Management and outcomes of isolated renal artery aneurysms in the endovascular era

Management of renal artery aneurysms: A retrospective study

BACKGROUND

Although renal artery aneurysms (RAAs) are rare and often asymptomatic with slow growth, their natural progression and optimal management are not well understood. Treatment recommendations for RAAs do exist; however, they are supported by limited data.

METHODS

A retrospective cohort study was conducted to explore the management of patients diagnosed with an RAA at our institution from January 1st, 2013, to December 31st, 2020. Patients were identified through a search of our radiological database, followed by a comprehensive chart review for further assessment. Data collection encompassed patient and aneurysm characteristics, the rationale for initial imaging, treatment, surveillance, and all-cause mortality.

RESULTS

One hundred eighty-five patients were diagnosed with or treated for RAAs at our center during this timeframe, with most aneurysms having been discovered incidentally. Average aneurysm size was 1.40 cm (±0.05). Of those treated, the mean size was 2.38 cm (±0.24). Among aneurysms larger than 3 cm in size, comprising 3.24% of the total cases, 83.3% underwent treatment procedures. Only 20% of women of childbearing age received treatment for their aneurysms. There was one instance of aneurysm rupture, with no associated mortality or significant morbidity.

CONCLUSIONS

Our institution's management of RAAs over the period of the study generally aligned with guidelines. One potential area of improvement is more proactive intervention for women of childbearing age.

Visceral Aneurysms: Systematic Review and Meta-analysis of Endovascular Versus Open Repair

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID 348699.

Safety of Patients with Renal Artery Aneurysm to Proceed with Living Donation

BACKGROUND

Renal artery aneurysm (RAA) is a rare condition that involves dilation of all layers of the arterial wall of the renal artery. The risk of rupture is rare, but intervention is recommended for larger aneurysms. Surgical decision-making regarding live donor renal transplantation (LDRT) centers around safety for the living donor, and laterality of the donated kidney is based on providing the donor with the best longevity pertaining to the remaining kidney. We looked to review our long-term outcomes surrounding live donor transplants from donors with RAA with ex vivo resection and reconstruction prior to implantation.

METHODS

A retrospective review was done of all laparoscopic live donor transplant nephrectomies with ex vivo aneurysm resection, reconstruction, and implantation at a single center.

RESULTS

Three pairs of patients underwent successful laparoscopic donor nephrectomy, RAA resection, reconstruction, and transplantation of kidney. 2 males and 1 female ages 47 to 58 years of age underwent transplantation. The donors at 5 years of follow-up were noted to be functioning appropriately with no long-term sequelae of their donation and a mean remanent kidney function of 63 mL/min.

DISCUSSION

For potential live donors with asymptomatic, unilateral renal artery aneurysm and no systemic disease, live donation with ex vivo resection and reconstruction can be performed with excellent long-term donor and recipient outcomes.

An Anatomic Classification Scheme for Surgical Planning of Renal Artery Aneurysms

PURPOSE

Renal artery aneurysm (RAA) is a rare disease. This study proposed and evaluated a new classification for RAA to assist in surgical decision-making.

MATERIALS AND METHODS

Single-center data of 105 patients with RAAs from the vascular department of vascular surgery were collected retrospectively. A new classification scheme was proposed. Type I aneurysms arise from the main trunk, accessory branch, or first-order branches away from any bifurcation. Type II aneurysms arise from the first bifurcation with narrow necks (defined as dome-to-neck ratio >2) or from intralobular branches. Type III aneurysms with a wide neck arise from the first bifurcation and affect 2 or more branches that cannot be sacrificed without significant infarction of the kidney.

RESULTS

There was 50 (47.62%) type I, 33 (31.43%) type II, and 22 (20.95%) type III aneurysms. The classification assigned endovascular repair as first-line treatment (for type I or II), while open techniques were conducted if anatomically suitable (for type III). A kappa level of 0.752 was achieved by the classification compared with a level of 0.579 from the classic Rundback classification. Technical primary success was achieved in 100% and 96.05%, and symptoms were completely resolved in 100% and 84.85%, while hypertension was relieved in 84.21% and 72.92% of patients receiving open surgery or endovascular repair, respectively. No significant difference was observed for perioperative or long-term complications among the 3 classification types.

CONCLUSION

The new classification proved to be a convenient and effective method for facilitating choice of intervention for RAAs.

CLINICAL IMPACT

This study proposed and evaluated a new classification scheme for renal artery aneurysms, which proved to be a convenient and effective method for facilitating surgical decision-making. Coil embolization was the first-line treatment if suitable, while aneurysm resection and reconstruction with vein graft were conducted for some complex lesions. The safety and efficacy of both open and endovascular methods were validated.

Outcomes of endovascular, open surgical and autotransplantation techniques for renal artery aneurysm repair: a systematic review and meta-analysis

BACKGROUND

Renal artery aneurysms (RAA) can be repaired with endovascular exclusion (EVR), open repair (OR), or ex-vivo repair with renal autotransplantation (ERAT). This systematic review compares repair indications, aneurysm characteristics, and complications following these interventions.

METHODS

A systematic review of databases including MEDLINE, PUBMED, and EMBASE by two independent reviewers for studies from January 2000-November 2022. All studies evaluating repair indications, RAA morphology, morbidity and mortality following EVR, OR, and ERAT were included.

