Renal Artery Patency Research Articles

Issues of differential diagnosis of diseases accompanied by impaired patency of renal arteries at a young age

The article considers the most common causes of renal artery patency, diagnostic process algorithms and differential diagnosis for renal artery stenosis at different ages. The first significant clinical manifestation of renal artery stenosis of various etiologies is arterial hypertension (AH). It is poorly controlled AH, including resistant AH, developing at a young age, that is the basis for the diagnostic search for secondary causes of high blood pressure, including narrowing of the renal arteries. The article presents a clinical case of uncontrolled AH in a young man. A comprehensive assessment of clinical manifestations, laboratory and instrumental examination results made it possible to diagnose unilateral renal artery stenosis of atherosclerotic genesis.

Early multicentric outcomes of the on-label and CE-marked combination of the Endurant with the Radiant chimney graft for the chimney endovascular aortic repair (EnChEVAR): The LaMuR Registry.

The aim of this study was to evaluate the early results of the CE-marked standardized device combination consisting of Endurant and the Radiant chimney graft (En-ChEVAR) for the treatment of juxtarenal aortic aneurysms. We analyzed multicentric non-industry sponsored case series evaluating the EnChEVAR technique for patients treated between December 2022 and February 2024. Clinical, perioperative procedure-related and radiological data were collected. The primary outcome measure was the freedom of a type Ia gutter-related endoleak at postoperative computed tomography angiography (CTA). Secondary outcome measures included early type Ia endoleak-related reinterventions, target vessel complications including dissection or loss of target vessel, major adverse events, and mortality. Continuous variables were presented as median (interquartile range [IQR]) and categorical variables as count and percentage. Ten patients were included in the present study. Eight (80%) were males, in nine cases a single chimney was implanted, and the other one was a double chimney graft placement. The treated aneurysms had an infrarenal neck length of 3.4 (1.2) mm. The rate of main body oversizing was 30%. The new neck length after chimney graft placement was 18 (3) mm. The median procedural time was 130 (17) mm, contrast medium use was 109 (26) mL, radiation time was 45 (12) min. The technical success was 100%. No type Ia endoleak was detected at the postoperative CTA. There were no target vessel issues. No major adverse events or death were observed. First reported cohort of patients treated with EnChEVAR demonstrated reproducible clinical and procedural outcomes within the 3 vascular centers with total exclusion of the aneurysms, patent renal arteries, and no evidence of gutter-related type IA endoleak. Further evidence with larger sample size of treated patients and longer follow-up are needed.

Evaluation of the EMBOPIPE flow diverter device: in vivo and in vitro experiments

BackgroundAlthough flow diverter device (FDD) has brought revolutionized advances in endovascular treatment of intracranial aneurysms, it also presents considerable drawbacks as well, as the innovation for novel device has never stopped. This preclinical research aims to evaluate the safety and efficacy of a newly developed FDD, the EMBOPIPE, through in vivo and in vitro experiments.MethodsAneurysms were induced in 20 New Zealand white rabbits which were randomized to three follow-up groups according to the time elapsed after EMBOPIPE implantation (28, 90, and 180 days). Additional EMBOPIPEs were implanted in the abdominal aorta to cover the renal artery in nine rabbits. Angiography was performed immediately after device placement in all groups. Aneurysm occlusion, patency of renal arteries, and pathological outcomes were assessed. For the in vitro experiments, we measured the thrombogenic potential of EMBOPIPEs (n = 5) compared with bare stents (n = 5) using the Chandler loop model. Evaluation indicators were the platelet counts, macroscopic observations and scanning electron microscopy.ResultsEMBOPIPEs were successfully deployed in 19 of 20 rabbit aneurysms (95.0%). The rates of complete or near-complete aneurysm occlusion were 73.3%, 83.3%, and 100% in the 28-, 90-, and 180-day groups, respectively. All renal arteries covered by EMBOPIPEs remained patent, and the mean difference in renal artery diameter before and after the device placement in the three groups was 0.07 mm, 0.10 mm, and 0.10 mm, respectively (p = 0.77). Renal pathology was normal in all cases. The pathological findings of the aneurysms were as follows: thickened and adequate neointimal coverage at the aneurysm neck, minimal inflammatory response, near-complete smooth muscle cell layer, and endothelialization along the device. In vitro experiments showed that the platelet counts were significantly higher in EMBOPIPE blood samples than in bare stent samples and that platelet adhesion to the device was lower in the EMBOPIPE stent struts compared with bare stent struts through macroscopic observations and scanning electron microscopy.ConclusionsThe EMBOPIPE can achieve high rates of aneurysm occlusion while maintaining excellent branch artery patency. It exhibited wonderful pathological results. This novel device with phosphorylcholine surface modification could reduce platelet thrombus attached to the stent struts.

