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Purpose: Here, we describe nutcracker syndrome management using intravascular ultrasound (IVUS) during endovascular stent placement of the renal vein., Case Report: A 60-year-old woman with a known Factor V Leiden mutation, long-standing smoking history, and family history of pancreatic cancer presented with 2 years of intermittent left upper quadrant pain (LUQ) and a 15 lb unintentional weight loss. Work-up included abdominal ultrasound (US) and abdominal computerized tomography (CT) scan. Abdominal US and Chest CT scan were negative while the abdominal CT scan revealed severe compression of the left renal vein by the superior mesenteric artery, consistent with nutcracker syndrome. Renal venogram and endovascular stent placement performed under IVUS guidance. IVUS was used to determine stent size and measure flow and assess patency after stent placement., Conclusions: Post-renal vein stent placement, the patient had resolution of her symptoms with follow-up duplex renal ultrasound exam demonstrating restored blood flow in the left renal vein with improved patency., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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., (© 2024. The Author(s) under exclusive licence to Italian Society of Nephrology.)

This study represents a concise review of Nutcracker syndrome with its history, incidence, clinical presentation and currently available diagnostic criteria and treatment options. This should help any clinician identify and better serve patients with rare venous disorders such as this. Although the literature is scarce, clinicians should be keen to diagnose and treat patients with this potentially debilitating syndrome.

Background: Changes in Doppler flow patterns of hepatic veins (HV), portal vein (PV) and intra-renal veins (RV) reflect right atrial pressure and venous congestion; the feasibility of obtaining these assessments and the clinical relevance of the findings is unknown in a general ICU population. This study compares the morphology of HV, PV and RV waveform abnormalities in prediction of major adverse kidney events at 30 days (MAKE30) in critically ill patients., Study Design and Methods: We conducted a prospective observational study enrolling adult patients within 24 h of admission to the ICU. Patients underwent an ultrasound evaluation of the HV, PV and RV. We compared the rate of MAKE-30 events in patients with and without venous flow abnormalities in the hepatic, portal and intra-renal veins. The HV was considered abnormal if S to D wave reversal was present. The PV was considered abnormal if the portal pulsatility index (PPI) was greater than 30%. We also examined PPI as a continuous variable to assess whether small changes in portal vein flow was a clinically important marker of venous congestion., Results: From January 2019 to June 2019, we enrolled 114 patients. HV abnormalities demonstrate an odds ratio of 4.0 (95% CI 1.4-11.2). PV as a dichotomous outcome is associated with an increased odds ratio of MAKE-30 but fails to reach statistical significance (OR 2.3 95% CI 0.87-5.96), but when examined as a continuous variable it demonstrates an odds ratio of 1.03 (95% CI 1.00-1.06). RV Doppler flow abnormalities are not associated with an increase in the rate of MAKE-30 INTERPRETATION: Obtaining hepatic, portal and renal venous Doppler assessments in critically ill ICU patients are feasible. Abnormalities in hepatic and portal venous Doppler are associated with an increase in MAKE-30. Further research is needed to determine if venous Doppler assessments can be useful measures in assessing right-sided venous congestion in critically ill patients.

Acutely increased renal venous pressure (RVP) impairs renal function, but the long-term impact is unknown. We investigated whether chronic RVP elevation impairs baseline renal function and prevents exacerbation of renal dysfunction and cardiovascular instability upon further RVP increase. RVP elevation (20-25 mmHg) or sham operation (sham) was performed in rats. After 1 wk ( n = 17) or 3 wk ( n = 22), blood pressure, RVP, renal blood flow (RBF), renal vascular conductance (RVC), and glomerular filtration rate (GFR) were measured at baseline and during superimposed RVP increase. Chronic RVP elevation induced extensive renal venous collateral formation. RVP fell to 6 ± 1 mmHg at 1 wk and 3 ± 1 mmHg at 3 wk. Baseline blood pressure and heart rate were unaltered compared with sham. RBF, RVC, and GFR were reduced at 1 wk but normalized by 3 wk. Upon further RVP increase, the drop in mean arterial pressure was attenuated at 3 wk compared with 1 wk ( P < 0.05), whereas heart rate fell comparably across all groups; the mean arterial pressure-heart rate relationship was disrupted at 1 and 3 wk. RBF fell to a similar degree as sham at 1 wk (-2.3 ± 0.7 vs. -3.9 ± 1.2 mL/min, P = 0.066); however, at 3 wk, this was attenuated compared with sham (-1.5 ± 0.5 vs. -4.2 ± 0.7 mL/min, P < 0.05). The drop in RVC and GFR was attenuated at 1 and 3 wk ( P < 0.05). Thus, chronic RVP elevation induced by partial renal vein ligation elicits extensive renal venous collateral formation, and although baseline renal function is impaired, chronic RVP elevation in this manner induces protective adaptations in kidneys of healthy rats, which attenuates the hemodynamic response to further RVP increase.

