Kidney volume changes in patients with autosomal dominant polycystic kidney disease after renal transplantation. Transplantation. 2012;93:794-798. [PMID: 22491657 DOI: 10.1097/tp.0b013e318246f910]

Native nephrectomy in polycystic kidney disease patients on transplant lists: how and when?

Autosomal dominant polycystic kidney disease (ADPKD), the most common hereditary kidney disease, accounts for approximately 10% of the patients on kidney transplantation waitlists. High rates of complications including hemorrhage, infections, nephrolithiasis and kidney size-related compressive complaints have been reported among ADPKD patients. Therefore, the need for routine native nephrectomy and timing of such procedure in ADPKD patients being prepared for transplantation are debated. Even though pre-transplant nephrectomy has the potential to provide fewer infectious complications due to lack of immunosuppressive medication use, such procedure has been associated with longer hospital stay, loss of residual kidney function and need for dialysis. Although simultaneous nephrectomy and transplantation could potentially lead to longer perioperative duration, perioperative complications and need for blood transfusions, this was not confirmed in cohort studies. Therefore, some institutions routinely perform simultaneous unilateral nephrectomy and kidney transplantation. In this narrative review, our aim is to evaluate the current evidence regarding the need and timing of nephrectomy in ADPKD patients in relation to kidney transplantation.

Case report: Genotype-phenotype characteristics of nine novel PKD1 mutations in eight Chinese patients with autosomal dominant polycystic kidney disease

Introduction

Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder. The PKD1 gene is responsible for the majority of ADPKD cases, and the mutations in this gene exhibit high genetic diversity. This study aimed to investigate the association between genotype and phenotype in ADPKD patients with PKD1 gene mutations through pedigree analysis.

Methods

Eight Chinese pedigrees affected by ADPKD were analyzed using whole-exome sequencing (WES) on peripheral blood DNA. The identified variants were validated using Sanger sequencing, and clinical data from the patients and their families were collected and analyzed.

Results

Nine novel mutation sites in PKD1 were discovered across the pedigrees, including c.4247T > G, c.3298_3301delGAGT, c.4798A > G, c.7567G > A, c.11717G > C, c.7703 + 5G > C, c.3296G > A, c.8515_8516insG, and c.5524C > A. These mutations were found to be associated with a range of clinical phenotypes, including chronic kidney disease, hypertension, and polycystic liver. The age of onset and disease progression displayed significant heterogeneity among the pedigrees, with some individuals exhibiting early onset and rapid disease progression, while others remained asymptomatic or had milder disease symptoms. Inheritance patterns supported autosomal dominant inheritance, as affected individuals inherited the mutations from affected parents. However, there were instances of individuals carrying the mutations who remained asymptomatic or exhibited milder disease phenotypes.

Conclusion

This study highlights the importance of comprehensive genotype analysis in understanding the progression and prognosis of ADPKD. The identification of novel mutation sites expands our knowledge of PKD1 gene mutations. These findings contribute to a better understanding of the disease and may have implications for personalized therapeutic strategies.

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.

The Need for Routine Native Nephrectomy in the Workup for Kidney Transplantation in Autosomal Dominant Polycystic Kidney Disease Patients

INTRODUCTION

There is no consensus if nor when a native nephrectomy should be performed in the workup for kidney transplantation in ADPKD patients. In our PKD Expertise Center, a restrictive approach is pursued in which nephrectomy is performed only in patients with severe complaints, i.e., in case of serious volume-related complaints, lack of space for the allograft, recurrent cyst infections, persistent cyst bleedings, or chronic refractory pain. We analyzed in a retrospective cohort study whether this approach is justified.

METHODS

All ADPKD patients who received kidney transplantation between January 2000 and January 2019 were reviewed. Patients were subdivided into three groups: no nephrectomy (no-Nx), nephrectomy performed before (pre-Tx), or after kidney transplantation (post-Tx). Simultaneous nephrectomy together with transplantation were not performed in our center.