Association of Baseline Chronic Kidney Disease Stage With Short- and Long-Term Outcomes After Fenestrated Endovascular Aneurysm Repair

Fenestrated endovascular aneurysm repair (FEVAR) is a well-established treatment approach for juxtarenal and short-neck infrarenal aortic aneurysms. Recommendations and clinical outcomes are lacking for offering FEVAR in patients with chronic kidney disease (CKD). We aimed to compare short- and long-term outcomes for patients with none-to-mild versus moderate-to-severe CKD undergoing FEVAR. We retrospectively reviewed consecutive patients undergoing standard FEVAR with Cook devices at a single institution. The cohort was stratified by preoperative CKD stage none-to-mild or moderate-to-severe (CKD 1-2 and CKD 3-5, respectively). The primary outcome was postoperative acute kidney injury (AKI). Secondary outcomes included 30-day perioperative complications, 1- and 5-year rates of overall survival, dialysis, renal target artery patency, endoleak, and reintervention assessed by the Kaplan-Meier method. Aneurysm sac regression, number of surveillance computed tomography (CT) scans, and CKD stage progression were assessed at latest follow-up. Multivariate Cox proportional hazards modeling was used to evaluate the association of CKD stage 3 and stage 4-5 with all-cause mortality, controlling for differences in baseline characteristics. From 2012- to 2022, 184 patients (of which 82% were male) underwent FEVAR with the Cook ZFEN device (mean follow-up 34.3months). Group CKD 3-5 comprised 77 patients (42%), was older (75.2 vs. 73.0years, P=0.04), had increased preoperative creatinine (1.6 vs. 0.9mg/dL, P<0.01), and demonstrated increased renal artery ostial calcification (37.7% vs. 21.5%, P=0.02) compared with Group CKD 1-2. Perioperatively, CKD 3-5 sustained higher estimated blood loss (342 vs. 228ml, P=0.01), longer operative times (186 vs. 162min, P=0.04), and longer length of stay (3 vs. 2days, P<0.01). Kaplan-Meier 1- and 5-year survival estimates were lower for CKD 3-5 (82.3% vs. 95.1%, P<0.01 and 55.4% vs. 70.8%, P=0.02). Fewer CKD 3-5 patients remained free from chronic dialysis at 1year (94.4% vs. 100%, P=0.015) and 5years (84.7% vs. 100%, P<0.01). There were no significant differences in postoperative AKI rate (CKD 1-2 6.5% vs. CKD 3-5 14.3%, P=0.13), long-term renal artery patency, reinterventions, type I or III endoleak, mean sac regression, or total follow-up CT scansbetween groups. CKD stage progression occurred in 47 patients (31%) at latest follow-up but did not differ between stratified groups (P=0.17). On multivariable modeling, age (hazardratio 1.05, 95% confidence interval 1.01-1.09, P=0.02) and CKD stage 4-5 (hazard ratio 6.39, 95% confidence interval 2.26-18.05, P<0.01) were independently associated with mortality. Preoperative CKD status did not negatively impact the durability or technical success related to aneurysm outcomes after FEVAR. Worsening CKD stage was associated with lower 1- and 5-year overall survival and freedom from dialysis after FEVAR with no statistically significant differences in 30-day or long-term technical aneurysm outcomes.

Editor's Choice – Long Term Outcomes of the Advanta V12 Covered Bridging Stent for Fenestrated and Branched Endovascular Aneurysm Repair in 1 675 Target Vessels

To report outcomes of the Advanta V12 as a covered bridging stent in fenestrated and branched endovascular aneurysm repair (F/BEVAR). Patients treated with F/BEVAR and followed in a single centre receiving the Advanta V12 as a covered bridging stent between January 2010 and May 2020 were included. A total of 636 patients (543 men) were analysed. A total of 1 675 target vessels (TVs) were bridged with the Advanta V12. Estimated TV patency at one, five, and eight years was 99.1% ± 0.2%, 96.9% ± 0.5% and 96.2% ± 0.7%, respectively. Estimated patency at eight years was 98.1% ± 0.5% for fenestrations and 87.3% ± 2.9% for branches (p < .001). Estimated patency of renal arteries was statistically significantly lower for those targeted with branches compared with fenestrations (p= .001). Multivariable analysis showed that targeting a TV with a branch compared with a fenestration was the only independent risk factor for occlusion during follow up (hazard ratio 6.41, 95% CI 3.4 - 11.9; p < .001). Estimated freedom from endoleak at one, five, and eight years was 99.4% ± 0.2%, 96.4% ± 0.6%, and 95.4% ± 0.8%, respectively. Estimated freedom from target vessel instability (TVI) at one, five, and eight years was 98.5% ± 0.3%, 93.0% ± 0.8%, and 91.3% ± 1%, respectively. Estimated freedom from TVI at eight years was 93.2% ± 0.9% for fenestrations and 82.7% ± 3.5% for branches (p < .001). Estimated freedom from TVI was statistically significantly lower for renal arteries targeted with branches compared with those targeted with fenestrations (p < .001) CONCLUSION: The Advanta V12 shows excellent technical success rates as a covered bridging stent in F/ΒEVAR. Late outcomes remain good with low rates of TV occlusion, endoleak, and re-intervention. Renal arteries targeted with branches demonstrated a higher risk of occlusion and instability compared with those targeted with fenestrations.