Objectives: Spontaneous splenorenal shuntis a type of portosystemic shunt that develops frequently in the setting of chronic portal hypertension. It remains controversial whether shuntinterventions during liver transplant improve transplant outcomes., Materials and Methods: We conducted a retrospective comparison between deceased-donor liver transplant recipients who received spontaneous splenorenal shunt intervention and those who did not at a tertiary center between 2012 and 2017. Primary outcomes of interest included intraoperative transfusion requirement, hospital length of stay, acute kidney injury posttransplant, portal vein thrombosis, thrombocytopenia, and 1-year graft and patient survival., Results: Of 268 liver transplant recipients, 50 (18.6%) had large spontaneous splenorenal shunts pretransplant, with 45 patients having available radiologic and outcome data. Nine of 45 patients (20%) received shunt intervention, including pretransplant balloonoccluded retrograde transvenous obliteration (n = 5), intraoperative ligation of the left renal vein (n = 3), and intraoperative direct shunt ligation (n = 1). Demographic data, clinical characteristics, and Model for End-Stage Liver Disease scores were not different between the intervention and the nonintervention groups. Intraoperative transfusion, length of hospitalization, portal vein thrombosis, thrombocytopenia, and 1-year graft and patient survival were also similar between the 2 groups. However, the rate of posttransplant acute kidney injury was significantly lower in patients in the intervention group (0 cases vs 12 cases; odds ratio = 0.73; 95% confidence interval, 0.59-0.90). Patients with no SRS intervention (n = 36) were followed radiologically for 1 year posttransplant, with follow-up data showing complete resolution of spontaneous splenorenal shunt in just 4 patients (15%) and no changes in the remaining patients., Conclusions: Peritransplant interventions for spontaneous splenorenal shunt may reduce posttransplant acute kidney injury. In patients without intervention, spontaneous splenorenal shunt predominantly persisted 1 year posttransplant.

Objectives: Nutcracker syndrome is rare, and a proportion of patients with this syndrome continue to have intractable pain and symptoms. Due to the heterogeneity of patients' chief complaints and symptoms, the surgeon's preferred approach may be inherently different but is of paramount importance to the outcome., Materials and Methods: We present 4 cases in which renal autotransplant with extraction and ligation of previously placed gonadal coils was performed following previously attempted renal vein stenting or combined renal vein transposition followed by renal vein stenting., Results: Autotransplant resulted in flank pain resolution with improvement in symptoms associated with pelvic congestion syndrome., Conclusions: The approach to such cases requires meticulous and adequate vena cava exposure, with preparation for potential caval reconstruction. No firm inferences can be made from such a small series; however, we believe in renal autotransplant as first-line therapy, and failure after an initial renal vein stent should be salvaged by renal autotransplant over further endovascular attempts.

Background: Open surgery of abdominal aortic aneurysm (AAA) or aortoiliac occlusive disease (AIOD) sometimes requires left renal vein division (LRVD) to gain adequate exposure of the abdominal aorta. The aim of this study is to evaluate the effect of LRVD on the postoperative renal function using propensity score matching (PSM)., Methods: From July 1996 to January 2018, we retrospectively reviewed 698 patients who underwent open aortic surgery, including 543 AAAs and 155 AIODs, at a single institution. 66 patients (9.6%, 47 AAAs, 19 AIODs) needed LRVD during the operation. A 1:3 ratio PSM was used to control the selective bias between the LRVD and non-LRVD groups. We investigated preoperative and postoperative renal function including serum creatinine (sCr) level and estimated glomerular filtration rate (eGFR, mL/min/1.73 m 2 ). Major complications, long-term renal function, and 30-day mortality were also compared., Results: The LRVD group had a significantly higher rate of renal artery reconstruction (15.2% vs. 3.3%, P < 0.001) and suprarenal clamping (54.6% vs. 9.5%, P < 0.001) and higher incidence of juxtarenal AIOD (24.2% vs. 5.4%, P < 0.001). With PSM, 63 patients in the LRVD group and 144 patients in the non-LRVD group were enrolled in this study. The baseline characteristics were well balanced in the groups after PSM. There were no significant differences in preoperative eGFR (72.4 ± 21.3 vs. 76.1 ± 25.0, P = 0.306) and postoperative eGFR on day 3 (69.5 ± 26.6 vs. 77.5 ± 28.5, P = 0.065), day 7 (73.3 ± 24.8 vs. 78.5 ± 27.4, P = 0.264), and in the long-term follow-up period (69.0 ± 22.2 vs. 68.9 ± 27.1, P = 0.986, 50.2 month ± 45.50) in the 2 groups. Only the sCr level (1.40 ± 0.59 vs. 1.21 ± 0.62, P = 0.045) and eGFR (59.5 ± 23.9 vs. 71.4 ± 26.0, P = 0.002) were significantly worse on postoperative day 1 in the LRVD than in the non-LRVD group. There were no significant differences in 30-day mortality (1.6% vs. 1.6%, P = 1.00)., Conclusions: The patients in the LVRD group underwent initial drop in renal function; however, eGFR improved during the follow-up period. There was no difference in renal function and postoperative mortality between LRVD and non-LRVD groups. Therefore, LRVD is a safe and durable procedure during complex abdominal aortic surgery., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: Recent studies have demonstrated an association between maternal supine sleep position and an increased risk of late stillbirth. During late pregnancy, the gravid uterus compresses the inferior vena cava (IVC) when a woman lies in the supine position. The azygos system of veins is the dominant pathway of collateral venous return back to the heart in the event of acute obstruction of the IVC. It is suggested that this pathway provides adequate collateral venous circulation in the event of IVC compression in the supine position during late pregnancy. Objective: Investigate the effect of supine positioning on maternal hemodynamics during late pregnancy and the role of collateral venous circulation. Methods: Ethics approval was obtained and 12 women with singleton pregnancies between 35- and 38-week gestation underwent magnetic resonance imaging in the supine and left lateral decubitus positions using a Skyra 3T system (Siemens). Phase-contrast images were evaluated to measure cardiac output, blood flow through the azygos vein, and blood flow through the abdominal aorta (AA) and IVC at two levels: at the level of aortic bifurcation and immediately above the renal veins. Results: The supine position was associated with a 16.4% reduction in cardiac output when compared to the left lateral position. In addition, blood flow through the IVC decreased at its origin by 85.3% and by 44.4% at the level of the renal veins. Blood flow through the azygos vein increased in the supine position by 220%. Blood flow through the AA at the level of the renal veins did not differ significantly; however, it is reduced by 32.3% at the level of the aortic bifurcation. Conclusions: Women in late pregnancy experience an increase in collateral venous blood flow when lying supine, likely as a response to marked compression of the IVC in this position. However, cardiac output and aortic blood flow were found to decrease while in the supine position.

