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

Findings of Cardiovascular Workup of Kidney Transplant Candidates: A Retrospective Study of a Single-Center in Saudi Arabia

Background

There are limited data about the prevalence of cardiovascular (CV) risk factors and the findings of CV workup among kidney transplant (KTx) recipients (KTRs) in Saudi Arabia.

Methods

A single-center retrospective study of KTRs who underwent KTx from 2017 to 2020 was performed. We reviewed the prevalence of CV risk factors and the results of the pre-KTx CV workup which was derived from the American Heart Association guidelines.

Results

We included 254 KTRs. The mean age was 43.1 ± 15.9 years, and 55.5% were men and 79.5% were living-donor KTRs. Pre-emptive KTx was 9.8%, peritoneal dialysis was 11.8%, and hemodialysis was 78.3% (arteriovenous fistula: 33.1% versus hemodialysis catheter: 66.9%). The mean dialysis vintage was 4.8 ± 3.3 years for deceased-donor KTRs versus 2.4 ± 2.6 years for living-donor KTRs. CV risk factors were hypertension: 76%, diabetes: 40.6% (type 1 : 25.2% versus type 2 : 74.7%), hyperlipidemia (low-density lipoprotein >2.6 mmol/L): 40.2%, coronary artery disease (CAD): 12.6%, smoking: 9.1%, peripheral vascular disease: 2.8%, and cerebral vascular disease: 2.4%. The prevalence of obesity stage 1 was 19.7% and obesity stage 2 was 4%. Left ventricular hypertrophy was present in 38.5%. The ejection fraction was abnormal (<55%) in 22%. Abnormal wall motion was present in 34 patients (13.4%). A cardiac (PET-CT) stress test was conducted on 129 patients (50.8%) which showed abnormal perfusion in 37 patients (28.7%). Out of those who required PET-CT, 18.6% had a coronary artery calcium scoring (CACS) of more than 400, 41.8% had a CACS of zero, 29.4% had a CACS of 1-100, and 14.7% had a CACS of 100-400. Coronary angiogram was required in only 41 patients (16.1%), 12 (29.3%) required coronary interventions, 25 (61%) were treated medically, and 4 (9.8%) did not have any CAD. CT scans of pelvic arteries were performed in 118 patients (46.5%). It showed moderate or severe calcifications in only 7 patients (5.9%), whereas it was normal in 97 patients (82.2%), or it showed only mild calcifications in 14 patients (11.9%).

Conclusion

This study outlines the prevalence of CV risk factors and the findings of the pretransplant CV workup among KTx candidates who underwent KTx. Multicenter national studies will be helpful to validate the generalizability of these findings.

Findings of Cardiovascular Workup of Kidney Transplant Candidates: A Retrospective Study of a Single-Center in Saudi Arabia.. [DOI: 10.21203/rs.3.rs-3030184/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: There are limited data about the prevalence of cardiovascular (CV) risk factors and the findings of CV workup among kidney transplant (KTx) recipients (KTRs) in Saudi Arabia. Method: A single-center retrospective study of KTRs who underwent KTx from 2017 to 2020. We reviewed the prevalence of CV risk factors and the results of the pre-KTx CV workup which was derived from the American Heart Association guidelines. Results: We included 254 KTRs. The mean age was 43.1±15.9 years, 55.5% were men and 79.5% were living-donor KTRs. Pre-emptive KTx was 9.8%, peritoneal dialysis: 11.8% and hemodialysis: 78.3% (arteriovenous fistula: 33.1% versus hemodialysis catheter: 66.9%). Mean dialysis vintage was 4.8±3.3 years for deceased-donor KTRs versus 2.4±2.6 years for living-donor KTRs. CV risk factors were hypertension: 76%, diabetes: 40.6% (type 1: 25.2% versus type 2: 74.7%), hyperlipemia (low-density lipoprotein> 2.6 mmol/L): 40.2%, coronary artery disease (CAD): 12.6%, smoking: 9.1%, peripheral vascular disease: 2.8%, and cerebral vascular disease: 2.4%. The prevalence of obesity stage 1 was 19.7% and obesity stage 2 was 4%. Left ventricular hypertrophy was present in 38.5%. Ejection fraction was abnormal (<55%) in 22%. Abnormal wall motion was present in 34 patients (13.4%). Cardiac (PET-CT) stress test was indicated in 129 patients (50.8%) and showed abnormal perfusion in 37 patients (28.7%). Out of those who required PET-CT, 18.6% had coronary artery calcium scoring (CACS) more than 400, 41.8 had CACS of zero, 29.4% had CACS of 1-100, and 14.7% had CACS of 100-400. Coronary angiogram was required in only 41 patients (16.1%), 12 (29.3%) required coronary interventions, 25 (61%) were treated medically, and 4 (9.8%) did not have any CAD. CT scans of pelvic arteries were performed in 118 patients (46.5%). It showed moderate or severe calcifications in only 7 patients (5.9%), whereas it was normal in 97 patients (82.2%), or it showed only mild calcifications in 14 patients (11.9%). Conclusion: This study outlines the prevalence of CV risk factors and the findings of the pretransplant CV workup among KTx candidates who underwent KTx. Multicenter national studies will be helpful to validate the generalizability of these findings.

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.

Emerging Evidence on Coronary Heart Disease Screening in Kidney and Liver Transplantation Candidates: A Scientific Statement From the American Heart Association: Endorsed by the American Society of Transplantation

Coronary heart disease is an important source of mortality and morbidity among kidney transplantation and liver transplantation candidates and recipients and is driven by traditional and nontraditional risk factors related to end-stage organ disease. In this scientific statement, we review evidence from the past decade related to coronary heart disease screening and management for kidney and liver transplantation candidates. Coronary heart disease screening in asymptomatic kidney and liver transplantation candidates has not been demonstrated to improve outcomes but is common in practice. Risk stratification algorithms based on the presence or absence of clinical risk factors and physical performance have been proposed, but a high proportion of candidates still meet criteria for screening tests. We suggest new approaches to pretransplantation evaluation grounded on the presence or absence of known coronary heart disease and cardiac symptoms and emphasize multidisciplinary engagement, including involvement of a dedicated cardiologist. Noninvasive functional screening methods such as stress echocardiography and myocardial perfusion scintigraphy have limited accuracy, and newer noninvasive modalities, especially cardiac computed tomography-based tests, are promising alternatives. Emerging evidence such as results of the 2020 International Study of Comparative Health Effectiveness With Medical and Invasive Approaches-Chronic Kidney Disease trial emphasizes the vital importance of guideline-directed medical therapy in managing diagnosed coronary heart disease and further questions the value of revascularization among asymptomatic kidney transplantation candidates. Optimizing strategies to disseminate and implement best practices for medical management in the broader end-stage organ disease population should be prioritized to improve cardiovascular outcomes in these populations.