Intravascular lithotripsy angioplasty for treatment of atherosclerotic coral-reef occlusion of the infrarenal aorta and its bifurcation.

In the present report, we have described the use of intravascular lithotripsy angioplasty for heavily calcified occlusions of the infrarenal aorta and its bifurcation in two patients. In the first patient, two lithotripsy balloons in kissing conformation were simultaneously used to allow for dilatation of the distal aorta and its bifurcation with preservation of accessory renal artery patency, followed by stenting of the iliac arteries. For the second patient, the infrarenal aorta occlusion was first treated with a single lithotripsy balloon, followed by covered stenting. Intravascular lithotripsy could represent a valid endovascular adjunct to optimize outcomes in the treatment of coral reef aortas and aortic bifurcation occlusion.

Abstract 12986: Internal Iliac Artery Occlusion With the Amplatzer Vascular Plug During Endovascular Repair of Large Abdominal Aortic Aneurysm

Background: Retrograde blood flow from the internal iliac artery resulting in a type II endoleak is a challenging complication of endovascular aorto-iliac aneurysm repair. Several methods have been developed to address this concern. We present a case where the Amplatzer vascular plug was used to embolize the internal iliac artery in a patient undergoing aorto-iliac stent-grafting with extension of the graft into the external iliac artery. Case: A 67-year-old male presented with abdominal pain. Abdominal contrast computed tomography confirmed a large infrarenal abdominal aortic aneurysm (AAA) measuring 100 mm across, extending into the common iliac artery on the right and the external iliac artery on the left, with perianeurysmal fat stranding indicating impending rupture. The patient was taken emergently to the operating room. Vascular access was obtained through bilateral common femoral arteries. The left internal iliac was occluded with an Amplatzer 16 mm by 12 mm vascular plug, with excellent angiographic apposition. A bifurcated aorto-iliac graft was then sequentially deployed to repair the aneurysm. Final angiography showed patent renal arteries with no endoleak. The patient was discharged home the following day. Discussion: Embolization of the internal iliac artery is indicated in endovascular aorto-iliac aneurysm repair to prevent endoleak formation. Traditionally performed with coils, the Amplatzer vascular plug has emerged as a safe and effective alternative, with the added advantage of recoverability prior to definitive release. Conclusion: Endovascular repair of an AAA must consider the complication of endoleak formation. In this case, the use of an Amplatzer vascular plug was successful in preventing a type II endoleak from the internal iliac artery. Panel A. 3D reconstruction of aneurysm anatomy; Panel B. Angiogram showing final result of endovascular repair with successful occlusion of the left internal iliac artery

RENAL EXTRACTION EFFICIENCY FOR PAH IS COMPARABLE IN ESSENTIAL HYPERTENSION AND RENAL FIBROMUSCULAR DYSPLASIA

Objective: Previously, we demonstrated that intrarenal blood flow in most patients with renal fibromuscular dysplasia (FMD) does not differ from that of patients with essential hypertension and patent renal arteries. In the present study, we assessed whether the renal extraction of para-aminohippurate (PAH) as a marker of tubular function was affected by the presence of FMD. Design and method: We studied 136 hypertensive patients who were scheduled for diagnostic renal angiography with arterial and renal venous blood sampling. In all of them, a continuous infusion of PAH was started two hours before the procedure to obtain steady state plasma levels at the time of sampling. Blood was collected simultaneously from the arterial and venous catheter prior to the administration of contrast material. Mean renal blood flow (MRBF) was measured simultaneously using the 133Xenon washout technique. Results: Altogether, 21 patients were diagnosed with renal FMD, 45 with atherosclerotic renal artery stenosis (ARAS) and 70 with essential hypertension (EH). Extraction ratio of PAH (ER-PAH) in the patients with renal FMD averaged 72 + 4% which did not differ significantly from that in patients with EH (74 + 3%). MBRF did not differ between these two groups either. Per contra, in patients with ARAS both MRBF and ER-PAH were significantly lower as compared to the other groups. ER-PAH in FMD patients was not modified by age, sex, height of blood pressure or MBRF. Conclusions: The ER of PAH in patients with renal FMD does not differ from that in EH. Thus, both flow and tubular function are well preserved in FMD when is EH is taken as control. This suggests that the pathophysiological mechanism which contribute to hypertension in FMD are different from those which are active in ARAS.

