Preliminary Evaluation of Hemodynamic Effects of Fontan Palliation on Renal Artery Using Computational Fluid Dynamics

Background:The assessment of renal function is important to the prognosis of patients needing Fontan palliation due to the reconstructed compromised circulation.To know the relationship between the kidney perfusion and hemodynamic characteristics during surgical design could reduce the risk of acute kidney injury(AKI)and the postoperative complications.However,the issue is still unsolved because the current clinical evaluation methods are unable to predict the hemodynamic changes in renal artery(RA).Methods:We reconstructed a three-dimensional(3D)vascular model of a patient requiring Fontan palliation.The technique of computational fluid dynamics(CFD)was utilized to explore the changes of RA hemodynamics under different possible blood flow rates.The relationship between the kidney perfusion and hemodynamic characteristics was investigated.Results:The calculated results indicated the declined tendency of the pressure and pressure drop as the flow rate decreased.When the flow rate decreased to two-thirds of its baseline,both the pressure of left renal artery(LRA)and the pressure of right renal artery(RRA)dipped below 50%,and the pressure of RRA fell more quickly than that of LRA.Uneven distribution of WSS was observed on the trunk of RA,and the lowest WSS was found at the distal of RA.The average WSS in RA dropped to around 50%as the flow rate reached one-third of its baseline.Conclusions:As a promising approach,CFD can be utilized to quantitatively evaluate the hemodynamic characteristics of RA and contribute to offsetting the drawbacks of clinical assessments of renal function,to help realize better prognosis for the patients with Fontan palliation.

Effects of renal artery stenosis on realistic model of abdominalaorta and renal arteries incorporating fluid-structureinteraction and pulsatile non-Newtonian blood flow

The effects of the renal artery stenosis （RAS） on the blood flow and vessel walls are investigated. The pulsatile blood flow through an anatomically realistic model of the abdominal aorta and renal arteries reconstructed from CT-scan images is simulated, which incorporates the fluid-structure interaction （FSI）. In addition to the investigation of the RAS effects on the wall shear stress and the displacement of the vessel wall, it is determined that the RAS leads to decrease in the renal mass flow. This may cause the activation of the renin-angiotension system and results in severe hypertension.

Renal artery embolization in the treatment of urinary fistula after renal duplication:A case report and review of literature

BACKGROUND Duplicate renal malformation is a congenital disease of the urinary system,with an incidence rate of 0.8%.Surgical treatment is suitable for symptomatic patients.Urinary fistula is one of the complications of heminephrectomy.Long-term urinary fistula has a great impact on patients'lives.CASE SUMMARY This article mainly reports on a 47-year-old man with duplication of kidney deformity,long urinary fistula after partial nephrectomy,and no improvement after conservative treatment.We have achieved positive results in the arterial embolization treatment of the residual renal artery,indicating that selective arterial embolization is a good way to treat urinary fistula after partial nephrectomy.It is worth noting that this patient violated the Weigert-Meyer law,which also gave us more consideration.CONCLUSION Renal artery embolization may be a simple and safe method to treat urinary fistula inefficacy with conservative treatment.