Objective: Pelvic venous incompetence or pelvic congestion syndrome (commonly referred to as pelvic venous disorder [PVD]) is increasingly diagnosed, especially in multiparous women. This may be either primary or secondary to pelvic venous outflow obstruction-left common iliac vein (LCIV) or left renal vein (LRV) stenosis. Intravascular ultrasound (IVUS) examination performed in the supine position is commonly used for diagnosis of LRV and LCIV stenosis; however, body position may affect the cross-sectional area (CSA) of both of these veins during IVUS. The aim of the study was to test the hypothesis that postural changes may significantly affect the CSA of the LRV and LCIV., Methods: A single-arm, single-center cohort study of women suffering from PVD was performed at a tertiary hospital in Poland. It comprised consecutive patients with either pelvic vein reflux or suggestion of LCIV or LRV obstruction but no signs of deep venous thrombosis. IVUS examination of the iliac veins, inferior vena cava, and LRV was performed in the supine position. IVUS of the LRV and LCIV was performed also with a Valsalva maneuver and with patients lying on the left side and standing. A 60% CSA reduction was used as a cutoff value between significant and nonsignificant vein stenosis., Results: A total of 41 women were examined. Significant stenosis of the LRV was seen in 22 patients (55%) supine but in only 4 (10%) patients studied when lying on the left side and in 27 (67.5%) patients studied while standing. Significant stenosis of the LCIV was seen in 26 supine patients (63.4%), in 8 lying on the left side (19.5%), and in 10 (24.4%) standing., Conclusions: Postural changes dramatically affect CSA of the LCIV and LRV and thus the degree of stenosis in women diagnosed with PVD. Stenosis found in patients while supine often disappears when the position is changed to lying on the left side or to standing. Therapeutic decisions based on assessment of CSA reduction in the supine position are likely to be inadequate., (Copyright © 2019 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Nutcracker syndrome (NCS) is a rare condition that can be manifested with hematuria, flank pain, pelvic varicosities, or chronic pelvic congestion related to left renal vein (LRV) compression. Open surgery, specifically LRV transposition, has been the mainstay of treatment, but in the past few years, LRV stenting has emerged as a less invasive alternative without sufficient evidence to support it. This study aimed to assess outcomes of renal vein stenting in the treatment of NCS., Methods: A retrospective chart review of patients with NCS who underwent LRV stenting between 2010 and 2018 was performed. End points were perioperative adverse outcomes, symptom relief, and stent patency. Symptom resolution was classified as complete, partial, and none on the basis of the interpretation of medical records on clinical follow-up. Standard descriptive statistics and survival analysis were used., Results: Eighteen patients (17 female; mean age, 38.1 ± 16.9 years) diagnosed with NCS and treated with LRV stenting were identified. Five of these had a prior LRV transposition that had failed within a mean of 7.0 ± 4.9 months, manifested by symptom recurrence (or no improvement) along with imaging evidence of persistently severe renal vein stenosis. Twelve patients had coexisting pelvic congestion syndrome treated with gonadal vein embolization. The most frequent sign and symptom were hematuria (10/18 patients) and flank pain (15/18 patients), respectively. All patients received self-expanding stents (mean diameter, 12.8 ± 1.6 mm), the smaller ones typically placed in the previously transposed LRVs. No perioperative complications occurred. Nine patients were discharged on the same day; the remaining patients stayed longer for pain control (mean hospital stay, 1.0 ± 1.3 days). At an average follow-up of 41.4 ± 26.6 months, 13 (72.2%) patients had symptoms resolved or improved (9 complete, 4 partial). Three of the five patients whose symptoms remained unchanged had previous LRV transposition surgery, and two of these three patients eventually required renal autotransplantation. Six of 10 patients who presented with hematuria had it resolved. Three patients underwent a stent reintervention at 5.8 months, 16.8 months, and 51.7 months because of symptom recurrence or stent restenosis. The two early ones required balloon venoplasty and the third one restenting. Two-year primary and primary assisted patency was 85.2% and 100%, respectively. No stent migration occurred., Conclusions: Endovascular treatment with renal vein stenting is safe, providing encouraging results with good midterm patency rates and symptom relief. Minimally invasive approaches may have a potential role in the treatment of NCS. Larger series and longer follow-up are needed to better assess the comparative performance against LRV transposition., (Copyright © 2019 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

We report a unique case of unusual drainage of the bifurcated retroaortic left renal vein, with the cranial wider branch draining into a dilated lumbar azygos vein and caudal thinner branch connecting with the inferior vena cava. The right renal vein was duplicated. The anomaly was discovered on multimodal 18 F-labeled fluorodeoxyglucose positron emission tomography/computed tomography performed for oncological purposes. The basis enabling occurrence of such variation was probably persistent developmental extra left-right venous connections, intercardinal, or intersupracardinal, depending on the theory. The embryology of the chest and abdominal veins is a complicated process and there is no unanimity concerning its concepts. The old models are currently being questioned and reevaluated. Knowledge of possible variants of renal and azygos veins course is important from clinical, imaging, and surgical points of view. The retroaortic left renal veins course may sometimes cause pain, hematuria, proteinuria, and pelvic congestion syndromes. Dilated parts of uncommonly located veins, because of assuming a nodular shape on transverse images, may be mistaken for abnormal lymph nodes, other tumors or aneurysms on imaging. During a variety of surgical procedures, including venous sampling, renal transplantation, or any retroperitoneal surgery, knowledge of an aberrant venous course may be important for the success of the procedure and may be crucial even earlier during the qualification process.