Single Centre Experience in Open and Endovascular Treatment of Renal Artery Aneurysms

Background: The true incidence and natural history of renal artery aneurysm (RAA) remain unclear and still exists controversy over indication for treatment. Several techniques of conventional surgical reconstructions are described in literature, and more recently endovascular therapies have been reported with satisfying results and lower complication rate. This paper aims to investigate the outcomes of both endovascular and open repair of RAA achieved in a single institution involving 3 medical teams (urology, vascular surgery and neuroradiology). Material and Methods: We conducted a single-centre retrospective observational study about all patients surgically or endovascularly treated for RAA over a 15-year period. Pre-operative, procedural and post-operative data at the early, mid- and long-term follow-up were collected and analysed, focusing on operative technique used for repair and related outcomes. Results: A total of 27 patients (n = 17 (63%) women, mean age 58 ± 13.2, n = 26 saccular RAA) were included. Mean aneurysm was size was 18.8 ± 6.3 mm. Most diagnosis were accidental. Symptomatic RAA showed with macroscopic haematuria (n = 3, 25.9%), unstable hypertension (n = 2; 7%), chronic lumbar pain (n = 1, 3.7%) and renal infarct (n = 1, 3.7%).Conventional surgery (ex-vivo repair, aneurysmorraphy, aneurysm resection and end-to-end anastomosis) was performed in 14 (51.8%) cases and endovascular coiling embolization in 13 (48.2%). Mean hospital length of stay was 5.4 ± 3.6 days. Intensive Care Unit stay was needed only in the surgically treated patients (mean 1.1 ± 1.2 days). During the early follow-up, morbidity rate was 7/14 in surgically treated patients vs. 1/13 in endovascular group; it included bleeding, retroperitoneal hematoma, arterial thrombosis and bowel obstruction. The discharge imaging showed complete aneurysm exclusion and renal artery patency in all cases.At a mean follow-up of 39 ± 42 months, 3 patients (11%) were lost to follow up and 2 (7.4 %) died from unrelated cause. None of these patients required dialysis but a statistically significant (P = 0.09) decrease in GFR was noted between the preoperative period and last follow-up control. RAA repair neither showed blood pressure control improvement nor reduced the need for anti-hypertensive drug use. Conclusion: Open or endovascular techniques are both safe and efficient to treat RAA. Even though, surgical management is burdened with higher morbidity rate, the operative technique should be selected according to anatomical features, diameters and location of RRA; and the number of renal branches involved. Further larger studies are needed to define the feasibility and safety for a wider application of the endovascular approach.

Transbrachial and transfemoral approaches combined with visceral protection for the treatment of juxtarenal aortoiliac occlusive disease: Technical issues and clinical outcomes.

To evaluate the safety and efficacy of transbrachial and transfemoral approaches combined with visceral protection for the endovascular treatment of juxtarenal aortoiliac occlusive disease (AIOD) over an average 19-month follow-up period. In this retrospective analysis, all patients with juxtarenal AIOD at a single institution were reviewed from June 2015 to January 2020. Patient characteristics, angiographic results, and follow-up outcomes were retrospectively recorded. The indications for treatment were critical limb threatening ischemia in 12 patients and bilateral claudication in five patients. Percutaneous access via the left brachial artery was first obtained to recanalize the infrarenal occluded lesions. After that, femoral accesses were achieved. A 4-Fr catheter, a 4mm balloon, or a 6-Fr 90-cm-long sheath was used to complete visceral artery protection. A total of 17 juxtarenal AIOD patients (14 males; mean age, 63.4 ± 8.1years) underwent endovascular treatment. The technical success rate was 100%. Complete reconstruction was achieved in 15 (88.2%) patients. The infrarenal aorta was reconstructed with kissing covered stent grafts (n = 7), kissing bare-metal stents (n = 2), covered stent grafts (n = 2), bare-metal stents (n = 1), or the off-label use of iliac limb stent grafts (n = 5). Renal embolization was found in 3 (17.6%) patients during intraoperative angiography. There was 1 (5.9%) case of distal runoff embolization after CDT and 1 (5.9%) case of left iliac artery rupture. One (5.9%) death occurred due to acute myocardial infarction 20 days after the operation. The average follow-up period was 19.3 ± 16.7months (range, 1-54months) in the remaining 16 cases. The renal artery patency rate was 100%. The estimated cumulative primary patency rates were 92.3% at 12months and 59.3% at 36months according to the Kaplan-Meier method. Transbrachial and transfemoral approaches combined with visceral protection offer a safe and effective alternative to open revascularization for the endovascular treatment of juxtarenal AIOD.

In-hospital and mid-term outcome after complex endovascular aortic repair with fenestrated and branched stent-grafts

