A new notable compression source of left renal vein entrapment: right renal artery.

PURPOSE: To estimate the incidences of left renal vein (LRV) entrapment by right renal artery (RRA), a phenomenon primarily reported as case reports. METHODS: The cross-sectional study consecutively screened renal vessel CT data of 38 (Renal) patients with nephropathy and 305 (Non-renal) patients with peripheral arterial diseases in a teaching hospital in northeast China between November 2018 and March 2023. The LRV compression by adjacent anatomical structures, including but not limited to RRA and multiple compression-related parameters, were investigated through multiplanar analysis of the CT data. RESULTS: The overall LRV entrapment rates by adjacent structures were 41.93% (12/31) and 24.00% (6/25), the rates of RRA-sourced LRV compression 22.58% (7/31) and 20.00% (5/25), and the rates of compression by superior mesenteric artery (SMA) 16.13% (5/31) and 4.00% (1/25) in the Renal and Non-renal groups, respectively, with no significance. The venous segments distal to the RRA-compressed site had a significantly larger transectional lumen area than those of the non-compressed veins in both groups (3.09 ± 1.29 vs. 1.82 ± 0.23, p < 0.001 and 4.30 ± 2.65 vs. 2.12 ± 0.55, p = 0.006; maximum-to-minimum area ratios in Renal and Non-renal groups, respectively). Nearly 80% of RRAs were found arising anteriorly rightwards instead of passing straight to the right. CONCLUSION: RRA-sourced LRV compression was not rare, and its incidence was higher than that of the compression by SMA in both patient cohorts. RRA could be a more common compression source than SMA concerning LRV entrapment. Further investigations involving different populations, including healthy individuals, are needed.

Transarterial Embolization of Renal Arteriovenous Malformations: Treatment Outcomes According to Angiographic Classification.

PURPOSE: To assess the different adjunctive catheter techniques required to achieve complete occlusion of renal arteriovenous malformations (rAVMs) of different angioarchitectural types. MATERIALS AND METHODS: Overall, data on 18 patients with rAVM (Type 1, n = 7; Type 2, n = 2; Type 3, n = 9; mean age, 53.8 years) who underwent 25 procedures between 2011 and 2022 were reviewed. The clinical presentations, endovascular techniques, arteriovenous malformation (AVM) occlusion rate, adverse events (including the incidence of renal infarction), and clinical symptoms and outcomes (including recurrence/increase of AVM) were analyzed according to the Cho-Do angioarchitectural classification. Posttreatment renal infarction was classified as no infarction, small infarction (<12.5%), medium infarction (12.5%-25%), and large infarction (>25%) using contrast-enhanced computed tomography or magnetic resonance imaging. RESULTS: Hematuria and heart failure were presenting symptoms in 10 and 2 patients, respectively. The embolic materials used were as follows: Type 1 rAVM, coils alone or with n-butyl-2-cyanoacrylate (nBCA); Type 2 rAVM, nBCA alone or with coils; and Type 3 rAVMs, nBCA alone. Fourteen patients underwent adjunctive catheter techniques, including flow control with a balloon catheter and multiple microcatheter placement, alone or in combination. Immediate postprocedural angiography revealed complete occlusion in 15 patients (83%) and marked regression of rAVM in 3 (17%). Small asymptomatic renal infarctions were observed in 6 patients with Type 3 rAVMs without any decrease in renal function. No major adverse events were observed. All symptomatic patients experienced symptom resolution. Recurrence/increase of rAVM was not observed during the mean 32-month follow-up period (range, 2-120 months). CONCLUSIONS: Transarterial embolization using adjunctive catheter techniques according to angioarchitectural types can be an effective treatment for rAVMs.

Orthostatic proteinuria due to inferior vena cava interruption without nutcracker phenomenon in an old obese female: a case report and literature review.