RESULTS

391 patients (54 ± 9 years, 55% male) were included. The majority of patients did not undergo a nephrectomy (n = 257, 65.7%). A nephrectomy was performed pre-Tx in 114 patients (29.2%). After Tx, nephrectomy was performed in only 30 patients (7.7%, median 4.4 years post-Tx). Surgery-related complication rates did not differ between both groups (38.3% pre-Tx vs. 27.0% post-Tx, p = 0.2), nor were there any differences in 10-year patient survival (74.4% pre-Tx vs. 80.7% post-Tx vs. 67.6% no-Nx, p = 0.4), as well as in 10-year death-censored graft survival (84.4% pre-Tx vs. 85.5% post-Tx vs. 90.0% no-Nx, p = 0.9).

CONCLUSIONS

This study indicates that with a restrictive nephrectomy policy in the workup for kidney transplantation, only a part of ADPKD patients need a native nephrectomy.

Changes in Kidney and Liver Volumes in Patients With Autosomal Dominant Polycystic Kidney Disease Before and After Dialysis Initiation

Objective

To examine the changes in total kidney volume (TKV) and total liver volume (TLV) before and after dialysis initiation in patients with autosomal dominant polycystic kidney disease.

Patients and Methods

This was a retrospective, single-center cohort study to investigate the changes in TKV and TLV before and after dialysis initiation, along with influencing factors, using linear mixed models. We enrolled 95 patients with autosomal dominant polycystic kidney disease (85 receiving hemodialysis [HD] and 10 receiving peritoneal dialysis [PD]) who began receiving dialysis at Toranomon Hospital from January 1, 2008, to December 31, 2020.

Results

The least squares mean TKV ratio (TKV at each time point/TKV at dialysis initiation) was 63.8% (95% confidence interval [CI], 54.7%-72.9%) at 6 years before dialysis initiation and 95.5% (95% CI, 82.9%-108.2%) at 6 years after dialysis initiation (P<.001). A multivariate linear mixed model analysis revealed that dialysis style (HD or PD) had the strongest effect on changes in TKV (P=.002). The least squares mean TLV ratio was 98.2% (95% CI, 88.4%-108.0%) at 6 years before dialysis initiation and 95.7% (95% CI, 85.2%-106.2%) at 6 years after dialysis initiation (P=.01). Although PD did not have significant effects on changes in TLV (P=.27), the changes in TLV were greater in patients on PD than in those on HD.

Conclusion

The TKV increased until dialysis initiation and generally decreased after dialysis initiation. The TLV continued to increase even after dialysis initiation, however, changes in the TLV significantly decreased after dialysis initiation. The increases in TKV and TLV were greater in patients on PD than in those on HD.

The Natural Course of Total Kidney Volume in Patients with Autosomal Dominant Polycystic Kidney Disease undergoing Hemodialysis

Objectives: The natural course of native kidneys after hemodialysis initiation in patients with autosomal dominant polycystic kidney disease (ADPKD) remains poorly understood.Methods: We measured the total volumes of native kidneys in 12 patients who had at least one enhanced computed tomography (CT) image both before and after initiation of hemodialysis (group 1) and in 18 patients who had no image before dialysis but more than two images after dialysis (group 2). In patients with images, the last image was used for analysis only after dialysis.Results: The mean total kidney volume (TKV) (± SD) before hemodialysis initiation was 3132 ± 1413 mL and the mean TKV of the last image was 3047 ± 1323 mL in group 1. The mean TKV change rate (%) was - 5.2 ± 27.4% (P > 0.05) during follow-up of 3.9 ± 1.9 years in group 1. The mean TKV change rate was 2.8 ± 34.4% (P > 0.05) in group 2. The follow-up period after dialysis initiation ranged from 4.2 ± 4.7 to 8.0 ± 5.2 years.Conclusions: The results suggest that the TKV of native polycystic kidneys decreases substantially after hemodialysis initiation. This reduction occurs mainly during the early post-hemodialysis period and followed by a slow enlargement of TKV.

The importance of kidney volume as a marker in the assessment of living-donor kidney transplantation in Japan

BACKGROUND

In living kidney transplantation, predicting the risk of end-stage kidney disease in the organ donors though crucial remains to be resolved. Thus, any useful biomarker to predict kidney outcome would be highly desirable to safeguard donors.

METHODS

This retrospective study was conducted at Nagoya Daini Red Cross Hospital to confirm whether an increase in preserved kidney volume (PKV) was a predict marker of proteinuria. A change of PKV before and 1 year after kidney donation was measured, and its association with proteinuria 3 years after the donation was analyzed.

