of relative wall thickness (RWT) to left ventricular mass index (LVMI) in predicting post-transplant MACE is unclear.

Material/Methods

In this multi-ethnic Canadian single-center cohort study, we identified 1063 adults undergoing pre-transplant TTE within 1 year pre-transplant and with minimum 6 months of post-kidney transplant follow-up for MACE, defined as a composite of coronary revascularization, myocardial infarction, stroke, and cardiac death. Left ventricular hypertrophy (LVH, >131 g/m² in men and >100 g/m² in women) and increased RWT (>0.45) were a priori used to define normal (no LVH, normal RWT), concentric remodeling (no LVH, increased RWT), eccentric hypertrophy (LVH, normal RWT), and concentric hypertrophy (LVH, increased RWT).

Results

There were 134 MACE over 3577 patient-years of post-transplant follow-up. Both LVH (HR 1.58, p=0.022) and high RWT (HR 1.44, p=0.041) predicted MACE in multivariate survival regression analysis independently of common pre-transplant MACE risk factors. Concentric remodeling, concentric hypertrophy, and eccentric hypertrophy all increased the risk for MACE (4.44, 5.05, and 5.55 events per 100 patient-years, respectively) versus normal echocardiography (2.71 events per 100 patient-years, all p<0.05 for difference). In Cox interactive regression analysis, LVMI and RWT were independently associated with MACE (p=0.015, p=0.025) and significantly interacted (p=0.008).

Conclusions

LV geometric parameters beyond LVH alone can assist post-transplant prognostication in kidney transplant candidates.

Feasibility of exercise stress echocardiography for cardiac risk assessment in chronic kidney disease patients prior to renal transplantation

BACKGROUND

Pharmacologic stress testing is utilized in preference to exercise stress echocardiography (ESE) for cardiac risk evaluation in potential renal transplant recipients due to the perceived lower feasibility of ESE for achieving adequate workload and target heart rate (THR) in this population.

METHODS

Consecutive patients referred for cardiac risk evaluation prior to potential kidney transplantation were evaluated. All patients attempted ESE before pharmacologic testing was considered. Treadmill ESE utilized BRUCE protocol to maximum capacity. THR was defined as >85% of the maximum predicted heart rate (220-age). Functional capacity was assessed by metabolic equivalents (METs) and the rate pressure product (RPP).

RESULTS

Of 535 patients (349 male, age 56±11), 372(70%) reached THR. Mean METs were 10±3 with 531(99%) achieving ≥4 METs and 87% ≥7 METs. Mean RPP was 25 821±5820 bpm×mm Hg (83% achieving >20 000 bpm×mm Hg). On multivariate analysis, independent predictors of failure to reach THR were rate-control medication and diabetes; failure to reach 7 METs: females, diabetics, age≥65, and previous cardiac disease; failure to reach RPP>20 000: rate-control medication. There were 97% of ESE completed to physiologic endpoints.

CONCLUSION

In unselected potential renal transplant candidates, cardiac assessment by ESE is well tolerated, with 9-in-10 exercising to satisfactory functional capacity. ESE should be considered a feasible alternative to pharmacologic testing in this population.

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

Cardiac risk assessment prior to kidney and liver transplantation is controversial. Given the paucity of available organs, selecting appropriate recipients with favorable short- and long-term cardiovascular risk profile is crucial. Using noninvasive cardiac imaging tools to guide cardiovascular risk assessment and management can also be challenging and controversial. In this article, we address the burden of coronary artery disease among kidney and liver transplant candidates and review the literature pertaining to the diagnostic accuracy and the prognostic value of noninvasive cardiac imaging techniques in this population.

Safety and feasibility of dobutamine stress cardiac magnetic resonance for cardiovascular assessment prior to renal transplantation

AIMS

Current guidelines recommend cardiovascular risk assessment prior to renal transplantation. There is currently no evidence for the role of cardiovascular magnetic resonance (CMR) in this population, despite an established evidence base in the non-chronic kidney disease (CKD) population. Our aim is to determine the feasibility and safety of dobutamine stress CMR (DSCMR) imaging in the risk stratification of CKD patients awaiting renal transplantation.

METHODS

CKD patients who were deemed at high risk for coronary artery disease (CAD) and awaiting renal transplantation underwent DSCMR.