Is Exclusion of Coronary Artery Disease in the Kidney Allocation System Preventing Optimal Longevity Matching?

BACKGROUND

Coronary artery disease (CAD) in a kidney transplant candidate is an important predictor of posttransplant mortality. It is not known how the exclusion of CAD in the kidney allocation system has impacted its goal of longevity matching.

METHODS

This is an observational study on adult deceased donor kidney transplant alone recipients between December 4, 2014, and December 31, 2018, with Medicare fee for service (FFS) insurance. Patients were categorized on the basis of Kidney Donor Profile Index (KDPI), Estimated Posttransplant Survival (EPTS), and CAD. Outcomes studied were mortality, death with a functioning graft, overall graft loss, and death-censored graft loss.

RESULTS

Among 21 151 patients with Medicare FFS coverage for >1 y before transplant, there were 2869 and 18 282 patients with and without CAD, respectively. On Kaplan-Meier analysis, there was higher risk of mortality, death with a functioning graft, overall graft loss, and death-censored graft loss with CAD ( P < 0.05 for all). Mortality was higher for CAD group within each category of KDPI and among patients with Estimated Posttransplant Survival 0% to 20% receiving kidneys with KDPI <20% ( P < 0.001 for all). On Cox multivariate analysis, the hazard ratios (HRs) of mortality and graft loss were higher with CAD diagnosis without intervention (HR 1.38 [1.25-1.52] and 1.29 [1.18-1.4]), CAD with stents (HR 2.76 [1.68-4.53] and 2.36 [1.46-3.81]), and CAD with bypass surgery (HR 1.56 [1.29-1.89] and 1.39 [1.17-1.65]). Posttransplant CAD events were higher in patients with preexisting CAD ( P < 0.001).

CONCLUSIONS

The exclusion of a candidate's history of CAD in the kidney allocation system adversely impacts its goal of optimal longevity matching.

Incidence, Clinical Correlates, and Outcomes of Pulmonary Hypertension After Kidney Transplantation: Analysis of Linked US Registry and Medicare Billing Claims

BACKGROUND

The incidence, risks, and outcomes associated with pulmonary hypertension (P-HTN) in the kidney transplant (KTx) population are not well described.

METHODS

We linked US transplant registry data with Medicare claims (2006-2016) to investigate P-HTN diagnoses among Medicare-insured KTx recipients (N = 35 512) using billing claims. Cox regression was applied to identify independent correlates and outcomes of P-HTN (adjusted hazard ratio [aHR] 95%LCLaHR95%UCL) and to examine P-HTN diagnoses as time-dependent mortality predictors.

RESULTS

Overall, 8.2% of recipients had a diagnostic code for P-HTN within 2 y preceding transplant. By 3 y posttransplant, P-HTN was diagnosed in 10.310.6%11.0 of the study cohort. After adjustment, posttransplant P-HTN was more likely in KTx recipients who were older (age ≥60 versus 18-30 y a HR, 1.912.403.01) or female (aHR, 1.151.241.34), who had pretransplant P-HTN (aHR, 4.384.795.24), coronary artery disease (aHR, 1.051.151.27), valvular heart disease (aHR, 1.221.321.43), peripheral vascular disease (aHR, 1.051.181.33), chronic pulmonary disease (aHR, 1.201.311.43), obstructive sleep apnea (aHR, 1.151.281.43), longer dialysis duration, pretransplant hemodialysis (aHR, 1.171.371.59), or who underwent transplant in the more recent era (2012-2016 versus 2006-2011: aHR, 1.291.391.51). Posttransplant P-HTN was associated with >2.5-fold increased risk of mortality (aHR, 2.572.843.14) and all-cause graft failure (aHR, 2.422.642.88) within 3 y posttransplant. Outcome associations of newly diagnosed posttransplant P-HTN were similar.

CONCLUSIONS

Posttransplant P-HTN is diagnosed in 1 in 10 KTx recipients and is associated with an increased risk of death and graft failure. Future research is needed to refine diagnostic, classification, and management strategies to improve outcomes in KTx recipients who develop P-HTN.

Chronic Renal Failure and Cardiovascular Disease: A Comprehensive Appraisal

Coronary artery disease is highly prevalent in patients with chronic kidney disease. The concomitant renal disease often poses a major challenge in decision making as symptoms, cardiac biomarkers and noninvasive studies for evaluation of myocardial ischemia have different sensitivity and specificity thresholds in this specific population. Moreover, the effectiveness and safety of intervention and medical treatment in those patients is of great doubt as most clinical studies exclude patients with advance CKD. In the present paper, we discuss and review the literature in the diagnosis, treatment and prevention of CAD in the acute and chronic setting, in patients with CKD.

Coronary artery calcium burden, carotid atherosclerotic plaque burden, and myocardial blood flow in patients with end-stage renal disease: A non-invasive imaging study combining PET/CT and 3D ultrasound

BACKGROUND

Imaging-based measures of atherosclerosis such as coronary artery calcium score (CACS) and coronary flow reserve (CFR) as well as carotid atherosclerotic plaque burden (cPB) are predictors of cardiovascular events in the general population. The objective of this study was to correlate CACS, cPB, myocardial blood flow (MBF), and CFR in patients with end-stage renal disease (ESRD).