Abstract Objective The aim of the study is to evaluate in-hospital and mid-term outcome after complex endovascular aortic repair with fenestrated and branched stent-grafts (fEVAR / bEVAR). Methods This is a single-center retrospective analysis from a prospectively collected database of all patients treated electively with fEVAR or bEVAR for para/suprarenal (PAA) and thoraco-abdominal aortic aneurysm (TAAA) between September 2010 and June 2019. In-hospital and mid-term mortality, major adverse events and re-interventions were assessed. Results Fifty-one patient (84% male) with a mean age of 74±7 years were analysed. Eighteen patients (35%) had TAAA, four patients (8%) suprarenal, and 29 patients (57%) pararenal aortic aneurysms. Mean aneurysm diameter was 64±8 mm. Thirty-eight patients (75%) underwent fEVAR and 13 patients (25%) bEVAR. A total of 157 target vessels were incorporated: 22 celiac trunks (CT), 40 superior mesenteric arteries (SMA), 92 renal arteries (RA), two separate hepatic arteries and one splenic artery. No in-hospital death or stroke was recorded. One patient suffered from early postoperative paraplegia and did not recover and one had paraparesis after 38 days and recovered completely. Six patients (12%) with patent renal arteries experienced acute postoperative kidney injury; one required temporary dialysis. Five in-hospital re-interventions were stent-graft related (four bridging stents angioplasty and one iliac leg extension) and seven re-interventions were not stent-graft related. Mean follow-up was 19±17 months. Eleven patients (22%) died during follow-up: nine were not aortic-related and two were unknown. The Kaplan-Meier estimated survival rates at 1 and 2 years were 81% and 77%, respectively. Five renal stents (5%, 5/92) occluded during follow-up: three were successfully recanalized and two remained occluded. Ten stents (three CT, five SMA, and two RA stents required relining after 13±16 months postoperatively, resulting with estimated primary assisted patency at 2 years of 100%, 100%, 93%, and 95% for the CT, SMA, right RA and left RA, respectively. Conclusion Complex endovascular aortic repair with fEVAR / bEVAR for PAA and TAAA is safe with very low early mortality and morbidity. In-stent stenosis/occlusions occurred within the first two years. However, primary assisted patency was high. A surveillance program to detect potential stent-graft related complications is mandatory.

Imaging strategies for safety surveillance after renal artery denervation.

Renal denervation has emerged as a safe and effective therapy to lower blood pressure in hypertensive patients. In addition to the main renal arteries, branch vessels are also denervated in more contemporary studies. Accurate and reliable imaging in renal denervation patients is critical for long-term safety surveillance due to the small risk of renal artery stenosis that may occur after the procedure. This review summarizes three common non-invasive imaging modalities: Doppler ultrasound (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). DUS is the most widely used owing to cost considerations, ease of use, and the fact that it is less invasive, avoids ionizing radiation exposure, and requires no contrast media use. Renal angiography is used to determine if renal artery stenosis is present when non-invasive imaging suggests renal artery stenosis. We compiled data from prior renal denervation studies as well as the more recent SPYRAL-HTN OFF MED Study and show that DUS demonstrates both high sensitivity and specificity for detecting renal stenosis de novo and in longitudinal assessment of renal artery patency after interventions. In the context of clinical trials DUS has been shown, together with the use of the baseline angiogram, to be effective in identifying stenosis in branch and accessory arteries and merits consideration as the main screening imaging modality to detect clinically significant renal artery stenosis after renal denervation and this is consistent with guidelines from the recent European Consensus Statement on Renal Denervation.

Multilayer stents affect the final diameter of aortic aneurysms and maintain renal artery patency for a short time in a swine experimental model

OBJECTIVES:We sought to analyze the hemodynamic effects of the multilayer flow-modulated stent (MFMS) in Thoracoabdominal aortic aneurysms (TAAAs).METHODS:The hemodynamic effects of MFMS were analyzed in aortic thoracoabdominal aneurysms in experimental swine models. We randomly assigned 18 pigs to the stent or control groups and underwent the creation of an artificial bovine pericardium transrenal aneurysm. In the stent group, an MFMS (Cardiatis, Isnes, Belgium) was immediately implanted. After 4 weeks, we evaluated aneurysm sac thrombosis and renal branch patency by angiography, duplex scan, and morphological analysis.RESULTS:All the renal arteries remained patent after re-evaluation in both groups. Aneurysmal sac thrombosis was absent in the control group, whereas in the stent group it was present in 66.7% of aneurysmal sacs (p=0.061).The mean final aneurysm sac diameter was significantly lower in the stent group (mean estimated reduction, 6.90 mm; p=0.021). The proximal neck diameter decreased significantly in the stent group (mean difference, 2.51 mm; p=0.022) and grew significantly in the control group (mean difference, 3.02 mm; p=0.007). The distal neck diameter increased significantly in the control group (mean difference, 3.24 mm; p=0.017). There were no significant findings regarding distal neck measurements in the stent group.CONCLUSION:The MFMSs remained patent and did not obstruct the renal arteries within 4 weeks. In the stent group, the device was also associated with a significant decrease in aneurysmal sac diameter and a large proportion (albeit non-significant) of aneurysmal sac thrombosis.