RESULTS

A total of 119 kidney donors who met the Japanese donor guideline were enrolled. The mean age was 57.4 years, 46.2% were male. The mean values of the variables before kidney donation (baseline) were: BMI levels: 23.4 kg/m², BSA-adjusted PKV: 132.9 cm³/1.73 m², and estimated glomerular filtration rate (eGFRave): 82.9 mL/min/1.73 m². A positive correlation was noted between BSA-adjusted PKV and eGFRave (r = 0.61, p < 0.001). BSA-adjusted PKV increased by 19.5% 1 year after donation, and the median urine protein was 0.04 g/gCre. Linear regression analyses showed that change of PKV and BSA-adjusted PKV before the donation were significantly associated with proteinuria 3 years after donation.

CONCLUSION

Change of PKV and BSA-adjusted PKV before donation is important factors for proteinuria after donation under the Japanese donor guidelines. Further studies are needed to confirm whether these factors are associated with renal survival after donation.

Advances in Autosomal Dominant Polycystic Kidney Disease: A Clinical Review

Polycystic kidney disease (PKD) is a multiorgan disorder resulting in fluid-filled cyst formation in the kidneys and other systems. The replacement of kidney parenchyma with an ever-increasing volume of cysts eventually leads to kidney failure. Recently, increased understanding of the pathophysiology of PKD and genetic advances have led to new approaches of treatment targeting physiologic pathways, which has been proven to slow the progression of certain types of the disease. We review the pathophysiologic patterns and recent advances in the clinical pharmacotherapy of autosomal dominant PKD. A multipronged approach with pharmacologic and nonpharmacologic treatments can be successfully used to slow down the rate of progression of autosomal dominant PKD to kidney failure.

Kidney transplant patient with immunoglobulin A nephropathy subsequently diagnosed as concurrent autosomal dominant polycystic kidney disease during 17-year follow-up

A 14-year-old Japanese boy was diagnosed with immunoglobulin A nephropathy resulting in end-stage kidney disease (ESKD). He underwent ABO-compatible living kidney transplantation from his father at the age of 27. In the process of selecting a donor before the transplantation, it turned out that his mother had polycystic kidneys and that her family had a history of hypertension and cerebrovascular diseases. The patient himself also had bilateral multiple kidney cysts, with a normal-sized kidney, confusing us to make the diagnosis of acquired cystic kidney disease (ACKD) or ADPKD difficult at that point. Seventeen years later, his native kidneys showed bilateral swelling with multiple cysts. This, along with the histories of his mother and her relatives and with the existence of multiple liver cysts, led us to confirm the diagnosis of autosomal dominant polycystic kidney disease, not of ACKD. Contrary to previous studies that have suggested the size of cysts both in ADPKD and ACKD reduced with time, the present case showed an increase of 3.0% per year in total kidney volume (TKV) by computed tomography. It suggested the possibility that TKV, after decreasing in the relatively early stage after transplantation, may later increase in the long term after ESKD due to another kidney injury.

Autosomal dominant polycystic kidney disease: updated perspectives

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited multisystem disorder, characterized by renal and extra-renal fluid-filled cyst formation and increased kidney volume that eventually leads to end-stage renal disease. ADPKD is considered the fourth leading cause of end-stage renal disease in the United States and globally. Care of patients with ADPKD was, for a long time, limited to supportive lifestyle measures, due to the lack of therapeutic strategies targeting the main pathways involved in the pathophysiology of ADPKD. As the first FDA approved treatment of ADPKD, Vasopressin (V2) receptor blocking agent, tolvaptan, is an urgently awaited advance for ADPKD patients. In our review, we also shed some lights on what is beyond Tolvaptan as there are other medications in the pipeline and many medications have been or are currently being studied in clinical trials such as Tesevatinib, Metformin and Pravastatin, with the goal of slowing the rate of progression of ADPKD by reducing the increase in total kidney volume or maintaining eGFR. Here, we review updates in the perspectives and management of ADPKD.