METHODS AND RESULTS

39 patients (mean age 53 ± 12 years) with ESRD prior to kidney transplantation were enrolled. MBF and CFR were quantified at baseline and under hyperemia by 13N-NH3-PET/CT. CACS was calculated from low-dose CT scans acquired for PET attenuation correction. cPB was assessed by 3D ultrasound. Uni- and multivariate regression analyses between these and clinical parameters were performed. Median follow-up time for clinical events was 4.4 years. Kaplan-Meier survival estimates with log-rank test were performed with regards to cardiovascular (CV) events and death of any cause. CACS and cPB were associated in ESRD patients (r = 0.48; p ≤ 0.01). While cPB correlated with age (r = 0.43; p < 0.01), CACS did not. MBFstress was negatively associated with age (r = 0.44; p < 0.01) and time on dialysis (r = 0.42; p < 0.01). There were negative correlations between MBFstress and CACS (r = - 0.62; p < 0.001) and between MBFstress and cPB (r = - 0.43; p < 0.01). Age and CACS were the strongest predictors for MBFstress. CFR was impaired (< 2.0) in eight patients who also presented with higher cPB and higher CACS compared to those with a CFR > 2.0 (p = 0.06 and p = 0.4). In contrast to MBFstress, there was neither a significant correlation between CFR and CACS (r = - 0.2; p = 0.91) nor between CFR and cPB (r = - 0.1; p = 0.55). CV event-free survival was associated with reduced CFR and MBFstress (p = 0.001 and p < 0.001) but not with cPB or CACS.

CONCLUSIONS

CACS, cPB, and MBFstress are associated in patients with ESRD. Atherosclerosis is earlier detected by MBFstress than by CFR. CV event-free survival is associated with impaired CFR and MBFstress.

Screening for occult coronary artery disease in potential kidney transplant recipients: time for reappraisal?

Screening for occult coronary artery disease in potential kidney transplant recipients has become entrenched in current medical practice as the standard of care and is supported by national and international clinical guidelines. However, there is increasing and robust evidence that such an approach is out-dated, scientifically and conceptually flawed, ineffective, potentially directly harmful, discriminates against ethnic minorities and patients from more deprived socioeconomic backgrounds, and unfairly denies many patients access to potentially lifesaving and life-enhancing transplantation. Herein we review the available evidence in the light of recently published randomized controlled trials and major observational studies. We propose ways of moving the field forward to the overall benefit of patients with advanced kidney disease.

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.

The transition clinic in chronic kidney disease care

People with advanced chronic kidney disease and evidence of progression have a high risk of renal replacement therapy. Specialized transition clinics could offer a better option for preparing these patients for dialysis, transplantation or conservative care. This review focuses on the different aspects of such transition clinics. We discuss which patients should be referred to these units and when referral should take place. Patient involvement in the decision-making process is important and requires unbiased patient education. There are many themes, both patient-centred and within the healthcare structure, that will influence the process of shared decision-making and the modality choice. Aspects of placing an access for haemodialysis and peritoneal dialysis are reviewed. Finally, we discuss the importance of pre-emptive transplantation and a planned dialysis start, all with a focus on multidisciplinary collaboration at the transition clinic.

Outcomes of Surgical Coronary Revascularization Performed Before Solid Abdominal Organ Transplants

BACKGROUND

Cardiac risk stratification and coronary angiography are routinely performed as part of kidney and liver transplant candidacy evaluation. There are limited data on the outcomes of surgical coronary revascularization in this patient population. This study investigated outcomes in patients with end- stage renal or hepatic disease who were undergoing coronary artery bypass grafting (CABG) to attain kidney or liver transplant candidacy.

METHODS

This study was a retrospective analysis of all patients who underwent isolated CABG at our institution, Indiana University School of Medicine (Indianapolis, IN), between 2010 and 2016. Patients were divided into 2 cohorts: pretransplant (those undergoing surgery to attain renal or hepatic transplant candidacy) and nontransplant (all others). Baseline characteristics and postoperative outcomes were compared between the groups.

RESULTS

A total of 1801 patients were included: 28 in the pretransplant group (n = 22, kidney; n = 7, liver) and 1773 in the nontransplant group. Major adverse postoperative outcomes were significantly greater in the pretransplant group compared with the nontransplant group: 30-day mortality (14.3% vs 2.8%; P = .009), neurologic events (17.9% vs 4.8%; P = .011), reintubation (21.4% vs 5.8%; P = .005), and total postoperative ventilation (5.2 hours vs 5.0 hours; P = .0124). The 1- and 5-year mortality in the pretransplant group was 17.9% and 53.6%, respectively. Of the pretransplant cohort, 3 patients (10.7%) underwent organ transplantation (all kidney) at a mean 436 days after CABG. No patients underwent liver transplantation.

CONCLUSIONS

Outcomes after CABG in pre-kidney transplant and pre-liver transplant patients are poor. Despite surgical revascularization, most patients do not ultimately undergo organ transplantation. Revascularization strategies and optimal management in this high-risk population warrant further study.

Predictors of postoperative cardiovascular complications up to 3 months after kidney transplantation

Background

Renal transplant patients have a high peri-operative risk for cardiovascular events. Pre-operative screening for cardiac ischaemia might lower this risk, but there are no specific guidelines.

Methods

We conducted a chart review for all renal transplants performed between January 2010 and December 2013. We collected data about patient characteristics, pre-operative cardiac evaluation before referral, diagnostic tests and interventions. Logistic regression analyses were then applied to relate these factors to the composite endpoint of cardiac death, myocardial infarction, coronary revascularisation or admission for heart failure within 3 months after transplantation.

Results

A total of 770 kidney transplants were performed in 751 patients. In 750 cases (97%) a referral to the cardiologist was made. Non-invasive ischaemia detection by myocardial perfusion scintigraphy, exercise stress test or dobutamine stress echocardiography was carried out in 631 cases (82%). Coronary angiography was performed in 85 cases, which revealed significant coronary artery disease in 19 cases. Prophylactic revascularisation was done in 7 cases. The incidence of the study endpoint was 8.6%. In multivariable regression analysis, age at transplantation, pre-transplant myocardial infarction or heart failure, post-operative decrease in haemoglobin and positive non-invasive ischaemia testing were significantly associated with the study endpoint. However, when analysed separately, none of the different non-invasive ischaemia detection modalities were related to the study endpoint.

Conclusion

Especially those renal transplant candidates with a cardiac history carry a high risk for a cardiovascular event post-transplantation. Uniformity in cardiac screening of renal transplant candidates and better pre-operative preparation might lower this post-operative risk. Besides, post-transplant anaemia should be prevented.

