Autosomal Dominant Polycystic Kidney Disease and Intracranial Aneurysms: Is There an Increased Risk of Treatment?

Autosomal Dominant Polycystic Kidney Disease: Extrarenal Involvement

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disorder, but kidneys are not the only organs involved in this systemic disorder. Individuals with the condition may display additional manifestations beyond the renal system, involving the liver, pancreas, and brain in the context of cystic manifestations, while involving the vascular system, gastrointestinal tract, bones, and cardiac valves in the context of non-cystic manifestations. Despite kidney involvement remaining the main feature of the disease, thanks to longer survival, early diagnosis, and better management of kidney-related problems, a new wave of complications must be faced by clinicians who treated patients with ADPKD. Involvement of the liver represents the most prevalent extrarenal manifestation and has growing importance in the symptom burden and quality of life. Vascular abnormalities are a key factor for patients' life expectancy and there is still debate whether to screen or not to screen all patients. Arterial hypertension is often the earliest onset symptom among ADPKD patients, leading to frequent cardiovascular complications. Although cardiac valvular abnormalities are a frequent complication, they rarely lead to relevant problems in the clinical history of polycystic patients. One of the newest relevant aspects concerns bone disorders that can exert a considerable influence on the clinical course of these patients. This review aims to provide the "state of the art" among the extrarenal manifestation of ADPKD.

Risk Factor Analysis of Complications and Mortality Following Coil Procedures in Patients with Intracranial Unruptured Aneurysms Using a Nationwide Health Insurance Database

(1) Background: Unruptured intracranial aneurysm (UIA) occurs in 1-2% of the population and is being increasingly detected. Patients with UIA are treated with close observation, endovascular coiling or surgical clipping. The proportion of endovascular coiling has been rising. However, complications such as cerebral infarction (CI), intracranial hemorrhage (ICRH), and death remain crucial issues after coil treatment. (2) Methods: We analyzed the incidence and risk factors of complications after the use of coil in patients with UIA based on the patients' characteristics. We utilized the Health Insurance Review and Assessment (HIRA) database. Patients treated with coils for UIA between 1 January 2015 and 1 December 2021 were retrospectively analyzed. (3) Results: Of the total 35,140 patients, 1062 developed ICRH, of whom 87 died, with a mortality rate of 8.2%. Meanwhile, 749 patients developed CI, of whom 29 died, with a mortality rate of 3.9%. The overall mortality rate was 1.8%. In a univariate analysis of the risk factors, older age, males, a higher Charlson Comorbidity Index (CCI) score, and diabetes increase the risk of CI. Meanwhile, males with higher CCI scores and hemiplegia or paraplegia show increased ICRH risk. Older age, males and metastatic solid tumors relate to increased mortality risk. (4) Conclusions: This study is significant in that the complications based on the patient's underlying medical condition were analyzed.

Vascular Complications in Autosomal Dominant Polycystic Kidney Disease: Perspectives, Paradigms, and Current State of Play

Autosomal dominant polycystic kidney disease (ADPKD) is the leading cause of inherited kidney disease with significant contributions to CKD and end-stage kidney disease. The underlying polycystin proteins (PC1 and PC2) have widespread tissue expression and complex functional roles making ADPKD a systemic disease. Vascular complications, particularly intracranial aneurysms (ICA) are the most feared due to their potential for devastating neurological complications and sudden death. Intracranial aneurysms occur in 8-12% of all patients with ADPKD, but the risk is intensified 4-5-fold in those with a positive family history. The basis for this genetic risk is not well understood and could conceivably be due to features of the germline mutation with a significant contribution of other genetic modifiers and/or environmental factors. Here we review what is known about the natural history and genetics of unruptured ICA in ADPKD including the prevalence and risk factors for aneurysm formation and subarachnoid hemorrhage. We discuss two alternative screening strategies and recommend a practical algorithm that targets those at highest risk for ICA with a positive family history for screening.

Characteristics and Distribution of Intracranial Aneurysms in Patients with Autosomal Dominant Polycystic Kidney Disease Compared with the General Population: A Meta-Analysis

Key Points

IAs location distribution in patients with ADPKD differ from the ones in non-ADPKD patients IAs in patients with ADPKD are more commonly located in the anterior circulation and in large caliber arteries Because of IA multiplicity and singular IA distribution, patients with ADPKD represent a special population who need to be closely followed

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic condition associated with intracranial aneurysms (IAs). The associated pathophysiology remains unknown, but an association with wall shear stress is suspected. Cerebral arterial location is the principal factor influencing IA natural history. This study aims to compare IA location-specific distribution between ADPKD and non-ADPKD patients.

