Native Nephrectomy with Renal Transplantation is Associated with a Decrease in Hypertension Medication Requirements for Autosomal Dominant Polycystic Kidney Disease

Native nephrectomy and arterial embolization of native kidney in autosomal dominant polycystic kidney disease patients: indications, timing and postoperative outcomes

INTRODUCTION

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common causes of a need of renal replacement therapy. The need (elective vs. systematic) and timing of native kidney nephrectomy (before, after or during kidney transplantation) is a matter of debate and alternatives to surgery, mainly transcatheter arterial embolization have been explored. We performed a systematic review to report all available evidence on postintervention outcomes of native nephrectomy and arterial embolization in ADPKD patients.

EVIDENCE ACQUISITION

A search on Medline, Embase, and Cochrane databases was performed to identify all studies reporting outcomes of native nephrectomy or arterial embolization in APKDs.

EVIDENCE SYNTHESIS

Concerning native nephrectomy, a total of 3626 patients in 37 studies were included with 735, 210 and 2681 patients who underwent native nephrectomy respectively before, after or during kidney transplantation. Major complications were 12.2% in unilateral nephrectomy before transplantation, 25.0% in bilateral nephrectomy before transplantation, 17.7% in unilateral nephrectomy during transplantation, 20.8% in bilateral nephrectomy during transplantation and 23.8% in unilateral and bilateral nephrectomy after transplantation. A total of 230 patients in 7 series of arterial embolization were included. All arterial embolization were performed before transplantation. Mean volume reduction ranged from 36.3% at 3 months to 49% at 6 months. The major postintervention complication rate was 1%.

CONCLUSIONS

Unilateral native nephrectomy before kidney transplantation was associated with the lowest major postoperative complication rate and appears to be the preferred strategy. Arterial embolization reduces kidney volume by 49% at 6 months. Arterial embolization could be considered when the reduction in size of the native kidney is not urgent.

Contribution of Afferent Renal Nerves to Cystogenesis and Arterial Pressure Regulation in a Preclinical Model of Autosomal Recessive Polycystic Kidney Disease

Polycystic kidney disease (PKD) is the most common inheritable cause of kidney failure, and the underlying mechanisms remain incompletely uncovered. Renal nerves contribute to hypertension and chronic kidney disease - frequent complications of PKD. There is limited evidence that renal nerves may contribute to cardiorenal dysfunction in PKD, and no investigations of the role of sympathetic versus afferent nerves in PKD. Afferent renal nerve activity (ARNA) is elevated in models of renal disease and fibrosis. However, it remains unknown if this is true in PKD. We tested the hypothesis that ARNA is elevated in a preclinical model of autosomal recessive PKD (ARPKD), and that targeted renal nerve ablation would attenuate cystogenesis and cardiorenal dysfunction. We tested this by performing a total (T-RDNx) or afferent (A-RDNx) denervation in 4-week-old male and female PCK rats, then quantifying renal and cardiovascular responses 6 weeks following treatment. Cystogenesis was attenuated with A-RDNx and T-RDNx vs. sham controls, highlighting a crucial role for renal afferent nerves in cystogenesis. In contrast, blood pressure was improved with T-RDNx but not A-RDNx. Importantly, treatments produced similar results in both males and females. Direct renal afferent nerve recordings revealed that ARNA was 2-fold greater in PCK rats vs. non-cystic controls and was directly correlated to cystic severity. To our knowledge, we are the first to demonstrate that PCK rats have greater ARNA than non-cystic, age-matched controls. The findings of these studies support a novel and crucial role for renal afferent innervation in cystogenesis in the PCK rat.

Approach and Management of Hypertension After Kidney Transplantation

Hypertension is one of the most common cardiovascular co-morbidities after successful kidney transplantation. It commonly occurs in patients with other metabolic diseases, such as diabetes mellitus, hyperlipidemia, and obesity. The pathogenesis of post-transplant hypertension is complex and is a result of the interplay between immunological and non-immunological factors. Post-transplant hypertension can be divided into immediate, early, and late post-transplant periods. This classification can help clinicians determine the etiology and provide the appropriate management for these complex patients. Volume overload from intravenous fluid administration is common during the immediate post-transplant period and commonly contributes to hypertension seen early after transplantation. Immunosuppressive medications and donor kidneys are associated with post-transplant hypertension occurring at any time point after transplantation. Transplant renal artery stenosis (TRAS) and obstructive sleep apnea (OSA) are recognized but common and treatable causes of resistant hypertension post-transplantation. During late post-transplant period, chronic renal allograft dysfunction becomes an additional cause of hypertension. As these patients develop more substantial chronic kidney disease affecting their allografts, fibroblast growth factor 23 (FGF23) increases and is associated with increased cardiovascular and all-cause mortality in kidney transplant recipients. The exact relationship between increased FGF23 and post-transplant hypertension remains poorly understood. Blood pressure (BP) targets and management involve both non-pharmacologic and pharmacologic treatment and should be individualized. Until strong evidence in the kidney transplant population exists, a BP of <130/80 mmHg is a reasonable target. Similar to complete renal denervation in non-transplant patients, bilateral native nephrectomy is another treatment option for resistant post-transplant hypertension. Native renal denervation offers promising outcomes for controlling resistant hypertension with no significant procedure-related complications. This review addresses the epidemiology, pathogenesis, and specific etiologies of post-transplant hypertension including TRAS, calcineurin inhibitor effects, OSA, and failed native kidney. The cardiovascular and survival outcomes related to post-transplant hypertension and the utility of 24-h blood pressure monitoring will be briefly discussed. Antihypertensive medications and their mechanism of actions relevant to kidney transplantation will be highlighted. A summary of guidelines from different professional societies for BP targets and antihypertensive medications as well as non-pharmacological interventions, including bilateral native nephrectomy and native renal denervation, will be reviewed.

Superior Hypertension Management in Pediatric Kidney Transplant Patients After Native Nephrectomy

BACKGROUND

Native nephrectomy in pediatric kidney transplant recipients is performed for multiple indications. Posttransplant hypertension requiring medical management is common, and the effect of native nephrectomy on posttransplant hypertension is poorly studied. Our aim is to evaluate the impact of native nephrectomy on posttransplant hypertension.

METHODS

One hundred thirty-six consecutive pediatric kidney transplant recipients from 2007 to 2012 were studied at a single institution and divided into 2 groups: no nephrectomy and native nephrectomy (unilateral and bilateral nephrectomy). Antihypertensive medication use was evaluated before nephrectomy/transplant, at discharge from transplant and at 1, 3, and 5 years posttransplant.

RESULTS

In a bivariate analysis, nephrectomy was associated with a significant reduction in the percentage of patients requiring antihypertensive medication at the time of discharge (27.3%) and 1 year posttransplant (10.7%) as compared with patients without nephrectomy (71.7%, and 50%, respectively, P < 0.05). This trend toward reduction in antihypertensive medication in the nephrectomy group as compared with the no nephrectomy group persisted at 3 (18.6% versus 43.2%) and 5 years (19.7% versus 37.5%) posttransplant. Multivariable logistic regression demonstrated that patients without native nephrectomy had higher odds of requiring antihypertensive medication at the time of discharge (3.3) and 1 year (5.2) as compared with patients who underwent native nephrectomy (P = 0.036 and P = 0.013, respectively).

CONCLUSIONS

Native nephrectomy reduces the odds of needing antihypertensive medication after transplant. The impact of native nephrectomy is crucial to the comprehensive management of pediatric transplant recipients where medication compliance is challenging and lifelong hypertension is known to negatively impact cardiovascular health.

[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.