Waiting List and Kidney Transplant Vascular Risk: An Ongoing Unmet Concern

BACKGROUND

Chronic kidney disease (CKD) is an important independent risk factor for adverse cardiovascular events in patients waitlisted for kidney transplantation (KT). Although KT reduces cardiovascular risk, these patients still have a higher all-cause and cardiovascular mortality than the general population. This concerning situation is due to a high burden of traditional and nontraditional risk factors as well as uremia-related factors and transplant-specific factors, leading to 2 differentiated processes under the framework of CKD, atherosclerosis and arteriosclerosis. These can be initiated by insults to the vascular endothelial endothelium, leading to vascular calcification (VC) of the tunica media or the tunica intima, which may coexist. Several pathogenic mechanisms such as inflammation-related endothelial dysfunction, mineral metabolism disorders, activation of the renin-angiotensin system, reduction of nitric oxide, lipid disorders, and the fibroblast growth factor 23-klotho axis are involved in the pathogenesis of atherosclerosis and arteriosclerosis, including VC.

SUMMARY

This review focuses on the current understanding of atherosclerosis and arteriosclerosis, both in patients on the waiting list as well as in kidney transplant recipients, emphasizing the cardiovascular risk factors in both populations and the inflammation-related pathogenic mechanisms. Key Message: The importance of cardiovascular risk factors and the pathogenic mechanisms related to inflammation in patients waitlisted for KT and kidney transplant recipients.

Canadian-Australasian Randomised trial of screening kidney transplant candidates for coronary artery disease-A trial protocol for the CARSK study

Transplantation is the preferred treatment for patients with kidney failure, but the need exceeds the supply of transplantable kidneys, and patients routinely wait >5 years on dialysis for a transplant. Coronary artery disease (CAD) is common in kidney failure and can exclude patients from transplantation or result in death before or after transplantation. Screening asymptomatic patients for CAD using noninvasive tests prior to wait-listing and at regular intervals (ie, annually) after wait-listing until transplantation is the established standard of care and is justified by the need to avoid adverse patient outcomes and loss of organs. Patients with abnormal screening tests undergo coronary angiography, and those with critical stenoses are revascularized. Screening is potentially harmful because patients may be excluded or delayed from transplantation, and complications after revascularization are more frequent in this population. CARSK will test the hypothesis that eliminating screening tests for occult CAD after wait-listing is not inferior to regular screening for the prevention of major adverse cardiac events defined as the composite of cardiovascular death, nonfatal myocardial infarction, urgent revascularization, and hospitalization for unstable angina. Secondary outcomes include the transplant rate, safety measures, and the cost-effectiveness of screening. Enrolment of 3,306 patients over 3 years is required, with patients followed for up to 5 years during wait-listing and for 1 year after transplantation. By validating or refuting the use of screening tests during wait-listing, CARSK will ensure judicious use of health resources and optimal patient outcomes.

Factors associated with adverse outcomes from cardiovascular events in the kidney transplant population: an analysis of national discharge data, hospital characteristics, and process measures

Background

Kidney transplant (KT) patients presenting with cardiovascular (CVD) events are being managed increasingly in non-transplant facilities. We aimed to identify drivers of mortality and costs, including transplant hospital status.

Methods

Data from the 2009–2011 Nationwide Inpatient Sample, the American Hospital Association, and Hospital Compare were used to evaluate post-KT patients hospitalized for MI, CHF, stroke, cardiac arrest, dysrhythmia, and malignant hypertension. We used generalized estimating equations to identify clinical, structural, and process factors associated with risk-adjusted mortality and high cost hospitalization (HCH).

Results

Data on 7803 admissions were abstracted from 275 hospitals. Transplant hospitals had lower crude mortality (3.0% vs. 3.8%, p = 0.06), and higher un-adjusted total episodic costs (Median $33,271 vs. $28,022, p < 0.0001). After risk-adjusting for clinical, structural, and process factors, mortality predictors included: age, CVD burden, CV destination hospital, diagnostic cardiac catheterization without intervention (all, p < 0.001). Female sex, race, documented co-morbidities, and hospital teaching status were protective (all, p < 0.05). Transplant and non-transplant hospitals had similar risk-adjusted mortality. HCH was associated with: age, CVD burden, CV procedures, and staffing patterns. Hospitalizations at transplant facilities had 37% lower risk-adjusted odds of HCH. Cardiovascular process measures were not associated with adverse outcomes.

Conclusion

KT patients presenting with CVD events had similar risk-adjusted mortality at transplant and non-transplant hospitals, but high cost care was less likely in transplant hospitals. Transplant hospitals may provide better value in cardiovascular care for transplant patients. These data have significant implications for patients, transplant and non-transplant providers, and payers.

The impact of systematic review of status 7 patients on the kidney transplant waitlist

Background

Increased morbidity and mortality are well documented in Status 7(inactive list) patients. Delays in transplantation secondary to prolonged periods on inactive status also negatively impacts transplant outcomes. We developed an effective system to reduce the proportion of status 7 patients on our kidney transplant waitlist. This can easily be reproduced by other transplant centers since concerns about Status 7 list size are commonplace.

Methods

Meetings of a dedicated status 7 focus group were undertaken biweekly beginning in April 2016, each lasting for 1 hour or less. The group was led by a transplant physician and comprised of members from all disciplines of the kidney transplant department. Individual patient barriers to activation were systematically evaluated and action plans were developed to overcome those. The formal meetings were supplemented by updates to an electronic database accessible to all members of the team.

Results

In the first 2 years of the program, we were able to activate and eventually transplant 18% of the formerly inactive patients. Forty percent of all inactive patients were removed from the waitlist due to one or more unsurmountable barriers. The median time patients stayed inactive on the waitlist was shortened from 1344 days at the start of this initiative to 581 days at the end.

Conclusion

This strategy of systematic reevaluation of status 7 patients resulted in successful disposition of a substantial number of inactive patients. Further, waitlist time was reduced and transplantation expedited for the appropriate individuals. This approach could easily be adapted by other transplant centers with minimum utilization of resources.

The association of preoperative cardiac stress testing with 30-day death and myocardial infarction among patients undergoing kidney transplantation

BACKGROUND

Although periodic cardiac stress testing is commonly used to screen patients on the waiting list for kidney transplantation for ischemic heart disease, there is little evidence to support this practice. We hypothesized that cardiac stress testing in the 18 months prior to kidney transplantation would not reduce postoperative death, total myocardial infarction (MI) or fatal MI.

METHODS

Using the United States Renal Data System, we identified ESRD patients ≥40 years old with primary Medicare insurance who received their first kidney transplant between 7/1/2006 and 11/31/2013. Propensity matching created a 1:1 matched sample of patients with and without stress testing in the 18 months prior to kidney transplantation. The outcomes of interest were death, total (fatal and nonfatal) MI or fatal MI within 30 days of kidney transplantation.