Pharmacokinetics of Native r-SAK in Rabbit's Femoral Artery Thrombosis Model

Objective: To study the pharmacokinetics of native r SAK in rabbit's femoral artery thrombosis model, the “lytic circle' method was used to determine plasma levels of r SAK. Methods: Thirty New Zealand rabbits were randomly assigned to the control (saline 10 ml, 30 min), r SAK low dose (0.25 mg/kg, 30 min), medial dose (0.50 mg/kg, 30 min), high dose (1.00 mg/kg, 30 min), single bolus (0.50 mg/kg, 2 min) and conjunctive therapy (initiated with heparin 200 U/kg, followed by infusion of r SAK 0.50 mg/kg for 30 min, and subsequently infused heparin 50 U/(kg·h) to endpoint) groups. The right femoral artery thrombosis model in rabbit was made by balloon injury, then the thrombolytic agents were infused through parallel ear vein and the blood samples were collected pre thrombolysis and at different time post thrombolysis to determine the plasma levels of r SAK by “lytic circle' method, the plasma levels of r SAK were processed by pharmacokinetic computing procedure to fit the model. Results: The plasma levels of r SAK and the diameters of lytic circles showed a pretty good linear correlation under the scope of 2.0×10 4 2.0×10 6 U/L, and the averaged recycle rate was (96.05±11.35)%(RSD =±11.82%).All peak concentration time in each infusion group was 30 min, and the peak concentrations positively correlated with the doses administrated in infusion groups(r=0.999 98, P <0.000 1). In single bolus group, Peak concentration time was 2 min, and the peak concentration reached (5.16±1.02) mg/L, which was significant higher than that in the same dose r SAK infusion group ( P <0.01). In conjunctive therapy group, the peak concentration showed no significant difference from that in the same dose r SAK infusion group ( P >0.05). The plasma levels of r SAK fit in two compartment model as processed by pharmacokinetic computing procedure in each group. Conclusion: The “lytic circle' method is a simple, practical and reliable method to determine the plasma level of r SAK, and the pharmacokinetics of native r SAK infusion fits in two compartment model in rabbit's femoral artery thrombosis model.

Retrieval of dislodged coronary stent from left renal artery by gooseneck snare

A rapamycin-eluting stent was dislodged during attempt of implantation at the proximal right coronary artery,which was found by fluoroscopy to have migrated into the anterior trunk of the left renal artery.We chose a 5 mm diameter Amplatz gooseneck snare and successfully retrieved the lost stent from the lodging vessel.

Rotarex mechanical thrombectomy in renal artery thrombosis:A case report

BACKGROUND Acute renal artery thrombosis is a relatively rare disease.Early diagnosis and emergent treatment can prevent the loss of renal function and the development of hypertension.CASE SUMMARY We report a patient with acute renal artery thrombosis who presented to our hospital with acute-onset right flank pain and was treated by percutaneous mechanical thrombectomy using the Rotarex device.After 2 mo,right kidney function had recovered slightly.CONCLUSION Renal artery thrombosis may lead to loss of renal function and the development of hypertension.Rotarex mechanical thrombectomy may be a viable treatment option for rapid recanalization of the renal artery in patients with renal artery thrombosis.

Renal function after renal artery stenting

Atherosclerotic renal artery stenosis (ARAS), a common clinical finding, is increasing in prevalence as the population ages. ARAS is seen in ～ 7% of persons over 65 years of age1 and in ～ 20% of patients at the time of coronary angiography.2 It is an important cause of chronic kidney disease and may result in 11-14% of cases of end stage renal disease.

Main Renal Artery Plus Branch Ablation in the Treatment of Resistant Hypertension with Renal Denervation

Objective:To study the safety and effi cacy of denervation of renal artery branches in the treatment of resistant hy-pertension.Methods:Sixty patients with resistant hypertension were enrolled.The patients were randomly assigned to the main renal artery plus branch ablation group or the main renal artery ablation group.The clinical data and operation-related parameters,including number of ablation points,temperature,and average energy,were recorded.Ambulatory blood pressure was taken for all patients at the baseline and at 6 months after treatment.Offi ce blood pressure was recorded before treatment and after treatment every 3 months for 2 years.Results:Sixty patients with resistant hypertension were enrolled in this study.There were 30 patients in each group.Angiography was performed after ablation.No renal artery complications,such as stenosis and dissection,occurred in the two groups.There was no signifi cant difference in age,sex,BMI,comorbid disease,and medication between the two groups(P>0.05).The number of ablation points for the main renal artery plus branch ablation group was greater than that for the main renal artery ablation group.The offi ce blood pressure and 24-hour blood pressure were signifi cantly lower 6 months after treatment than before treatment in both groups(P<0.05).Offi ce blood pressure in the main renal artery plus branch ablation group was lower than that in the main renal artery ablation group during the 3-12-month follow-up period,with a statistical difference.However,as the follow-up time increased,the difference disappeared.Conclusion:The results of this study show that main renal artery plus branch ablation is a safe interventional method,but there was no obvious advantage on long-term follow-up compared with only main renal artery ablation.

