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.

Treatment of Nutcracker Syndrome with Left Renal Vein Transposition and Endovascular Stenting.

BACKGROUND: Nutcracker syndrome is a rare condition that occurs as a result of the entrapment of the left renal vein (LRV) between the aorta and the superior mesenteric artery. It is typically associated with symptoms such as left flank pain, hematuria, proteinuria, and pelvic congestion. The current treatment approach may be conservative in the presence of tolerable symptoms, and surgical or hybrid and stenting procedures in the order of priority in the presence of intolerable symptoms. The aim of this study is to review our experiences to evaluate the results of both methods in this series in which we have a greater tendency toward surgery instead of stenting. METHODS: The clinical data of consecutive patients with nutcracker syndrome who underwent LRV transposition and LRV stenting between July 2019 and October 2023 were retrospectively reviewed. The patients were divided into 2 groups based on the methods of treatment: surgical and stenting. For procedure selection, LRV transposition was primarily recommended, with stenting offered to those who declined. Primary end points were morbidity and mortality. Secondary end points included late complications, patency, freedom from reintervention, and resolution of symptoms. Standard basic statistics and survival analysis methods were employed. RESULTS: Nineteen patients with nutcracker syndrome (female: 100%) were treated with LRV stentings (n = 5) and LRV transposition (n = 14). The mean age was 24 (20-27, interquartile range [IQR]) years. The mean follow-up was 23 (9-32, IQR) months. There were no major complications and mortality after both procedures. The most frequent sign and symptom associated with LRV entrapment were left flank pain 100% (n = 19), proteinuria 88% (n = 15), and hematuria 47% (n = 9). The mean peak velocity ratio on Doppler ultrasound was 6.13 (6-6.44, IQR). Aortomesenteric angle, beak angle (beak sign), and mean diameter ratio on computed tomography were 26° (22.6-28.5, IQR), 25° (23.9-28, IQR), and 5.3 (5-6, IQR), respectively. Venous pressure measurements were only used to confirm the diagnosis in 5 patients in the stenting group. The measured renocaval gradient was 4 (3.9-4.4, IQR) mm Hg. After both procedures, the classical symptoms, including left flank pain, proteinuria, and hematuria, resolved in 89.5% (n = 17), 57.8% (n = 11), and 82.3% (n = 15) of the cases, respectively. A total of 4 patients required reintervention, 3 patients after LRV transposition (occlusion, n = 2; stenosis, n = 1), and 1 patient after stenting (occlusion, n = 1). The 1-year and 3-year primary patency for the 19 patients was 87% and 80%, respectively. Three-year primary-assisted patency was 100%. Similarly, the 1-year and 3-year freedom from reintervention rate was 83% and 72%, respectively. Additionally, the 1-year and 3-year primary patency for the surgical group was 91% and 81%, respectively, and the 1-year and 3-year primary patency for the stenting group was 75%. CONCLUSIONS: Nutcracker syndrome should be kept in mind in cases where flank pain and hematuria cannot be associated with kidney diseases. Radiographic evidence must be accompanied by serious symptoms to initiate the treatment of nutcracker syndrome with LRV transposition and endovascular stenting procedures. Both procedures, along with their respective advantages and disadvantages, can be preferred as primary treatments for nutcracker syndrome. Our study demonstrates that both procedures can be safely and effectively performed, yielding good outcomes.

Pre-operative colour Doppler ultrasound for the prevention of bleeding complications after renal biopsy: A rare case of left renal lower pole vein.