RESULTS

A total of 38 studies were included with 1540 EVR, 2377 OR and 109 ERAT subjects. Increasing aneurysm size, or diameters >20 mm, were the most common repair indications across EVR and OR (n = 537; 48%), and ERAT (n = 23; 52%). All ERAT repairs were at or distal to renal artery bifurcations (n = 46). Meta-analyses demonstrated significantly shorter length of stay (LOS) with EVR compared to OR (mean difference -4.06, 95% confidence interval (CI) -5.69 to -2.43, P < 0.001). No significant differences were found in mean aneurysm diameter (P = 0.23), total complications (P = 0.17), and mortality (P = 0.85). Major complications (Clavien-Dindo ≥III) across studies most commonly included acute renal failure (EVR 4.9% vs. OR 7.0%). Nephrectomy was the most common major complication in ERAT (5.5%).

CONCLUSIONS

Outcomes following EVR and OR of RAAs are comparable. EVR offers a shorter LOS, with no difference in morbidity or mortality. ERAT is currently only utilized for distal RAAs, however carries higher risk of infarction and nephrectomy necessitating specialized expertise or algorithms to assist appropriate selection of repair methods.

Laparoscopic nephrectomy, ex vivo renal artery aneurysm repair, and autotransplantation for symptomatic aneurysm with thromboembolism

Renal artery aneurysms involving segmental branches pose a technical challenge to repair. Both endovascular and open repair techniques have been described. This case illustrates the clinical presentation of a patient with a symptomatic renal artery aneurysm with thromboembolic renal infarction managed with laparoscopic nephrectomy, ex vivo aneurysm resection, renal artery reconstruction, and autotransplantation.

Blood pressure and renal outcomes after renal artery aneurysm intervention: Single-center experience and review of literature

Objective

To explore the results of hypertension improvement and renal function preservation after renal artery aneurysm (RAA) repair.

Methods

This study retrospectively analyzed the change in blood pressure (BP) and renal outcomes of 59 RAA patients throughout either open or endovascular operations and follow-up at a large center. Patients were grouped according to the difference in their BP at the last follow-up vs. their baseline value. Logistic regression was conducted to explore risk factors for perioperative BP relief and long-term hypertension reonset. Previous studies of RAA with records of BP, blood creatinine level, or GFR/eGFR results are reviewed.

Results

Hypertension was observed in 62.7% (37/59) of the patients included. Postoperative BP declined from 132.20 ± 16.46/79.92 ± 9.64 mmHg to 122.41 ± 11.17/71.10 ± 9.82 mmHg, while eGFR changed from 108.17 ± 24.73 to 98.92 ± 23.87 ml/min/1.73 m². The median follow-up was 854 [IQR: 1,405] days. Both open and endovascular techniques significantly relieved hypertension and did not impair renal function much. Lower preoperative systolic BP (SBP) was significantly associated with hypertension relief (OR = 0.83, 95% CI: 0.70-0.99). Among patients with normal BP after the operation, higher postoperative SBP was significantly associated with new-onset hypertension (OR = 1.14, 95% CI: 1.01-1.29). Literature review indicated that renal function usually remained normal at follow-up, whereas relief of hypertension varied.

Conclusion

Patients with lower preoperative SBP were likely to benefit more from the operation, while higher postoperative SBP indicated a higher chance of hypertension reonset. Creatinine level and eGFR generally remained stable regardless of operation type.

Eighteen cases of renal aneurysms: Clinical retrospective analysis and experience of endovascular interventional treatment

Background

Development of endovascular interventional techniques gradually replaced traditional open surgery and has become the preferred treatment for renal aneurysms. This study aimed to analyze the clinical characteristics of renal artery aneurysm (RAA) and the safety and efficacy of intravascular interventional treatment.

Materials and Methods

We retrospectively analyzed the clinical characteristics and imaging data of 23 aneurysms in 18 patients with RAA. The technical success rate, complication rate, mortality rate, reintervention rate, and use of embolization materials were evaluated.

Results

In 18 patients with RAA (age, 32-72 years, average age, 52.2 ± 11.2 years), a total of 23 aneurysms were found (diameter 0.5-5.5 cm, average diameter 2.2 ± 1.4 cm). Among them, 11 cases (61.1%) were discovered accidentally, and the remaining patients were diagnosed due to the following major complaints: four cases (22.2%) presented low back pain, two (11.1%) were due to high blood pressure, and one (5.5%) had low back pain with gross hematuria. A total of 14 aneurysms in 13 patients received endovascular interventional therapy. The technical success rate of 13 patients with renal aneurysms was 100%. Three of the 18 patients were lost to follow-up, and the remaining were followed up for 4-89 months. There was no recurrence of the aneurysm or displacement of the stent or coil.

Conclusion

Endovascular treatment for RAA has a high success rate, low complication rate, and low reintervention rate. It has the advantage of less trauma and is flexible and more targeted for different types of renal aneurysms.

Renal Artery Aneurysms in the Inpatient Setting

BACKGROUND

The risk of rupture of renal artery aneurysms (RAAs) remains undefined. A recent paper from the Vascular Low-Frequency Disease Consortium (VLFDC) identified only 3 ruptures in 760 patients. However, over 80% of patients in the VLFDC study were treated at large academic centers, which may not reflect the pattern of care of RAAs nationwide. Thus, the purpose of this study was to evaluate the pattern of nonelective versus elective surgery requiring inpatient admission for RAAs, including nephrectomies, and their outcomes using a national database.