Common trunk of the right accessory renal artery and right inferior phrenic artery originating from the thoracic artery:An unreported variation

Accessory renal arteries(ARAs)are common and usually originate from the abdominal aorta and the renal artery.Inferior phrenic arteries(IPAs)can also arise from the abdominal aorta or its branches.In this paper,we present the first case of a common trunk of the right ARA and right IPA arising from the thoracic artery at the level of T10,which was discovered by multidetector-row computed tomography in pretherapeutic evaluation and clearly confirmed by selective angiography.It is important to recognize this anatomical variation when performing cardiovascular and interventional radiological procedures.

Enlarged and Colored Enhanced 3D Printing of Renal Artery Aneurysms for Improved Imaging and Treatment Planning

Three dimensional printing (3D printing) technology is increasingly used to improve results in many areas of medicine. Physical models produced by this technology allow better appreciation of complex anatomical and pathologic conditions. In cardiovascular medicine and surgery, 3D modeling has been reported to be of help in treatment planning of abdominal aortic aneurysm, especially in cases of complex angulations and branching at the aneurysm neck. Here we report the use of 3D printing in cases of renal aneurysms. Enhanced 3D models of CTA images of renal aneurysms were prepared in house using common and freely available software programs, and an accurate desktop 3D printer. Eight reconstructed models were enlarged by a factor of 2 or more and then differentially painted to delineate normal arteries and aneurysmatic ones. These enhanced 3D solid models allowed visual and tactile inspection for a better appreciation of complex aneurysms. Color enhancement of these models added another dimension of comprehension, even for experienced surgeons and invasive radiologists, and allowed more accurate measurements of branch numbers, distances, and angles in space even with severe tortuosity. Endovascular use of covered stents and embolization techniques could be easily envisioned preoperatively. We conclude that enhanced, enlarged, and colored 3D printed models are a powerful tool for preoperative endovascular treatment planning of complex renal artery aneurysms.

Acute renal artery occlusion following infliximab infusion

We report the case of a 44-year-old male patient who presented with acute renal artery occlusion, 3 d after frst injection of infiximab for steroid refractory attack of ulcerative colitis. Extensive work-up provided no evidence of predisposing factors for arterial thrombosis. Infiximab was thus suspected in the genesis of throm-bosis, based on both intrinsic and extrinsic criteria. At month 3 after thrombosis with ongoing anticoagulation, angio-tomodensitometry showed complete revascularization of the left renal artery with renal atrophy. Renal function remained normal and the patient was still in steroid free remission on mercaptopurin monotherapy at maximal follow-up. Few thromboembolic events have been described with anti- tumor necrosis factor （TNF） agents, but it is the frst case reported of renal artery thrombosis after infiximab infusion. In addition, we re-view thrombosis associated with anti-TNF agents.

Risk factors of renal artery pseudoaneurysm following partial nephrectomy

Objective To study the risk factors of renal artery pseudoaneurysm ( RAP) following partial nephrectomy. Methods Open partial nephrectomhy was performed on a total of 464 cases of renal cell cancer from July 2003 to May 2010. Five patients ( 1. 1% ) had postoperative hem-

Response of blood pressure after percutaneous transluminal renal artery angioplasty and stenting