Albeit rare, renal vein abnormalities on autopsy and in cases of abdominal surgery complications have been reported and should be kept in mind when performing invasive procedures, such as renal biopsy. We detected a rare renal vein abnormality on colour Doppler ultrasound before renal biopsy, thereby, avoiding a haemorrhagic complication. A 10-year-old boy presented to our department for the first time because of incidental findings of haematuria and proteinuria. We suspected chronic glomerulonephritis and scheduled an ultrasound-guided percutaneous renal biopsy. A simple screening ultrasound at the initial visit revealed no renal or vascular abnormalities. The day before the renal biopsy, we confirmed the biopsy site by performing a colour Doppler ultrasound, which showed abnormal blood flow from the lower pole of the left kidney, which was the planned puncture site; therefore, we changed the biopsy site to the right and completed the examination. Subsequent computed tomography angiography depicted two renal veins; one was the usual left renal vein draining from the kidney hilum, and the second was an accessory vein draining from the inferior pole of the left kidney and entering the inferior vena cava through the dorsal side of the aorta. Although rare, abnormalities in the renal vessels on the inferior pole of the kidney, which is the usual site of renal biopsy, are essential to rule out preoperatively by colour Doppler ultrasound, because these can cause significant bleeding during renal biopsy if not recognized.

Doppler Ultrasound of the Renal Vasculature.

Ultrasound is the first-line imaging modality used in patients with suspected renovascular disease. Common indications include renovascular hypertension and unexplained renal dysfunction. We review the ultrasound imaging findings of various pathologies involving the renal vessels, including the renal arteries (atherosclerotic stenosis, fibromuscular dysplasia, dissection, arteriovenous fistula, and aneurysm) and veins (tumor and bland thrombus as well as vascular compression syndromes). The current role of renal artery stent placement for atherosclerotic stenosis is also discussed.

Postpartum ovarian vein thrombosis with left renal venous infarction after vaginal delivery.

A primipara in her late 20s presented with abdominal pain and pain in the left flank 14 days after a ventouse delivery. She was treated with antibiotics, antiemetics and analgesics with the initial differential diagnosis of cystitis, pyelonephritis or nephrolithiasis. Despite the treatment, the patient experienced increased colic pain and nausea. An ultrasound showed an enlarged left kidney, suggesting pyelonephritis, and thereby, the antibiotic treatment was adjusted accordingly. Despite additional pain medication, pain relief could not be achieved. The diagnosis of ovarian venous thrombosis was considered, and an abdominal CT scan confirmed the diagnosis. The patient was treated with anticoagulant therapy. Hypercoagulability work-up revealed a heterozygous mutation of the Factor V Leiden. Our patient awaits a haematologic follow-up.

Migration of sclerosant material to the left renal vein following coil embolisation of a varicocele.

Percutaneous testicular varicocele embolisation for symptomatic and subfertile males is often preferred over surgical ligation of the gonadal vein due to its minimally invasive approach and reduced complication rate. Glues, coils, vascular plugs, balloons and sclerosants are used in various combinations to achieve sufficient venous occlusion. Here, we report on the first known case of sclerosant material migration beyond the placement of an embolisation coil for treatment of a varicocele, resulting in a left renal vein thrombus. A man in his 20s presented to the emergency department 2 days following uncomplicated left varicocele embolisation with acute left-sided abdominal pain, found to have sclerosant material causing an ipsilateral non-occlusive left renal vein thrombus with extension towards his inferior vena cava on CT. He was treated with 3 months of anticoagulation and follow-up imaging at 3 months showed resolution of this thrombus without renal impairment.

Case of Isolated Absence of the Azygos Vein: Evaluation Using Photon-counting Detector CT.

The isolated absence of the azygos vein was incidentally found on computed tomography (CT) examination in a 60-year-old female. The exact anomaly can be evaluated on high-resolution images of 0.4-mm slice thickness with low keV using photon-counting detector CT. The azygos vein, including the azygos arch, was absent, and a mildly dilated hemiazygos vein flowed to the left brachiocephalic vein through the left superior intercostal vein. A hemiazygos vein connected the left renal vein at the level of the first lumbar vertebra. This patient was the second patient to undergo evaluation using volume rendering images. High-resolution maximum-intensity projection images were useful for assessing the anatomy. Radiation dose was decreased compared with that in conventional CT.

Robotic Renal Vein Bypass: A Novel Technique for Treating a Challenging Case of Nutcracker Syndrome.

