Risk factors and outcome of stroke in renal transplant recipients

Trends and Outcomes of Left Atrial Appendage Occlusion in Renal and Liver Transplant Recipients: Insights From the United States National Inpatient and Readmission Database

Left atrial appendage occlusion using the Watchman device has emerged as an alternative treatment strategy for preventing strokes in patients with atrial fibrillation. However, there is no data on its safety and clinical outcomes in prior renal or liver transplant recipients. We included a total of 61,995 patients from the National Inpatient Sample (NIS, in-hospital outcomes) and 55,048 patients from the National Readmission Database (NRD, 30-day outcomes) who underwent percutaneous left atrial appendage occlusion (LAAO). From this group, 0.65% (n=405) and 0.62% (n=339) were renal and liver transplant recipients in NIS and NRD respectively. Transplant recipients were younger compared with non-transplant recipients (mean age 69 vs 77 years, P=<0.01). There was little difference in terms of in-hospital mortality (0% vs 0.2%, P=0.43), major complications (6.2% vs 5.6%, P=0.61), cardiovascular complications (2.5% vs 2.8%, P=0.73), neurological complications (1.2% vs 0.7%, P=0.21) or bleeding complications (1.2% vs 0.7%, P=0.99) between transplant vs. non-transplant patients. Based on the NRD database, 30-day readmission rate was not meaningfully different for transplant recipients undergoing LAAO (9.44%) when compared to non-transplant patients (8.12%, [log-rank, P=0.56]). There was no difference between 30-day major or cardiovascular complications, however vascular complication rates were significantly higher for transplant recipients (OR 2.56, 95% CI [(1.66-3.47]). Our study findings suggest that LAAO may be safe for patients with a prior renal or liver transplant in terms of major complications, cardiovascular complications, and all-cause readmission rates. However vascular complications may be higher in transplant recipients. Further large-scale studies are needed to confirm these findings.

Outcomes of acute ischemic stroke in kidney transplant recipients: An analysis of US Nationwide inpatient sample

A kidney transplant is often the treatment of choice for end-stage kidney disease, compared with a lifetime on dialysis. Kidney transplant recipients (KTRs) have a reduced risk for new strokes than patients with chronic kidney disease (CKD) G5 treated by dialysis (CKD G5D). However, the benefit of Kidney transplant on post-stroke hospitalization outcomes has not been well studied. This study aimed to evaluate the outcomes of hospitalization after acute ischemic stroke (AIS) in KTRs and patients with CKD G5D. This retrospective study used patient data from the US Nationwide Inpatient Sample database. From 2005 to 2018, patients hospitalized with AIS were classified into 3 groups, including KTRs (n = 1,833), patients with CKD G5D (n = 26,767), and those without CKD (CKD-free, n = 986,945). Patients with CKD G1–G4 or unspecified stage, and graft failure requiring dialysis were excluded. In-hospital mortality, medical complications, transfer to nursing homes, and length of stay (LOS) were compared. Compared to CKD-free group, KTRs had no significant higher risks for in-hospital mortality, transfer to nursing homes, and LOS, but a greater risk for medical complications after adjusting for relevant factors. CKD G5D group had higher risks for in-hospital mortality (adjusted odds ratio (aOR): 2.04, 95% confidence interval (CI): 1.93–2.15), medical complications (aOR: 1.49, 95% CI: 1.45–1.54), and transfer to nursing homes (aOR: 1.10, 95% CI: 1.07–1.13), and a 0.07 day (95% CI: 0.06–0.08) longer LOS than CKD-free group. In conclusion, the outcomes of AIS hospitalization were more favorable in KTRs as compared with CKD G5D. Furthermore, the risks for in-hospital mortality, transfer to long-term care facilities, and LOS were not significantly different between KTRs and CKD-free patients.

The Prevalence of Neurological Complication after Renal Transplantation

Objective

To evaluate the incidence of neurological complications (NCs) after renal transplantation by meta-analysis.

Methods

A broad literature search in PubMed, Embase, and Cochrane-Library was performed from inception to December 31, 2021, to collect published studies on the incidence of NCs after kidney transplantation. The R language meta-package was used to organize and analyze the data.