AIM: To evaluate the short and intermediate term out-come of percutaneous transluminal renal artery angioplasty (PTRA) and stenting particularly on blood pressure (BP) control and renal function and to evaluate predictors of poor BP response after successful PTRA and stenting. METHODS: We conducted a prospective analysis of all patients who underwent PTRA and stenting in our institute between August 2010 to September 2012. A total number of 86 patients were underwent PTRA and renal stenting. Selective angiography was done to confirm at least 70% angiographic stenosis. The predilatation done except few cases with critical stenosis, direct stenting was done in the rest of cases. All patients received aspirin 325 mg orally, and clopidogrel 300 mg orally within 24 h before the procedure. Heparin was used as the procedural anticoagulant agent. Optimal results with TIMI-Ⅲ flow obtained in all cases. Following stent placement, aspirin 150 mg orally once daily was continued for a minimum of 12 mo and clopidogrel 75 mg orally once daily for at least 4 wk. The clinical, radiological, electrocardiography, echocardiography and treatment data of all patients were recorded. The BP measurement, serum creatinine and glomerular filtration rate (GFR) were recorded before the procedure and 1 and 6 mo after PTRA. RESULTS: A total of 86 patients were included in the study. The mean age of study population was 55.87±11.85 years old and 67 (77.9%) of patients were male. There was a significant reduction in both systolic and diastolic BP at 1 mo after the procedure: 170.15±20.10 mmHg vs 146.60±17.32 mmHg and 98.38±10.55 mmHg vs 89.88±9.22 mmHg respectively (P=0.0000). The reduction in BP was constant throughout the follow-up period and was evident 6 mo after the procedure: 144.23±18.19 and 88.26±9.79 mmHg respectively (P=0.0000). However, no improvement in renal function was observed at any time during the follow-up period. After multivariate analysis, we found male sex, low GFR (<60 mL/min) and higher baseline mean BP as a poor predictors of successful outcome on BP response after PTRA and stenting. CONCLUSION: The PTRA and stenting can be considered as an effective therapeutic intervention for improving BP control with minimal effect on renal function. The male sex, higher baseline BP and low GFR are associated with poor BP response after successful PTRA and stenting.

Successful endovascular treatment of endoscopically unmanageable hemorrhage from a duodenal ulcer fed by a renal artery: A case report

A 52-year-old woman was admitted with hypovolemic shock. Emergency endoscopy revealed three hemorrhagic duodenal ulcers(all stage A1) with exposed vessels. Two ulcers were successfully treated by endoscopic clipping; however, the remaining ulcer on the posterior wall of the horizontal portion of the duodenum could not be clipped. Because her vital signs were rapidly worsening, we performed transcatheter arterial embolization(TAE) as it is less invasive than surgery. Computed tomography aortography showed that the duodenal hemorrhage was sourced from the lower branch of the right renal artery. In general, the duodenum is fed by branches from the gastroduodenal artery or superior mesenteric artery. However, this patient had three right renal arteries. The lower branch of the right renal artery at the L3 vertebral level was at the same level as the horizontal portion of the duodenum. Complete hemostasis was achieved by TAE using metallic coils and n-butyl-2-cyanoacrylate. After TAE, she recovered from the hypovolemic shock and was discharged from hospital. She has had no recurrence of the hemorrhagic duodenal ulcer for over 1 yr, and followup endoscopy showed no necrosis or stricture of the duodenum. Although she developed a small infarct of her right kidney, her renal function was satisfactory. In summary, the present case is the first reported case of hemorrhagic duodenal ulcer in which the culprit vessel was a renal artery that was successfully treated by TAE. Computed tomography aortography before TAE provides valuable information regarding the source of a duodenal hemorrhage.