Methods

The ADPKD group comprised data from a systematic review of the literature (2016–2020, N =7) and three cohorts: integrated biomedical informatics for the management of cerebral aneurysms, Novosibirsk, and Unruptured Cerebral Aneurysms Study. The non-ADPKD group was formed from the integrated biomedical informatics for the management of cerebral aneurysms, Unruptured Cerebral Aneurysms Study, International Stroke Genetics Consortium, and the Finnish cohort from the literature. Patients and IAs characteristics were compared between ADPKD and non-ADPKD groups, and a meta-analysis for IA locations was performed.

Results

A total of 1184 IAs from patients with ADPKD were compared with 21,040 IAs from non-ADPKD patients. In total, 78.6% of patients with ADPKD had hypertension versus 39.2% of non-ADPKD patients. A total of 32.4% of patients with ADPKD were smokers versus 31.5% of non-ADPKD patients. In total, 30.1% of patients with ADPKD had a positive family history for IA versus 15.8% of the non-ADPKD patients. Patients with ADPKD showed a higher rate of IA multiplicity (33.2% versus 23.1%). IAs from patients with ADPKD showed a significant predominance across the internal carotid and middle cerebral arteries. Posterior communicating IAs were more frequently found in the non-ADPKD group. The meta-analysis confirmed a predominance of IAs in the patients with ADPKD across large caliber arteries (odds ratio [95% confidence interval]: internal carotid artery: 1.90 [1.10 to 3.29]; middle cerebral artery: 1.18 [1.02–1.36]). Small diameter arteries, such as the posterior communicating, were observed more in non-ADPKD patients (0.21 [0.11–0.88]).

Conclusion

This analysis shows that IAs diagnosed in patients with ADPKD are more often localized in large caliber arteries from the anterior circulation in comparison with IAs in non-ADPKD patients. It shows that primary cilia driven wall shear stress vessel remodeling to be more critical in cerebral anterior circulation large caliber arteries.

Should we screen for intracranial aneurysms in children with autosomal dominant polycystic kidney disease?

This is an overview of the challenges associated with screening for asymptomatic intracranial aneurysms (ICA) in children with autosomal dominant polycystic kidney disease (ADPKD). ADPKD is the most common inherited kidney disease affecting 1 in 1,000 people. ICAs are an extra-kidney manifestation of ADPKD, and while the exact pathophysiology of how they develop is unknown, we know that they more commonly occur in the adult rather than paediatric population. ICAs can be found in up to 9-11.5% of adults with ADPKD, but ICA rupture remains a rare event in adults with an incidence of 0.04 per 100 patient years. ICA size is an important factor in determining the risk of aneurysm rupture and therefore affects the decision on intervention in asymptomatic adults. For some, unruptured aneurysms cause no clinical significance, but those that rupture can be associated with devastating morbidity and mortality. Therefore, if detected, the treatment for unruptured ICAs is usually endovascular coiling, alongside recognising the importance of preventative interventions such as hypertension management. There are, however, no current guidelines for either adult or paediatric patients with ADPKD supporting regular screening for asymptomatic ICAs, although there is a suggestion for individualised practice, for example, with those with a positive family history. The UK clinical guidelines for ADPKD in children make research recommendations due to a lack of published literature, which in itself indicates that ICA rupture is an extremely rare phenomenon in children.

A Systematic Review of Reported Outcomes in ADPKD Studies

Introduction

Methods

Results

Conclusion

Consensus document on autosomal dominant polycystic kindey disease from the Spanish Working Group on Inherited Kindey Diseases. Review 2020

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent cause of genetic renal disease and accounts for 6-10% of patients on kidney replacement therapy (KRT). Very few prospective, randomized trials or clinical studies address the diagnosis and management of this relatively frequent disorder. No clinical guidelines are available to date. This is a revised consensus statement from the previous 2014 version, presenting the recommendations of the Spanish Working Group on Inherited Kidney Diseases, which were agreed to following a literature search and discussions. Levels of evidence mostly are C and D according to the Centre for Evidence-Based Medicine (University of Oxford). The recommendations relate to, among other topics, the use of imaging and genetic diagnosis, management of hypertension, pain, cyst infections and bleeding, extra-renal involvement including polycystic liver disease and cranial aneurysms, management of chronic kidney disease (CKD) and KRT and management of children with ADPKD. Recommendations on specific ADPKD therapies are provided as well as the recommendation to assess rapid progression.