METHODS

The National Inpatient Sample (NIS) database from 2012 to 2018 was utilized. Patients with a primary diagnosis of RAAs were identified using ICD-9 and ICD-10 codes. Ruptured RAAs (rRAAs) were identified utilizing surrogate ICD codes. The primary outcome variables for this study were proportion of RAAs requiring non-elective surgery and in-hospital mortality.

RESULTS

A total of 590 inpatient admissions for RAA were identified with 554 procedures at 467 hospitals across the country. Of the 590 inpatient admissions, 380 (64.4%) admissions were deemed nonelective. There was an increasing proportion of nonelective admissions over the study period. The overall rate of nephrectomies was 7.1% (n = 42). In-hospital mortality rate for the cohort was 1.4% (n = 8) with no differences in in-hospital mortality in the elective versus nonelective setting (1.0% vs. 1.6%; P = 0.718). In the nonelective setting, patients requiring a nephrectomy (n = 23) had significantly higher rates of in-hospital mortality compared those not requiring a nephrectomy (8.7% vs. 1.1%, P = 0.045). rRAA (n = 50) patients had significantly higher in-hospital mortality compared to the remainder of the cohort (6.0% vs. 0.9%, P = 0.024). rRAA patients were also more likely to undergo a nephrectomy compared to the remainder of the cohort (16.0% vs. 6.3%, P = 0.019).

CONCLUSIONS

These data demonstrate that treatment of RAAs are primarily done in the nonelective setting with a high proportion of ruptures, which could continue to rise as the threshold for repair has decreased.

3D-Printed Cold Preservation Device in Renal Autotransplantation for the Treatment of a Patient With Renal Artery Stenosis

Percutaneous transluminal angioplasty (PTRA) is a common treatment method for renal vascular disease (RVD). However, PTRA may not be effective in patients with abnormal vascular disease. Renal autotransplantation (RAT) has been used as an alternative therapy for these diseases. Restrictions due to intracorporeal kidney cold preservation and the renal function of intracorporeal RAT were not as well protected compared with open operation. We developed this technique of 3D-printed polylactide (PLA) cold jackets for laparoscopic complete intracorporeal RAT for the purpose of better protecting the renal function and determining the feasibility of this novel procedure. The procedure was successfully applied to a 51-year-old woman with bilateral renal artery stenosis. The operation time was 5 hours, and blood loss was 200 ml. The patient’s blood pressure remained constant throughout the operation, and the pressure was maintained at 120-140/70–90 mmHg without antihypertensive drugs 1 week after the operation. B-ultrasound showed that the blood flow signal of the transplanted kidney was normal and the boundary between the skin and medulla was clear. The patient was discharged 2 weeks after surgery. One year postoperatively, Doppler ultrasound of the autotransplant showed that the transplanted kidney was normal in size and shape. Radionuclide renal dynamic imaging revealed that the glomerular filtration rate (GFR) of the transplanted kidney was 36.9 ml/min. 3D-printed polylactide (PLA) cold jackets for laparoscopic complete intracorporeal RAT are a safe and effective method for the treatment of renal artery stenosis and represent a feasible method for preserving the renal function of severe renal artery stenosis patients; however, the technology is still at the exploratory stage and has room for further improvements.

Iliac Artery Aneurysms Expand in Quadratically Proportion to the Diameter

BACKGROUND

Iliac artery aneurysms (IAAs) are life-threatening once ruptured. Although some studies have revealed the pathology of IAAs, clinical information on IAAs is still limited. Moreover, previous studies were conducted in Western countries; thus, we aimed to identify the natural history of iliac artery aneurysms in a Japanese cohort. The purpose of this study was to investigate the IAA expansion rate in a Japanese cohort to consider the management of small IAAs and to identify indications for surgical intervention.

METHODS

Patients with iliac artery aneurysms were retrospectively reviewed. The primary outcome was the expansion rate of IAAs. We also investigated the correlation between expansion rate and patients' characteristics. Natural histories, including surgical interventions and rupture, were also assessed.

RESULTS

The mean expansion rate in our study was 1.59 ± 1.16 mm/year. There was a positive correlation between expansion rate and aneurysm diameter, which was estimated by y = 0.0052 × (X - 23.270)² + 0.0632 × X - 0.0517, where y is the expansion rate, and X is aneurysm diameter. The freedom from surgical intervention rate of IAAs was 85.5% at 1 year, 54.0% at 3 years, and 41.5% at 5 years. No factors, except initial aneurysm diameter, were revealed as independent predictors of surgical intervention. We experienced one ruptured IAA, which showed unexpected rapid growth from 30.1 mm to 56.3 mm over 15 months during conservative management. This case demonstrated that IAAs ≥30 mm should be carefully followed up and considered for surgical intervention.

CONCLUSIONS

We conclude that larger aneurysms have greater expansion rates. Because IAAs ≥30 mm carry a risk of rapid expansion resulting in rupture, careful follow-up, and surgical intervention should be performed if iliac artery aneurysms are ≥30 mm in diameter.