Drug coated balloon angioplasty for renal artery stenosis due to Takayasu arteritis: Report of five cases

BACKGROUND Takayasu arteritis is a rare but intractable chronic disease in young female patients. Percutaneous transluminal angioplasty of the involved renal arteries has been reported;however, few studies have reported the use of drug coated balloon angioplasty in the treatment of Takayasu arteritis. We aimed to demonstrate five young female patients who presented with a history of hypertension due to Takayasu arteritis. CASE SUMMARY From April 2017 to October 2018, five female patients were diagnosed with hypertension due to Takayasu arteritis by computed tomography angiography (CTA) and laboratory tests. Four patients had a complaint of headache with or without dizziness, and one patient showed no symptom. There was no significant family or past history of hypertension or kidney disease, and the physical examinations were almost normal on admission. We performed a treatment by drug coated balloon angioplasty. Blood pressure decreased dramatically in all patients after balloon angioplasty, and the patency of treated renal artery was demonstrated with CTA over 5 months after the angioplasty procedure. CONCLUSION Drug coated balloon angioplasty is safe and effective for renal artery stenosis due to Takayasu arteritis. A prospective study with a larger sample size is necessary to further demonstrate the effectiveness of the treatment.

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

BACKGROUND Multiple renal artery aneurysms (RAAs) involving multiple branches in a solitary kidney are rare and present a major challenge to surgeons.Ex vivo or in situ repair combined with renal artery revascularization is the classical procedure for these complicated cases,which are not suitable for endovascular repair.The choice of bypass graft remains controversial because of the risk of aneurysmal degeneration for autologous graft.CASE SUMMARY A 39-year-old female patient presented with left lumbar pain for more than 3 mo.Computed tomography angiography showed congenital absence of the right kidney and three left RAAs involving multiple distal branches.This patient met the criteria for surgical repair due to symptoms of threatened rupture.According to the anatomy and location of multiple RAAs,ex vivo revascularization with saphenous vein graft (SVG) was performed.At the 3-year follow-up,computed tomography angiography demonstrated the aneurysmal degeneration of the Yshaped SVG.The patient remained asymptomatic and follow-up ultrasound showed no continuous growth of SVG aneurysm.CONCLUSION SVG aneurysm in RAA revascularization causes us to reflect on the choice of graft,especially for solitary kidney patients.

Successful endovascular treatment of transplant intrarenal artery stenosis in renal transplant recipients: Two case reports

Transplant renal artery stenosis(TRAS) is a relatively rare complication after renal transplantation. The site of the surgical anastomosis is most commonly involved, but sites both proximal and distal to the anastomosis may occur, as well. Angioplasty is the gold standard for the treatment of the stenosis, especially for intrarenal lesions. We report two cases of intrarenal TRAS and successful management with angioplasty without stent placement. Both patients were male, 44 and 55 years old respectively, and they presented with elevated blood pressure or serum creatinine within three months after transplantation. Subsequently, they have undergone angioplasty balloon dilatation with normalization of blood pressure and serum creatinine returning to baseline level. Percutaneous transluminal balloon renal angioplasty is a safe and effective method for the treatment of the intrarenal TRAS.

Laparoscopic Partial Nephrectomy With Segmental Renal Artery Clamping:Technique and Clinical Outcomes

Background:Warm ischemic injury is one of the most important factors affecting renal function in partial nephrectomy(PN).The technique of segmental renal artery clamping emerges as an alternative to conventional renal artery clamping for renal hilar control.Objective:To evaluate the feasibility and efficiency of laparoscopic PN(LPN) with segmental renal artery clamping in comparison with the conventional technique.Design,setting,and participants:A total of 75 patients underwent LPN from June 2007 to November 2009.All patients had T1a or T1b tumor in one kidney and a normal contralateral kidney.Thirty-seven patients underwent surgeries with main renal artery clamping,and 38 underwent surgeries with segmental artery clamping.Intervention:All procedures were performed by the same laparoscopic surgeon.Measurements:Blood loss,operation time,warm ischemia(WI) time,and complications affected renal function before and after operation were recorded.Results and limitations:All LPNs were completed without conversion to open surgery or nephrectomy.The novel technique slightly increased WI time(p < 0.001) and intraoperative blood loss(p = 0.006),while it provided better postoperative affected renal function(p < 0.001) compared with the conventional technique.The total complication rate was 12%.Among the 38 cases where segmental renal artery clamping was performed,7 had to convert to the conventional method.Tumor size and location influenced the number of clamped segmental arteries.Long-term postoperative renal function is still awaited.Conclusions:LPN with segmental artery clamping is safe and feasible in clinical practice.It minimizes the intraoperative WI injury and improves early postoperative affected renal function compared with main renal artery clamping.(C) 2010 European Association of Urology.Published by Elsevier B.V.All rights reserved.