Background: The effect of left renal vein division (LRVD) during open surgery (OS) for pararenal and juxtarenal abdominal aortic aneurysm (P/JRAA) on postoperative renal function remains controversial, so we focused on chronic renal decline (CRD) and separately examined renal volume as a surrogate index of split renal function., Methods and results: The 115 patients with P/JRAA treated with OS from June 2007 to January 2017 were reviewed: 26 patients without LRVD were matched to 27 patients with LRVD according to preoperative chronic kidney disease (CKD) stage and proximal clamp sites. The effect of LRVD on CRD was investigated by a time-to-event analysis. During a median follow-up of 23.5 months, CRD occurred in 5 patients with LRVD and in 4 patients without LRVD. Comparison of freedom from CRD showed no significant difference between the matched groups (P=0.870). The separate renal volumes were evaluated before surgery and at 1 and 2 years of follow-up using CT images from 18 patients with LRVD. At 2 years, the mean renal volume had decreased by 15% in the left kidney and by 9% in the right kidney (P=0.052 and 0.148, respectively), but the left-to-right renal volume ratio showed no significant change (P=0.647)., Conclusions: LRVD had no significant effect on CRD or left renal volume relative to the right renal volume for up to 2 years.

Acute kidney injury in the context of nephrotic syndrome is a serious and alarming clinical problem. Largely, acute kidney injury is a relatively frequent complication among patients with comorbidities while it has been independently associated with an increased risk of adverse outcomes, including death and chronic kidney disease. Nephrotic syndrome, without hematuria or with minimal hematuria, includes a list of certain glomerulopathies; minimal change disease, focal segmental glomerulosclerosis and membranous nephropathy. In the light of primary nephrotic syndrome, pathophysiology of acute kidney injury is differentiated by the nature of the primary disease and the severity of the nephrotic state. This review aims to explore the clinical circumstances and pathogenetic mechanisms of acute kidney injury in patients with nephrotic syndrome due to primary glomerulopathies, focusing on newer perceptions regarding the pathogenesis and management of this complicated condition, for the prompt recognition and timely initiation of appropriate treatment in order to restore renal function to its baseline level. Prompt recognition of the precise cause of acute kidney injury is crucial for renal recovery. Clinical characteristics, laboratory and serological findings along with histopathological findings, if required, will reveal the implicated pathway leading to individualized approach and management.

Introduction: Venous thromboembolism (VTE) of the lower extremities frequently occurs after surgery. It is unknown whether the complication of renal vein thrombosis (RVT) develops after an open repair (OR) for abdominal aortic aneurysm (AAA). Furthermore, anticoagulation therapy with apixaban, a direct oral anticoagulant (DOAC), has not been described as treatment for RVT in such cases., Case: A 64-year-old man underwent OR for AAA. Postoperative computed tomography revealed RVT in the left renal vein. Apixaban (5 mg twice a day) therapy was initiated. Six months later, we discontinued anticoagulation therapy and observed no recurrence. Following OR, our patient developed RVT for which DOACs were very useful., Conclusion: Thus, RVT can manifest as VTE after OR and direct anticoagulants can be considered as a therapeutic option.