RESULTS

In the propensity-matched cohort of 17,304 patients, death within 30 days occurred in 72 of 8,652 (0.83%) patients who underwent stress testing and in 65 of 8,652 (0.75%) patients who did not (OR 1.07; 95% CI: 0.79-1.45; P = 0.66). MI within 30 days occurred in 339 (3.9%) patients who had a stress test and in 333 (3.8%) patients who did not (OR 1.03; 95% CI: 0.89-1.21; P = 0.68). Fatal MI occurred in 17 (0.20%) patients who underwent stress testing and 15 (0.17%) patients who did not (OR 0.97; 95% CI: 0.71-1.32; P = 0.84).

CONCLUSION

Stress testing in the 18 months prior to kidney transplantation is not associated with a reduction in death, total MI or fatal MI within 30 days of kidney transplantation.

Hospitalizations for Cardiovascular Disease After Liver Transplantation in the United States

Cardiovascular disease (CVD) is a leading cause of post-liver transplant death, and variable care patterns may affect outcomes. We aimed to describe epidemiology and outcomes of inpatient CVD care across US hospitals. Using a merged data set from the 2002-2011 Nationwide Inpatient Sample and the American Hospital Association Annual Survey, we evaluated liver transplant patients admitted primarily with myocardial infarction (MI), stroke (cerebrovascular accident [CVA]), congestive heart failure (CHF), dysrhythmias, cardiac arrest (CA), or malignant hypertension. Patient-level data include demographics, Charlson comorbidity index, and CVD diagnoses. Facility-level variables included ownership status, payer-mix, hospital resources, teaching status, and physician/nursing-to-bed ratios. We used generalized estimating equations to evaluate patient- and hospital-level factors associated with mortality. There were 4763 hospitalizations that occurred in 153 facilities (transplant hospitals, n = 80). CVD hospitalizations increased overall by 115% over the decade (P < 0.01). CVA and MI declined over time (both P < 0.05), but CHF and dysrhythmia grew significantly (both P < 0.03); a total of 19% of hospitalizations were for multiple CVD diagnoses. Transplant hospitals had lower comorbidity patients (P < 0.001) and greater resource intensity including presence of cardiac intensive care unit, interventional radiology, operating rooms, teaching status, and nursing density (all P < 0.01). Transplant and nontransplant hospitals had similar unadjusted mortality (overall, 3.9%, P = 0.55; by diagnosis, all P > 0.07). Transplant hospitals had significantly longer overall length of stay, higher total costs, and more high-cost hospitalizations (all P < 0.05). After risk adjustment, transplant hospitals were associated with higher mortality and high-cost hospitalizations. In conclusion, CVD after liver transplant is evolving and responsible for growing rates of inpatient care. Transplant hospitals are associated with poor outcomes, even after risk adjustment for patient and hospital characteristics, which may be attributable to selective referral of certain patient phenotypes but could also be related to differences in quality of care. Further study is warranted.

The utility of myocardial perfusion imaging before renal transplantation: a retrospective analysis

BACKGROUND

Renal transplantation (RT) reduces morbidity and mortality in patients with end-stage renal failure. Myocardial perfusion imaging provides prognostic information in patients with renal failure, but its role before transplantation remains unclear. We performed a retrospective review assessing the prognostic value of technetium-99m sestamibi myocardial perfusion imaging at a tertiary UK centre.

PATIENTS AND METHODS

We included scans performed between 2005 and 2012. Available scans were reanalysed to calculate the semiquantitative summed scores: sum rest score (SRS), sum stress score (SSS), sum difference score and sum motion score (SMS). Kaplan-Meier survival estimates assessed all-cause mortality and cardiac events according to scan findings, transplant decision and SSS. Cox-proportional hazards tested for an association between clinical/scan variables and all-cause mortality, and combined all-cause mortality/cardiovascular (CV) events.

RESULTS

One hundred and thirty-eight scans were identified with complete follow-up. During a median 40.4-month follow-up, 21 patients died, with 11 nonfatal CV events. There was no significant difference between groups according to scan findings for mortality (log-rank P=0.17) or mortality/CV events (P=0.06). An SSS greater than 8 was associated with higher mortality and CV events combined (P=0.028). An abnormal baseline ECG [hazard ratio (HR): 16.1] and higher SRS (HR: 2.3) were associated independently with higher mortality; an abnormal ECG (HR: 3.4) also predicted higher cardiac events/mortality.

CONCLUSION

Moderate to severe perfusion defects by SSS were associated with higher mortality and CV events. Higher SRS was associated independently with increased mortality on multivariable analysis, highlighting a key role for semiquantitative analysis methods for risk stratification. An abnormal ECG was associated strongly with both endpoints, and may be a useful screening tool to select patients for further investigation.

A comparative analysis of survival of patients on dialysis and after kidney transplantation

Background

Kidney transplant survival benefits are not observed for around 8 months after transplantation because of a higher complications rate in early post-transplant periods. This study compares survival of patients awaiting transplantation with survival of transplant recipients and non-listed dialysis patients in Ireland.

Methods

In this retrospective analysis, the relative-risk (RR) of death was assessed with time-dependent, non-proportional hazards analysis, with adjustment for age, cause of end-stage kidney disease (ESKD), time from first treatment for ESKD to placement on the waiting list and year of initial placement on the list.

Results

A total of 3597 patients were included. Annual death rates per 100 patient-years at risk for all patients on dialysis, waiting-list patients and transplant recipients were 16.5, 2.4 and 1.2, respectively. Death rate was highest among diabetics. The relative risk of death for all patients on dialysis was five times higher than the waiting-list patients [RR, 4.90; 95% confidence interval (CI), 3.70–6.52; P < 0.001]. Time to survival equilibration was 1 year. Thereafter, the 5-year mortality risk was estimated to be 47% lower than that of the patients on the waiting list (RR, 0.53; 95% CI, 0.37–0.77; P = 0.001).

Conclusions

Transplant recipients had a higher risk of death initially, but a better long-term survival. Time to death risk equilibration was longer compared with other studies. This could be explained by better survival rates in our waiting-list cohort.

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.

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

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

Patterns of Care and Outcomes in Cardiovascular Disease After Kidney Transplantation in the United States

Background

Cardiovascular disease (CVD) is an important driver of mortality after kidney transplantation. Its broader impact on posttransplant health care utilization in US hospitals is unknown.