Histomorphological observation in arterial remodeling following New Zealand rabbit auto-extremity artery transplantation

Objective： To investigate the histomorphological change in auto-extremity artery following transplantation. Methods： 50 New Zealand rabbits were randomly divided into 5 groups（postoperative 1 d, 3 d, 7 d, 14 d, 56 d, n = 10）. Femoral artery was harvested and end-to-side anastomosed with carotid in order to build the auto-extremity arterial graft animal model. On the postoperative 1^st, 35^nd, 7^th, 14th and 56^th days, grafts for morphometric analysis under the Image analysis system were obtained; and electron microscope was scanned to observe endothelial cells. In addition, Immunostaining of sections were performed with the mouse monoclonal antibody of the a -smooth muscle isoform of actin and proliferating cell nuclear antigen antibody. Results： Overall patency rate for all conduits was 86%.The intimal hyperplasia was first observed in the 7^th day group, and continued to increase in the 56^th day group（183.21 ± 111.74） μ m, P 〈 0.01. Additionally, the luminal narrowed（32.43 ± 18.28）% in the 56^th day group. Smooth muscle cells were the mainly hyperplastic components. The most active proliferation of cells was detected in the 14^th day group, where the extracellular matrix gradually deposited in the intima. Conclusion： Moderate intimal hyperplasia occurred in arterial conduits and vascular structure experienced constrictive remodeling after auto-transplantation.

Terutroban, a TP receptor antagonist, restores renal artery tone, but not renal function in mouse with 5/6 nephrectomy

Aim Thromboxane A2（TXA2） is assumed to contribute to the process of renal dysfunction. The pres- ent study was designed to investigate whether terutroban, a specific antagonist of thromboxane/prostaglandin？ （TP） receptor, protects against renal damage in 5/6 nephrectomy. Methods C57/BL6 mice were randomly grouped into sham-operated （2K）, 5/6 nephroectomy groups （5/6K-off） and 5/6 nephroectomy treated with ter- utroban （10 mg · kg^-1 · d^-l） groups （Yerutroban）. Renal artery and kidney were collected for vascular function study, Western blot, immunohistochemistry （IHC） assay and enzyme-linked immunosorbent assay （ELISA）, re- spectively. Results Four weeks after the surgery, arterial blood pressure was comparable among the three groups. However mice in terutroban group had higher levels of serum creatinine and lower survival. Compared with 2K groups, 5/6K-off mice had significantly higher levels of renal blood flow as well as a blunted relaxation to acetyl- choline. Production of prostacyclin （PGI2） and thromboxane B2 （ TXB2）, but no prostaglandin E2 （ PGE2）, were significantly increased in the renal artery of 5/6K-off group. Terutroban restored the renal blood flow, but not the acetylcholine-induced relaxation in the renal artery. It is probably due to the blockade effect of terutroban on the smooth muscle since terutroban treatment significantly reduced U46619-induced vasconstriction in renal arteries. Interestingly, terutroban increased the production of TXB2, but not PGI2 or PGE2, in the renal artery. This proba-bly is a compensatory effect on prostaglandins production. In kidney cortex, 5/6K-off group had significantly lower levels of PGE2 and TXB2 when compared with 2 K group. Terutroban markedly increased all three prostaglandins levels. Conclusion Terutroban restores renal artery function, but not renal function in mouse with 5/6 nephrecto- my. It suggests that kidney has more complicated regulations than renal artery. High levels of prostanoids in kid- neys may contribute to renal damage in terutroban group. Further experiments will focus on examining the underly- ing mechanisms.