KDIGO Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation

The 2020 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation is intended to assist health care professionals worldwide who evaluate and manage potential candidates for deceased or living donor kidney transplantation. This guideline addresses general candidacy issues such as access to transplantation, patient demographic and health status factors, and immunological and psychosocial assessment. The roles of various risk factors and comorbid conditions governing an individual's suitability for transplantation such as adherence, tobacco use, diabetes, obesity, perioperative issues, causes of kidney failure, infections, malignancy, pulmonary disease, cardiac and peripheral arterial disease, neurologic disease, gastrointestinal and liver disease, hematologic disease, and bone and mineral disorder are also addressed. This guideline provides recommendations for evaluation of individual aspects of a candidate's profile such that each risk factor and comorbidity are considered separately. The goal is to assist the clinical team to assimilate all data relevant to an individual, consider this within their local health context, and make an overall judgment on candidacy for transplantation. The guideline development process followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Guideline recommendations are primarily based on systematic reviews of relevant studies and our assessment of the quality of that evidence, and the strengths of recommendations are provided. Limitations of the evidence are discussed with differences from previous guidelines noted and suggestions for future research are also provided.

Cerebral Aneurysms in Autosomal Dominant Polycystic Kidney Disease: A Comparison of Management Approaches

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a risk factor for formation of intracranial aneurysms (IAs), though the ideal screening and treatment strategies in this population are unclear.

OBJECTIVE

To report outcomes of observation, open surgical, or endovascular management of ruptured and unruptured aneurysms in patients with ADPKD.

METHODS

We performed a retrospective analysis of all patients with ADPKD and IAs at a single center from 2000 to 2016.

RESULTS

Forty-five patients with ADPKD harboring 71 aneurysms were identified, including 11 patients with subarachnoid hemorrhage (SAH). Of 22 aneurysms managed with observation, none ruptured in 136 yr of clinical follow-up. Thirty-five aneurysms were treated with open surgery and 14 with an endovascular approach. Among treated aneurysms, poor neurologic outcome (modified Rankin scale >2) was seen only in patients presenting with SAH (17% SAH vs 0% elective, P = .06). Acute kidney injury (AKI) was also significantly associated with SAH presentation (22% SAH vs 0% elective, P = .05). Neither procedural complications nor AKI were associated with treatment modality. Among 175 yr of radiographic follow-up in patients with known IAs, 8 de novo aneurysms were found, including 3 that were treated. Of 11 patients with SAH, 7 ruptured in the setting of previously known ADPKD, including 2 with prior angiographic screening and 5 without screening.

CONCLUSION

Poor outcomes occurred only with ruptured presentation but were equivalent between treatment modalities. Screening is performed only selectively, and 64% (7 of 11) of patients presenting with SAH had previously known ADPKD.

Presymptomatic Screening for Intracranial Aneurysms in Patients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND AND OBJECTIVES

Intracranial aneurysm rupture is the most devastating complication of autosomal dominant polycystic kidney disease. Whether selective or widespread intracranial aneurysm screening is indicated remains controversial.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Records of 3010 patients with autosomal dominant polycystic kidney disease evaluated at the Mayo Clinic between 1989 and 2017 were reviewed. Those who had presymptomatic magnetic resonance angiography screening were included.

RESULTS

Ninety-four intracranial aneurysms were diagnosed in 75 of 812 (9%) patients who underwent magnetic resonance angiography screening. Sex, age, race, and genotype were similar in the groups with and without aneurysms; hypertension and history of smoking were more frequent in the aneurysm group. Twenty-nine percent of patients with aneurysms compared with 11% of those without aneurysms had a family history of subarachnoid hemorrhage (P<0.001). Most aneurysms were small (median diameter =4 mm; range, 2-12 mm); 85% were in the anterior circulation. During a total imaging follow-up of 469 patient-years, de novo intracranial aneurysms were detected in five patients; eight intracranial aneurysms grew (median =2 mm; range, 1-3 mm). During a total clinical follow-up of 668 patient-years, seven patients had preemptive clipping or coil embolization; no intracranial aneurysms ruptured. During a total clinical follow-up of 4783 patient-years in 737 patients with no intracranial aneurysm detected on the first magnetic resonance angiography screening, two patients had an intracranial aneurysm rupture (0.04 per 100 person-years; 95% confidence interval, 0 to 0.10). The rate of intracranial aneurysm rupture in large clinical trials of autosomal dominant polycystic kidney disease was 0.04 per 100 patient-years (95% confidence interval, 0.01 to 0.06).