Methods

We used administrative claims data from the Nationwide Inpatient Sample and the American Hospital Association Annual Survey to identify hospitalizations for kidney transplant patients with a cardiovascular diagnosis from 2005 to 2011. CVD hospitalizations were stratified by transplant hospital status to characterize patterns in inpatient health care utilization and outcomes. Based on these analyses, the domestic burden of treatment for posttransplant CVD (myocardial infarction, stroke, congestive heart failure, dysrhythmia, cardiac arrest, malignant hypertension) was estimated.

Results

The total domestic burden of post-kidney transplant hospitalization between 2005 and 2011 is estimated at 389 138 of which 26.5% of episodes were related to CVD (n = 103 118). CVD was responsible for a growing proportion of post-transplant hospitalizations over time (24.4%-30.4%, P < 0.001). Compared with nontransplant hospitals, transplant hospitals had similar length of stay (median length of stay, 3.7 days), higher median costs per hospitalization (US $10 364 vs US $8606, overall US $9324), and lower adjusted mortality (3.2% vs 3.9%, overall 3.6%; P = 0.003).

Conclusions

Inpatient CVD care is increasing over time for kidney transplant patients, accounting for 30% of all post-transplant hospitalizations. Variation exists in the inpatient care, outcomes, and costs between by hospital type. Further studies are needed to better understand the mechanisms behind these phenomena.

Management of the obese kidney transplant candidate

Obesity is an increasingly common condition that can exclude end stage renal disease patients from consideration of kidney transplantation. The optimal management of obese transplant candidates is uncertain, especially the use of pharmacologic therapies or bariatric surgery. We review the rationale to consider transplantation in obese patients, the impact of obesity on access to kidney transplantation, the evidence for obese patients to lose weight loss prior to kidney transplantation, peri-operative management considerations and specific weight loss strategies prior to transplantation. We also propose an algorithm for pre-transplant management of obese transplant candidates that takes into consideration the patient's peri-operative risk, the anticipated time to transplantation and the risk of delayed graft function. Finally, we suggest a number of areas in need of further research as well as health policy considerations to improve the care of obese kidney transplant candidates.

Older candidates for kidney transplantation: Who to refer and what to expect?

The number of older end-stage renal disease patients being referred for kidney transplantation continues to increase. This rise is occurring alongside the continually increasing prevalence of older end-stage renal disease patients. Although older kidney transplant recipients have decreased patient and graft survival compared to younger patients, transplantation in this patient population is pursued due to the survival advantage that it confers over remaining on the deceased donor waiting list. The upper limit of age and the extent of comorbidity and frailty at which transplantation ceases to be advantageous is not known. Transplant physicians are therefore faced with the challenge of determining who among older patients are appropriate candidates for kidney transplantation. This is usually achieved by means of an organ systems-based medical evaluation with particular focus given to cardiovascular health. More recently, global measures of health such as functional status and frailty are increasingly being recognized as potential tools in risk stratifying kidney transplant candidates. For those candidates who are deemed eligible, living donor transplantation should be pursued. This may mean accepting a kidney from an older living donor. In the absence of any living donor, the choice to accept lesser quality kidneys should be made while taking into account the organ shortage and expected waiting times on the deceased donor list. Appropriate counseling of patients should be a cornerstone in the evaluation process and includes a discussion regarding expected outcomes, expected waiting times in the setting of the new Kidney Allocation System, benefits of living donor transplantation and the acceptance of lesser quality kidneys.

A Comparison of Different Algorithms for the Assessment of Cardiovascular Risk in Patients at Waiting List for Kidney Transplantation

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death after renal transplantation with a high prevalence in dialysis patients. It is still a matter of debate how to assess the cardiovascular risk in kidney transplant candidates. Several approaches and scores exist and found their way into the guidelines.

METHODS AND RESULTS

We herein assessed PROCAM, Framingham, ESC-SCORE and our own dedicated algorithm in patients applying for renal transplantation at our transplantation center between July 2006 and August 2009. Data of 347 consecutive patients were recorded at baseline and during a follow-up of 4.1 years regarding cardiovascular (CV) events and event-free and overall survival. During follow-up 31 (8.9%) patients died, 24 (6.9%) myocardial infarctions occurred and 19 (5.5%) patients received a new diagnosis of cerebrovascular disease. Predictors for event-free survival identified by univariable Cox regression analysis were age at start of dialysis, ESC-SCORE as well as our own score. Final multivariable model with a stepwise model building procedure revealed age at start of dialysis and smoking to be prognostic for event-free (hazard ratio 1.07/year and 2.15) and overall survival (1.10/year and 3.72).

CONCLUSION

Comparison of CV risk assessment scores showed that ESC-SCORE most robustly predicted event-free and overall survival in our cohort. We conclude that CV risk assessment by ESC-SCORE can be reasonably performed in kidney transplant candidates.

Clinical and economic consequences of first-year urinary tract infections, sepsis, and pneumonia in contemporary kidney transplantation practice

We examined United States Renal Data System registry records for Medicare-insured kidney transplant recipients in 2000-2011 to study the clinical and cost impacts of urinary tract infections (UTI), pneumonia, and sepsis in the first year post-transplant among a contemporary, national cohort. Infections were identified by billing diagnostic codes. Among 60 702 recipients, 45% experienced at least one study infection in the first year post-transplant, including UTI in 32%, pneumonia in 13%, and sepsis in 12%. Older recipient age, female sex, diabetic kidney failure, nonstandard criteria organs, sirolimus-based immunosuppression, and steroids at discharge were associated with increased risk of first-year infections. By time-varying, multivariate Cox regression, all study infections predicted increased first-year mortality, ranging from 41% (aHR 1.41, 95% CI 1.25-1.56) for UTI alone, 6- to 12-fold risk for pneumonia or sepsis alone, to 34-fold risk (aHR 34.38, 95% CI 30.35-38.95) for those with all three infections. Infections also significantly increased first-year costs, from $17 691 (standard error (SE) $591) marginal cost increase for UTI alone, to approximately $40 000-$50 000 (SE $1054-1238) for pneumonia or sepsis alone, to $134 773 (SE $1876) for those with UTI, pneumonia, and sepsis. Clinical and economic impacts persisted in years 2-3 post-transplant. Early infections reflect important targets for management protocols to improve post-transplant outcomes and reduce costs of care.

