Cardiovascular Outcomes in Kidney Transplant Recipients With ADPKD

Endothelial dysfunction in the kidney transplant population: Current evidence and management strategies

The endothelium modulates vascular homeostasis owing to a variety of vasoconstrictors and vasodilators. Endothelial dysfunction (ED), characterized by impaired vasodilation, inflammation, and thrombosis, triggers future cardiovascular (CV) diseases. Chronic kidney disease, a state of chronic inflammation caused by oxidative stress, metabolic abnormalities, infection, and uremic toxins damages the endothelium. ED is also associated with a decline in estimated glomerular filtration rate. After kidney transplantation, endothelial functions undergo immediate but partial restoration, promising graft longevity and enhanced CV health. However, the anticipated CV outcomes do not happen due to various transplant-related and unrelated risk factors for ED, culminating in poor CV health and graft survival. ED in kidney transplant recipients is an under-recognized and poorly studied entity. CV diseases are the leading cause of death among kidney transplant candidates with functioning grafts. ED contributes to the pathogenesis of many of the CV diseases. Various biomarkers and vasoreactivity tests are available to study endothelial functions. With an increasing number of transplants happening every year, and improved graft rejection rates due to the availability of effective immunosuppressants, the focus has now shifted to endothelial protection for the prevention, early recognition, and treatment of CV diseases.

Echocardiographic characteristics of autosomal dominant polycystic kidney disease

Cardiovascular complications in patients with autosomal dominant polycystic kidney disease (ADPKD) are frequently investigated extrarenal manifestations with contradictory outcomes. The primary goal of this study is to explore the prevalence of cardiovascular abnormalities using echocardiography and analyze their associations with clinical characteristics at different stages of chronic kidney disease (CKD) progression in ADPKD patients. We included sixty-eight patients in the study. All patients underwent transthoracic echocardiography using GE Vingmed Ultrasound (GE Norway Health Tech, Oslo, Norway). Demographic information, prior medical history, and antihypertensive medication use were recorded. To diagnose the rapid progression of CKD, creatinine levels were measured twice, with a one-year interval. Analysis revealed left ventricular hypertrophy (LVH) in over 40% of ADPKD patients, as indicated by various LVH parameters. Notably, a decline in estimated glomerular filtration rate (eGFR) after one year of observation was associated with increased left ventricular mass. Other prevalent findings included asymptomatic left ventricular diastolic dysfunction (ALVDD) in 39% of patients, left atrium (LA) enlargement in 39%, and mild valvular regurgitations in 80%. Ejection fraction, aortic root dimension, and the prevalence of mitral valve prolapse were not significantly increased. Cardiac indices did not differ substantially across the different eGFR stages. LVH, LA enlargement, ALVDD and valvular regurgitations are characteristics of cardiac phenotype in ADPKD. Cardiac indices were not different across different stages of CKD pointing towards the diagnosis of ADPKD being the main drive of their occurrence.

Clinical characteristics and outcomes of kidney transplantation in autosomal dominant polycystic kidney disease patients

BACKGROUND

Kidney transplantation (KT) is the best kidney replacement treatment for autosomal dominant polycystic kidney disease (ADPKD). We aimed to investigate the clinical characteristics and outcomes of KT in ADPKD patients compared to those in non-ADPKD patients.

METHODS

We retrospectively analyzed KT recipients in two Korean transplantation centers from 2005 to 2020. Propensity score-matching and Cox regression analysis were used to assess the clinical outcomes of ADPKD compared to non-ADPKD and identify prognostic factors influencing outcomes in ADPKD.

RESULTS

Among a total of 4452 KT patients, 189 (4.2%) were ADPKD patients. Median age at transplantation was 53.0 and 47.0 in ADPKD and non-ADPKD patients, respectively. In both groups, living-donor KT was more common than deceased-donor KT. The ADPKD group had a 4.09-fold higher risk of post-transplant diabetes mellitus and a 1.65-fold higher risk of post-transplant infection compared to the non-ADPKD group; however, subjects with ADPKD had similar risk of rejection, graft failure, and mortality. In the ADPKD group, kidney volume decreased after KT, irrespective of kidney volume status (Mayo classification), while the size of hepatic cysts increased. Neither kidney volume nor nephrectomy of native kidneys were associated with risk of infection, graft failure, or mortality in the ADPKD group.