Multimodal repair of renal artery aneurysm-10-year single center experience

OBJECTIVES

Renal artery aneurysm (RAA) is a rare disease with various treatment options in indicated patients. In the current survey, the ten-year experience in treatment of RAAs using different endovascular and surgical treatments depending on RAA characteristics is discussed.

METHODS

All patients undergone RAA treatment via endovascular or surgical approaches at our center between January 2010 and December 2020 were enrolled. Patient demographics and peri-operative and late results were collected from a prospectively maintained database.

RESULTS

Eleven patients with RAA underwent treatment as follows: four patients received endovascular approach, four patients underwent in-situ RAA repair, and kidney autotransplantations were carried out in three patients. In all three treatment groups, the first therapeutic attempt was successful and none of the patients underwent secondary intervention due to RAA. Kidney autotransplantation was associated with a higher blood loss and a longer time of procedure compared to that of endovascular approach and in-situ repair. In-hospital postoperative complications were reported in five patients, including renal pole perfusion defect, renal artery thrombosis, and urinary tract infection. No acute kidney organ loss was seen, but one patient suffered from chronic kidney loss due to renal artery occlusion. In one patient undergoing autotransplantation, ureter anastomosis was reported, which led to acute renal failure, and a surgical treatment with resection and reanastomosis of the ureter was necessary. Hypertension was not resolved after RAA repair in any of the patients with preoperative hypertension.

CONCLUSIONS

RAA treatment selection depends on patient characteristics, anatomy, location, and arising branches of the aneurysm. In cases with complex anatomy, treatment strategy could not be just decided based on consensus guidelines, but a multidisciplinary team is required. Interventional therapies showed excellent results in non-complicated proximal aneurysms, especially regarding the length of hospital stay and postoperative morbidities. Open surgery is a complementary alternative in cases where minimally invasive therapy is not possible. Ex-situ repair with autotransplantation could be considered for anatomically complex distal aneurysms.

Renal autotransplantation for the treatment of renal artery aneurysm

OBJECTIVE

Renal artery aneurysms are a rare condition; however, the rate of diagnosis has been increasing, because of the increasing use of complementary diagnostic methods. The best treatment strategy for RAAs remains controversial. Data on ex-vivo surgery associated with kidney autotransplantation are scarce. As a result, the goal of this study was to describe this technique and to report our results.

METHODS

A retrospective monocentric study was undertaken using the clinical records and images of 35 patients diagnosed with renal artery aneurysm from 01/01/2010 to 31/12/2018. Indications for ex vivo surgery and autotransplantation were complex aneurysms with diameter >20 mm or rapid growth or symptomatic aneurysms or women wishing to become pregnant. Complex aneurysms were defined by anatomical criteria (bifurcation of the renal artery and its primary branches or hilar aneurysms) and/or physiological criteria (when time of warm ischemia in in-situ reconstruction is expected to last more than 45 minutes). The technique of ex-vivo surgery and autotransplantation consists of performing a nephrectomy, renal cooling, treatment of aneurysm in banking and implantation of the kidney in the homolateral iliac fossa.

RESULTS

A total of 35 patients with 56 renal artery aneurysms (26 women, mean age 52.4 years-minimum and maximum 16 and 74 years) were included. Of these, 27 were treated by surgery and 8 were followed clinically. Among those treated surgically, 24 performed ex vivo surgery associated with autotransplantation. Regarding ex vivo surgery, nephrectomy was performed by laparoscopic surgery in 24 of the 27 surgeries, the mean surgical time was 5.3 hours, the median warm ischemia time was 4 minutes and the length of hospital stay was 12.2 days. Mortality was 0% and the kidney patency rate was 93% with a follow up of 47.2 months. Of the 17 patients with hypertension, 6 cured it, 4 improved and 7 maintained hypertension.

CONCLUSION

Kidney autotransplantation appears to be efficient for most complex RAA with the possibility to minimize surgical aggression by performing laparoscopic nephrectomy.

Successful Prophylactic Embolization of a Renal Artery Aneurysm During Pregnancy

Renal artery aneurysms (RAA) have an increased risk of rupture during pregnancy with high mortality rates for the mother and fetus. There are many reports on the treatment of ruptured RAA during pregnancy and the Society for Vascular Surgery recommends to prophylactically treat unruptured RAA of any size in women of reproductive age to limit risk of rupture during pregnancy. However, to the best of our knowledge, there is no reported case of prophylactic treatment of unruptured RAA during pregnancy. Here we report the case of a 39-year-old G2P1 who had prophylactic endovascular coiling of an unruptured left RAA during her second trimester of pregnancy. Our case report is the first to demonstrate that unruptured RAA can be safely intervened endovascularly to prevent rupture without disrupting the pregnancy.

Endovascular interventions in management of renal artery aneurysm

Renal artery aneurysm (RAA) is a rare disease. With modern non-invasive imaging modalities, the disease is being increasingly diagnosed. It is a slow-growing aneurysm with high mortality in the event of rupture; especially in pregnant females for in which case patients were treated surgically. With advances in endovascular therapy, numerous techniques have been employed to manage complex RAA in artery bifurcation, branch and segmental arteries with excellent technical and clinical success. The various recent techniques include the use of flow diverter stents, remodelling with stent-assisted coil embolization (SACE), balloon-assisted coil embolization (BACE), selective embolization with coils-sac packing, inflow occlusion and coil trapping and selective embolization with liquid embolic agents-hystroacril and onyx. A combination of stent-graft with liquid embolization and liquid with microcoil embolization has been advocated with success. The most common complication encountered is renal infarction. This is mostly without impairment of renal function and secondary to embolization. Endovascular therapy has shorter operative time, less blood loss, shorter intensive care stay, done under conscious sedation and is associated with lesser postoperative morbidity compared to surgery. Reduction in hypertension, improvement of renal function and symptoms has been seen in most studies. Endovascular management of RAA has become the management of choice even with complex anatomy and technically challenging lesions.

