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.

Efficacy and safety of low-dose aspirin on preventing transplant renal artery stenosis: a prospective randomized controlled trial

Background:Transplant renal artery stenosis(TRAS)is a vascular complication after kidney transplantation associated with poor outcomes.This study aimed to analyze the efficacy and safety of low-dose aspirin for preventing TRAS.Methods:After kidney transplantation,patients were enrolled from January 2018 to December 2020 in Henan Provincial People’s Hospital.A total of 351 enrolled recipients were randomized to an aspirin group with low-dose intake of aspirin in addition to standard treatment(n=178),or a control group with only standard treatment(n=173).The patients was initially diagnosed as TRAS(id-TRAS)by Doppler ultrasound,and confirmed cases were diagnosed by DSA(c-TRAS).Results:In the aspirin and control groups,15.7%(28/178)and 22.0%(38/173)of the recipients developed id-TRAS,respectively,with no statistical difference.However,for c-TRAS,the difference of incidence and cumulative incidence was statistically significant.The incidence of c-TRAS was lower in the aspirin group compared with the control group(2.8%[5/178]vs.11.6%[20/173],P=0.001).Kaplan–Meier estimates and Cox regression model identified the cumulative incidence and hazard ratio(HR)of TRAS over time in two groups,showing that recipients treated with aspirin had a significantly lower risk of c-TRAS than those who were not treated(log-rank P=0.001,HR=0.23,95%confidence interval[CI]:0.09–0.62).The levels of platelet aggregation rate(P<0.001),cholesterol(P=0.028),and low-density lipoprotein cholesterol(P=0.003)in the aspirin group were decreased compared with the control group in the third-month post-transplantation.For the incidence of adverse events,there was no statistical difference.Conclusion:Clinical application of low-dose aspirin after renal transplant could prevent the development of TRAS with no significant increase in adverse effects.Trial Registration:Clinicaltrials.gov,NCT04260828.

Analysis of Renal Artery Stenosis in Patients with Heart Failure： A RASHEF Study

Background： Previous data are controversial about the association of renal artery stenosis （RAS） with clinical outcome in patients with heart failure. Definition of RAS in previous studies might not be appropriate. By definition of RAS with renal duplex sonography, we investigated the association of RAS with clinical outcome in patients with heart failure. Methods： In this retrospective study, we identified 164 patients with heart failure （New York Heart Association classification ≥11; left ventricular ejection fraction 〈50%） who had received renal duplex sonography during hospital stay. RAS was defined as renal-aortic ratio 〉3.5 or a peak systolic velocity ≥200 cm/s （or both）, or occlusion of the renal artery. Categorical data of patients were compared using the Chi-square test or Fisher＇s exact test. Cox proportional hazards regression modeling technique was used to investigate the prognostic significance of possible predictors. Results： Finally, 143 patients were enrolled, Median follow-up time was 32 months （1-53 months）. Twenty-two patients were diagnosed as RAS by renal duplex sonography, including 13 unilateral RAS （3 left RAS, l0 right RAS） and 9 bilateral RAS. There were more all-cause mortality and cardiovascular death in patients with RAS than patients without RAS. By multivariate analysis, RAS was a significant predictor for all-cause death and cardiovascular death （hazard ratio [HR] = 4.155, 95% confidence interval [（7/]： 1.546-1 1. 164, P = 0.005; and MR = 3.483, 95% CI： 1.200-10.104, P = 0.022, respectively）. As for composite endpoint events, including death, nonfatal myocardial infarction, ischemic stroke or intracranial hemorrhage, rehospitalization for cardiac failure, and renal replacement therapy, only angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker was significant predictor. RAS was not a significant predictor for composite endpoint events. Conclusions： Our data suggested that RAS is associated with a poorer clinical outcome in patients with heart failure.

Percutaneous transluminal renal angioplasty with stent is effective for blood pressure control and renal function improvement in atherosclerotic renal artery stenosis patients

Background Percutaneous transluminal renal angioplasty with stent is an effective procedure for atherosclerotic renal artery stenosis. However, the decision to perform this procedure has recently raised considerable debate. The aim of this study was to assess the effects of percutaneous transluminal renal angioplasty with stent in atherosclerotic renal artery stenosis patients, especially as it relates to blood pressure control and renal function improvement. Methods A retrospective analysis was made of the clinical data from 125 atherosclerotic renal artery stenosis patients who underwent percutaneous transluminal renal angioplasty from July 2004 to June 2008 in the Department of Vascular Surgery of Beijing Chaoyang Hospital. We compared blood pressure, number of oral antihypertensive medications, and renal function changes pre and post-procedure at 24 months follow-up. Results A total of 125 atherosclerotic renal artery stenosis patients underwent percutaneous transluminal renal angioplasty and 143 stents were placed. At 24 months follow-up, both systolic and diastolic blood pressure and the number of oral antihypertensive medications were significantly reduced （P 〈0.05）. Overall, the estimated glomerular filtration rate did not change significantly （P〉0.05）; however, a significant increase in estimated glomerular filtration rate was observed in the subgroup of patients with a lower baseline estimated glomerular filtration rate and in the subgroup of patients with bilateral renal artery stenosis （P 〈0.05）. Conclusion Percutaneous transluminal renal angioplasty patients, providing a significant improvement in blood antihypertensive medications. s a safe procedure for atherosclerotic renal artery stenosis pressure control and reduction in the number of oral