Change in kidney volume after kidney transplantation in patients with autosomal polycystic kidney disease

Background

The indication to bilateral nephrectomy in patients with autosomal dominant polycystic kidney scheduled for kidney transplantation is controversial. Indeed, the progressive enlargement of cysts may increase the risk of complications and the need for nephrectomy. However, very few studies investigated the change in kidney volume after kidney transplantation.

Material and methods

In this prospective cohort study, the change in native kidney volume in polycystic patients was evaluated with magnetic resonance imaging. Forty patients were included in the study. Kidney diameters and total kidney volume were evaluated with magnetic resonance imaging in patients who underwent simultaneous nephrectomy and kidney transplantation and in patients with kidney transplant alone, before transplantation and 1 year after transplantation.

Results

There was a significant reduction of kidney volume after transplantation, with a mean degree of kidney diameters reduction varying from 12.24% to 14.43%. Mean total kidney volume of the 55 kidney considered in the analysis significantly reduced from 1617.94 ± 833.42 ml to 1381.42 ± 1005.73 ml (P<0.05), with a mean rate of 16.44% of volume decrease. More than 80% of patients had a volume reduction in both groups.

Conclusions

Polycystic kidneys volume significantly reduces after kidney transplantation, and this would reduce the need for prophylactic bilateral nephrectomy in asymptomatic patients.

Effect of Sirolimus on Native Total Kidney Volume After Transplantation in Patients with Autosomal Dominant Polycystic Kidney Disease: A Randomized Controlled Pilot Study

BACKGROUND

The mammalian target of rapamycin (mTOR) pathway has been shown to be central to cyst formation and growth in patients with autosomal dominant polycystic kidney disease (ADPKD). Drugs that suppress mTOR signaling are frequently used as antiproliferative agents for maintenance immunosuppression in patients who have undergone kidney transplantation. The aim of this study was to determine the effect of sirolimus, an mTOR inhibitor, on cyst volume regression in patients with ADPKD who have undergone renal transplantation.

METHODS

In this single-center, prospective, open-label, parallel-group, randomized trial, 23 adult patients with ADPKD who successfully underwent renal transplantation from 2008 to 2012 were subsequently randomized (on a 1:1 basis) to a maintenance immunosuppression regimen with either sirolimus (sirolimus, tacrolimus, prednisone) or mycophenolate (mycophenolate, tacrolimus, prednisone). Total kidney volumes were measured by means of high-resolution magnetic resonance imaging within 2 weeks after transplantation and at 1 year. The primary end point was change in total kidney volume at 1 year.

RESULTS

Sixteen patients completed the 1-year study (8 patients in each group). There was a decrease in kidney volume in both the sirolimus group (percentage change from baseline, 20.5%; P < .001) and mycophenolate group (percentage change from baseline, 17%; P = .048), but there was no significant difference in percentage change of total kidney volume between the groups (P = .665).

CONCLUSIONS

In ADPKD patients at 1 year after kidney transplantation, there was a similar decrease in polycystic kidney volume in patients receiving an immunosuppression regimen containing sirolimus compared with patients receiving mycophenolate.

[Polycystic kidney disease and kidney transplantation]

OBJECTIVES

To perform a state of the art about autosomal dominant polykystic kidney disease (ADPKD), management of its urological complications and end stage renal disease treatment modalities.

MATERIAL AND METHODS

An exhaustive systematic review of the scientific literature was performed in the Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of the following keywords (MESH): "autosomal dominant polykystic kidney disease", "complications", "native nephrectomy", "kidney transplantation". Publications obtained were selected based on methodology, language, date of publication (last 10 years) and relevance. Prospective and retrospective studies, in English or French, review articles; meta-analysis and guidelines were selected and analyzed. This search found 3779 articles. After reading titles and abstracts, 52 were included in the text, based on their relevance.

RESULTS

ADPKD is the most inherited renal disease, leading to end stage renal disease requiring dialysis or renal transplantation in about 50% of the patients. Many urological complications (gross hematuria, cysts infection, renal pain, lithiasis) of ADPKD required urological management. The pretransplant evaluation will ask the challenging question of native nephrectomy only in case of recurrent kidney complications or large kidney not allowing graft implantation. The optimum timing for native nephrectomy will depend on many factors (dialysis or preemptive transplantation, complication severity, anuria, easy access to transplantation, potential living donor).