Endovascular coiling in the treatment of patients with renal artery aneurysms

Endovascular coiling is a percutaneous endovascular technique used in the management of arterial aneurysms with high success rates and minimal associated morbidity. We present a series of three patients with incidental renal artery aneurysms treated successfully with endovascular coiling, despite comorbidities. One patient had an aneurysm associated with a solitary kidney. The decision to use this technique becomes critical when the aneurysm involves a single functioning kidney. Each renal artery aneurysm was successfully coiled by combining vascular and neurointerventional techniques. The results from the present case series also highlight the challenges faced in therapeutic decision-making in complex situations with limited error margins.

Packing Technique with or without Remodeling for Endovascular Coil Embolization of Renal Artery Aneurysms: Safety, Efficacy and Mid-Term Outcomes

The endovascular treatment of renal artery aneurysms (RAAs) has lower morbidity and shorter stay lengths compared to surgical repair. Here, we describe coil packing with or without remodeling and assess outcomes and complications. We retrospectively identified the 19 consecutive preventive endovascular RAA coil embolizations done in 18 patients at our center in 2010-2020. Patient and aneurysm characteristics, technical success rate, complications, and recurrences were recorded. Mean patient age was 63 ± 13 years. The RAA was >1.5 cm in 11 cases, and in four cases, the aneurysm-to-parent artery size ratio was >2. Simple coiling was performed for 11 (57.9%) aneurysms, stent-assisted coiling for seven (36.8%) aneurysms, and balloon-assisted coiling for one (5.3%) aneurysm. Technical success rate was 100%. Complete definitive RAA exclusion was achieved with a single procedure for 17 (89.5%) aneurysms, whereas two (10.5%) aneurysms required a repeat procedure. Four minor complications occurred but resolved with no long-term consequences. No major complications occurred during the mean follow-up of 41.1 ± 29.7 months. Coil embolization by sac packing or remodeling proved very safe and effective. Together with the known lower morbidity and shorter stay length compared to open surgery, these data indicate that this endovascular procedure should become the preventive treatment of choice for RAAs.

Repair of renal artery aneurysm with stent angiography and coil embolization

Renal artery aneurysms (RAAs) are rare and are frequently discovered incidentally during the workup for other renal issues. Open surgery has been a popular approach to managing RAAs; however, endovascular techniques have recently emerged as a less invasive option. Endovascular therapy involves stent angiography and coil embolization of the aneurysm. RAA classification (type 1, 2, and 3) is determined by its anatomical location and shape, which has been demonstrated to affect whether an open or an endovascular method is most suitable. We report two patients with type 1 RAAs and a history of hypertension who were successfully repaired endovascularly using VBX stents.

Mid-term Results of Coil Embolization Alone and Stent-assisted Coil Embolization for Renal Artery Aneurysms

BACKGROUND

Coil embolization (CE) alone and stent-assisted coil embolization (SCE) are two major endovascular techniques to treat renal artery aneurysms (RAAs). This study aimed at providing safety and efficacy data of CE and SCE for RAAs.

METHODS

Between August 2015 and June 2019, 40 RAA patients treated with CE or SCE were included in the retrospective study. Patients' demographics, clinical manifestations, aneurysm characteristics, treatment strategies, and follow-up results were collected and analyzed.

RESULTS

There were 26 and 14 patients in the CE and SCE group, respectively. The mean aneurysm diameter was 2.5 ± 1.5 cm and 2.2 ± 0.8 cm (CE versus SCE, P = 0.52). The neck width of the aneurysm was 0.63 ± 0.37 cm and 1.07 ± 0.42 cm (CE versus SCE, P = 0.021). Technical success was achieved in 97.5% patients. No death or aneurysm rupture occurred. During the perioperative period, 12% and 7.1% patients suffered partial renal infarction (CE versus SCE, P = 0.45). The mean duration of follow-up was 8.8 ± 9.4 months and 16.1 ± 16.3 months (CE versus SCE, P = 0.158) by imaging and 20.8 ± 11.3 and 22.7 ± 16.5 months by visit/telephone (CE versus SCE, P = 0.703). During the follow-up, 17.4% patients in the CE group and 30.8% patients in the SCE group suffered partial renal infarction, while their overall renal function remained normal. In addition, there was no aneurysm recurrence, sac enlargement, or death in both groups.

CONCLUSIONS

Both CE and SCE were safe and effective to treat RAAs. In addition, SCE may prevent coil migration in the wide neck aneurysm in selected patients.

Results of Surgical Repair of Hilar Renal Artery Aneurysm to Preserve Renal Blood Flow

Objective: Surgical indications and procedures for hilar renal artery aneurysm (HRAA) are controversial in terms of invasiveness and feasibility. Catheter treatment is minimally invasive but leads to renal dysfunction due to renal infarction. This study aims to investigate the results of surgical repair of HRAA.