Results

17 articles including 1,1119 participants were considered eligible. There were 3 studies that recorded unclassified NCs (249 participants), 6 that recorded nervous system CMV infection (1489 participants), 3 that recorded headache (243 participants), and 5 that recorded cerebrovascular events (9138 participants). There was significant heterogeneity (all I ² ≥ 75%) in all analyses, and random-effects models were selected. Meta-analysis results showed that the incidence of unclassified NCs was 0.29 (95% CI (0.16-0.48)), the incidence of nervous system CMV infection was 0.38 (95% CI (0.26-0.52)), the incidence of headache was 0.55 (95% CI (0.44-0.66)), and the incidence of stroke was 0.05 (95% CI (0.02-0.09)). Egger's test showed that there was no conspicuous publication bias in the included literature in each group.

Conclusions

Headache had the highest incidence (55%) in the nervous system after KT, followed by nervous system CMV infection (38%) and stroke (5%). Nevertheless, due to the inconsistencies in the types of NCs included and the follow-up time, our results might only serve as an epidemiological reference for the specific incidence differences.

Risk factors for graft loss and death among kidney transplant recipients: A competing risk analysis

INTRODUCTION

Kidney transplantation is the best therapeutical option for CKD patients. Graft loss risk factors are usually estimated with the cox method. Competing risk analysis could be useful to determine the impact of different events affecting graft survival, the occurrence of an outcome of interest can be precluded by another. We aimed to determine the risk factors for graft loss in the presence of mortality as a competing event.

METHODS

A retrospective cohort of 1454 kidney transplant recipients who were transplanted between July 1, 2008, to May 31, 2019, in Colombiana de Trasplantes, were analyzed to determine risk factors of graft loss and mortality at 5 years post-transplantation. Kidney and patient survival probabilities were estimated by the competing risk analysis. The Fine and Gray method was used to fit a multivariable model for each outcome. Three variable selection methods were compared, and the bootstrapping technique was used for internal validation as split method for resample. The performance of the final model was assessed calculating the prediction error, brier score, c-index and calibration plot.

RESULTS

Graft loss occurred in 169 patients (11.6%) and death in 137 (9.4%). Cumulative incidence for graft loss and death was 15.8% and 13.8% respectively. In a multivariable analysis, we found that BKV nephropathy, serum creatinine and increased number of renal biopsies were significant risk factors for graft loss. On the other hand, recipient age, acute cellular rejection, CMV disease were risk factors for death, and recipients with living donor had better survival compared to deceased-donor transplant and coronary stent. The c-index were 0.6 and 0.72 for graft loss and death model respectively.

CONCLUSION

We developed two prediction models for graft loss and death 5 years post-transplantation by a unique transplant program in Colombia. Using a competing risk multivariable analysis, we were able to identify 3 significant risk factors for graft loss and 5 significant risk factors for death. This contributes to have a better understanding of risk factors for graft loss in a Latin-American population. The predictive performance of the models was mild.

New Approaches to Cardiovascular Disease and Its Management in Kidney Transplant Recipients

Cardiovascular events, including ischemic heart disease, heart failure, and arrhythmia, are common complications after kidney transplantation and continue to be leading causes of graft loss. Kidney transplant recipients have both traditional and transplant-specific risk factors for cardiovascular disease. In the general population, modification of cardiovascular risk factors is the best strategy to reduce cardiovascular events; however, studies evaluating the impact of risk modification strategies on cardiovascular outcomes among kidney transplant recipients are limited. Furthermore, there is only minimal guidance on appropriate cardiovascular screening and monitoring in this unique patient population. This review focuses on the limited scientific evidence that addresses cardiovascular events in kidney transplant recipients. Additionally, we focus on clinical management of specific cardiovascular entities that are more prevalent among kidney transplant recipients (ie, pulmonary hypertension, valvular diseases, diastolic dysfunction) and the use of newer evolving drug classes for treatment of heart failure within this cohort of patients. We note that there are no consensus documents describing optimal diagnostic, monitoring, or management strategies to reduce cardiovascular events after kidney transplantation; however, we outline quality initiatives and research recommendations for the assessment and management of cardiovascular-specific risk factors that could improve outcomes.