BACKGROUND: Nutcracker syndrome (NCS) caused by left renal vein (LRV) entrapment, is one of the most common causes of orthostatic proteinuria. In stereotype, orthostatic proteinuria is often accompanied by left renal vein obstruction and is found in young and underweight individuals. Here, we report a rare case with orthostatic proteinuria in an old obese female caused by a rare type of congenital inferior vena cava (IVC) interruption. CASE PRESENTATION: A 65-year-old obese woman, who suffered from fluctuated proteinuria, had been misdiagnosed as chronic glomerulitis for 30 years. Instead of having any sign of NCS, she had a unique type of IVC interruption. Most venous blood from infrarenal IVC and right kidney drained into her LRV, and then through the expanded communicating vessel, drained into the left ascending lumbar vein which extended as hemiazygos vein. To the best of our knowledge, this is one of the first cases reported of orthostatic proteinuria attributed to the subsequent hemodynamic irregularity caused by IVC interruption without nutcracker phenomenon. CONCLUSION: Adult-onset orthostatic proteinuria is relatively rare, hard to be recognized and could be misdiagnosed as chronic glomerulonephritis. The case provided a novel differential diagnostic condition for those who suffered from fluctuated proteinuria of unknown causes.

Hypertension Caused by Renal Arteriovenous Fistula with Multiple Renal Artery Aneurysms.

Renal arteriovenous fistula with renal artery aneurysms and dilated renal veins presents as an infrequent lesion. Endovascular therapy has recently been considered the first-line treatment for these conditions. We report a case of a patient with idiopathic renal arteriovenous fistula concomitant with multiple renal artery aneurysms that was successfully treated by the placement of a covered stent.

An Uncommon Variant of Nutcracker Syndrome Secondary to Left Renal Vein Compression Between the Right Renal Artery and The Proper Hepatic Artery.

Nutcracker syndrome refers to the compression of the left renal vein between the abdominal aorta and the superior mesenteric artery. The subsequent venous congestion of the left kidney, when symptomatic, could be associated with left flank pain, hematuria, varicocele, dyspareunia, dysmenorrhea, and proteinuria. Here we describe a 42-year-old female patient with simultaneous Dunbar syndrome and a rare variant of nutcracker syndrome in which the left renal vein (LRV) compression is secondary to the unusual path of the vein between the right renal artery and the proper hepatic artery. For both the nutcracker syndrome and the Dunbar syndrome, open approach by median mini-laparotomic access for transposition of LRV, and resection of the diaphragmatic pillars and arcuate ligament was attempted. During the intervention, due to anatomical issues, the LRV transposition was converted to endovascular stenting of the LRV, moreover the implanted stent was transfixed with an external non-absorbable suture to avoid migration. At the 12 months follow-up the patient was asymptomatic, and the duplex scan confirmed the patency of the celiac trunk without re-stenosis and a correct position of the LRV stent with no proximal or distal migration.

Is a Retroaortic Vein a Risk Factor in Laparoscopic Living Donor Nephrectomy?

INTRODUCTION: In living donor transplantation choosing the right donor and donor side for laparoscopic donor nephrectomy is a challenging task in clinical practice. Knowledge about anomalies in renal blood supply are crucial to evaluate the feasibility of the operative procedure. Few data so far exist whether the existence of a retroaortic left renal vein has an impact on living kidney transplantation outcome for donor and recipient. MATERIALS AND METHODS: We retrospectively analyzed 221 patients who underwent laparoscopic living donor nephrectomy between 2011 and 2017 for existence of a retroaortic left renal vein. Clinical characteristics and operative outcomes for donors and recipients were analyzed. RESULTS: 221 patients underwent donor nephrectomy between 2011 and 2017; 11 patients (4.98%) showed the feature of a retroaortic left renal vein, and in 8 patients (72.7%) out of those 11 the left kidney was chosen for transplantation. Mean preoperative serum creatinine was 0.77 (0.49-0.98) mg/dL and 1.28 (0.97-1.64) mg/dL at discharge. In recipients mean serum creatinine preoperatively, after 1 week, 1 month,1 year, 2 and 3 years of follow-up was 10.36 (6.09-20.77) mg/dL, 1.71 (0.67-2.72), 1.33 (0.70-1.89), 1.31 (0.95-2.13), 1.31 (0.98-2.13) and 1.33 (1.03-1.84), respectively. Neither donors nor recipients suffered from any operative complications. CONCLUSIONS: Laparoscopic living donor nephrectomy of a left kidney with retroaortic renal vein is safe for the donor, without limitation in the outcome for the recipient.