CONCLUSIONS

Intracranial aneurysms were detected by presymptomatic screening in 9% of patients with autosomal dominant polycystic kidney disease, more frequently in those with familial history of subarachnoid hemorrhage, hypertension, or smoking. None of the patients with and two of the patients without aneurysm detection on screening suffered aneurysmal ruptures. The overall rupture rate in our autosomal dominant polycystic kidney disease cohort was approximately five times higher than that in the general population.

Procedural Clinical Complications, Case-Fatality Risks, and Risk Factors in Endovascular and Neurosurgical Treatment of Unruptured Intracranial Aneurysms: A Systematic Review and Meta-analysis

Importance

The risk of procedural clinical complications and the case-fatality rate (CFR) from preventive treatment of unruptured intracranial aneurysms varies between studies and may depend on treatment modality and risk factors.

Objective

To assess current procedural clinical 30-day complications and the CFR from endovascular treatment (EVT) and neurosurgical treatment (NST) of unruptured intracranial aneurysms and risk factors of clinical complications.

Data Sources

We searched PubMed, Excerpta Medica Database, and the Cochrane Database for studies published between January 1, 2011, and January 1, 2017.

Study Selection

Studies reporting on clinical complications, the CFR, and risk factors, including 50 patients or more undergoing EVT or NST for saccular unruptured intracranial aneurysms after January 1, 2000, were eligible.

Data Extraction and Synthesis

Per treatment modality, we analyzed clinical complication risk and the CFR with mixed-effects logistic regression models for dichotomous data. For studies reporting data on complication risk factors, we obtained risk ratios (RRs) or odds ratios (ORs) with 95% CIs and pooled risk estimates with weighted random-effects models.

Main Outcomes and Measures

Clinical complications within 30 days and the CFR.

Results

We included 114 studies (106 433 patients with 108 263 aneurysms). For EVT (74 studies), the pooled clinical complication risk was 4.96% (95% CI, 4.00%-6.12%), and the CFR was 0.30% (95% CI, 0.20%-0.40%). Factors associated with complications from EVT were female sex (pooled OR, 1.06 [95% CI, 1.01-1.11]), diabetes (OR, 1.81 [95% CI, 1.05-3.13]), hyperlipidemia (OR, 1.76 [95% CI, 1.3-2.37]), cardiac comorbidity (OR, 2.27 [95% CI, 1.53-3.37]), wide aneurysm neck (>4 mm or dome-to-neck ratio >1.5; OR, 1.71 [95% CI, 1.38-2.11]), posterior circulation aneurysm (OR, 1.42 [95% CI, 1.15-1.74]), stent-assisted coiling (OR, 1.82 [95% CI, 1.16-2.85]), and stenting (OR, 3.43 [95% CI, 1.45-8.09]). For NST (54 studies), the pooled complication risk was 8.34% (95% CI, 6.25%-11.10%) and the CFR was 0.10% (95% CI, 0.00%-0.20%). Factors associated with complications from NST were age (OR per year increase, 1.02 [95% CI, 1.01-1.02]), female sex (OR, 0.43 [95% CI, 0.32-0.85]), coagulopathy (OR, 2.14 [95% CI, 1.13-4.06]), use of anticoagulation (OR, 6.36 [95% CI, 2.55-15.85]), smoking (OR, 1.95 [95% CI, 1.36-2.79]), hypertension (OR, 1.45 [95% CI, 1.03-2.03]), diabetes (OR, 2.38 [95% CI, 1.54-3.67]), congestive heart failure (OR, 2.71 [95% CI, 1.57-4.69]), posterior aneurysm location (OR, 7.25 [95% CI, 3.70-14.20]), and aneurysm calcification (OR, 2.89 [95% CI, 1.35-6.18]).