CONCLUSION

Pretransplant management of ADPKD is challenging. A conservative strategy should be promoted to avoid anuria (and its metabolic complications) and to preserve a functioning low urinary tract and quality of life. When native nephrectomy should be performed, surgery remains the gold standard but renal arterial embolization may be a safe option due to its low morbidity.

Simultaneous Native Nephrectomy and Kidney Transplantation in Patients With Autosomal Dominant Polycystic Kidney Disease

Introduction

To evaluate the feasibility of simultaneous unilateral nephrectomy with kidney transplantation and to determine the effect of this procedure on perioperative morbidity and mortality and graft and patient survival.

Methods

Between January 2000 and May 2015, 145 patients with autosomal dominant polycystic kidney disease (ADPKD) underwent kidney transplantation. Of those, 40 (27.5%) underwent concurrent ipsilateral native nephrectomy (group NT). Patients in group NT were compared with patients with ADPKD not undergoing concurrent nephrectomy (group NT-) and asymptomatic patients undergoing pretransplant nephrectomy (group PNT).

Results

The average follow-up was 66 months. The graft survival rate at 1 and 5 years was 95% and 87.5% versus 93% and 76.2% in the NT and NT- groups, respectively (P = .903 and P = .544, respectively); 1-year patient survival was 100% for NT and 97% for NT- patients (P = .288), whereas 5-year patient survival was 100% and 92% for NT and NT- groups, respectively (P = .128). After propensity score matching (34 patients per group) no significant differences were observed in 1-year (97.1% in NT and 94.1%; P = 1) and 5-year (88.2% in NT and 91.2% in NT-; P = 1) graft survival, and in 1-year (100% for both groups; P = 1) and 5-year (100% in NT and 94.1% in NT-; P = 1) patient survival. Perioperative mortality was 0% among NT and 1.2% among NT- patients, whereas perioperative surgical complications were similar in both groups. One- and 5-year graft and patient survival were similar between the NT and PNT groups, but patients in the PNT group had significantly lower levels of hemoglobin and residual diuresis volumes at the time of transplant. Moreover, PNT patients had a longer pretransplant dialysis and a longer time on the waiting list.

Conclusions

Simultaneous unilateral nephrectomy does not have a negative effect on patient and graft survival in patients with ADPKD and is associated with low morbidity. Pretransplant nephrectomy should be restricted only to highly symptomatic patients, whereas unilateral nephrectomy in asymptomatic patients should be performed during kidney transplantation only if massive kidney size precludes graft positioning.

Native Nephrectomy in Renal Transplant Recipients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Native nephrectomy (NNx) is often done in patients with autosomal dominant polycystic kidney disease (ADPKD). Controversy exists concerning the need and timing of nephrectomy in transplant candidates. We hypothesize that post-transplant NNx does not negatively impact patient and graft survival.

METHODS

Among 470 ADPKD transplant recipients included in the study, 114 (24.3%) underwent pre- (30.7%) or post-transplant (69.3%) NNx. Clinical data was retrieved from electronic records. Follow up was until death, graft loss or June 2014. Perioperative complications were compared between the surgical techniques (open or laparoscopic) and between the pre- and post-transplant nephrectomy groups. The effect of nephrectomy on graft survival was analyzed as a time-dependent covariate when performed post-transplant.

RESULTS

Mean age at transplant was 52.4 years, 53.8% were male, 93% white, 70% were from living donors and 56.8% were pre-emptive. Nephrectomy was done laparoscopically in 31% and 86% in the pre- and post- transplant nephrectomy groups, respectively. Complications were less common in those who underwent nephrectomy post-transplant (26.6% vs. 48%, p=0.03) but were similar regardless of surgical technique (open, 33.3% vs. laparoscopic 33%, p=0.66). Patient and graft survival were similar between those who underwent pre-transplant nephrectomy and the rest of the recipients. In the post-transplant nephrectomy group, nephrectomy did not affect patient (HR 0.77, CI 0.38-1.54, p=0.45) or graft survival (HR 1.0, CI 0.57-1.76, p=0.1).

CONCLUSIONS

Nephrectomy does not adversely affect patient or graft survival. Post-transplant nephrectomy is feasible when indicated without compromising long term graft outcome and has fewer complications than pre-transplant nephrectomy.