A Case of Right Renal Arteriovenous Malformation Mimicking the Symptoms of Urinary Tract Infection in the Emergency Department.

BACKGROUND: Renal arteriovenous malformation (AVM) is a rare cause of massive hematuria, and patients with renal AVM may present with symptoms like urinary tract infections in the emergency department. CASE REPORT: A 37-year-old woman presented to the emergency department with symptoms of hematuria, urinary hesitancy, and severe suprapubic pain that had been present for a few hours. A urine examination revealed no pyuria, but urine occult blood for 3+ and a red blood cell count of >100 per high-power field. Bedside echocardiography revealed right kidney hydronephrosis and a distended bladder with a blood clot. A 3-way Foley catheter was inserted and drained 800 mL of bloody urine. A contrast-enhanced computed tomography scan was ordered that showed a 1.1-cm hypervascular tumor in the lower pole of right kidney, with active bleeding and rupture into the adjacent collecting system. Active renal tumor bleeding or renal AVM was suspected. The patient was transferred to a tertiary medical center where right renal artery angiography was arranged and disclosed an AVM with aneurysm formation at the right renal lower pole. Transarterial embolization was performed immediately to embolize the 3 feeders of the AVM. WHY SHOULD EMERGENCY PHYSICIANS BE AWARE OF THIS?: Renal AVM is a rare but potentially life-threatening cause of massive hematuria. Delayed or missed diagnosis is possible because renal AVM may present with symptoms like urinary tract infection, especially in young females. Renal artery angiography is the diagnosis of choice, and emergent transarterial embolization is now the standard of treatment.

Efficacy and Safety of Transvenous Embolization of Type II Renal Arteriovenous Malformations with Coils.

PURPOSE: To evaluate the efficacy and safety of transvenous coil embolization of the venous sac for type II renal arteriovenous malformation (AVM). MATERIALS AND METHODS: A retrospective review was conducted of 8 patients (5 women and 3 men; mean age, 57 years; age range, 41-69 years) who underwent transvenous coil embolization for type II congenital renal AVM at 5 different hospitals between 2012 and 2018. Additional intra-arterial ethanol injection was performed if shunt flow persisted after venous sac coiling. Technical success was defined as complete occlusion of shunt flow with coil embolization. Clinical success was defined as no symptom recurrence during the follow-up period. The renal parenchymal infarction rate was measured on computed tomography (CT), and procedure-related complications were reviewed. RESULTS: Nine sessions of embolization were performed for 8 patients. The mean venous sac size was 24 mm (range, 10-39 mm), and a mean of 14 micro and/or micro-detachable coils (range, 3-50) were used. The technical success rate was 88% (7 of 8) using coil embolization. One patient (12%) required additional ethanol injection to complete occlusion of the shunt flow and had a less than 10% parenchymal infarction on follow-up CT. No procedure-related complications or recurrences occurred during a mean clinical follow-up period of 20.8 months (range, 4.7-76.6 months). CONCLUSIONS: Transvenous coil embolization of type II renal AVM showed an 88% technical success rate. One patient (12%) showed less than 10% renal parenchymal infarction after additional ethanol injection. No additional complications or recurrences occurred during the follow-up period.

Embolization of high-output idiopathic renal arteriovenous fistula primarily using an atrial septal defect occluder via venous access: a case report.

BACKGROUND: The case report is to evaluate the efficacy and safety of embolization of a high-output idiopathic renal arteriovenous fistula (IRAVF) with an atrial septal defect occluder (ASDO) via venous access. CASE PRESENTATION: A 57-year-old male diagnosed with high-output IRAVF received embolization with an ASDO via renal venous access and compact occlusion with 3 vascular plugs and a detachable elastic coil. The IRAVF was successfully occluded. After a follow-up of 2 months, renal arterial computed tomography angiography (CTA) showed the precise location of the ASDO. No complications were observed after 2 years' follow-up. CONCLUSIONS: Based on present results, embolization of a high-output IRAVF with an ASDO via venous access might be an efficient and safe method.