Conclusions and Relevance

This study identifies risk factors for procedural complications. Large data sets with individual patient data are needed to develop and validate prediction scores for absolute complication risks and CFRs from EVT and NST modalities.

MR Angiography Screening and Surveillance for Intracranial Aneurysms in Autosomal Dominant Polycystic Kidney Disease: A Cost-effectiveness Analysis

Background Autosomal dominant polycystic kidney disease (ADPKD) affects one in 400 to one in 1000 individuals; 10%-11% of these individuals have intracranial aneurysms. The frequency and patterns of screening for intracranial aneurysms have not been defined. Purpose To evaluate different MR angiography screening and surveillance strategies for unruptured intracranial aneurysms in patients with ADPKD. Materials and Methods A Markov decision-analytic model was constructed accounting for both costs and outcomes from a societal perspective. Five different management strategies were evaluated: (a) no screening for intracranial aneurysm, (b) one-time screening with annual MR angiography follow-up in patients with intracranial aneurysm, (c) MR angiographic screening every 5 years with endovascular treatment in detected intracranial aneurysm, (d) MR angiography screening every 5 years with annual MR angiography follow-up in patients with intracranial aneurysm, and (e) MR angiography screening every 5 years with biennial follow-up in patients with intracranial aneurysm. One-way, two-way, and probabilistic sensitivity analyses were performed. Results Base case calculation shows that MR angiography screening of patients with ADPKD every 5 years and annual follow-up in patients with detected intracranial aneurysm is the optimal strategy (cost, $19 839; utility, 25.86 quality-adjusted life years), which becomes more favorable as the life expectancy increases beyond 6 years. The conclusion remains robust in probabilistic and one-way sensitivity analyses. When the prevalence of intracranial aneurysms is greater than 10%, annual rupture risk is 0.35%-2.5%, and the rate of de novo aneurysm detection is lower than 1.8%, MR angiography screening every 5 years with annual MR angiography follow-up is the favorable strategy. Conclusion Screening for intracranial aneurysms with MR angiography in patients with autosomal dominant polycystic kidney disease is cost-effective. Repeat screening every 5 years should be performed after a negative initial study. Annual surveillance MR angiography is optimal in patients with detected, incidental intracranial aneurysm, and treatment may be considered in patients with growing, high-risk aneurysms. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Anzai in this issue.

Polycystic kidney disease

Cystic kidneys are common causes of end-stage renal disease, both in children and in adults. Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are cilia-related disorders and the two main forms of monogenic cystic kidney diseases. ADPKD is a common disease that mostly presents in adults, whereas ARPKD is a rarer and often more severe form of polycystic kidney disease (PKD) that usually presents perinatally or in early childhood. Cell biological and clinical research approaches have expanded our knowledge of the pathogenesis of ADPKD and ARPKD and revealed some mechanistic overlap between them. A reduced 'dosage' of PKD proteins is thought to disturb cell homeostasis and converging signalling pathways, such as Ca²⁺, cAMP, mechanistic target of rapamycin, WNT, vascular endothelial growth factor and Hippo signalling, and could explain the more severe clinical course in some patients with PKD. Genetic diagnosis might benefit families and improve the clinical management of patients, which might be enhanced even further with emerging therapeutic options. However, many important questions about the pathogenesis of PKD remain. In this Primer, we provide an overview of the current knowledge of PKD and its treatment.

A Large Database Analysis of Rates of Aneurysm Screening, Elective Treatment, and Subarachnoid Hemorrhage in Patients With Polycystic Kidney Disease

BACKGROUND

Professional societies provide conflicting guidelines on aneurysm screening in patients with polycystic kidney disease (PKD), and the rate of subarachnoid hemorrhage (SAH) is poorly understood.

OBJECTIVE

To evaluate screening, elective treatment, and the rate of SAH in patients with known PKD.

METHODS

We examined longitudinally linked claims data from a large private insurer, identifying screening, elective treatment, aneurysmal subarachnoid hemorrhage (aSAH) and secured aneurysmal SAH (saSAH) in 2004 to 2014 amongst patients with known PKD.