The Influence of 3D Printed Aortic Models on the Evolution of Physician Modified Stent Grafts for the Urgent Treatment of Thoraco-abdominal and Pararenal Aortic Pathologies

The aim was to describe the outcomes of high risk patients with symptomatic or contained rupture of pararenal (PRAs) and thoraco-abdominal aortic aneurysms (TAAAs) with anatomy unsuitable for commercially available stent grafts who underwent fenestrated endovascular aneurysm repair (FEVAR) using physician modified stent grafts (PMSGs) planned with 3D image analysis software (3DIMAS), and 3D printed aortic models (3DAMs). Nineteen consecutive patients (17 male; mean age, 70±9 years) underwent PMSG-FEVAR between 2015 and 2019. 3DAMs to plan the PMSGs were introduced in 2018. End points were all cause mortality, freedom from any endoleak, target vessel patency, and re-intervention. Seven patients (36.8%) were treated with PMSGs using 3DIMAS (three PRAs, three type IV, and one type III TAAAs), and 12 patients (63.2%) received PMSGs using 3DAMs (five PRAs, seven type IV TAAAs). Six patients presented with contained aortic rupture and 13 patients were treated for symptomatic aortic aneurysm. Mean aortic diameter was 72±10mm. The choice of stent graft for fenestration was the Valiant Captivia Closed Web (Medtronic), except for one patient. Sixteen (84.2%) stent grafts were manufactured with four fenestrations. Technical success was 100%. Seventy-one renovisceral branch vessels were targeted with fenestrations. Mean length of hospital stay was 17.3±10.4 days. Thirty day mortality was 0%. Two patients developed reversible spinal cord injury. Mean follow up was 14.4 months (range 1-52 months). During follow up one non-aneurysm related death occurred, and two successful re-interventions were performed: one to re-establish renal artery patency, and one to treat a type 1c endoleak. PMSGs for urgent treatment of pararenal and thoraco-abdominal aortic aneurysms in high risk patients unsuitable for commercially available stent grafts are feasible and safe. 3D printing technology may improve urgent construction of patient specific devices for treatment of complex aortic pathologies and improve outcomes.

Percutaneous transluminal renal angioplasty attenuates poststenotic kidney mitochondrial damage in pigs with renal artery stenosis and metabolic syndrome.

Percutaneous transluminal renal angioplasty (PTRA) has been used to treat renovascular disease (RVD), a chronic condition characterized by renal ischemia and metabolic abnormalities. Mitochondrial injury has been implicated as a central pathogenic mechanism in RVD, but whether it can be reversed by PTRA remains uncertain. We hypothesized that PTRA attenuates mitochondrial damage, renal injury, and dysfunction in pigs with coexisting renal artery stenosis (RAS) and metabolic syndrome (MetS). Four groups of pigs (n = 6 each) were studied after 16 weeks of diet-induced MetS and RAS (MetS + RAS), MetS + RAS treated 4 weeks earlier with PTRA, and Lean and MetS Sham controls. Single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were assessed in vivo with multidetector computed tomography, and renal tubular mitochondrial structure and function and renal injury ex vivo. PTRA successfully restored renal artery patency, but mean arterial pressure remained unchanged. Stenotic kidney RBF and GFR, which fell in MetS + RAS compared to MetS, rose after PTRA. PTRA attenuated MetS + RAS-induced mitochondrial structural abnormalities in tubular cells and peritubular capillary endothelial cells, decreased mitochondrial H2 02 production, and increased renal cytochrome-c oxidase-IV activity and ATP production. PTRA also improved cortical microvascular and peritubular capillary density and ameliorated tubular injury and tubulointerstitial fibrosis in the poststenotic kidney. Importantly, renal mitochondrial damage correlated with poststenotic injury and dysfunction. Renal revascularization attenuated mitochondrial injury and improved renal hemodynamics and function in swine poststenotic kidneys. This study suggests a novel mechanism by which PTRA might be relatively effective in ameliorating mitochondrial damage and improving renal function in coexisting MetS and RAS.

Abstract 471: Combination of Allogeneic Mesenchymal and Kidney Stem Cells Ameliorates Chronic Kidney Disease Induced Heart Failure With Preserved Ejection Fraction

Background: Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous condition involving multiple comorbidities. Phenotypic classification of HFpEF associated with chronic kidney disease (CKD) manifests worse outcomes, compared to other HFpEF phenotypes. Few treatments improve morbidity and mortality in HFpEF. Stem cell therapy promotes cardiac repair in ischemic and non-ischemic cardiomyopathies. We hypothesized that allogeneic stem cell treatment ameliorates HFpEF in a large animal model of CKD. Methods: Yorkshire pigs (n=26) underwent 5/6 embolization-mediated nephrectomy and 4-weeks later received either: allogeneic mesenchymal stem cells (MSCs) (10х10 6 ), Kidney stem cells (KSC; 10х10 6 ), combination (ACCT; MSC+KSC; 1:1 ratio [5х10 6 each]), or placebo (n=6-7/ group). Cell therapy was delivered via the patent renal artery of the remnant kidney. RNAsec analysis compared placebo and ACCT groups. Results: Mean arterial pressure increased significantly in the placebo- (21.89±6.05 mmHg, p&lt;0.0001) compared to the ACCT-group (p=0.04) at 12 weeks. Glomerular filtration rate improved significantly in the ACCT group (p=0.002). RNAseq analysis revealed a significant decrease in genes normally increased during kidney transplant rejection (q&lt;10 -6 , NES = -2.32) in ACCT. Consistent with these results, there was a downregulation of canonical drivers of tubular damage and regeneration, including SOX9 (-2.39 fold, p=0.0004) and apoptosis of kidney cell types (-24.89 fold, p=0.004), including podocytes (-2.065 fold, p=0.04) with ACCT. ACCT administration also downregulated genes related to oxidative stress (-4.6 fold, p&lt;0.0001), fibrosis, inflammatory response (-4.760 fold, p=&lt;0.05), and renin-angiotensin signaling (-3.162 fold, p=0.024), which are related to cardiac hypertrophy pathways (-7.23, fold, p&lt;0.0001). EDPVR improved in with ACCT (p=0.003), indicating decreased ventricular stiffness. Ejection fraction, relative wall thickness, and left ventricular mass did not differ between groups at 12 weeks. Conclusion: Intra-renal artery allogeneic cell therapy was safe. Beneficial effects were observed in the ACCT and MSC groups in the kidney and heart. These findings have important implications on the use of cell therapy for HFpEF and cardiorenal syndrome.