Characteristics and Prognosis of Stroke in Living Donor Renal Transplant Recipients

Aims: We aimed to determine the characteristics and vascular outcomes of stroke in renal transplant (RT) recipients and compare them with those in patients on hemodialysis (HD) and those with no renal replacement therapy (RRT).

Methods: In this prospective observational study, 717 patients (mean age, 70.8 years; male, 60.5%) with acute ischemic stroke within one week of onset were consecutively enrolled and followed for one year. The patients were classified into three groups: (1) living donor RT recipients (n=27); (2) patients on maintenance HD before the index stroke (n=39); and (3) those with no history of RRT (n=651). The primary outcome was a composite of major adverse cardiovascular events (MACE).

Results: Diabetic nephropathy was the most common reason for RRT in both RT and HD patients. RT patients were more likely to have embolic stroke of undetermined source (33.3%) than others, whereas HD patients more often had cardioembolism (51.3%). No difference was observed in the MACE risk between the patients in RT and non-RRT groups (annual rate, 11.3% vs. 13.1%; log-rankP=0.82; hazard ratio [95% confidence interval], 0.92 [0.29-2.98]). In contrast, HD patients had a greater risk of MACE than those with no RRT (annual rate, 28.2% vs. 13.1%; log-rankP=0.019; hazard ratio [95% confidence interval], 2.24 [1.16-4.3]).

Conclusions: The underlying etiologies of stroke differed in RT and HD patients. The one-year risk of MACE for stroke patients who had received an RT was lower than that for patients undergoing HD and comparable with that of patients with no RRT.

Central and peripheral arterial diseases in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Chronic kidney disease (CKD) affects about 10% of all populations worldwide, with about 2 million people requiring dialysis. Although patients with CKD are at high risk of cardiovascular disease and events, they are often underrepresented or excluded in clinical trials, leading to important knowledge gaps about how to treat these patients. KDIGO (Kidney Disease: Improving Global Outcomes) convened the fourth clinical Controversies Conference on the heart, kidney and vasculature in Dublin, Ireland, in February 2020, entitled Central and Peripheral Arterial Diseases in Chronic Kidney Disease. A global panel of multidisciplinary experts from the fields of nephrology, cardiology, neurology, surgery, radiology, vascular biology, epidemiology, and health economics attended. The objective was to identify key issues related to the optimal detection, management, and treatment of cerebrovascular diseases, central aortic disease, renovascular disease, and peripheral artery disease in the setting of CKD. This report outlines the common pathophysiology of these vascular processes in the setting of CKD, describes best practices for their diagnosis and management, summarizes areas of uncertainty, addresses ongoing controversial issues, and proposes a research agenda to address key gaps in knowledge that, when addressed, could improve patient care and outcomes.

Chronic Kidney Disease and Cerebrovascular Disease: Consensus and Guidance From a KDIGO Controversies Conference

The global health burden of chronic kidney disease is rapidly rising, and chronic kidney disease is an important risk factor for cerebrovascular disease. Proposed underlying mechanisms for this relationship include shared traditional risk factors such as hypertension and diabetes, uremia-related nontraditional risk factors, such as oxidative stress and abnormal calcium-phosphorus metabolism, and dialysis-specific factors such as cerebral hypoperfusion and changes in cardiac structure. Chronic kidney disease frequently complicates routine stroke risk prediction, diagnosis, management, and prevention. It is also associated with worse stroke severity, outcomes and a high burden of silent cerebrovascular disease, and vascular cognitive impairment. Here, we present a summary of the epidemiology, pathophysiology, diagnosis, and treatment of cerebrovascular disease in chronic kidney disease from the Kidney Disease: Improving Global Outcomes Controversies Conference on central and peripheral arterial disease with a focus on knowledge gaps, areas of controversy, and priorities for research.