Hematuria as the only symptom at initial presentation of hypovolemic shock caused by ruptured renal arteriovenous malformations.

Gross hematuria is a very common complaint in emergency departments and outpatient clinics. Globally, the incidence of hematuria is 4 per 1000 patients per year. Infection, urolithiasis, and neoplasm are the most common etiologies. However, hematuria rarely causes hypovolemic shock or an emergent, life-threatening condition at the initial presentation. In this report, we describe the case of a 64-year-old man who suffered a life-threatening gross hematuria in a very short time due to ruptured renal arteriovenous malformations (AVMs).

Posterior nutcracker syndrome - a systematic review.

Posterior nutcracker syndrome (PNCS) is the entrapment of the left renal vein between the aorta and the vertebral column. Although uncommon, it is still an important diagnosis due to the high morbidity associated with the risk of secondary anaemia from haematuria, from long-term left renal vein hypertension, vascular thrombosis, and even blood clots in the urinary system. A literature search of PubMed and EMBASE databases was performed and 27 publications containing 27 cases were included for the final analysis. The following frequency of clinical signs and symptoms was noted: twenty-five patients had haematuria, 13 patients had flank pain, and two had hypertension. Overall, male-female distribution was balanced and there were more adult than paediatric (age < 18 years) patients. All symptoms of patients with conservative treatment were either well-controlled or under spontaneous resolution. Conservative management instead of surgical treatment should be preferred in most cases. Taken together, despite the low incidence of PNCS, its recognition and management are highly important. This systematic study explores the evidence base for conservative and medical options.

Hepatic encephalopathy secondary to a splenorenal shunt that manifested a long time after a liver transplantation.

Splenorenal shunts are a rare cause of hyperammonemia and hepatic encephalopathy in the absence of cirrhosis. We report the case of a woman, who presented hepatic encephalopathy, with a normal functioning graft, after 14 years of liver transplantation, confirmed by liver biopsy.

[Surgical correction of retroaortic position of the left renal vein]. / Khirurgicheskaia korrektsiia retroaortal'nogo raspolozheniia levoi pochechnoi veny.

Described herein is a variant of surgical reconstruction performed in a male patient with a retroaortic position of the left renal vein by means of creating a vein-allograft-vein configuration. Unfortunately, to date, there are no generally accepted recommendations on proper treatment of patients presenting with similar pathology. A situation wherein it is impossible to create an intervenous anastomosis (because of a significantly altered portion of the vein and prestenotic dilataion) dictates the necessity of searching for new variants of surgical management.

Embolization of Congenital Renal Arteriovenous Malformations Using Ethanol and Coil Depending on Angiographic Types.

PURPOSE: To evaluate effectiveness and safety of embolization of congenital renal arteriovenous malformations (AVMs) using ethanol and/or coil according to angiographic type. MATERIALS AND METHODS: Between August 2010 and October 2015, 11 patients (13 sessions; 10 women and 1 man; mean age, 50.8 y) with congenital renal AVMs were treated using ethanol and/or coils via 2 approaches (transarterial access or direct puncture). Demographics, clinical findings, diagnostic modalities, angiographic types, technical and clinical success rates, and complications were reviewed. Renal AVMs were classified into 3 angiographic types, and treatment was based on this classification. RESULTS: Technical success rate was 91% (10/11), and clinical success rate was 100% (11/11). Of patients, 7 had type III AVMs, 3 had type I AVMs, and 1 had type II AVM. Embolic agents were ethanol in 5 patients, coils with ethanol in 3 patients, and coils in 3 patients. Of the 8 patients treated with ethanol, 6 had infarcted renal areas of 3.5%-30% (mean, 14.6%). After a mean follow-up period of 16.3 months, there was no evidence of recurrent AVMs on imaging or laboratory studies. CONCLUSIONS: Embolization of congenital renal AVMs via transarterial or direct percutaneous approaches using ethanol and/or coils based on a simple angiographic classification was safe and effective and elicited good outcomes. Most of the patients with congenital renal AVMs were women.