This case report highlights the successful application of a robotic-assisted surgical approach in managing Nutcracker syndrome. The patient, a 36-year-old female presented with severe symptoms and underwent robotic left renal vein transposition after failing conservative management. The procedure was performed through a minimally invasive approach utilizing the Da Vinci robotic system™ which offers enhanced visualization and precision. However, challenges arose during the renal vein anastomosis due to tension and poor flow through the transposition, requiring two revisions with a bovine pericardial patch. Ultimately, an 8 mm ringed PTFE bypass was anastomosed from the distal left renal vein to the Inferior Vena Cava. Despite these challenges, the patient experienced a successful outcome with complete symptom resolution of this complicated pathology.

Resection of primary left renal vein leiomyosarcoma with renal preservation following an unusual clinical presentation.

An elderly man was referred to vascular surgery on incidental discovery of a left retroperitoneal mass ultimately found to be of left renal vein (LRV) origin. He initially presented with recurring lower back pain. CT of the abdomen/pelvis showed a 6.0×5.5 cm lobulated retroperitoneal mass anterior to the infrarenal aorta. Resection of the mass necessitated a multidisciplinary team consisting of medical oncologists, radiation oncologists, urologists and vascular surgeons. In efforts to obtain an R0 margin, en-bloc resection of the LRV from its confluence with the inferior vena cava (IVC) was necessary. A primary repair of the IVC was performed with preservation of the left kidney. The patient's back pain has since resolved after the surgery. A literature search found IVC reconstructions to be safe and effective in the removal of vascular leiomyosarcomas.

Surgical management of renal cell carcinoma with subhepatic inferior vena cava tumor thrombus: a case report and review of the literature.

BACKGROUND: Renal cell carcinomas are the most common form of kidney cancer in adults. In addition to metastasizing in lungs, soft tissues, bones, and the liver, it also spreads locally. In 2-10% of patients, it causes a thrombus in the renal or inferior vena cava vein; in 1% of patients thrombus reaches the right atrium. Surgery is the only curative option, particularly for locally advanced disease. Despite the advancements in laparoscopic, robotic and endovascular techniques, for this group of patients, open surgery continues to be among the best options. CASE REPORT: Here we present a case of successful tumor thrombectomy from the infrahepatic inferior vena cava combined with renal vein amputation and nephrectomy. Our patient, a 58 year old Albanian woman presented to the doctors office with flank pain, weight loss, fever, high blood pressure, night sweats, and malaise. After a comprehensive assessment, which included urine analysis, complete blood count, electrolytes, renal and hepatic function tests, as well as ultrasonography and computed tomography, she was diagnosed with left kidney renal cell carcinoma involving the left renal vein and subhepatic inferior vena cava. After obtaining informed consent from the patient we scheduled her for surgery, which went well and without complications. She was discharged one week after to continue treatment with radiotherapy, chemotherapy, and immunotherapy. CONCLUSION: Open surgery is a safe and efficient way to treat renal cell carcinoma involving the renal vein and inferior vena cava. It is superior to other therapeutic modalities. When properly done it provides acceptable long time survival and good quality of life to patients.

An unusual cause of renal vein thrombosis in a newborn: COVID-19.

There is no information on renal vein thrombosis induced by COVID-19 infection in a neonate. Few cases of renal vein thrombosis caused by COVID-19 infection have been reported in predominantly adult patients. On day 25 after birth, a newborn whose mother was infected with COVID-19 had renal vein thrombosis. We believed that our patient's renal vein thrombosis was caused by postnatal transmission of the COVID-19 infection that the mother had acquired during birth. The clinical and radiologic findings of these unusual renal complications in a neonate, as well as treatment options, are presented.

Hemodynamics in nutcracker syndrome: implications for diagnosis.