RESULTS

Forty-one patients whose median age was 56 years (range 28–73 years) underwent DSCMR. Nineteen were undergoing haemodialysis, 10 peritoneal dialysis and 12 pre-dialysis. The aetiology of the renal failure was diabetes mellitus in 29%, glomerulonephritis in 24%, hypertension in 22% and autosomal dominant polycystic kidney disease in 10%. Thirty-eight patients (93%) achieved the end point, either positive for ischaemia or negative, achieving at least 85% of age-predicted heart rate. Two of them did not achieve target heart rate and one was discontinued because of severe headache. Of the 38 patients who achieved the end point, 35 (92%) were negative for inducible wall motion abnormalities and four (10%) were positive. There were no serious adverse effects.

CONCLUSION

DSCMR is a well tolerated and viable investigation for the cardiovascular risk stratification of high-risk CKD patients prior to renal transplantation. DSCMR already has an established evidence base in the non-CKD population with superiority over other noninvasive techniques. Larger studies with outcome data are now required to define its true utility in the CKD population.

Predictors and prognostic implications of major adverse cardiovascular events after renal transplant: 10 years outcomes in 321 patients

Renal transplantation is the treatment of choice in patients with end-stage renal disease. Major adverse cardiac events (MACE) are common after renal transplant, especially in the perioperative period, leading to excess morbidity and mortality. The predictors and long-term prognostic implications of MACE are poorly understood. We analyzed predictors and implications of MACE in a cohort of 321 consecutive adult patients, who received renal allograft transplantation between 1995 and 2003 at our institution. The characteristics of 321 patients were: age at transplant 44 ± 13 years, 60% male, 36% diabetes mellitus (DM), left ventricular ejection fraction (LVEF) 60 ± 16%. MACE occurred in 21 patients with cumulative rate of 6.5% over 3 years after renal transplant, 57% occurring within 30 days, 67% within 90 days, and 86% within 180 days. MACE was not predicted by any clinical or pharmacological variables including age, gender, hypertension, DM, prior myocardial infarction, smoking, duration of dialysis, LVEF, or therapy with β-blockers (BB), angiotensin converting enzyme inhibitors, or calcium channel blockers. However, a clinical decision to perform a stress test or a coronary angiogram was predictive of higher MACE rate. MACE, irrespective of type, was independently associated with higher mortality over a period up to 15 years and this seemed to be blunted by BB therapy. MACE rate after renal transplantation decreases over time, most occurring in the first 90 days and is not predicted by any of the traditional risk factors or drug therapies. It is associated with higher long-term mortality.

Coronary artery disease in patients with chronic kidney disease: a clinical update

Chronic kidney disease (CKD) is an independent risk factor for coronary artery disease (CAD). Coronary artery disease is the leading cause of morbidity and mortality in patients with CKD. The outcomes of CAD are poorer in patients with CKD. In addition to traditional risk factors, several uremia-related risk factors such as inflammation, oxidative stress, endothelial dysfunction, coronary artery calcification, hyperhomocysteinemia, and immunosuppressants have been associated with accelerated atherosclerosis. A number of uremia-related biomarkers are identified as predictors of cardiac outcomes in CKD patients. The symptoms of CAD may not be typical in patients with CKD. Both dobutamine stress echocardiography and radionuclide myocardial perfusion imaging have moderate sensitivity and specificity in detecting obstructive CAD in CKD patients. Invasive coronary angiography carries a risk of contrast nephropathy in patients with advanced CKD. It should be reserved for those patients with a high risk for CAD and those who would benefit from revascularization. Guideline-recommended therapies are, in general, underutilized in renal patients. Medical therapy should be considered the initial strategy for clinically stable CAD. The effects of statins in patients with advanced CKD have been neutral despite a lipid-lowering effect. Compared to non-CKD population, percutaneous coronary intervention (PCI) is associated with higher procedure complications, restenosis, and future cardiac events even in the drug-eluting stent era in patients with CKD. Compared with PCI, coronary artery bypass grafting (CABG) reduces repeat revascularizations but is associated with significant perioperative morbidity and mortality. Screening for CAD is an important part of preoperative evaluation for kidney transplant candidates.

The Prognostic Significance of Resting Regional Left Ventricular Function in Patients With Varying Degrees of Myocardial Ischemia

Background

Our aim was to determine whether regional left ventricular (LV) function on a resting transthoracic echo (TTE) provides prognostic information in patients with varying degrees of ischemia on myocardial perfusion imaging.

Methods

Between 2004 - 2009, we identified 503 patients (mean age 69 (SD 11); 79% male) with reversible ischemia on a myocardial SPECT scan who had a TTE within 30 days. We evaluated the rate of subsequent revascularization and death for all patients.