Method: Fourteen patients (58.7±11.6 years old, 7 male) who underwent surgical repair of HRAA were retrospectively reviewed. Nine patients (64%) developed HRAA in the right renal artery, and the mean maximum aneurysmal diameter was 25.9±10.3 mm. HRAA was exposed via the extraperitoneal approach. HRAA was resected completely, and reconstruction of renal arteries was performed by direct closure in two, direct anastomosis in nine, and interposition of saphenous vein graft in three patients.

Results: The average operation and renal ischemic times were 186±49 and 35±16 min, respectively. No operative death occurred, and postoperative renal function at the time of discharge had not deteriorated (creatinine, 0.74±0.15 mg/dl). During the follow-up periods (4.7±5.1 years), there was no death, no new introduction of hemodialysis, and no recurrence of renal artery aneurysm.

Conclusion: Surgical repair of HRAA remains a valid option because of its operative safety, preservation of renal function, and long-term feasibility and patency.

Acute renal artery stenting recovered renal function after spontaneous rupture of renal artery aneurysm - case report

Purpose

Renal artery aneurysms (RAAs) are a rare vascular pathology with an estimated prevalence of 0.1% to 2.5%. Rupture of RAA is an extremely unusual cause of acute flank pain and haemodynamic instability with acute kidney failure and high mortality rate (20%).

Case report

A 37-year-old male with no relevant history presented to the Emergency Room with acute right flank pain. Initial examination revealed BP 90/60 mm Hg and tachycardia. Initial blood testing was unremarkable, with a haemoglobin level of 9.4 g/dl. Urinalysis revealed moderate blood. Ultrasound (US) examination depicted aneurysm of the right renal artery 6 x 6 cm, with signs of blood extravasation visible in colour and power Doppler. The patient was referred for urgent computed tomography angiography, which revealed active bleeding from the ruptured aneurysm with haematoma spreading into the right retroperitoneum. He was subjected to emergency endovascular treatment. The patient was treated by successful implantation of a Viabahn stent (GORE, Daleware, USA). Selective nephrography revealed lack of flow through one of the segmental arteries resulting from vasospasm due to the placement of the guiding wire necessary for safe stent implantation.

Conclusions

The authors present a rare case of spontaneous RAA rupture in a young male successfully treated with endovascular methods. Stent implantation required selective catheterisation of segmental arteries of the kidney, which resulted in the loss of one of them. However, control Doppler US disclosed no ischaemia and successful exclusion of the aneurysm.

Ex vivo repair and renal auto-transplantation for treatment of a renal artery aneurysm after endovascular failure

Renal artery aneurysms are rare and typically found incidentally. Risk of rupture drives the incentive for repair, which can be achieved by both open and endovascular techniques. Ex vivo repair with renal auto-transplantation is recommended for complex aneurysms involving distal or multiple arteries. Here we describe a successful treatment of a renal artery aneurysm after previous endovascular treatment failure. A multi-layered stent was left misplaced inside of the aneurysm. Ex vivo repair with renal auto-transplantation allowed for complete aneurysm exclusion. With increasing use of endovascular techniques, failure of endovascular treatment might become a common indication for ex vivo repair in renal artery aneurysms.

Ex vivo revascularization of renal artery aneurysms in a patient with solitary kidney: A case report

BACKGROUND

Multiple renal artery aneurysms (RAAs) involving multiple branches in a solitary kidney are rare and present a major challenge to surgeons. Ex vivo or in situ repair combined with renal artery revascularization is the classical procedure for these complicated cases, which are not suitable for endovascular repair. The choice of bypass graft remains controversial because of the risk of aneurysmal degeneration for autologous graft.

CASE SUMMARY

A 39-year-old female patient presented with left lumbar pain for more than 3 mo. Computed tomography angiography showed congenital absence of the right kidney and three left RAAs involving multiple distal branches. This patient met the criteria for surgical repair due to symptoms of threatened rupture. According to the anatomy and location of multiple RAAs, ex vivo revascularization with saphenous vein graft (SVG) was performed. At the 3-year follow-up, computed tomography angiography demonstrated the aneurysmal degeneration of the Y-shaped SVG. The patient remained asymptomatic and follow-up ultrasound showed no continuous growth of SVG aneurysm.

CONCLUSION

SVG aneurysm in RAA revascularization causes us to reflect on the choice of graft, especially for solitary kidney patients.

Endovascular Treatment of Ruptured Renal Artery Aneurysm: A Case-Based Literature Review

Renal artery aneurysms are extremely uncommon with a reported incidence of less than one percent in general population. They are being more frequently detected due to increasing availability and use of abdominal imaging. Renal artery aneurysm rupture is an extremely unusual cause of acute flank pain with hemodynamic instability. Given the rarity of diagnoses, clinicians may not consider and address this ruptured renal artery aneurysm early which can potentially lead to adverse clinical outcomes. We report the case of a 55-year-old male who presented with retroperitoneal bleeding from a ruptured aneurysm of the interlobular branch of renal artery. He was endovascularly treated with coil embolization. We have also reviewed the inherent literature.