Radiologic Assessment of Native Renal Vasculature: A Multimodality Review.

A wide range of clinically important anatomic variants and pathologic conditions may affect the renal vasculature, and radiologists have a pivotal role in the diagnosis and management of these processes. Because many of these entities may not be suspected clinically, renal artery and vein assessment is an essential application of all imaging modalities. An understanding of the normal vascular anatomy is essential for recognizing clinically important anatomic variants. An understanding of the protocols used to optimize imaging modalities also is necessary. Renal artery stenosis is the most common cause of secondary hypertension and is diagnosed by using both direct ultrasonographic (US) findings at the site of stenosis and indirect US findings distal to the stenosis. Fibromuscular dysplasia, while not as common as atherosclerosis, remains an important cause of renal artery hypertension, especially among young female individuals. Fibromuscular dysplasia also predisposes individuals to renal artery aneurysms and dissection. Although most renal artery dissections are extensions of aortic dissections, on rare occasion they occur in isolation. Renal artery aneurysms often are not suspected clinically before imaging, but they can lead to catastrophic outcomes if they are overlooked. Unlike true aneurysms, pseudoaneurysms are typically iatrogenic or posttraumatic. However, multiple small pseudoaneurysms may be seen with underlying vasculitis. Arteriovenous fistulas also are commonly iatrogenic, whereas arteriovenous malformations are developmental (ie, congenital). Both of these conditions involve a prominent feeding artery and draining vein; however, arteriovenous malformations contain a nidus of tangled vessels. Nutcracker syndrome should be suspected when there is distention of the left renal vein with abrupt narrowing as it passes posterior to the superior mesenteric artery. Filling defects in a renal vein can be due to a bland or tumor thrombus. A tumor thrombus is most commonly an extension of renal cell carcinoma. When an enhancing mass is located predominantly within a renal vein, leiomyosarcoma of the renal vein should be suspected. ©RSNA, 2017.

Transarterial embolisation for congenital renal arteriovenous malformations improves clinical condition even with partial obliteration.

AIM: To evaluate the efficacy and safety of transarterial embolisation (TAE), used to treat congenital renal arteriovenous malformations (CRAVMs). MATERIALS AND METHODS: The medical records were searched retrospectively to identify patients who underwent TAE to treat CRAVM from January 2003 to August 2015. Patient demographics, clinical presentations, and imaging findings were reviewed. TAE outcomes, including complete or partial obliteration, clinical success, complications, renal function changes, and relapse of symptoms or signs after the final TAE, were assessed. RESULTS: Over the 12-year period, 16 patients (nine male, seven female; median age, 47 years) who underwent 21 TAE procedures to treat 16 CRAVMs were enrolled in the study. The most common clinical presentation was haematuria (81.3%). Thirteen patients (81.3%) had cirsoid and three (18.7%) had aneurysmal CRAVMs. Of the 16 CRAVMs, 11 (68.8%) were peripheral, four (25%) were central, and one (6.3%) was both peripheral and central. The complete obliteration rate was 56.3%. The clinical success rate was 87.5% over a median follow-up period of 398.5 days. Two (9.5%) major complications and 14 (66.7%) minor complications were encountered. No statistically significant change in renal function was evident after TAE. CONCLUSION: TAE was safe and effective when used to treat CRAVM; the complication profile was acceptable and renal function was preserved. TAE improved the clinical condition of CRAVM patients even when obliteration was only partial.

Renal Arteriovenous Malformations: A Rare Vascular Cause of Back Pain.