RESULTS

We identified 20 704 patients diagnosed with PKD. Among patients with an initial PKD diagnosis, 51/446 (15.9%) underwent angiographic screening within 2 yr. Forty aneurysms were treated electively in 48 868 yr at risk in PKD patients (82/100K patient yr, 95% confidence interval [CI] 60-112) vs 24 elective treatments in 349 861 yr at risk in age- and sex-matched controls (7/100K patient yr, 95% CI 5-10, P < .0001). Eleven admissions for aSAH were identified in PKD patients (23/100K patient yr, 95% CI 13-41) and 22 admissions for aSAH in controls (6/100K patient yr, 95% CI 4-10), giving an incidence rate ratio (IRR) of 3.6 (95% CI 1.7-7.4, P < .0001) and a comorbidity-adjusted IRR of 3.1 (95% CI 1.4-6.9). The incidence of saSAH was proportionally even higher in PKD patients than controls, 16 vs 2/100K patient years, IRR 9.5 (95% CI 3.3-27.5, P < .0001).

CONCLUSION

Screening in PKD is performed only selectively, though resulting rates of elective treatment were over 10× those of controls. Despite screening and treatment, the rate of SAH remains significantly elevated over that of controls.

Canonical Wnt inhibitors ameliorate cystogenesis in a mouse ortholog of human ADPKD

Autosomal dominant polycystic kidney disease (ADPKD) can be caused by mutations in the PKD1 or PKD2 genes. The PKD1 gene product is a Wnt cell-surface receptor. We previously showed that a lack of the PKD2 gene product, PC2, increases β-catenin signaling in mouse embryonic fibroblasts, kidney renal epithelia, and isolated renal collecting duct cells. However, it remains unclear whether β-catenin signaling plays a role in polycystic kidney disease phenotypes or if a Wnt inhibitor can halt cyst formation in ADPKD disease models. Here, using genetic and pharmacologic approaches, we demonstrated that the elevated β-catenin signaling caused by PC2 deficiency contributes significantly to disease phenotypes in a mouse ortholog of human ADPKD. Pharmacologically inhibiting β-catenin stability or the production of mature Wnt protein, or genetically reducing the expression of Ctnnb1 (which encodes β-catenin), suppressed the formation of renal cysts, improved renal function, and extended survival in ADPKD mice. Our study clearly demonstrates the importance of β-catenin signaling in disease phenotypes associated with Pkd2 mutation. It also describes the effects of two Wnt inhibitors, XAV939 and LGK974, on various Wnt signaling targets as a potential therapeutic modality for ADPKD, for which there is currently no effective therapy.

Screening for intracranial aneurysms in autosomal dominant polycystic kidney disease is cost-effective

Intracranial aneurysm rupture is a dramatic complication of autosomal dominant polycystic kidney disease (ADPKD). It remains uncertain whether screening should be widespread or only target patients with risk factors (personal or familial history of intracranial aneurysm), with an at-risk profession, or those who request screening. We evaluated this in a single-center cohort of 495 consecutive patients with ADPKD submitted to targeted intracranial aneurysm screening. Cerebral magnetic resonance angiography was proposed to 110 patients with a familial history of intracranial aneurysm (group 1), whereas it was not our intention to propose it to 385 patients without familial risk (group 2). Magnetic resonance angiography results, intracranial aneurysm prophylactic repair, rupture events, and cost-effectiveness of intracranial aneurysm screening strategies were retrospectively analyzed. During a median follow up of 5.9 years, five non-fatal intracranial aneurysm ruptures occurred (incidence rate 2.0 (0.87-4.6)/1000 patients-year). In group 1, 90% of patients were screened and an intracranial aneurysm was detected in 14, treated preventively in five, and ruptured in one patient despite surveillance. In group 2, 21% of patients were screened and an intracranial aneurysm was detected in five, and treated preventively in one. Intracranial aneurysm rupture occurred in four patients in group 2. Systematic screening was deemed cost-effective and provides a gain of 0.68 quality-adjusted life years compared to targeted screening. Thus, the intracranial aneurysm rupture rate is high in ADPKD despite targeted screening, and involves mostly patients without familial risk factors. Hence, cost-utility analysis suggests that intracranial aneurysm screening could be proposed to all ADPKD patients.

Natural history of intracranial aneurysms in autosomal dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease (ADPKD) is a relatively frequent genetic disorder that is associated with increased prevalence of intracranial aneurysms (IAs). However, evidence on the natural history of IAs in ADPKD is suboptimal. That leads to difficulties in development of recommendations on surveillance on patients with IAs in their medical history, or the need for repeat imaging for IAs in those with a negative result of the initial screening. The aim of the article is to present our experience on the natural history of IAs in ADPKD patients.