In situ revascularization of bilateral complicated giant renal artery aneurysms: Case report

RATIONALE

Renal artery aneurysm (RAA) is a rare entity, bilateral multiple RAAs near hilum with a maximum diameter of 7 cm are even rare and bring a great challenge to surgeons. As the technique of vessel reconstruction is quite difficult for the RAAs near hilum, some surgeons choose to resect the involved kidney. We reported a young female patient with the threatened rupture symptoms for further treatment. The details of revascularization methods and procedure design were discussed in the report.

PATIENT CONCERNS

A young female patient complained with lumbar and abdominal pain for 1 month. Computed tomography angiography showed bilateral RAAs with the maximum diameter of 6 and 7 cm on the left and right side separately. For the right RAA, apart from a giant aneurysm, there was another small aneurysm with a diameter of 3 cm located on the inferior polar right renal artery. There was a mild tenderness on the left lumbar and lower abdomen, no rebound tenderness was detected.

DIAGNOSIS

According to the image feature and symptoms, the diagnosis for this patient was bilateral giant RAAs with threatened ruptured.

INTERVENTIONS

Dissection of the bilateral giant RAA and in situ revascularization of renal arteries with prosthetic graft was performed.

OUTCOMES

The follow-up results showed the satisfactory patency of prosthetic graft and obvious improvement of renal function.

LESSONS

This complicated bilateral giant RAAs was successfully revascularized through in situ renal artery repair with a very difficult procedure process. For the RAA near hilum, vessel reconstruction no matter through in situ or ex vivo are both difficult for surgeons. This extremely rare and difficult case could bring more confidence to surgeons who meet such complicated bilateral RAAs for choosing the vessel reconstruction rather than kidney resection.

Role of heterotopic kidney auto-transplantation for renal artery aneurysms

To assess the applicability and surgical outcomes of ex vivo repair with heterotopic kidney auto-transplantation (HKA) for the treatment of renal artery aneurysms (RAA).We retrospectively examined 36 cases presenting with RAA from September 2005 to June 2016. Patient demographics, estimated glomerular filtration rate (eGFR), and common vascular risk factors were evaluated. Patients were classified into 3 groups: those who received endovascular treatment, in situ open surgical repair, or ex vivo repair with HKA. The findings were compared among the groups.The endovascular repair, in situ open repair, and ex vivo repair with HKA groups included 14, 9, and 13 patients, respectively (mean follow-up, 30.42 ± 30.54 months). The eGFR (P = .32) and number of anti-hypertension medications (P = .33) did not significantly differ among the groups. Moreover, 3 renal infarctions were detected in the endovascular group and only 1 was detected in the in situ repair group. One patient in the endovascular repair group required dialysis due to renal failure. Patients in the ex vivo repair with HKA group did not exhibit any complications.With safety and effectiveness comparable to other RAA treatment methods, ex vivo repair with HKA for RAA treatment appears suitable particularly in cases with complicated renal artery branch aneurysm and marginal renal function.

Coil embolization of renal artery bifurcation and branch aneurysms with flow preservation

OBJECTIVE

Coil embolization is one of the most common endovascular approaches to treatment of renal artery aneurysms (RAAs). The purpose of this retrospective study was to compare complications, mortality, and morbidity associated with sac packing, coil trapping, and inflow occlusion.

METHODS

The records of all patients with RAAs treated with coil embolization at our center from June 2003 to May 2017 were retrospectively reviewed. Demographics of the patients, aneurysm characteristics, management strategies, perioperative and long-term outcomes, and complications were analyzed.

RESULTS

A total of 52 patient records were reviewed; 28 patients received sac packing and 24 patients underwent coil trapping/inflow occlusion. There was no significant difference in patients' demographics or RAA characteristics between the groups. The mean aneurysm diameter was 25.6 ± 8.4 mm in the sac packing group and 31.1 ± 16.8 mm in the coil trapping/inflow occlusion group (P = .130). Most aneurysms in the sac packing group originated from the main renal artery bifurcation (67.9%), whereas in the coil trapping/inflow occlusion group, most aneurysms originated from the renal segmental branch arteries (54.2%). The immediate technical success rate was 100%, and the in-hospital mortality rate was 0% in both groups. Sac packing was more likely to be associated with endoleak immediately after the procedure (28.6% vs 8.3%; P = .065). The overall perioperative complication rate was not statistically different between the groups (7.1% vs 16.7%; P = .284). The mean duration of follow-up was 37.67 ± 29.84 months and 49.35 ± 28.11 months in the sac packing and coil trapping/inflow occlusion groups, respectively (P = .192). No deaths related to RAAs or aneurysm rupture occurred in either group. The overall morbidity rate was similar between groups (12.5% vs 25%; P = .284). Partial renal infarction occurred in two and five patients in the sac packing and coil trapping/inflow occlusion groups, respectively (8.3% vs 25%; P = .132). Impaired renal function was more frequent after coil trapping/inflow occlusion (0% vs 15%; P = .049). A single patient in the sac packing group required further intervention for reperfusion of the aneurysmal sac at 4 months (4.2% vs 0%; P = .356).

CONCLUSIONS

Sac packing might be a safe and effective way to treat RAAs located at the main bifurcation or in branch arteries and may be preferable to coil trapping/inflow occlusion, considering the potential loss of functional renal mass.

Natural History and Chronological Growth Rate of Renal Artery Aneurysms

Objective: Renal artery aneurysm (RAA) is an uncommon disease, the natural course of which is still not well known. The objective of this study is to define factors that affect the growth rate of RAAs.