Current management of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD), the most frequent cause of genetic renal disease affecting approximately 4 to 7 million individuals worldwide and accounting for 7%-15% of patients on renal replacement therapy, is a systemic disorder mainly involving the kidney but cysts can also occur in other organs such as the liver, pancreas, arachnoid membrane and seminal vesicles. Though computed tomography and magnetic resonance imaging (MRI) were similar in evaluating 81% of cystic lesions of the kidney, MRI may depict septa, wall thickening or enhancement leading to upgrade in cyst classification that can affect management. A screening strategy for intracranial aneurysms would provide 1.0 additional year of life without neurological disability to a 20-year-old patient with ADPKD and reduce the financial impact on society of the disease. Current treatment strategies include reducing: cyclic adenosine monophosphate levels, cell proliferation and fluid secretion. Several randomised clinical trials (RCT) including mammalian target of rapamycin inhibitors, somatostatin analogues and a vasopressin V2 receptor antagonist have been performed to study the effect of diverse drugs on growth of renal and hepatic cysts, and on deterioration of renal function. Prophylactic native nephrectomy is indicated in patients with a history of cyst infection or recurrent haemorrhage or to those in whom space must be made to implant the graft. The absence of large RCT on various aspects of the disease and its treatment leaves considerable uncertainty and ambiguity in many aspects of ADPKD patient care as it relates to end stage renal disease (ESRD). The outlook of patients with ADPKD is improving and is in fact much better than that for patients in ESRD due to other causes. This review highlights the need for well-structured RCTs as a first step towards trying newer interventions so as to develop updated clinical management guidelines.

Autosomal-dominant polycystic kidney disease (ADPKD): executive summary from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Autosomal-dominant polycystic kidney disease (ADPKD) affects up to 12 million individuals and is the fourth most common cause for renal replacement therapy worldwide. There have been many recent advances in the understanding of its molecular genetics and biology, and in the diagnosis and management of its manifestations. Yet, diagnosis, evaluation, prevention, and treatment vary widely and there are no broadly accepted practice guidelines. Barriers to translation of basic science breakthroughs to clinical care exist, with considerable heterogeneity across countries. The Kidney Disease: Improving Global Outcomes Controversies Conference on ADPKD brought together a panel of multidisciplinary clinical expertise and engaged patients to identify areas of consensus, gaps in knowledge, and research and health-care priorities related to diagnosis; monitoring of kidney disease progression; management of hypertension, renal function decline and complications; end-stage renal disease; extrarenal complications; and practical integrated patient support. These are summarized in this review.

[Pathophysiology, epidemiology, clinical presentation, diagnosis and treatment options for autosomal dominant polycystic kidney disease]

Autosomal dominant polycystic kidney disease (ADPKD) is the leading genetic cause of end-stage renal disease (ESRD) worldwide. Its prevalence is evaluated according to studies and population between 1/1000 and 1/4000 live births and it accounts for 6 to 8% of incident ESRD patients in developed countries. ADPKD is characterized by numerous cysts in both kidneys and various extrarenal manifestations that are detailed in this review. Clinico-radiological and genetic diagnosis are also discussed. Mutations in the PKD1 and PKD2 codifying for polycystin-1 (PC-1) and polycystin-2 (PC-2) are responsible for the 85 and 15% of ADPKD cases, respectively. In primary cilia of normal kidney epithelial cells, PC-1 and PC-2 interact forming a complex involved in flow- and cilia-dependant signalling pathways where intracellular calcium and cAMP play a central role. Alteration of these multiple signal transduction pathways leads to cystogenesis accompanied by dysregulated planar cell polarity, excessive cell proliferation and fluid secretion, and pathogenic interactions of epithelial cells with an abnormal extracellular matrix. The mass effect of expanding cyst is responsible for the decline in glomerular filtration rate that occurs late in the course of the disease. For many decades, the treatment for ADPKD aims to lessen the condition's symptoms, limit kidney damage, and prevent complications. Recently, the development of promising specific treatment raises the hope to slow the growth of cysts and delay the disease. Treatment strategies targeting cAMP signalling such as vasopressin receptor antagonists or somatostatin analogs have been tested successfully in clinical trials with relative safety. Newer treatments supported by preclinical trials will become available in the next future. Recognizing early markers of renal progression (clinical, imaging, and genetic markers) to identify high-risk patients and multidrug approaches with synergistic effects may provide new opportunities for the treatment of ADPKD.