Dynamic changes of renal cortical blood perfusion before and after percutaneous transluminal renal artery stenting in patients with severe atherosclerotic renal artery stenosis

Background:This study aims to observe the dynamic changes of renal artery(RA)disease and cortical blood perfusion(CBP)evaluated by contrast-enhanced ultrasound(CEUS)after percutaneous transluminal renal artery stenting(PTRAS)in patients with severe atherosclerotic renal artery stenosis(ARAS)and to analyze the relationship between CBP and prognosis.Methods:This was a single-center retrospective cohort study.A total of 98 patients with unilateral severe ARAS after successful PTRAS in Beijing Hospital from September 2017 to September 2020 were included.According to renal glomerular filtration rate(GFR)detected by radionuclide imaging at 12 months after PTRAS,all patients were divided into the poor prognosis group(n=21,GFR decreased by≥20%compared with baseline)and the control group(n=77,GFR decreased by<20%or improved compared with baseline).Renal artery stenosis was diagnosed by digital subtraction angiography,and renal CBP was evaluated by CEUS using TomTec Imaging Systems(Germany)before PTRAS,at 6 months and 12 months after discharge.The receiver operating characteristic(ROC)curve with area under the curve(AUC)was used to analyze the predictive value of CBP parameters,including area under ascending curve(AUC1),area under the descending curve(AUC2),rising time(RT),time to peak intensity(TTP),maximum intensity(IMAX),and mean transit time(MTT)for poor prognosis.Results:Among the 98 patients,there were 52 males(53.1%),aged 55–74 years old,with an average age of 62.1±8.7 years,and an average artery stenosis of 82.3±12.9%.The poor prognosis group was associated with significantly increased incidence of diabetes(76.2%vs.41.6%),and lower levels of GFR of the stenotic kidney(21.8 mL/min vs.25.0 mL/min)and total GFR(57.6 mL/min vs.63.7 mL/min)(all P<0.05),compared with the control group(P<0.05).In addition,the rate of RA restenosis was significantly higher in the poor prognosis group than in the control group(9.5%vs.0,χ^(2)=9.462,P=0.002).Compared with the control group,the poor prognosis group was associated with significantly decreased baseline AUC1 and AUC2,and extended duration of TTP and MTT(P<0.05).At 6 months and 12 months of follow-up,patients in the control group were associated with markedly increased AUC1,AUC2,and IMAX,and shorter duration of RT and MTT(P<0.05).The ROC curve showed that the predictive values of AUC1,AUC2,RT,TTP,IMAX,and MTT for poor prognosis were 0.812(95%CI:0.698–0.945),0.752(95%CI:0.591–0.957),0.724(95%CI:0.569–0.961),0.720(95%CI:0.522–0.993),0.693(95%CI:0.507–0.947),and 0.786(95%CI:0.631–0.979),respectively.Conclusions:Preoperative renal CBP in severe ARAS patients with poor prognosis is significantly reduced,and does not show significant improvement after stent treatment over the first year of follow-up.The parameter AUC1 may be a good predictor for renal dysfunction after PTRAS in severe ARAS patients.Trial Registration:ChiCTR.org.cn,ChiCTR1800016252.

Effect of Huanshuai Recipe Oral Liquid (缓衰口服液) on Renal Dysfunction Progression in Patients with Atherosclerotic Renal Artery Stenosis

Objective： To investigate the effect of Huanshuai Recipe Oral Liquid （缓衰口服液, HSR） on retarding the progression of renal dysfunction in patients with atherosclerotic renal artery stenosis （ARAS）. Methods： A total of 52 ARAS patients with the Chinese medicine （CM） syndrome of qi deficiency and blood stasis, phlegm and dampness retention were recruited and randomly assigned into the treatment group （36 cases） and the control group （16 cases）. Both groups received a basic treatment （high-quality low-protein diet, blood pressure control, lipid-lowering, correcting the acidosis, etc.）. In addition, the treatment group received 20 mL HSR and the control group received placebo, 3 times a day for 6 months. Renal function （serum creatinine, blood urea nitrogen and uric acid） and blood lipids （cholesterol, triglycerides and low density lipoprotein） were examined monthly. The estimated glomerular filtration rate （eGFR） and CM syndrome score were compared between groups. Results： After treatment, compared with the control group, the serum creatinine level, uric acid level and CM syndrome score of the treatment group were significantly decreased （P〈0.05 or P〈0.01）, and the eGFR in the treatment group were significantly increased （P〈0.05）. Conclusion： HSR can effectively improve the renal function and clinical symptoms of ARAS patients.