Atrial fibrillation in kidney transplant recipients: is there a place for the novel drugs?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia of high clinical importance, occurring in 2% of the general population and in 19-24% in patients with chronic kidney disease. It is a well-known risk factor for cardiovascular morbidity and mortality. Kidney transplant recipients with a history of AF were associated with significantly higher rate of ischaemic strokes, graft failure and post-transplant mortality. AF occurs in over 7% of kidney transplant recipients in the first 3 years after transplantation and is associated with reduced graft and patient survival. The incidence of stroke in patients after kidney transplantation (KTx) is higher than the general population, but markedly lower than those on dialysis. Oral anticoagulation (OAC) therapy is recommended in AF patients at high risk of stroke. There are no randomized studies assessing OAC in patients after KTx and there are no specific recommendations and guidelines on therapeutic strategies in these patients. KTx recipients are a vulnerable population, exposed to variations in renal function, being at higher risk of bleeding and thrombotic complications, with possible interactions with immunosuppression. Surely, there is a place for novel oral anticoagulants (NOACs) in this group of patients as long as the summary of product characteristics is followed, as they are a valuable anticoagulation therapy. On one hand, they are at least as effective as warfarin; on the other hand NOACs are safer, especially when it comes to intracranial haemorrhages. However, NOACs seem to be underused in this population as they are excreted via kidney, may interact with immunosuppressive therapy and physicians need more experience and confidence in their administration. Percutaneous left atrial appendage occlusion procedure may also be considered as an opportunity for this group of patients, in particular in the presence of contraindications to anticoagulation.

Renal replacement modality and stroke risk in end-stage renal disease-a national registry study

Background

The risk of stroke in end-stage renal disease (ESRD) on renal replacement therapy (RRT) is up to 10-fold greater than the general population. However, whether this increased risk differs by RRT modality is unclear.

Methods

We used data contained in the Scottish Renal Registry and the Scottish Stroke Care Audit to identify stroke in all adult patients who commenced RRT for ESRD from 2005 to 2013. Incidence rate was calculated and regression analyses were performed to identify variables associated with stroke. We explored the effect of RRT modality at initiation and cumulative dialysis exposure by time-dependent regression analysis, using transplant recipients as the reference group.

Results

A total of 4957 patients commenced RRT for ESRD. Median age was 64.5 years, 41.5% were female and 277 patients suffered a stroke (incidence rate was 18.6/1000 patient-years). Patients who had stroke were older, had higher blood pressure and were more likely to be female and have diabetes. On multivariable regression older age, female sex, diabetes and higher serum phosphate were associated with risk of stroke. RRT modality at initiation was not. On time-dependent analysis, haemodialysis (HD) exposure was independently associated with increased risk of stroke.

Conclusions

In patients with ESRD who initiate RRT, HD use independently increases risk of stroke compared with transplantation. Use of peritoneal dialysis did not increase risk on adjusted analysis.

Reduced risk of new onset stroke after kidney transplantation in Asian dialysis patients: a propensity score-matched, competing risk study in Taiwan

BACKGROUND

Kidney transplantation (KT) has been found to reduce cardiovascular events and mortality in chronic dialysis patients. There is little data, however, regarding the risk reduction of cerebrovascular events after KT in Asian populations. This study evaluates the risk of cerebrovascular events after KT in Taiwan.

METHODS

Tapping Taiwan's National Health Insurance claims data of patients with a diagnosis of end-stage renal disease (ESRD), we enrolled all KT recipients from 1999 to 2011 (n = 2908). For each KT patient, four controls (patients also diagnosed with ESRD) without KT were propensity matched by birth date, sex, selected comorbidities and duration of dialysis. All subjects were followed to the end of 2011.

RESULTS

The incidence rate for stroke in the KT recipients and comparison group were 52.63 and 137.26 per 10 000 person-years, respectively. After adjustment for age, gender and comorbidities with competing mortality, KT recipients had 60% reduction in all kinds of stroke, compared to those who did not receive procedure. They were found to have a 48 and 74% reduction in ischemic and hemorrhagic stroke risk, respectively. Subgroup analyses also showed similar trends in the improvement of stroke after KT. While elderly patients, men, and those with diabetes, hypertension and coronary artery disease are at increased risk for stroke, our log-rank test revealed those that received KT had significantly lower cumulative incidence rates of stroke than those that did not (P < 0.001).