Volume regression of native polycystic kidneys after renal transplantation

BACKGROUND

The natural course of native kidneys after renal transplantation (RT) or dialysis in patients with autosomal dominant polycystic kidney disease (ADPKD) remains poorly understood.

METHODS

We measured the total volumes of native kidneys and liver in 78 and 68 ADPKD patients, respectively, who had pre-transplant (within 2 years) and at least one post-transplant computed tomography (CT)/magnetic resonance imaging (MRI); in 40 patients with at least two post-transplant but no pre-transplant CT/MRIs; in 9 patients on chronic hemodialysis with at least one CT/MRI before and after beginning dialysis; and in 5 patients who had no image before and more than one image after dialysis. The last imaging was used in patients with multiple studies.

RESULTS

Mean total kidney volume (TKV) ( ± SD) prior to transplantation was 3187 ± 1779 mL in the 78 patients who had imaging before and after transplantation and decreased by 20.2, 28.6, 38.3 and 45.8% after 0.5-1 (mean 0.7), 1-3 (1.8), 3-10 (5.7) and >10 (12.6) years, respectively. In the multivariable analysis, time on dialysis prior to RT and time from baseline to transplantation were negatively associated with reduction in TKV, whereas estimated glomerular filtration rate (eGFR) after transplantation and time from transplantation were positively associated with percent reduction in TKV. In the 40 patients with imaging only after transplantation, TKV decreased by 3.2 ± 16.3% between 7.2 ± 6.0 and 11.2 ± 6.8 years after transplantation (P < 0.001). TKV was 11.2 ± 35.6% higher (P = NS) after a follow-up of 3.4 ± 2.0 years in the 9 patients with imaging before and after initiation of hemodialysis and 3.4 ± 40.2% lower (P = NS) in the 5 patients with imaging between 2.0 ± 2.1 and 3.5 ± 3.6 years after initiation of hemodialysis. In the 68 patients with liver measurements, volume increased by 5.8 ± 17.9% between baseline and follow-up at 3.7 ± 3.8 years after transplantation (P = 0.009).

CONCLUSIONS

TKV of native polycystic kidneys decreases substantially after RT. The reduction occurs mainly during the early post-transplantation period and more slowly thereafter.

Embolization of renal arteries before transplantation in patients with polycystic kidney disease: a single institution long-term experience

PURPOSE

We aimed to retrospectively assess the long-term safety and efficacy of embolization of renal arteries (ERA) in patients with polycystic kidney disease (PKD) before renal transplantation.

MATERIAL AND METHODS

Between January 2008 and November 2013, 82 ERA procedures were performed on 76 kidneys in 73 patients (mean age 53 years, range: 34-72). All patients had terminal-stage PKD and were under dialysis and on the renal transplant waiting list with a temporary contraindication due to excessive renal volume.

RESULTS

ERA was considered successful in 89.5% (68/76) of embolized kidneys, meaning that the temporary contraindication for transplantation could be withdrawn for 65 patients (on average 5.6 months, range: 2.8-24.3, after ERA). Mean volume reduction was 40 (range: 2-69) at 3 months and 59% (35-86) thereafter (both p < 0.001). Post-embolization syndrome occurred after 15 of 82 procedures (18.3%). The severe complication rate was 4.9%. Forty-three (67.7%) transplantations were successfully conducted after ERA, with a mean follow-up of 26.2 months (range: 1.8-59.5), and the estimated 5-year graft survival rate was 95.3% [95% CI: 82.7-98.8].

CONCLUSIONS

ERA is a safe and effective alternative to nephrectomy before renal transplantation in patients with PKD.

KEY POINTS

• Embolization of non-functioning polycystic kidneys allowed transplantation in 89.5% of cases. • Technical failure rate was 7.9% after embolization, irrespective of the technique used. • Post-embolization syndrome occurred after 18.3% of the procedures. • A low rate of severe complications (4.9%) was observed after renal embolization.