CONCLUSIONS

ADPKD patients have a higher risk of post-transplant diabetes mellitus and infection than non-ADPKD patients, with no significant impact of kidney volume or nephrectomy on post-transplant outcomes.

Long-Term Outcomes of Nephrectomy Before Kidney Transplantation in Patients With Polycystic Kidney Disease

BACKGROUND

Polycystic kidney disease (PKD) is the most common hereditary kidney disorder. In most patients, the disease progresses to end stage kidney disease, which is treated preferably by kidney transplantation. In certain clinical circumstances, a pretransplant nephrectomy is indicated. Data regarding long-term outcomes of pretransplant nephrectomy are limited. In this study, we aimed to compare patient and graft survival, as well as other long-term outcomes of kidney transplantation, between patients with PKD who had a pretransplant nephrectomy and those who have not.

METHODS

A retrospective analysis of 112 adult kidney transplant recipients with PKD, 36 (32.14%) of which underwent a pretransplant nephrectomy.

RESULTS

In a mean follow-up period of 79 and 129 months (for patients who underwent nephrectomy and patients who did not, respectively), no significant differences were found in patient and graft survival, after adjustment to age and donor type. In addition, rate of hospitalizations, urinary tract infections requiring hospitalization, diabetes mellitus, and erythrocytosis post-transplant were similar in both cohorts.

CONCLUSIONS

Pretransplant nephrectomy in patients with PKD is not associated with increased risk of mortality and other long-term complications following kidney transplantation.

People with genetic kidney diseases on kidney replacement therapy have different clinical outcomes compared to people with other kidney diseases

Despite increasing awareness of genetic kidney disease prevalence, there is limited population-level information about long term outcomes of people with genetic kidney disease receiving kidney replacement therapy. This analysis included people who commenced kidney replacement therapy between 1989 and 2020 as recorded in the Australian and New Zealand Dialysis and Transplant registry. Genetic kidney diseases were subclassified as majority and minority monogenic. Non-genetic kidney diseases were included as the comparator group. Primary outcome measures were 10-year mortality and 10-year graft failure. Cox proportional hazard regression were used to calculate unadjusted and adjusted hazard ratios (AHRs) for primary outcomes. There were 59,231 people in the dialysis subgroup and 21,860 people in the transplant subgroup. People on dialysis with genetic kidney diseases had reduced 10-year mortality risk (majority monogenic AHR: 0.70, 95% CI 0.66-0.76; minority monogenic AHR 0.86, 95% CI 0.80-0.92). This reduced 10-year mortality risk continued after kidney transplantation (majority monogenic AHR: 0.82, 95% CI 0.71-0.93; minority monogenic AHR 0.80, 95% CI 0.68-0.95). Majority monogenic genetic kidney diseases were associated with reduced 10-year graft failure compared to minority monogenic genetic kidney diseases and other kidney diseases (majority monogenic AHR 0.69, 95% CI 0.59-0.79). This binational registry analysis identified that people with genetic kidney disease have different mortality and graft failure risks compared to people with other kidney diseases.

Dialysis and Transplant Considerations in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the fourth leading cause of kidney replacement therapy. Unfortunately, the need for dialysis or kidney transplantation is a foreseeable outcome for many patients affected by ADPKD. We review some of the unique issues that should be considered in the management of patients with ADPKD who require dialysis or kidney transplantation. The choice of dialysis modality may be influenced by the enlarged kidneys and liver, but peritoneal dialysis should not be excluded as an option, as studies do not consistently show that there is an increased risk for technique failure or peritonitis. The optimal kidney replacement therapy option remains kidney transplantation; however, nephrectomy may be needed if there is insufficient space for the allograft. Living donor candidates from at-risk families need to be excluded from carrying the disease either by diagnostic imaging criteria or genetic testing. Other potential transplant issues, such as malignancy and cardiovascular and metabolic risks, should also be recognized. Despite these issues, patients with ADPKD requiring dialysis or kidney transplantation generally have more favorable outcomes as compared to those with other causes of chronic kidney disease. Further studies are still needed to personalize the therapeutic approach for those receiving kidney replacement therapy and eventually improve clinical outcomes.