Renal artery aneurysm (RAA) concomitant with a renal arteriovenous fistula (RAVF) is extremely rare. A 32-year-old man suffered from a giant RAA combined with high-flow RAVF. The computer tomographic angiography (CTA) demonstrated a RAA, which is 6.3 cm in length and 2.1 cm in diameter, combined with an arteriovenous fistula between the right renal artery and right renal vein (fistula area:1.05 cm × 1.0 cm). After a comprehensive preoperative assessment, a patent ductus arteriosus occluder (PDAO) was implanted. At a 1-year follow-up, the CTA study showed that the PDAO was in situ and there was no recanalization of the lesion. At a third-year follow-up, ultrasound examination showed an image of right renal atrophy. The results of long-term follow-up demonstrate that PDAO is safe and effective for the management of RAAs combined with high-flow RAVF., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The aim of this study was to describe our robot-assisted laparoscopic left renal vein (LRV) transposition experiences for nutcracker syndrome treatment., Methods: From August 2016 through May 2017, three patients with nutcracker syndrome underwent robot-assisted laparoscopic LRV transpositions. The patient demographics, surgical outcomes, and postoperative morbidities were reviewed., Results: Successful surgical procedures were performed in all three patients. The operative times for the three cases were 150, 175, and 162 minutes, respectively, while the LRV anastomosis times were 19, 22, and 13 minutes, respectively. No major perioperative complications were encountered, and the hematuria and flank pain were resolved in all three cases. At the 6-month follow-up, the computed tomography scan showed that the LRV narrowing had disappeared in two of the patients. Although one patient still exhibited LRV flattening, his symptoms were also relieved, and the varicose tributaries spontaneously ceased., Conclusions: Robot-assisted laparoscopic LRV transposition can be a viable minimally invasive treatment option for patients with nutcracker syndrome., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: To determine if stent placement across the renal vein inflow affects kidney function and renal vein patency., Methods: Between June 2008 and September 2016, 93 patients (mean age 39 years, range 15-70; 54 women) with iliocaval occlusion underwent venous stent placement and were retrospectively reviewed. For this analysis, the patients were separated into treatment and control groups: 51 (55%) patients had suprarenal and infrarenal iliocaval venous disease requiring inferior vena cava stent reconstruction across the renal vein inflow (treatment group) and 42 (45%) patients had iliac vein stenting sparing the renal veins (control group). Treatment group patients received Wallstents (n=15), Gianturco Z-stents (n=24), or suprarenal and infrarenal Wallstents such that the renal veins were bracketed with a "renal gap" (n=12). Stenting technical success, stent type, glomerular filtration rate (GFR), and creatinine before and after stent placement were recorded, along with renal vein patency and complications., Results: All procedures were technically successful. In the 51-patient treatment group, 15 (29%) patients received Wallstents and 24 (47%) received Gianturco Z-stents across the renal veins, while 12 (24%) were given a "renal gap" with no stent placement directly across the renal vein inflow. In the control group, 42 patients received iliac vein Wallstents only. Mean prestent GFR was 59±1.8 mL/min/1.73 m 2 and mean prestent creatinine was 0.8±0.2 mg/dL for the entire cohort. Mean prestent GFR and creatinine values in the Wallstent, Gianturco Z-stent, and "renal gap" subgroups did not differ from the iliac vein stent group. Mean poststent GFR and creatinine values were 59±3.3 mL/min/1.73 m 2 and 0.8±0.3 mg/dL, respectively. There were no differences between mean pre- and poststent GFR (p=0.32) or creatinine (p=0.41) values when considering all patients or when comparing the treatment subgroups and the control group. There were no differences in the poststent mean GFR or creatinine values between the Wallstent (p=0.21 and p=0.34, respectively) and Gianturco Z-stent (p=0.43 and p=0.41, respectively) groups and the "renal gap" group. One patient with a Wallstent across the renal veins developed right renal vein thrombosis 7 days after the procedure., Conclusion: Stent placement across the renal vein inflow did not compromise renal function. A very small risk of renal vein thrombosis was seen.

Renal artery aneurysm with concomitant presence of arteriovenous fistula is an extremely rare entity. Few reports have been described in the literature. Nowadays, endovascular repair with covered stents or transarterial embolization with coils or glue has become the first line of treatment. We present the successful repair of a distal renal artery aneurysm combined with arteriovenous fistula with stent graft., (Copyright © 2018 Elsevier Inc. All rights reserved.)

This study was designed to explore the safety and feasibility of robotic-assisted laparoscopic nephrectomy with vein thrombectomy (RAL-NVT) for the treatment of renal cell carcinoma (RCC) with venous tumor thrombus (VTT). Clinical data of 6 patients treated with RAL-NVT between July 2016 and November 2017 in our hospital were retrospectively collected and analyzed. There were 5 males and 1 female with their age ranging from 48 years to 68 years. Five renal tumors were right-sided and one left-sided. Three cases fell in level 0 VTT, one in level I and two in level II. Preoperative imaging revealed lymph node involvement in 1 case and distant metastasis in 2 cases. For RCC with level 0 VTT, the renal vein of the affected side was adequately and carefully dissected around the thrombus to the proximity of inferior vena cava (IVC) and was ligated with Hem-o-loks without cross-clamping the IVC. For level I and II VTT, the IVC was crossclamped cephalically and caudally around the tumor thrombus and all tributaries were sequentially blocked to ensure the safe retrieval of VTT. All operations were successfully completed without conversion to open operation. The mean operative time was 150 (115-230) min. Cross-clamping of the IVC happened in 3 cases, and the blocking time was 14, 19 and 20 min, respectively. The mean estimated blood loss during the operation was 400 (200-580) mL. The peritoneal drainage tube was removed 5 to 9 days after the operation, and all patients were postoperatively discharged at 6 to 11 days. Postoperative pathological analysis confirmed that the RCCs were comprised of 4 clear cell RCCs, 1 papillary cell RCC, and 1 medullary cell RCC; 2 cases were Fuhrman grade II, 3 cases grade III, and 1 case undefined grade. No recurrence or progression was observed during the follow-up of 4.2 (3-6) months. We concluded that RAL-NVT is highly challenging but safe and feasible for the treatment of RCC with VTT.

Background Compression of left renal vein is an atypical cause of reflux in pelvic veins resulting in pelvic varices that in turn causes frequently lower limb varices in many cases. Methods A monocentric study was undertaken to report the treatment and five-year follow up of patients presenting left renal vein compression. Embolization of refluxive gonadal/pelvic veins was performed generally as the initial procedure. Left renal vein stenting was performed in patients presenting haematuria, severe lumbar pain or persistent pelvic/lower limb varices after embolization. Results From 462 cases of left renal vein compression, 40 were treated by stenting as first procedure. Four hundred twenty-two were treated by gonadal/pelvic vein embolization and only 15 needed complementary stenting. After follow-up, all cases with haematuria had improved and lumbar pain was eliminated in 81.5%. Patients with recurrent or persistant varices were all improved. Conclusion Left renal vein stenting should be considered an effective and safe procedure, with demonstrated durable efficacy and safety and no evidence of restenosis.