Role of non-contrast balanced steady-state free precession megnetic resonance angiography compared to contrast-enhanced megnetic resonance angiography in diagnosing renal artery stenosis： a meta-analysis

Background Balanced steady-state free precession MR angiography （b-SSFP MRA） has shown great promise in diagnosing renal artery stenosis （RAS） as a non-contrast MR angiography （NC-MRA） method. However, results from related studies are inconsistent. The purpose of this meta-analysis was to assess the accuracy of b-SSFP MIRA compared to contrast-enhanced MR angiography （CE-MRA） in diagnosing RAS. Methods English and Chinese studies that were published prior to September 4, 2013 and that assessed b-SSFP MRA diagnostic performance in RAS patients were reviewed. Quality of the literature was assessed independently by two observers. The statistical analysis was adopted by the software of Meta-Disc version 1.4. Using the heterogeneity test, a statistical effect model was chosen to calculate different pooled weighted values. The receiver operator characteristic （ROC） space and Spearman correlation coefficient were to explore threshold effect. Sensitivity analysis and the publication bias were performed to demonstrate if the pooled estimates were stable and reliable. We produced forest plots to calculate the pooled values and corresponding 95% confidence interval （Cl） of sensitivity, specificity, positive likelihood ratio （PLR）, negative likelihood ratio （NLR）, diagnostic odds ratio （DOR）, and constructed a summary receiver operating characteristic curve （SROC） to calculate the area under the curve （AUC）. Results A total of 10 high quality articles were used in this meta-analysis. The studies showed a high degree of heterogeneity. The ＂shoulder-arm＂ shape in the ROC plot and the Spearman correlation coefficient between the log（SEN） and Iog（1-SPE） suggested that there was a threshold effect. Sensitivity analysis demonstrated that the actual combined effect size was equal to the theoretical combined effect size. The publication bias was low after quality evaluation of the literature and the construction of a funnel plot. The pooled sensitivity was 0.88 （95% CI, 0.83-0.91） and pooled specificity was 0.94 （95% CI, 0.93-0.95）; pooled PLR was 14.57 （95% CI, 9.78-21.71]） and pooled NLR was 0.15 （95% CI, 0.11- 0.20）. The AUC was 0.964 3. Conclusion In contrast to CE-MRA, the b-SSFP MIRA is more accurate in diagnosing RAS, and may be able to replace other diagnostic methods in patients with renal insufficiency.

EXPERIMENTAL RENAL ARTERY STENOSIS AND ANGIOPLASTY THE MECHANISM OF THE ANGIOPLASTY

The mechanism of percutaneous transluminal renal angioplasty (PTRA) was studied in 18 dogs. The dogs were divided into two groups. Seven dogs were in the early group and eleven were within 1-3 weeks after PTRA. A 4 / 0 resorbable chronic catgut was used to Hgate subtotally the renal artery to create fibromuscular dysplasia. PTRA was performed after renal artery stenosis for 6-8 weeks. The changes of ultrastructure of renal artery were studied. A countrary orientation balance hypothesis was proposed to explain the mechanism of PTRA.

Accessory renal arteries-a source of hypertension:A case report

BACKGROUND Secondary hypertension is a relatively rare condition most commonly caused by renovascular disease due to atherosclerotic vascular disease or fibromuscular dysplasia.Although accessory renal arteries are frequent,to date,only six cases of secondary hypertension determined by their existence have been reported.CASE SUMMARY We describe a case of a 39-year-old female who came to the emergency department with an urgent hypertensive crisis and hypertensive encephalopathy.Despite normal renal arteries,the computed tomography angiography revealed an inferior polar artery with 50%stenosis of its diameter.Conservative treatment with amlodipine,indapamide and perindopril was adopted,leading to blood pressure control within one month.CONCLUSION To the best of our knowledge,there are controversies regarding accessory renal arteries as a potential etiology for secondary hypertension,but the seven similar cases already described,along with the current case,could reinforce the necessity of more studies concerning this subject.