Results

Following the SPECT scan and TTE, 246/503(49%) patients underwent revascularization, 64/503 (13%) patients died, 369 (73%) patients had a normal left ventricular ejection fraction (LVEF), 242 (48%) patients had a resting wall motion abnormality (WMA), 21/261 (8%) with no WMA died compared to 43/242 (18%) in patients with a WMA. In patients with a WMA (n = 242) there was no significant difference in mortality when comparing patients with small (< 6 segments) and large (> 6 segments) WMA (P = 0.44). In patients with moderate/severe ischemia, the presence of a resting WMA was associated with a higher mortality rate (18% v 7%; P = 0.005). In a multivariable model, LVEF (< 50%) was associated with a hazard ratio of 2.2 (P = 0.002, 95% CI 1.34 - 3.68) however, WMA and number of abnormal segments did not reach statistical significance.

Conclusion

A resting wall motion abnormality in patients with moderate/severe ischemia is associated with a higher mortality compared to patients with mild ischemia on myocardial perfusion imaging. Regional left ventricular dysfunction unlike LVEF was not an independent predictor of mortality.

Cardiac testing for coronary artery disease in potential kidney transplant recipients

BACKGROUND

Patients with chronic kidney disease (CKD) are at increased risk of coronary artery disease (CAD) and adverse cardiac events. Screening for CAD is therefore an important part of preoperative evaluation for kidney transplant candidates. There is significant interest in the role of non-invasive cardiac investigations and their ability to identify patients at high risk of CAD. 

OBJECTIVES

We investigated the accuracy of non-invasive cardiac screening tests compared with coronary angiography to detect CAD in patients who are potential kidney transplant recipients.

SEARCH METHODS

MEDLINE and EMBASE searches (inception to November 2010) were performed to identify studies that assessed the diagnostic accuracy of non-invasive screening tests, using coronary angiography as the reference standard. We also conducted citation tracking via Web of Science and handsearched reference lists of identified primary studies and review articles.  

SELECTION CRITERIA

We included in this review all diagnostic cross sectional, cohort and randomised studies of test accuracy that compared the results of any cardiac test with coronary angiography (the reference standard) relating to patients considered as potential candidates for kidney transplantation or kidney-pancreas transplantation at the time diagnostic tests were performed. 

DATA COLLECTION AND ANALYSIS

We used a hierarchical modelling strategy to produce summary receiver operating characteristic (SROC) curves, and pooled estimates of sensitivity and specificity. Sensitivity analyses to determine test accuracy were performed if only studies that had full verification or applied a threshold of ≥ 70% stenosis on coronary angiography for the diagnosis of significant CAD were included.

MAIN RESULTS

The following screening investigations included in the meta-analysis were: dobutamine stress echocardiography (DSE) (13 studies), myocardial perfusion scintigraphy (MPS) (nine studies), echocardiography (three studies), exercise stress electrocardiography (two studies), resting electrocardiography (three studies), and one study each of electron beam computed tomography (EBCT), exercise ventriculography, carotid intimal media thickness (CIMT) and digital subtraction fluorography (DSF). Sufficient studies were present to allow hierarchical summary receiver operating characteristic (HSROC) analysis for DSE and MPS. When including all available studies, both DSE and MPS had moderate sensitivity and specificity in detecting coronary artery stenosis in patients who are kidney transplant candidates [DSE (13 studies) - pooled sensitivity 0.79 (95% CI 0.67 to 0.88), pooled specificity 0.89 (95% CI 0.81 to 0.94); MPS (nine studies) - pooled sensitivity 0.74 (95% CI 0.54 to 0.87), pooled specificity 0.70 (95% CI 0.51 to 0.84)]. When limiting to studies which defined coronary artery stenosis using a reference threshold of ≥ 70% stenosis on coronary angiography, there was little change in these pooled estimates of accuracy [DSE (9 studies) - pooled sensitivity 0.76 (95% CI 0.60 to 0.87), specificity 0.88 (95% CI 0.78 to 0.94); MPS (7 studies) - pooled sensitivity 0.67 (95% CI 0.48 to 0.82), pooled specificity 0.77 (95% CI 0.61 to 0.88)]. There was evidence that DSE had improved accuracy over MPS (P = 0.02) when all studies were included in the analysis, but this was not significant when we excluded studies which did not avoid partial verification or use a reference standard threshold of ≥70% stenosis (P = 0.09).  

AUTHORS' CONCLUSIONS

DSE may perform better than MPS but additional studies directly comparing these cardiac screening tests are needed. Absence of significant CAD may not necessarily correlate with cardiac-event free survival following transplantation. Further research should focus on assessing the ability of functional tests to predict postoperative outcome.

[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.