Treatment of renal vein thromboses has previously been limited to conventional anticoagulation. We describe a case of successful treatment of acute native renal vein thrombosis (RVT) in a 61-year-old fit-and-well female using mechanical thromboaspiration without the use of thrombolysis. The report demonstrates the computed tomographic appearances of an acute RVT, the venographic images taken before and after thromboaspiration, and the magnetic resonance imaging of the kidney performed 3 months later, showing complete resolution of the thrombus and normal appearances of the kidney. We believe this case to be the first published case of a safe and successful treatment of acute native RVT using the Penumbra Indigo ® mechanical aspiration system, highlighting the importance of access to skilled interventional radiologists for treatment of this rare condition., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: The objective of this study was to identify the effect of two left renal vasculature occlusion strategies on the duplex ultrasound-assessed rheology and histology of the contralateral kidney., Methods: Pigs were randomly assigned to one of two groups: left renal artery-only clamping (A group, n = 8) or left renal artery and vein clamping (AV group, n = 9). Bilateral renal parenchymal biopsy specimens were taken every 10 minutes for 90 minutes. Duplex ultrasound resistive index (RI) and pulsatility index (PI) were measured. Mixed models with normal distribution and first-order autoregressive correlation structure and generalized estimating equation models were used. Results are presented as adjusted means with standard errors, estimated proportions with standard errors, and line plots with 95% confidence intervals., Results: RI and PI increased in the nonischemic kidney. In A group animals, RI values increased significantly (P < .01) after 30 minutes of ischemia and PI increased significantly (P < .04) from 30 to 60 minutes of ischemia. The number of histologic abnormalities was higher in A group than in AV group biopsy specimens. The percentage of lesions increased significantly after 10 minutes in A group nonischemic kidneys (P < .02) and between 50 and 80 minutes in AV group nonischemic kidneys (P < .01)., Conclusions: Nonischemic kidneys were acutely affected by contralateral ischemia. Their function was more adversely affected by unilateral renal artery occlusion with preserved renal vein patency (A group)., (Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Although the indications for endovascular aneurysm repair for abdominal aortic aneurysm have been expanding, our primary strategy for pararenal and juxtarenal abdominal aortic aneurysm (P/JRAA) is open surgery (OS). One consequence of OS for P/JRAA is transient renal ischemia owing to renal artery clamping, which can be followed by acute kidney injury (AKI). Prior studies referred to the impact of renal ischemia on AKI, but they have rarely evaluated longer-term renal function. This study focused on a chronic renal decline (CRD) during follow-up., Methods: A retrospective review of our series of P/JRAA treated with OS from 2007 to 2015. Patients on hemodialysis at the time of surgery were excluded. Preoperative renal function was estimated using the chronic kidney disease (CKD) staging system. Postoperative AKI was defined by the RIFLE criteria (Risk, Injury, Failure, Loss of function, End-stage renal disease). CRD was defined as progression in CKD stage or estimated glomerular filtration rate (eGFR) decline of >20%., Results: Among 451 elective OS, 111 underwent repair for P/JRAA. Three patients were excluded because of preoperative hemodialysis. Consequently, 108 patients were enrolled. Preoperatively, 41 patients (38.0%) had CKD stage 3 (eGFR < 60 mL/min/1.73 m 2 ). Eight patients (7.2%) were in stage 4 (eGFR < 30 mL/min/1.73 m 2 ). Proximal clamping was supraceliac (6 patients), suprarenal (34 patients), and inter-renal (68 patients). The median renal ischemic time was 33 minutes. The left renal vein was divided in 24 patients. Fourteen renal arteries in 14 patients were revascularized. Cold renal perfusion was applied in 11 patients. One in-hospital death was excluded from these analyses. AKI was observed in 20 patients (18.7%). One patient required temporary hemodialysis. During a median renal function follow-up for 24.5 months (interquartile range, 3.34-48.4), 17 patients (15.9%) had CRD. One patient required hemodialysis 5 years after surgery. In univariate analysis, CKD stages 3 and 4 were significant predictors for CRD (P = .014 and P < .001, respectively). Cold renal perfusion was associated with a higher risk of CRD (P = .047). On multivariate analysis, preoperative CKD stage 3 (hazard ratio, 4.22; 95% confidence interval, 1.10-16.3; P = .036) and stage 4 (hazard ratio, 59.72; 95% confidence interval, 10.13-352.0; P < .001) were identified as risk factors. In patients with CKD stage ≤2, the estimated freedom from CRD at 5 years was 96.6 ± 3.4%., Conclusions: CKD stage ≥3 was a significant risk for CRD after OS for P/JRAA. Renal artery clamping seemed innocuous for patients with a preoperative eGFR of ≥60 mL/min/1.73 m 2 in terms of CRD. No significant impact of left renal vein division on CRD was confirmed., (Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