Negative impact of underlying non-insulin-dependent diabetes mellitus nephropathy on long-term allograft survival in kidney transplantation: a 10-year analysis from a single center

INTRODUCTION

We analyzed the relationship between underlying nephropathy and long-term outcomes in kidney transplant recipients.

METHODS

We retrospectively analyzed data from 678 patients who underwent kidney transplantation (KTx) between 1998 and 2011. Recipients with 13 major nephropathies were evaluated for graft and patient survival, and causes of graft loss.

RESULTS

The best 10-year graft survival rates (100%) were in the patients with autosomal-dominant polycystic kidney disease, preeclampsia, Alport syndrome, and purpura nephritis. The worst rate (50.8%) was in patients with non-insulin-dependent diabetes mellitus nephropathy (NIDDMN; P = .039). Causes of graft-loss in the NIDDM patients included chronic rejection (6 cases), acute rejection (3 cases), infection (2 cases), and cardiovascular event (2 cases). Significant risk factors for graft loss were donor age (P < .01) and NIDDMN (P < .01).

CONCLUSION

Underlying NIDDMN before KTx was a significant risk factor for long-term graft function. Immunologic factors and nonimmunologic factors influenced the long-term outcomes in patients with underlying NIDDMN.

Maximal kidney length predicts need for native nephrectomy in ADPKD patients undergoing renal transplantation

INTRODUCTION

Native nephrectomy in patients with autosomal dominant polycystic kidney disease (ADPKD) is performed on a case-by-case basis. We determine if pre-transplant maximal kidney length (MKL) can be used to predict ultimate nephrectomy status.

METHODS

We performed a retrospective review of ADPKD patients who underwent renal transplantation at our centre between January 2000 and December 2012. Pre-transplant measurements of MKL alone, MKL adjusted for height (HtMKL), weight (WtMKL) and body mass index (BMI-MKL) were each assessed for their predictive ability via a receiver operating characteristic (ROC) curve analysis.

RESULTS

In total, 84 patients met our inclusion criteria, of which 17 (20.2%) underwent native nephrectomy. An MKL ROC curve analysis revealed an area under the curve (AUC) of 0.867 (95% confidence interval [CI] 0.775-0.931; p < 0.001). An optimal cutoff criterion of >21.5 cm revealed a sensitivity of 94.1% (95% CI 71.3-99.9) and specificity of 70.1% (95% CI 57.7-80.7) for eventual nephrectomy. The AUC of HtMKL, WtMKL and BMI-MKL ROC curves did not differ significantly from MKL alone. HtMKL improved specificity, but not overall test performance. The determination of the cut-off MKL may be influenced by the single-centre retrospective nature of this analysis, as well as the fact that renal size was determined by ultrasound and not computerized tomography or magnetic resonance imaging.

CONCLUSION

MKL in patients with ADPKD is associated with the eventual need for nephrectomy and may be a useful clinical tool to risk stratify these patients and therefore guide patient conversations to a decision to leave the native kidneys in situ.

Renal transplantation in autosomal dominant polycystic kidney disease

In patients with autosomal dominant polycystic kidney disease (ADPKD) evaluated for kidney transplantation, issues related to native nephrectomy, cystic liver involvement, screening for intracranial aneurysms and living-related kidney donation deserve special consideration. Prophylactic native nephrectomy is restricted to patients with a history of cyst infection or recurrent haemorrhage or to those in whom space must be made to implant the graft. Patients with liver involvement require pretransplant imaging. Selection of patients for pretransplant screening of intracranial aneurysms should follow the general recommendations for patients with ADPKD. In living related-donor candidates aged <30 years and at-risk of ADPKD, molecular genetic testing should be carried out when ultrasonography and MRI findings are normal or equivocal. After kidney transplantation, patient and graft survival rates are excellent and the volume of native kidneys decreases. However, liver cysts continue to grow and treatment with a somatostatin analogue should be considered in patients with massive cyst involvement. Cerebrovascular events have a marginal effect on post-transplant morbidity and mortality. An increased risk of new-onset diabetes mellitus and nonmelanoma skin cancers has been reported, but several studies have challenged these findings. Finally, no data currently support the preferential use of mammalian target of rapamycin inhibitors as immunosuppressive agents in transplant recipients with ADPKD.