Serum paraoxonase activity is associated with epicardial fat tissue in renal transplant recipients

AIMS

Cardiovascular disease is a major cause of mortality in renal transplant recipients. Paraoxonase-1 (PON-1) has been shown to protect against atherosclerosis by modifying lipoproteins. Epicardial fat tissue (EFT) has been proposed as a new cardiovascular risk factor. The aim of this study was to investigate the relationship between PON-1 activity and EFT in renal transplant recipients.

METHODS

Eighty renal transplant recipients were enrolled in this cross-sectional study. PON-1 activity was assessed from the rate of enzymatic hydrolysis of paraoxon to p-nitrophenol. EFT was measured by echocardiography.

RESULTS

The mean age of the patients was 40.4 ± 12.3 years and mean post transplant follow-up duration was 57.2 ± 46 months. Mean PON-1 activity was 68.5 ± 30 U/L. PON-1 activity was positively correlated with age and body mass index and negatively correlated with parathyroid hormone, dialysis duration and EFT. The mean EFT thickness was 0.64 ± 0.17 cm. Multiple linear regression analysis was used to define independent determinants of EFT in renal transplant recipients. According to linear regression analysis, PON-1 levels and age were found to be independent predictors of EFT.

CONCLUSION

Reduced PON-1 activity was negatively associated with EFT and PON-1 activity independently predicts EFT in renal transplant recipients.

Prevalence and predictors of early cardiovascular events after kidney transplantation: evaluation of pre-transplant cardiovascular work-up

INTRODUCTION

Cardiovascular disease is the leading cause of mortality after renal transplantation. The purpose of this study was to analyze cardiovascular risk factors at transplantation, occurrence of cardiovascular events in the first year after transplantation and evaluate pre-transplant work-up.

MATERIAL AND METHOD

In total, 244 renal transplant recipients older than 50 years were included. The results of pre-transplant work-up, including clinical evaluation, electrocardiogram, echocardiography, myocardial perfusion testing and coronary angiography were analyzed.

RESULTS

Patients had multiple risk factors at inclusion on renal transplantation waiting list as high blood pressure (94.7%), dyslipidemia (81.1%), smoking (45.3%), diabetes (23.6%), past history of cardiovascular disease (21.3%) and obesity (12.7%). Following transplantation, 15.5% (n = 38) of patients experienced a cardiovascular event, including 2.8% (n = 7) acute coronary syndrome, 5.8% (n = 14) isolated increase in troponin level and 5.3% (n = 13) new onset atrial fibrillation. The pre-transplant parameters associated with a cardiovascular event were a past medical history of cardiovascular disease (HR = 2.06 [1.06-4.03], p = 0.03), echocardiographic left ventricular hypertrophy (HR = 2.04 [1.04-3.98], p = 0.037) and abnormal myocardial perfusion testing (HR = 2.25 [1.09 -5.96], p = 0.03). Pre-transplantation evaluation allowed the diagnosis of unknown coronary artery lesions in 8.9% of patients.

Prognostic value of cardiac tests in potential kidney transplant recipients: a systematic review

BACKGROUND

Whether abnormal myocardial perfusion scintigraphy (MPS), dobutamine stress echocardiography (DSE) or coronary angiography, performed during preoperative evaluation for potential kidney transplant recipients, predicts future cardiovascular morbidity is unclear. We assessed test performance for predicting all-cause mortality, cardiovascular mortality and major adverse cardiac events (MACE).

METHODS

We searched MEDLINE and EMBASE (to February 2014), appraised studies, and calculated risk differences and relative risk ratios (RRR) with 95% confidence intervals (95% CI) using random effects meta-analysis.

RESULTS

Fifty-two studies (7401 participants) contributed data to the meta-analysis. Among the different tests, similar numbers of patients experienced MACE after an abnormal test result compared with a normal result (risk difference: MPS 20 per 100 patients tested [95% CI, 0.11-0.29], DSE 24 [95% CI, 0.10-0.38], and coronary angiography 20 [95% CI, 0.08-0.32; P = 0.91]). Although there was some evidence that coronary angiography was better at predicting all-cause mortality than MPS (RRR, 0.69; 95% CI, 0.49-0.96; P = 0.03) and DSE (RRR, 0.72; 95% CI, 0.50-1.02; P = 0.06), noninvasive tests were as good as coronary angiography at predicting cardiovascular mortality (RRR, MPS, 0.89; 95% CI, 0.38-2.10; P = 0.78; DSE, 1.09; 95% CI, 0.12-10.05; P = 0.93), and MACE (RRR: MPS, 1.09; 95% CI, 0.64-1.86; P = 0.74; DSE, 1.56; 95% CI, 0.71-3.45; P = 0.25).

CONCLUSIONS

Noninvasive tests are as good as coronary angiography at predicting future adverse cardiovascular events in advanced chronic kidney disease. However, a substantial number of people with negative test results go on to experience adverse cardiac events.

Inactivity on the kidney transplant wait-list is associated with inferior pre- and post-transplant outcomes

BACKGROUND

The majority of kidney transplant (KT) candidates spend some time on the transplant wait-list (WL) prior to kidney transplantation. We examined the impact of WL inactivity on clinical outcomes.

METHODS

All adult KT candidates first actively wait-listed between January 1, 1996, and December 31, 2005, in the United States were grouped by frequency of inactivity on the WL. Transplantation rate, pre- and post-transplant patient survival and death-censored kidney graft survival were compared.

RESULTS

Of 159,774 candidates who were placed on the WL, 48,598 (30.4%) experienced one or more periods of inactivity. Candidates with inactivity once or more on the WL had 42% and 27% less likelihood of KT, respectively (HR 0.58, 95% CI 0.57, 0.59 and HR 0.73, 95% CI 0.71, 0.75). WL inactivity once or more was associated with a higher likelihood of death (HR 1.94, 95% CI 1.88, 2.00 and HR 2.13, 95% CI 2.02, 2.24). Among KT recipients, inactivity more than once on the WL was associated with a higher risk of death (HR 1.14, 95% CI 1.05, 1.23).

CONCLUSIONS

Periods of inactivity on the WL predict increased mortality pre- and post-transplantation. A better understanding of the reasons for WL inactivity is essential to improve WL management and post-transplant outcomes.