During pediatric kidney transplant, surgical challenges occasionally occur. In particular, vascular anastomosis should be considered for children with small body weight < 12 kg, multiple renal arteries, vascular anomaly, and inferior vena cava occlusion. In pediatric patients, a living-donor renal graft is usually donated from a parent. Therefore, the renal artery and vein are too large to be anastomosed with the recipient's internal iliac artery and external iliac vein. In children who are > 12 kg, the renal artery and vein could be anastomosed with the external iliac artery and the external iliac vein. In children who are < 10 kg, the renal artery and vein should be anastomosed directly with the aorta and inferior vena cava. A pediatric transplant surgeon should consider arterial and venous anastomosis sites before transplant surgery. In small children with partial or total inferior vena cava occlusion, the venous anastomosis site should be evaluated. If the graft is placed on the left side, a venous graft must be used as a bridge between the renal vein and inferior vena cava. In 13 kidney transplants in children with inferior vena cava occlusion, 7 were on the left and 6 were on the right side. A patent segment of the inferior vena cava, the left original renal vein, an ascending lumbar vein, an azygos vein, the first graft renal vein, and a portal vein were used for venous anastomosis in 6, 2, 2, 1, 1 and 1 recipient, respectively. One child had graft loss due to renal vein thrombosis and one died of hemorrhage immediately posttransplant. Three had grafts with relatively long-term function, but these were lost due to chronic allograft nephropathy 100, 122, and 137 months posttransplant. However, the other 8 recipients have so far maintained graft function from 6 to 138 months since transplant.

Objectives: Congenital renal arteriovenous malformations (rAVMs) represent rare vascular diseases. The heterogeneous vascular architecture of each rAVM determines the endovascular treatment techniques employed. We reported our experience with the endovascular treatment of a series of rAVMs., Materials: This retrospective study consisted of 12 patients with 12 rAVMs who underwent renal arterial embolization (RAE) in our hospital. Embolic materials, including particles, liquid embolic agents (n-butyl 2-cyanoacrylate, Onyx, and ethanol), and coils, were selectively used based on the decisions of interventional radiologists. Technical success was defined as the complete occlusion of the feeding arteries and nidus on postprocedure renal arteriography. Clinical success was defined as the resolution of hematuria or the disappearance of rAVM-relevant symptoms., Results: The median follow-up period was 13.5 months (range: 4-72). The technical success based on 12 procedures in 12 patients was 83.3% (10 of 12). In the 2 procedures that technically failed, the existence of multiple fine feeding arteries arising from the proximal portion of different segmental renal arteries explains the incomplete embolization. One of the 2 patients achieved clinical success without additional RAE. The other patient had recurrent hematuria 25 months after initial treatment, which was successfully managed conservatively with hemostatic agents. Thus, the clinical success was 91.7% (11 of 12)., Conclusions: Renal artery embolization with the selective use of various embolic materials is an effective treatment for patients with rAVMs. The existence of multiple fine feeding vessels arising from the proximal portion of different segmental renal arteries is likely to affect the technical success of treatment.

Background: Nutcracker syndrome is a rare entity, and in the majority of cases is the result of extrinsic compression of the left renal vein between the superior mesenteric artery and the aorta, associated with functional stenosis., Objective: To present the case of a 19-year-old female with no significant medical history with confirmed diagnosed of nutcracker syndrome treated successfully by endovascular means., Clinical Case: She was referred to the Vascular Surgery Department with a 6-month history of macroscopic haematuria, after other aetiologies were ruled out. Abdominal computed tomography angiography revealed compression of the left renal vein; the patient underwent endovascular treatment, and a 12×16 mm balloon expandable stent was placed with immediate angiographic improvement, decreased pressure gradients and progressive resolution of haematuria. At one year, she remains symptom-free., Conclusion: Nutcracker syndrome is uncommon, and a high index of suspicion is needed. Macroscopic haematuria is not always present, and in our case stent placement demonstrated effectiveness in the resolution of symptoms at 12 months' follow--up. We also present a brief review of the literature., (Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.)

A 39-year-old man with nephrotic syndrome was admitted due to right dorsal pain. Contrast-enhanced CT led to a diagnosis of renal vein thrombosis and segmental pulmonary thromboembolism. Treatment with heparin and warfarin was started. After 1 month, pulmonary thromboembolism recurred. Warfarin was switched to edoxaban, and steroid therapy was initiated, which led to the remission of nephrotic syndrome and the disappearance of renal vein thrombosis. The efficacy of edoxaban was demonstrated; however, this drug has not been routinely selected for patients with renal disease. Our results suggest that edoxaban is also effective for treating venous thrombosis patients with nephrotic syndrome.

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., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Acute kidney injury (AKI) induced by clamping of renal vein or pedicle is more severe than clamping of artery, but the mechanism has not been clarified. In the present study, we tested our hypothesis that increased proximal tubular pressure (P t ) during the ischemic phase exacerbates kidney injury and promotes the development of AKI. We induced AKI by bilateral clamping of renal arteries, pedicles, or veins for 18 min at 37°C, respectively. P t during the ischemic phase was measured with micropuncture. We found that higher P t was associated with more severe AKI. To determine the role of P t during the ischemic phase on the development of AKI, we adjusted the P t by altering renal artery pressure. We induced AKI by bilateral clamping of renal veins, and the P t was changed by adjusting the renal artery pressure during the ischemic phase by constriction of aorta and mesenteric artery. When we decreased renal artery pressure from 85 ± 5 to 65 ± 8 mmHg, P t decreased from 53.3 ± 2.7 to 44.7 ± 2.0 mmHg. Plasma creatinine decreased from 2.48 ± 0.23 to 1.91 ± 0.21 mg/dl at 24 h after renal ischemia. When we raised renal artery pressure to 103 ± 7 mmHg, P t increased to 67.2 ± 5.1 mmHg. Plasma creatinine elevated to 3.17 ± 0.14 mg·dl·24 h after renal ischemia. Changes in KIM-1, NGAL, and histology were in the similar pattern as plasma creatinine. In summary, we found that higher P t during the ischemic phase promoted the development of AKI, while lower P t protected from kidney injury. P t may be a potential target for treatment of AKI., (Copyright © 2017 the American Physiological Society.)