BACKGROUND: Nutcracker syndrome is a disease characterized by complex symptoms, making its diagnosis challenging and often delayed, often resulting in a painful experience for the patients. OBJECTIVE: This study aimed to investigate the pathogenesis of nutcracker syndrome through the perspective of hemodynamics by simulating blood flow with varying compression degrees of the left renal vein. METHODS: 3D patient-specific vascular models of the abdominal aorta, superior mesenteric artery and left renal vein were constructed based on CT images of patients suspected of having nutcracker syndrome. A hemodynamic simulation was then conducted using computational fluid dynamics to identify the correlation between alterations in hemodynamic parameters and varying degrees of compression. RESULTS: The study indicated the presence of an evident gradient in velocity distribution over the left renal vein with relatively high degrees of stenosis (α ≤ 50°), with maximum velocity in the central region of the stenosis. Additionally, when the compression degree of the left renal vein increases, the pressure distribution of the left renal vein presents an increasing number of gradient layers. Furthermore, the wall shear stress shows a correlation with the variation of blood flow velocity, i.e., the increase of wall shear stress correlates with the acceleration of the blood flow velocity. CONCLUSIONS: Using computational fluid dynamics as a non-invasive instrument to obtain the hemodynamic characteristics of nutcracker syndrome is feasible and could provide insights into the pathological mechanisms of the nutcracker syndrome supporting clinicians in diagnosis.

Resection of extensive segments of inferior vena cava without reconstruction in the treatment of renal carcinoma with inferior vena cava tumor thrombus: A case report.

We present a 55-year-old male patient with right renal carcinoma with long inferior vena cava (IVC) tumor thrombus who underwent robot-assisted laparoscopic radical nephrectomy with extensive IVC resection and left renal vein ligation. The patient had a history of hematuria only prior to admission. Our case involved resection of the entire abdominal segment of the IVC and left renal vein without reconstruction. Unfortunately, the patient passed away over a year after the surgery due to brain metastasis.

Doppler-based evaluation of intrarenal venous flow as a new tool to predict acute kidney injury: A systematic review and meta-analysis.

Congestion is a common complication in the critical care setting, these patients are at increased risk of developing acute kidney injury (AKI). Congestive nephropathy (CN) has recently been described as a mechanism of worsening renal function, and evaluation of renal venous flow by pulsed Doppler (PD) is a useful tool to assess the presence of renal vein congestion. We comprehensively explore the ability of the PD in the evaluation of the intrarenal venous flow (IRVF) to predict the development of AKI in critically ill patients. We searched Pubmed-MEDLINE, Scopus, Embase, and Cochrane Library of Systematic Reviews (to 31th December 2021). We evaluated the association between Doppler-based Intrarenal venous flow demodulation and AKI. CN was defined as the presence of a pulsatile pattern (biphasic or monophasic) in the PD. A total of 4 articles (660 patients) were included in our systematic review, three of these in the metanalysis (413 patients): one study was excluded because its data were inadequate for pooling. Two studies originated in Europe and the other two in the United States. AKI occurrence ranged between 34 and 68%. Patients who developed AKI had a significant difference in PD pattern (continuous vs. pulsatile) in the IRVF (RR=0.46; 95% CI 0.28-0.76). Nevertheless, a large heterogeneity was observed among the studies (I2=68.7%; p=0.04). Albeit preliminary, these findings suggest that the presence of a pulsatile pattern in the PD of the IRVF may be involved in the development of AKI in the critically ill patient. The effect of alterations in the IRVF and renal function warrant further investigation.

Síndrome del cascanueces / Nutcracker syndrome

El síndrome del cascanueces es una anomalía vascular en la que se comprime la vena renal izquierda a su paso entre la unión de la aorta y la arteria mesentérica superior, debido a un ángulo muy cerrado entre ambas arterias. Clínicamente puede presentarse como hematuria macro o microscópica, dolor episódico en flanco izquierdo, dolor pélvico, várices gonadales o simplemente cursar de forma asintomática. Presentamos dos casos clínicos, uno de ellos con dolor abdominal tipo cólico nefrítico y hematuria macroscópica y otro estudiado por hipertensión pero con antecedentes de embolización de la vena renal izquierda por varicocele izquierdo. Discutimos los aspectos clínicos, diagnósticos y terapéuticos de este síndrome.