Patient selection and preoperative evaluation for transplant surgery

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

A new risk score model to predict the presence of significant coronary artery disease in renal transplant candidates

BACKGROUND

Renal transplant candidates are at high risk of coronary artery disease (CAD). We sought to develop a new risk score model to determine the pre-test probability of the occurrence of significant CAD in renal transplant candidates.

METHODS

A total of 1,060 renal transplant candidates underwent a comprehensive cardiovascular risk evaluation. Patients considered at high risk of CAD (age ≥50 years, with either diabetes mellitus (DM) or cardiovascular disease (CVD)), or having noninvasive testing suggestive of CAD were referred for coronary angiography (n = 524). Significant CAD was defined by the presence of luminal stenosis ≥70%. A binary logistic regression model was built, and the resulting logistic regression coefficient B for each variable was multiplied by 10 and rounded to the next whole number. For each patient, a corresponding risk score was calculated and the receiver operating characteristic (ROC) curve was constructed.

RESULTS

The final equation for the model was risk score = (age × 0.4) + (DM × 9) + (CVD × 14) and for the probability of CAD (%) = (risk score × 2) - 23. The corresponding ROC for the accuracy of the diagnosis of CAD was 0.75 (P <0.0001) in the developmental model.

CONCLUSIONS

We developed a simple clinical risk score to determine the pre-test probability of significant CAD in renal transplant candidates. This model may help those directly involved in the care of patients with end-stage renal disease being considered for transplantation in an attempt to reduce the rate of cardiovascular events that presently hampers the long-term prognosis of such patients.

The survival benefit of kidney transplantation in obese patients

Obese patients have a decreased risk of death on dialysis but an increased risk of death after transplantation, and may derive a lower survival benefit from transplantation. Using data from the United States between 1995 and 2007 and multivariate non-proportional hazards analyses we determined the relative risk of death in transplant recipients grouped by body mass index (BMI) compared to wait-listed candidates with the same BMI (n = 208 498). One year after transplantation the survival benefit of transplantation varied by BMI: Standard criteria donor transplantation was associated with a 48% reduction in the risk of death in patients with BMI ≥ 40 kg/m(2) but a ≥ 66% reduction in patients with BMI < 40 kg/m2. Living donor transplantation was associated with ≥ 66% reduction in the risk of death in all BMI groups. In sub-group analyses, transplantation from any donor source was associated with a survival benefit in obese patients ≥ 50 years, and diabetic patients, but a survival benefit was not demonstrated in Black patients with BMI ≥ 40 kg/m(2). Although most obese patients selected for transplantation derive a survival benefit, the benefit is lower when BMI is ≥ 40 kg/m(2), and uncertain in Black patients with BMI ≥ 40 kg/m(2).

Dynamic cardiac dyssynchrony is strongly associated with 2-year dialysis adequacy in continuous ambulatory peritoneal dialysis patients

BACKGROUND

Left ventricular (LV) dyssynchrony is associated with increased risk of all-cause mortality in patients with end-stage renal disease. Our aim was to determine the associations of LV dynamic dyssynchrony with peritoneal solute clearance in continuous ambulatory peritoneal dialysis (CAPD) patients. Our primary objective was to determine the association between dynamic LV dyssynchrony and CAPD clearance at 2 years. Secondary objectives were to identify the factors influencing dynamic dyssynchrony, and to examine the association between dialysis adequacy and echocardiography-assessed LV outcomes.

METHODS

Fifty CAPD patients and 13 healthy volunteers underwent three-dimensional (3D) dobutamine stress echocardiography (DSE). The main endpoint was systolic dyssynchrony index (SDI). Secondary endpoints, including NT-proBNP, troponin I, Kt/V, and biochemical parameters, were measured before stress echocardiography, and Kt/V was measured again 2 years later. All values are expressed as medians and interquartile ranges (IQR).

RESULTS

NT-proBNP (3872 [808-11779] vs. 4.99 [4.99-36.83] pg/mL, P < 0.001), and log NT-proBNP (3.587 [2.896-4.071] vs. 0.698 [0.698-1.540], P < 0.001) levels were significantly higher in the CAPD group than in the control group. Real-time 3D DSE showed that the systolic dyssynchrony index was significantly different between the two groups at the peak dobutamine stage (1.11% [0.76-1.64%] vs. 0.66% [0.50-1.02%], P = 0.004), but not at resting (1.30% [0.89-1.74%] vs. 1.22 % [0.72-1.68%], P = 0.358).The subgroup of patients in the CAPD group with greater improvements in dialysis adequacy had lower baseline dynamic SDI and more favorable echocardiographic findings at 2 years. Dialysis adequacy decreased significantly at 2 year in patients with higher, but not in those with lower dynamic SDI at baseline. In multivariate linear regression analysis, log NT-proBNP and SDI at the peak dobutamine dose were significantly associated with Kt/V and weekly creatinine clearance at 2 years, while log NT-proBNP was significant associated with SDI at the peak dobutamine stage. Female CAPD patients group had more pronounced dynamic LV dyssynchrony compared with male patients.

CONCLUSIONS

Dynamic systolic dyssynchrony was strongly associated with future dialysis adequacy in CAPD patients. Log NT-proBNP was the important predictor of dynamic dyssynchrony. Our study confirmed the concept that cardiac dysfunction has an impact on dialysis adequacy.

Quantification of the early risk of death in elderly kidney transplant recipients

To inform decision making regarding transplantation in patients ≥ 65 years, we quantified the early posttransplant risk of death by determining the time to equal risk and equal survival between transplant recipients and wait-listed dialysis patients in the United States between 1995 and 2007 (total n = 25 468). Survival was determined using separate multivariate nonproportional hazards analyses in low-, intermediate- and high-risk cardiovascular risk patients. Compared to wait-listed patients with similar cardiovascular risk, standard criteria (SCD) and expanded criteria (ECD) recipients had a higher risk of death in the perioperative and early-posttransplant period. In contrast, low and intermediate risk living donor (LD) recipients had an immediate survival advantage compared to similar risk wait-listed patients. In all risk groups, transplantation was associated with a long-term survival advantage compared to dialysis, but there were marked differences in time to equal risk of death, and time to equal survival by donor type. For example, survival in high-risk recipients of an LD, SCD and ECD transplant became equal to that in similar risk wait-listed patients 130, 368 and 521 days after transplantation. Early posttransplant mortality risk is eliminated in low- and intermediate-risk patients, and markedly reduced in high-risk patients with LD transplantation.