MATERIAL AND METHODS

Thirty-four ADPKD patients, managed at our outpatient department, with imaging for intracranial aneurysms performed at least twice, were included into present retrospective analysis.

RESULTS

Among 8 patients with an IA in their medical history, no new IA was observed during 93 patient-years of follow-up. In 6 patients with untreated, unruptured IAs, IA growth was observed in 2 cases during 32 patient-years of follow-up. Finally, among 20 patients with a negative result of initial screening, 2 new IAs were noticed during 115 patient-years of follow-up, including 1 patient with a positive family history for an IA, and 1 patient without a family history.

CONCLUSIONS

Our observations support repeat imaging for IAs in patients with ADPKD, positive family history of IA, and negative result of initial screening. Additionally, efforts should be made to develop clinical and/or laboratory risk factors for IAs development in ADPKD patients without family history of IA, which enable to identify patients who should undergo repeat imaging for IAs.

[Screening and management of intracranial aneurisms in patients with autosomal dominant polycystic kidney disease]

Autosomal dominant polycystic kidney disease is the most frequent hereditary kidney disease. Intracranial aneurysm prevalence in this population is four to five times higher than the prevalence in the general population. The most frequent complication of intracranial aneurysms is rupture with subarachnoidal hemorrhage, which is associated with a high morbidity and mortality. The only identified risk factor for unruptured intracranial aneurysm is a family history of intracranial aneurysm. However, most cases of aneurysm rupture occur without any family history of intracranial aneurysm. Magnetic resonance angiography without contrast medium injection facilitates screening, and progress have been made in preventive (endovascular or neurosurgical) treatment of intracranial aneurysm. Recommendations have recently been published concerning intracranial aneurysm screening, and suggest screening patients with autosomal dominant polycystic kidney disease and a family history of intracranial aneurysm, those who have an at-risk activity and those who request screening despite adequate information. Conflicting opinions exist, however, in the literature. Furthermore, a study of practice was conducted among French-speaking nephrologists in Europe and showed that approximately a third of the participants were in favor of systematic screening for intracranial aneurysm in all patients with autosomal dominant polycystic kidney disease. Beyond intracranial aneurysm prevalence, it is necessary to better define rupture rates in the autosomal dominant polycystic kidney disease population, with and without familial history of intracranial aneurysm. This would allow optimizing intracranial aneurysm screening practices in autosomal dominant polycystic kidney disease.

Intracranial aneurysms in patients with autosomal dominant polycystic kidney disease: prevalence, risk of rupture, and management. A systematic review

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder associated with high incidences of intracranial aneurysms. We performed a systematic review with the purpose of clarifying the prevalence, risk of rupture, and appropriate management of intracranial aneurysms in the ADPKD population.

METHOD

PRISMA guidelines were followed. We conducted a comprehensive literature search of three databases (PubMed, Ovid MEDLINE, and Ovid EMBASE) on all series reporting ADPKD patients with intracranial aneurysms.

RESULTS

Our systematic review included 16 articles with a total of 563 patients with ADPKD and intracranial aneurysms. The prevalence of unruptured aneurysms was 11.5% (95% CI = 10.1-13%), whereas 1.9% (95% CI = 1.3-2.6%) of aneurysms were ruptured. Hypertension was present in 79.3% of patients with ADPKD and renal impairment in 65%. The mean size of ruptured aneurysms was slightly higher than unruptured (6 mm vs. 4.4 mm). The most common locations of unruptured and ruptured aneurysms were the ICA (40.5%) and MCA (45%), respectively. Asymptomatic patients studied with four-vessel angiography experienced 25% transient complications. Overall, 74% unruptured aneurysms were surgically treated with lower complication rates compared to endovascular treatment (11% vs. 27.7%). Among conservatively treated aneurysms, 2.9% ruptured at follow-up (rupture rate 0.4%/patient-year). Finally, the growth rate was 0.4% per patient-year, and the incidence of de novo aneurysm formation was 1.4% per patient-year.