Long-term Results of Renal Artery Patency in Physician-modified Endografts for Juxtarenal Aneurysms

Renal artery stents are commonly placed in physician-modified fenestrated endografts for juxtarenal aortic aneurysms, but long-term outcomes of these stents is unknown. The purpose of this study was to identify the long-term outcome of stented renal arteries in patients who undergo a physician-modified endovascular graft (PMEG) for repair of juxtarenal aortic aneurysms. Data were prospectively collected on patients treated with PMEG from August 2011 to September 2019 in a prospective, consecutively enrolling investigational device exemption clinical trial (NCT #01538056). Anatomic criteria, including native renal artery stenosis and angulation, were systematically measured using preoperative computed tomography. The primary outcome of renal artery reintervention after PMEG was assessed with Kaplan-Meier survival estimation. Cox proportional hazard models were used to predict renal artery reintervention after PMEG, adjusting for preoperative demographic and patient risk factors, antiplatelet use prestent and poststent placement, and evidence of preoperative stenosis by duplex criteria. We studied 141 patients who underwent PMEG during the study period, representing 282 renal arteries. During the study period, 246 out of 282 (87%) renal arteries were stented. Inability to cannulate the renal artery as the most common cause (n = 9) of inability to stent the artery. However in 25% (n = 9) of these situations, the renal artery was preserved and in 25% (n = 9) an effective proximal seal zone was obtained without renal stenting. Preoperative ostial stenosis was present in 23% (n = 62) of renal arteries by diameter reduction and 22% (n = 58) by duplex criteria. Over a follow-up period of 5 years, 15 renal arteries in 13 patients required reintervention, for an overall reintervention rate of 6.1%. All stented renal arteries remained patent. Median follow-up was 2 years (interquartile range, 0.5-4 years). The most common cause for reintervention during the first 6 months was failure to cannulate during the initial PMEG (15%, n = 2). In-stent restenosis was the reason for reinterventions for 30% (n = 4). Long-term follow-up revealed stent separation (15%, n = 2) and type IIIc endoleak (15%, n = 2) as the most common cause for reintervention. The predicted reintervention free survival of the renal artery at 5 years is 90% (95% confidence interval, 82%-95%) (Figure). Using a Cox proportional hazard model, no significant anatomic or patient-based predictors of reintervention were identified. Renal artery stents placed during physician-modified endografts show excellent long-term durability with a low rate of reintervention. No preoperative renal artery measurements are predictive of either renal stent patency or reintervention.

The Combined Use of a Distal Self-Expandable and Proximal Balloon-Expandable Stent Graft in Bridging Hostile Renal Arteries in Thoracoabdominal Branched Endografting

To evaluate early/midterm outcomes of a specific configuration of a bridging stent graft-that is a distal self-expandable (SE) stent graft combined with proximal balloon-expandable (BE) one-in hostile renal artery (RA) anatomy in branched thoracoabdominal aneurysm (TAAA) repair. Between 2010 and 2019, all TAAAs undergoing fenestrated and branched endografting (FB-EVAR) were prospectively collected. Preoperative, procedural, and postoperative data of RAs accommodated by branch design and patent at the completion angiography were retrospectively analyzed. Hostile RA anatomy included upward (type B) and downward+upward (type D) orientations. Type B and D RAs treated by the combination of an SE+BE stent graft as a bridging stent (BE+SE group) were compared with RAs treated by a BE stent graft only (BE group). RA occlusion, reinterventions, and branch instability were assessed. Over a total of 112 TAAAs undergoing FB-EVAR, 189 RAs were treated by fenestrations (113-60%) and branches (76-40%). Among the 66 (86%) RAs accommodated by branch and patent at completion angiography, 55 had a type B/D orientation. BE stent grafts were used in 15/55 (27%) RAs and SE+BE in 40/55 (73%). At a median follow-up of 12 (8) months, 5/55 (9%) RAs occluded: 4/15 (27%) in the BE group and 1/40(2.5%) in the SE+BE group (P: 0.017). RA patency was 83±5% at 24months. The SE+BE group had higher patency than the BE group (90±5% vs. 68±5% at 12months; P: 0.039). Overall freedom from RA-related reinterventions was 87±5% at 24months. Six (9%) RAs required reinterventions: 4/15 (27%) in the BE group and 2/40 (5%) in the BE+SE group (P: 0.041). RAs managed by an SE+BE stent graft had lower reinterventions than RAs treated by a BE stent graft only (93±5% vs. 76±5% at 12months; P: 0.01). Freedom from branch instability was 78±5% at 24months, with 8 overall cases (12%) occurring-5/15 (33.3%) in the BE group versus 3/40 (7.5%) in the SE+BE group (P: 0.02). RAs managed by an SE+BE stent graft had lower branch instability than RAs treated only by a BE stent graft (BE: 68±5% vs. SE+BE: 80±5% at 12months; P: 0.02). In hostile renal anatomy, the combination of a distal SE and proximal BE stent graft as a bridging stent in branched endografting is safe and effective with lower rates of occlusion, reinterventions, and branch instability at midterm follow-up compared with a BE stent graft alone.