Materials and Methods: We retrospectively reviewed 32 aneurysms in 26 patients at our institute between January 2010 and March 2016. Basal demographics, comorbidities, reason for diagnosis, and details of the aneurysms and interventions were recorded. The chronological changes in the diameter of the RAA using multiplanar reconstructions of computed tomography images were measured and analyzed.

Results: The baseline mean diameter was 20.1±8.4 mm (range: 9.9–41). The mean follow-up period was 3.13±2.1 y (range: 0.5–7.1). The median growth rate was 0.35 mm/y (interquartile range: 0.05, 0.62). The growth rate was slower when the initial diameter was <20 mm than when it was >20 mm (p=0.036). Also, whole-completed calcification was a significant factor for slower growth (p=0.016). We performed ex-vivo surgery in two cases and coil packing with stenting in one. No ruptures occurred during the study period.

Conclusion: Our results suggest that cases with an RAA diameter <20 mm do not require intervention. The interval period can be longer in whole-completed calcification types.

Stent-Assisted Coil Embolization of a Symptomatic Renal Artery Aneurysm at a Bifurcation Point

BACKGROUND

Symptomatic renal artery aneurysms at bifurcation points present challenging clinical scenarios rarely amenable to endovascular repair due to concerns regarding parenchymal loss following intervention. Herein, we add to the scant body of literature describing successful endovascular repair of a saccular, symptomatic renal artery aneurysm situated at a bifurcation point.

METHODS

A 52-year-old woman with a 2.5-cm extraparenchymal, saccular, symptomatic left renal artery aneurysm underwent self-expanding stent-assisted detachable platinum microcoil embolization.

RESULTS

Complete aneurysm exclusion was achieved with minimal parenchymal loss. There were no perioperative complications, and no evidence of acute kidney injury perioperatively or at 3-month follow-up. Sustained symptomatic relief was achieved.

CONCLUSIONS

Endovascular therapy can provide safe and effective aneurysm treatment within challenging bifurcated renal artery anatomy.

Manufacture of patient-specific vascular replicas for endovascular simulation using fast, low-cost method

Patient-specific vascular replicas are essential to the simulation of endovascular treatment or for vascular research. The inside of silicone replica is required to be smooth for manipulating interventional devices without resistance. In this report, we demonstrate the fabrication of patient-specific silicone vessels with a low-cost desktop 3D printer. We show that the surface of an acrylonitrile butadiene styrene (ABS) model printed by the 3D printer can be smoothed by a single dipping in ABS solvent in a time-dependent manner, where a short dip has less effect on the shape of the model. The vascular mold is coated with transparent silicone and then the ABS mold is dissolved after the silicone is cured. Interventional devices can pass through the inside of the smoothed silicone vessel with lower pushing force compared to the vessel without smoothing. The material cost and time required to fabricate the silicone vessel is about USD $2 and 24 h, which is much lower than the current fabrication methods. This fast and low-cost method offers the possibility of testing strategies before attempting particularly difficult cases, while improving the training of endovascular therapy, enabling the trialing of new devices, and broadening the scope of vascular research.

Reconstruction for renal artery aneurysms using the tailoring technique

OBJECTIVE

Renal artery (RA) aneurysm (RAA) is a rare and complex disease. Treatment options for a RAA include endovascular surgery and open surgery with ex vivo repair or in situ reconstruction. This study evaluated the long-term outcome after vascular reconstruction of RAAs using the tailoring technique. Tailoring or aneurysmorrhaphy means a partial resection of the aneurysm with direct suture of the remaining arterial wall.

METHODS

A single-center retrospective study was conducted between January 1990 and December 2015. The tailoring technique was used to surgically repair 88 RAAs in 80 patients (52 women) with a mean age of 52.9 years. Patients' demographic data, vascular therapy, and renal function during follow-up were retrospectively evaluated.

RESULTS

The localization of the RAA was at the right kidney in 58 patients. The mean size of the aneurysm was 21.4 ± 9.7 mm (range, 8-67 mm). Hypertension was diagnosed in 56 patients, and 23 were asymptomatic. One RAA was ruptured. The overall morbidity rate was 16.3%, including bleeding (n = 4), RA stenosis (n = 3), RA occlusion (n = 4), RA dissection (n = 1), and myocardial infarction (n = 1). One patient died of myocardial infarction for a 30-day mortality rate of 1.3%. The 30-day primary patency rate was 90.0%. The 30-day secondary patency rate was 95.0%. Follow-up data were obtained from 71 patients who underwent tailoring in 78 RAAs. The mean follow-up period was 60.7 months (range 2-229 months). In 76.4% of patients with RAA and hypertension, RAA reconstruction contributed to the cure or improvement of hypertension. The long-term patency after RAA reconstruction was demonstrated in a Kaplan-Meier curve, with cumulative patency rates of 98.7%, 97.4%, 94.8%, and 92.3% after 18, 24, 36, and 48 months, respectively. Estimated survival rates were 98.8%, 97.5%, and 96.3% after 12, 48, and 60 months, with an estimated mean time of 216.5 ± 7.2 months.

CONCLUSIONS

The tailoring technique is a safe and effective procedure with good long-term outcomes. RAA reconstruction contributed to the cure or improvement of renovascular hypertension.