CONCLUSIONS

The prevalence of unruptured intracranial aneurysms in the ADPKD population is approximately 11%. Given the non-negligible rate of procedural complications, the management of these patients must be cautious and individualised. The rupture rate appears comparable to that of the general population. On the other hand, the 1.4% rate per patient-year of de novo aneurysms is non-negligible. These findings should be considered when counselling ADPKD patients regarding the appropriate management of intracranial aneurysms.

Rapamycin treatment dose-dependently improves the cystic kidney in a new ADPKD mouse model via the mTORC1 and cell-cycle-associated CDK1/cyclin axis

Although translational research into autosomal dominant polycystic kidney disease (ADPKD) and its pathogenesis has made considerable progress, there is presently lack of standardized animal model for preclinical trials. In this study, we developed an orthologous mouse model of human ADPKD by cross‐mating Pkd2 conditional‐knockout mice (Pkd2^f3) to Cre transgenic mice in which Cre is driven by a spectrum of kidney‐related promoters. By systematically characterizing the mouse model, we found that Pkd2^f3/f3 mice with a Cre transgene driven by the mouse villin‐1 promoter (Vil‐Cre;Pkd2^f3/f3) develop overt cysts in the kidney, liver and pancreas and die of end‐stage renal disease (ESRD) at 4–6 months of age. To determine whether these Vil‐Cre;Pkd2^f3/f3 mice were suitable for preclinical trials, we treated the mice with the high‐dose mammalian target of rapamycin (mTOR) inhibitor rapamycin. High‐dose rapamycin significantly increased the lifespan, lowered the cystic index and kidney/body weight ratio and improved renal function in Vil‐Cre;Pkd2^f3/f3 mice in a time‐ and dose‐dependent manner. In addition, we further found that rapamycin arrested aberrant epithelial‐cell proliferation in the ADPKD kidney by down‐regulating the cell‐cycle‐associated cyclin‐dependent kinase 1 (CDK1) and cyclins, namely cyclin A, cyclin B, cyclin D1 and cyclin E, demonstrating a direct link between mTOR signalling changes and the polycystin‐2 dysfunction in cystogenesis. Our newly developed ADPKD model provides a practical platform for translating in vivo preclinical results into ADPKD therapies. The newly defined molecular mechanism by which rapamycin suppresses proliferation via inhibiting abnormally elevated CDK1 and cyclins offers clues to new molecular targets for ADPKD treatment.

Prevalence of Intracranial Aneurysms in Patients with Aortic Aneurysms

BACKGROUND AND PURPOSE

Previous studies have suggested an association between aortic aneurysms and intracranial aneurysms with a higher prevalence of intracranial aneurysms in patients with aortic aneurysms. The aims of the present study were to evaluate the incidence of intracranial aneurysms in a large cohort of patients with aortic aneurysms and to identify potential risk factors for intracranial aneurysms in this population.

MATERIALS AND METHODS

We included all patients with aortic aneurysms (either abdominal and/or thoracic) who had available cerebral arterial imaging and were seen at our institution during a 15-year period. We identified patients with intracranial aneurysms. Patient demographics, comorbidities, and aortic aneurysm and intracranial aneurysm sizes and locations were analyzed. Univariate analysis was performed with a χ(2) test for categoric variables and a Student t test or ANOVA for continuous variables.

RESULTS

A total of 1081 patients with aortic aneurysms were included. Of them, 440 (40.7%) had abdominal aortic aneurysms, 446 (41.3%) had thoracic aortic aneurysms, and 195 (18.0%) had both abdominal aortic and thoracic aortic aneurysms. The overall prevalence of associated intracranial aneurysms in patients with aortic aneurysms was 11.8% (128/1081), with 12.7% (56/440), 10.8% (48/446), and 12.3% (24/195), respectively, in patients with abdominal aortic aneurysms, thoracic aortic aneurysms, and both thoracic aortic aneurysms and abdominal aortic aneurysms. Female patients had a higher risk of associated intracranial aneurysms (OR = 2.08; 95% CI, 1.49-3.03; P = .0002). There was a slight association between abdominal aortic aneurysm size and the prevalence of intracranial aneurysms (OR = 1.02; 95% CI, 1.01-1.03; P = .045). There was no significant association between the locations of the aortic and intracranial aneurysms (P = .93).

CONCLUSIONS

The prevalence of intracranial aneurysms is high in patients with aortic aneurysms. Further studies examining the role and cost-effectiveness of intracranial aneurysm screening in patients are warranted.