Diagnosis and spontaneous healing of asymptomatic renal allograft extra-renal pseudo-aneurysm:A case report

BACKGROUND Transplant renal artery stenosis is a relatively frequent vascular complication after transplantation.However,extra-renal pseudo-aneurysms(EPSAs)are rare after transplantation;they can be life-threatening and usually need open surgical repair.We discuss the diagnosis and spontaneous healing of an asymptomatic renal allograft EPSA caused by renal artery anastomotic stenosis,which was diagnosed in a timely manner and managed by conservative treatments.CASE SUMMARY We present a 37-year-old male patient diagnosed with a renal allograft EPSA caused by renal artery anastomotic stenosis due to multiple atherosclerotic plaques with ultrasonographic examination 6 mo post transplantation.The stenosis rate of 90%and the EPSA were verified by computed tomography angiography.The diagnosis was further confirmed with digital subtraction angiography.Percutaneous transluminal angiography was conducted,and a metallic stent was successfully implanted at the stenosed site of the main renal artery trunk.No further intervention for the EPSA was undertaken due to the difficulty of stenting and the risk of bleeding;regular ultrasonographic follow-ups were recommended.The stenosis was significantly relieved immediately after stent implantation and the EPSA was healed spontaneously by completely filling with hypo-echoic thrombosis 8 mo after stenting.CONCLUSION Ultrasonography combined with a high-frequency linear probe can detect vascular complications post renal transplantation at an early stage and improve prognosis.

Effects of renal artery stenting on renal function and blood pressure in patients with atherosclerotic renovascular disease

Objective To study the effects of percutaneous renal artery intervention on renal function and blood pressure in patients with renal artery stenosis. Methods Eighty-seven patients with severe uni- or bi-lateral renal artery stenosis (luminal diameter narrowing ≥70%) and clinical hypertension received renal artery stenting between January 2002 and December 2002. The changes in blood pressure and serum creatinine level and creatinine clearance (CCr) 48 hours after intervention and during 6 months of follow-up were assessed.Results Renal stenting was performed in 98 stenotic arteries of 87 patients,and the procedural success rate was 100%. Serum creatinine level was slightly elevated from (176±21) μmol/L to (179±11) μmol/L ( P =0.15) 48 hours after the procedure,but significantly decreased to (149±15) μmol/L at 6 months ( P <0.001). CCr was also greatly improved [(37±11) ml/min before versus (51±8) ml/min at 6 months,P <0.001]. During follow-up,61% of the patients experienced a normal renal function. Despite conventional medical treatment,systolic and diastolic blood pressures were also significantly decreased after stenting [(163±23)/(96±13) mm Hg before versus (148±12)/(79±15) mm Hg at 6 months,all P <0.001],and hypertension was well controlled in 67% of the patients at 6 months’ follow-up.Conclusion Renal artery stenting has a high success rate and is effective in improving renal function and blood pressure for patients with severe renal artery stenosis.

Renal subcapsular haematoma： an unusual complication of renal artery stenting

After successful renal artery angioplasty and stent placement, a patient in a fully anticoagulated state developed hypotension and flank pain. Computed tomography （CT） of the abdomen revealed a large renal subcapsular haematoma which was successfully managed conservatively without embolotherapy and surgical intervention. To prevent hemorrhage after renal artery stenting, it is necessary to underscore the importance of reducing the contrast volume and pressure of angiography, controlling systemic blood pressure, and monitoring guide wire position at all times.

Recurrence of resistant hypertension after renal artery stent implantation: A case report

Takayasu＇s Arteritis is a chronic non-specific inflammatory vascular disease involving the aorta and its major branches. Takayasu＇s arteritis is one of important reason for renal artery stenosis（RAS） which may result in severe hypertension. Angioplasty, preferably with stenting, is recommended in RAS secondary to atherosclerosis. However, the safety and efficacy of stent implantation is still unclear in RAS caused by Takayasu＇s arteritis. In order to raise the awareness for the importance of Takayasu＇s arteritis in renal artery disease and further to discuss the endovascular revascularization strategies, we are going to present a case report regarding RAS resulted by Takayasu＇s arteritis and provide a timely summary and update on current understanding.

Noninvasive assessment of renal fractional flow reserve： are we there yet？

The highly diagnostic performance of renal transstenotic pressure gradients （TSPG） and fractional flow reserve （FFR） has been well validated for assessment of the hemodynamic renal artery stenosis （RAS）.1-4 Accordingly,an expert consensus panel of the American Heart Association recommended that a peak systolic gradient of at least 20 mmHg （1 mmHg=0.133 kPa）,or a mean pressure gradient of 10 mmHg,be used to identify candidate lesions for revascularization in symptomatic patients with RAS.

Fractional Flow Reserve： From Homeland to Colony

In current catheter research, there are 3 main directions with respect to fractional flow reserve （FFR）, including instantaneous wave-tree ratio, noninvasive measurement of FFR, and FFR transferred from coronary circulation to other ischemia-inducing circulation. Recently, an interesting study was published, in which FFR was performed to diagnose and guide stenting in chronic mesenteric ischemia （CMI）. We herein highlighted, the implications and limitations of FFR from coronary artery to renal artery and mesenteric artery for future investigations, respectively.