BACKGROUND: Renal arteriovenous malformation (AVM) is a very rare phenomenon (fewer than 200 cases in the literature), most commonly (75%) presenting with hematuria in young women. Renal AVMs may be cirsoid (multibranched) or cavernous, with cirsoid morphology predominating 3:1. The historical treatment is partial nephrectomy. Best endovascular therapy is divided among many options. We present 2 cases of large renal AVMs treated with single Amplatzer plugs. METHODS: During a 2-year period (2014-15), 2 patients presented for vascular evaluation of renal AVMs found incidentally on workup for nonspecific abdominal and back pain. Both were the less common cavernous-type AVM. Each noted back pain ipsilateral to the AVM. Neither had a history of trauma or renal procedures. Each underwent angiography and Amplatzer plug placement to occlude flow while preserving parenchyma. RESULTS: Each patient successfully underwent occlusion of the arterial feeding branch of the AVM with immediate angiographic success. Each patient subsequently underwent follow-up imaging that demonstrated absence of filling of the AVM with preservation of healthy renal parenchyma. CONCLUSIONS: Renal AVMs, although very rare, do present to vascular surgeons and may be managed successfully via an endovascular approach with standard techniques. Although renal AVMs are often managed with cyanoacrylate embolization, careful selective arterial catheterization allows for single plug embolization with excellent results and without requiring venous intervention.

Laparoscopic donor nephrectomy in unusual venous anatomy - donor and recepient implications.

OBJECTIVES: Laparoscopic donor nephrectomy is now a commonly performed procedure in most of renal transplantation centers. However, the suitability of laparoscopy for donors with abnormal venous anatomy is still a subject of debate. MATERIALS AND METHODS: Between August 2007 and August 2014, 243 laparoscopic donor nephrectomies were performed in our institution. All donors were evaluated with preoperative three-dimensional spiral computed tomography (CT) angiography Thirteen (5.35%) donors had a left renal vein anomaly. A retrospective analysis was performed to collect donor and recipient demographics and perioperative data. RESULTS: Four donors had a type I retroaortic vein, seven had type II retroaortic vein and a circumaortic vein was seen in three donors. The mean operative time was 114±11 minutes and mean warm ischemia time was 202±12 seconds. The mean blood loss was 52.7±18.4mL and no donor required blood transfusion. Mean recipient creatinine at the time of discharge was 1.15±0.18mg/dL, and creatinine at six months and one year follow-up was 1.12±0.13mg/dL and 1.2±0.14mg/dL, respectively. There were no significant differences in operative time, blood loss, warm ischemia time, donor hospital stay or recipient creatinine at 6 months follow-up, following laparoscopic donor nephrectomy in patients with or without left renal vein anomalies. CONCLUSION: Preoperative delineation of venous anatomy using CT angiography is as important as arterial anatomy. Laparoscopic donor nephrectomy is safe and feasible in patients with retroaortic or circumaortic renal vein with good recipient outcome.

Renal Arteriovenous Shunts: Clinical Features, Imaging Appearance, and Transcatheter Embolization Based on Angioarchitecture.

Renal arteriovenous (AV) shunt, a rare pathologic condition, is divided into two categories, traumatic and nontraumatic, and can cause massive hematuria, retroperitoneal hemorrhage, pain, and high-output heart failure. Although transcatheter embolization is a less-invasive and effective treatment option, it has a potential risk of complications, including renal infarction and pulmonary embolism, and a potential risk of recanalization. The successful embolization of renal AV shunt requires a complete occlusion of the shunted vessel while preventing the migration of embolic materials and preserving normal renal arterial branches, which depends on the selection of adequate techniques and embolic materials for individual cases, based on the etiology and imaging angioarchitecture of the renal AV shunts. A classification of AV malformations in the extremities and body trunk could precisely correspond with the angioarchitecture of the nontraumatic renal AV shunts. The selection of techniques and choice of adequate embolic materials such as coils, vascular plugs, and liquid materials are determined on the basis of cause (eg, traumatic vs nontraumatic), the classification, and some other aspects of the angioarchitecture of renal AV shunts, including the flow and size of the fistulas, multiplicity of the feeders, and endovascular accessibility to the target lesions. Computed tomographic angiography and selective digital subtraction angiography can provide precise information about the angioarchitecture of renal AV shunts before treatment. Color Doppler ultrasonography and time-resolved three-dimensional contrast-enhanced magnetic resonance angiography represent useful tools for screening and follow-up examinations of renal AV shunts after embolization. In this article, the classifications, imaging features, and an endovascular treatment strategy based on the angioarchitecture of renal AV shunts are described.