Nutcracker syndrome is a vascular anomaly consisting in the compression of the left renal vein between the superior mesenteric artery and the aorta. Clinical features in nutcracker syndrome include pelvic pain, flank pain, haematuria, gonadal varices or simply asymptomatic. We are presenting two cases, one of them with macroscopic haematuria and flank pain and the other was studied for hypertension but with previous antecedents of left renal vein embolization in the setting of varicocele. We discuss the clinical presentation as well as diagnostic and therapeutic aspects related to this syndrome.

An augmented patient-specific approach to administration of contrast agent for CT renal angiography

ABSTRACT Purpose This hybrid retrospective and prospective study performed on 200 consecutive patients undergoing renal CTA, investigates the opacification of renal vasculature, radiation dose, and reader confidence. Materials and Methods 100 patients were assigned retrospectively to protocol A and the other 100 were allocated prospectively to protocol B. Both protocols implemented a contrast material and saline flow rate of 4.5 mL/sec. Protocol A utilized a 100 mL of low-osmolar nonionic IV contrast material (Ioversol 350 mg I/mL) while protocol B employed a patient-tailored contrast media formula using iso-osmolar non-ionic (Iodixanol 320 mg I/mL). Results Arterial opacification in the abdominal aorta and in the bilateral main proximal renal arteries demonstrated no statistical significance (p>0.05). Only the main distal renal artery of the left kidney in protocol B was statistically significant (p<0.046). In the venous circulation, the IVC demonstrated a significant reduction in opacification in protocol B (59.39 HU ± 19.39) compared to A (87.74 HU ± 34.06) (p<0.001). Mean CNR for protocol A (22.68 HU ± 13.72) was significantly higher than that of protocol B (14.75 HU ± 5.76 p< 0.0001). Effective dose was significantly reduced in protocol B (2.46 ± 0.74 mSv) compared to A (3.07 ± 0.68 mSv) (p<0.001). Mean contrast media volume was reduced in protocol B (44.56 ± 14.32 mL) with lower iodine concentration. ROC analysis demonstrated significantly higher area under the ROC curve for protocol B (p< 0.0001), with inter-reader agreement increasing from moderate to excellent in renal arterial visualization. Conclusion Employing a patient-tailored contrast media injection protocol shows a significant refinement in the visualization of renal vasculature and reader confidence during renal CTA.

A teenage patient with autosomal recessive polycystic kidney disease, a splenorenal shunt, and congenital hepatic fibrosis: a case report / Doença renal policística autossômica recessiva, shunt esplenorrenal e fibrose hepática congênita em adolescente: relato de caso

ABSTRACT A 16-year-old female patient previously diagnosed with autosomal recessive polycystic kidney disease (ARPKD) presented with acute bilateral pneumonia, upper gastrointestinal bleeding caused by ruptured esophageal varices, ascites, and lower limb edema. She required intensive care and an endoscopic procedure to treat the gastrointestinal bleeding. The analysis of the differential diagnosis for chronic liver disease indicated she had a spontaneous splenorenal shunt. Ultrasound-guided biopsy revealed the patient had cirrhosis, as characteristically seen in individuals with ARPKD. She had no symptoms at discharge and was referred for review for a combined transplant.

RESUMO Relato de caso de uma paciente adolescente de 16 anos de idade com diagnóstico prévio de doença renal policística autossômica recessiva (DRPAR), que apresentou quadro agudo de pneumonia bilateral e hemorragia digestiva alta por ruptura de varizes esofágicas, bem como ascite e edema de membros inferiores. Necessitou de estabilização clínica intensiva e tratamento endoscópico do sangramento digestivo. Após investigação dos diagnósticos diferenciais da hepatopatia crônica, diagnosticou-se shunt esplenorrenal espontâneo, e realizou-se biópsia hepática guiada por ecografia com diagnóstico de cirrose, espectro típico da DRPAR. Recebeu alta hospitalar assintomática e foi encaminhada para avaliação de transplante duplo.