CONCLUSIONS

KT was associated with reduced risk of new onset stroke in chronic dialysis patients in Taiwan.

Epidemiology and Prognostic Importance of Atrial Fibrillation in Kidney Transplant Recipients: A Meta-Analysis

This meta-analysis was conducted with the aims to summarize all available evidence on (1) prevalence of pre-existing atrial fibrillation (AF) and/or incidence of AF following kidney transplantation; (2) the outcomes of kidney transplant recipients with AF; and (3) the trends of estimated incidence of AF following kidney transplantation over time. A literature search was conducted utilizing MEDLINE, EMBASE, and the Cochrane Database from inception through March 2018. We included studies that reported (1) prevalence of pre-existing AF or incidence of AF following kidney transplantation or (2) outcomes of kidney transplant recipients with AF. Effect estimates from the individual study were extracted and combined utilizing random-effect, generic inverse variance method of DerSimonian and Laird. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42018086192). Eight cohort studies with 137,709 kidney transplant recipients were enrolled. Overall, the pooled estimated prevalence of pre-existing AF in patients undergoing kidney transplantation was 7.0% (95% CI: 5.6⁻8.8%) and pooled estimated incidence of AF following kidney transplantation was 4.9% (95% CI: 1.7⁻13.0%). Meta-regression analyses were performed and showed no significant correlations between year of study and either prevalence of pre-existing AF (p = 0.93) or post-operative AF after kidney transplantation (p = 0.16). The pooled odds ratios (OR) of mortality among kidney transplant recipients with AF was 1.86 (3 studies; 95% CI: 1.03⁻3.35). In addition, AF is also associated with death-censored allograft loss (2 studies; OR: 1.55, 95% CI: 1.02⁻2.35) and stroke (3 studies; OR: 2.54, 95% CI: 1.11⁻5.78) among kidney transplant recipients. Despite advances in medicine, incidence of AF following kidney transplant does not seem to decrease over time. In addition, there is a significant association of AF with increased mortality, allograft loss, and stroke after kidney transplantation.

[Anticoagulation in patients with chronic kidney disease : Recommendations from the working group "Heart-Kidney" of the German Cardiac Society and the German Society of Nephrology]

Indications for anticoagulation are thromboembolic events, prosthetic heart valves, and atrial fibrillation with a corresponding risk score. Clinical trials have excluded patients with advanced chronic kidney disease and these data cannot be always generalized to patients with chronic kidney disease. Non-vitamin K antagonist oral anticoagulants (NOACs) are mostly not recommended or are contraindicated in advanced stages of chronic kidney disease. Observational studies have shown that dialysis patients with atrial fibrillation do not profit from coumarin anticoagulants; prospective studies are lacking.

Cardiovascular disease risk in patients receiving organ transplantation: a national cohort study

Although organ transplantation is the definitive treatment for end-stage organ failure, the post-transplant outcomes can be substantially influenced by cardiovascular complications. A national cohort study was performed to estimate risks of cardiovascular diseases in those with heart, lung, kidney, and liver transplantation. This cohort study consisted of 5978 solid organ transplantations identified using the Taiwan National Health Insurance Database. Cardiovascular and mortality risks in transplant recipients were evaluated using standardized incidence ratios, excess absolute risks, and standardized mortality ratios as compared to those in the general population. In heart, kidney, and liver recipients, the standardized incidence ratios of overall cardiovascular diseases were 9.41 (7.75-11.44), 3.32 (2.29-3.77), and 1.4 (1.15-1.7) and the overall standardized mortality ratios were 5.23 (4.54-6.03), 1.48 (1.34-1.63), and 3.95 (3.64-4.28), respectively. Except for heart organ recipients who were at highest risk for coronary artery disease with a standardized incidence ratio of 13.12 (10.57-16.29), kidney and liver organ recipients had a ninefold increased risk in developing deep vein thrombosis post-transplant. In conclusion, solid organ transplant patients are at risk of cardiovascular disease, in particular, deep vein thrombosis, which may warrant early identification of high-risk patients in addition to prompt and adequate thromboprophylaxis perioperatively.