Background: The aim of this study is to demonstrate the usefulness of adding 3-dimensional (3D) ultrasound in evaluation of renal transplant vasculature compared to 2-dimensional (2D) Duplex ultrasound., Methods: One hundred thirteen consecutive renal transplant 2D and 3D ultrasound examinations were performed and retrospectively reviewed by 2 board-certified radiologists and a radiology resident individually; each reviewed 2D and then 3D images, including color and spectral Doppler. They recorded ability to visualize the surgical anastomosis and rated visualization on a subjective scale. Interobserver agreement was evaluated. Variant anastomosis anatomy was recorded. Tortuosity or stenosis was evaluated if localized Doppler velocity elevation was present., Results: The reviewers directly visualized the anastomosis more often with 3D ultrasound ((Equation is included in full-text article.)=97.5%) compared with 2D ((Equation is included in full-text article.)=54.5%) [difference in means (DM) = 43% (95% confidence interval (CI) = 36%-50%) (P < 0.001)]. The reviewers visualized the anastomosis more clearly with 3D ultrasound (P < 0.001) [difference in medians = 0.5, 1.0, and 1.0, (95% CI = 0.5-1.0, 0.5-1.0, and 1.0-1.5)]. Detection of variant anatomy improved with 3D ultrasound by 2 reviewers [DM = 7.1% and 8.9% (95% CI = 1%-13% and 4%-14%, respectively) (P < 0.05)]. There was high interobserver agreement [(Equation is included in full-text article.)= 95.3%, (95% CI = 91.9%-98.7%) regarding anastomosis visualization among reviewers with wide-ranging experience., Conclusions: Direct visualization of the entire anastomosis was improved with 3D ultrasound. Three-dimensional evaluation improved detection of anatomic variants and identified tortuosity as the likely cause of borderline localized elevation in Doppler velocity. The data added by 3D ultrasound may obviate confirmatory testing with magnetic resonance angiography or computed tomographic angiography after equivocal 2D ultrasound results.

A 47-year-old male patient underwent living-related renal transplant. On day 3 posttransplant, without evidence of associated clinical symptoms, the patient's serum creatinine levels had increased. The patient was given immunosuppressive medication, and a followup Doppler ultrasonography revealed hypoechoic areas in the inferior pole of the renal parenchyma. Eventually, on day 25, there was no perfusion in the superior and inferior poles of the transplanted kidney. No venous flow was shown in the middle segment, and only arterial vascularization with a high resistive index and negative diastolic phase was observed. Renal biopsy showed acute humoral rejection. This was interpreted as venous thrombosis secondary to acute humoral rejection. Tissue plasminogen activator infusion, plasmapheresis, and hemodialysis were administered. After 1.5 months, arterial flow returned to its normal pattern and the renal allograft recovered by gaining back its full vascularity at the end of month 8.

Objectives: The purpose of this study was to examine whether the maternal renal interlobar vein impedance index as assessed by first-trimester sonography is able to predict the later development of hypertensive disorders of pregnancy., Methods: Venous Doppler parameters of both maternal kidneys were studied in 214 pregnant women at gestational ages of 11 weeks to 13 weeks 6 days. Patients were classified according to outcomes related to hypertensive disorders. Detection rates and areas under receiver operating characteristic curves were determined for the maternal renal interlobar vein impedance index as a first-trimester predictor of preeclampsia and gestational hypertension., Results: Among the 214 patients, 22 (10.3%) developed preeclampsia; 10 (4.7%) developed gestational hypertension; and 182 were unaffected by hypertensive disorders (controls; 85.0%). In the overall study population, there was no difference in the impedance index between the right (0.44; 95% confidence interval, 0.35-0.50) and left (0.43; 95% confidence interval, 0.35-0.53) sides (P = .86). The average impedance index did not differ among women destined to develop preeclampsia (0.46; 95% confidence interval, 0.38-0.57), gestational hypertension (0.39; 95% confidence interval, 0.33-0.46), or pregnancies uncomplicated by hypertensive disease (0.42; 95% confidence interval, 0.37-0.50; P = .15). Low detection rates and the area under the curve analysis demonstrated that the impedance index was not predictive of hypertensive disorders of pregnancy., Conclusions: The maternal renal interlobar vein impedance index should not be considered a first-trimester marker of hypertensive disorders of pregnancy., (© 2016 by the American Institute of Ultrasound in Medicine.)

The morbidity and mortality associated with preeclampsia is staggering. The physiology of the Page kidney, a condition in which increased intrarenal pressure causes hypertension, appears to provide a unifying framework to explain the complex pathophysiology. Page kidney hypertension is renin-mediated acutely and ischemia-mediated chronically. Renal venous outflow obstruction also causes a Page kidney phenomenon, providing a hypothesis for the increased vulnerability of a subset of women who have what we are hypothesizing is a "renal compartment syndrome" due to inadequate ipsilateral collateral renal venous circulation consistent with well-known variation in normal venous anatomy. Dynamic changes in renal venous anatomy and physiology in pregnancy appear to correlate with disease onset, severity, and recurrence. Since maternal recumbent position is well known to affect renal perfusion and since chronic outflow obstruction makes women vulnerable to the ischemic/inflammatory sequelae, heightened awareness of renal compartment syndrome physiology is critical. The anatomic and physiologic insights provide immediate strategies to predict and prevent preeclampsia with straightforward, low-cost interventions that make renewed global advocacy for pregnant women a realistic goal., (Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.)