Renal Artery Stenosis As Etiology of Recurrent Flash Pulmonary Edema and Role of Imaging in Timely Diagnosis and Management.

Renal hypoperfusion from renal artery stenosis (RAS) activates the renin-angiotensin system, which in turn causes volume overload and hypertension. Atherosclerosis and fibromuscular dysplasia are the most common causes of renal artery stenosis. Recurrent flash pulmonary edema, also known as Pickering syndrome, is commonly associated with bilateral renal artery stenosis. There should be a high index of clinical suspicion for renal artery stenosis in the setting of recurrent flash pulmonary edema and severe hypertension in patients with atherosclerotic disease. Duplex ultrasonography is commonly recommended as the best initial test for the detection of renal artery stenosis. Computed tomography (CT) angiography (CTA) or magnetic resonance (MR) angiography (MRA) are useful diagnostic imaging studies for the detection of renal artery stenosis in patients where duplex ultrasonography is difficult. If duplex ultrasound, CTA, and MRA are indeterminate or pose a risk of significant renal impairment, renal angiography is useful for a definitive diagnosis of RAS. The focus of medical management for RAS relies on controlling renovascular hypertension and aggressive lifestyle modification with control of atherosclerotic disease risk factors. The restoration of renal artery patency by revascularization in the setting of RAS due to atherosclerosis may help in the management of hypertension and minimize renal dysfunction.

Surgical management of pediatric renin-mediated hypertension secondary to renal artery occlusive disease and abdominal aortic coarctation

BackgroundRenovascular hypertension (RVH) associated with renal artery and abdominal aortic narrowings is the third most common cause of pediatric hypertension. Untreated children may experience major cardiopulmonary complications, stroke, renal failure, and death. The impetus of this study was to describe the increasingly complex surgical practice for such patients with an emphasis on anatomic phenotype and contemporary outcomes after surgical management as a means of identifying those factors responsible for persistent or recurrent hypertension necessitating reoperation. MethodsA retrospective analysis was performed of consecutive pediatric patients with RVH undergoing open surgical procedures at the University of Michigan from 1991 to 2017. Anatomic phenotype and patient risk factors were analyzed to predict outcomes of blood pressure control and the need for secondary operations using ordered and binomial logistic multinomial regression models, respectively. ResultsThere were 169 children (76 girls, 93 boys) who underwent primary index operations at a median age of 8.3 years; 31 children (18%) had neurofibromatosis type 1, 76 (45%) had abdominal aortic coarctations, and 28 (17%) had a single functioning kidney. Before treatment at the University of Michigan, 51 children experienced failed previous open operations (15) or endovascular interventions (36) for RVH at other institutions. Primary surgical interventions (342) included main renal artery (136) and segmental renal artery (10) aortic reimplantation, renal artery bypass (55), segmental renal artery embolization (10), renal artery patch angioplasty (8), resection with reanastomosis (4), and partial or total nephrectomy (25). Non-renal artery procedures included patch aortoplasty (32), aortoaortic bypass (32), and splanchnic arterial revascularization (30). Nine patients required reoperation in the early postoperative period. During a mean follow-up of 49 months, secondary interventions were required in 35 children (21%), including both open surgical (37) and endovascular (14) interventions. Remedial intervention to preserve primary renal artery patency or a nephrectomy if such was impossible was required in 22 children (13%). The remaining secondary procedures were performed to treat previously untreated disease that became clinically evident during follow-up. Age at operation and abdominal aortic coarctation were independent predictors for reoperation. The overall experience revealed hypertension to be cured in 74 children (44%), improved in 78 (46%), and unchanged in 17 (10%). Children undergoing remedial operations were less likely (33%) to be cured of hypertension. There was no perioperative death or renal insufficiency requiring dialysis after either primary or secondary interventions. ConclusionsContemporary surgical treatment of pediatric RVH provides a sustainable overall benefit to 90% of children. Interventions in the very young (<3 years) and concurrent abdominal aortic coarctation increase the likelihood of reoperation. Patients undergoing remedial surgery after earlier operative failures are less likely to be cured of hypertension. Judicious postoperative surveillance is imperative in children surgically treated for RVH.