Proximal Renal Artery Research Articles

Efficacy comparison of transcatheter aorticorenal ganglion ablation and renal denervation in a hypertensive canine model

Abstract Background Transcatheter renal sympathetic denervation (RDN) has been proposed to be an adjunctive treatment in uncontrolled hypertension. However, non-responders to RDN were not rare. Considering the lack of a procedure endpoint and the limitation of anatomic-based ablation strategy, incomplete or futile denervation may contribute to non-responsiveness. Aorticorenal ganglion (ARG) is a purely sympathetic ganglion that projects to the proximal and distal renal artery, forming the peri-arterial nerve network. Ablation of this ganglion results in significant renal denervation. However, it remains unknown whether ARG ablation has a superior effect in lowering blood pressure (BP) compared to RDN. Purpose The aim of the study was to determine whether ARG ablation improved the BP-lowering effect compared to RDN in a hypertensive canine model. Methods A total of 21 male Chinese Kunming dogs were included and randomized into three groups: ARG ablation group (n=7), RDN group (n=7) and control group (n=7). In the ARG ablation group, anatomically based high-frequency stimulation (HFS) was performed in the aorta and inferior vena cava (IVC) under the guidance of 3D anatomical construction (Figure 1A). ARG ablation sites were identified by HFS-induced BP elevation response (>10mmHg) and renal artery vasoconstriction (Figure 1B). In the RDN group, HFS-guided ablation was conducted at the positive site (BP elevation response >5mmHg) from the distal to proximal renal artery. Endpoint of the procedure was defined as the elimination or attenuation of BP elevation induced by HFS. BP was assessed at baseline and 4 weeks after the procedure. Results The left ARG ablations were performed at the inferior aspect of superior mesenteric artery (4/7), the abdominal aorta (2/7) and the proximal renal artery (1/7), while the right ARG ablations were performed at the posterior aspect of the IVC (6/7) and the ostium of the left renal vein (1/7). The gross anatomy of bilateral ARGs was shown in Figure 1C. The hemodynamic response to ARG stimulation was significantly greater than that of renal artery stimulation (40.0±13.4 vs 13.3±3.7 mmHg, Figure 2A, B); meanwhile, ARG ablation is more effective in blunting the BP elevation response compared to RDN (30.7±11.7 vs 9.6±2.6, P=0.001, Figure 2A, C). With a 4-week follow-up, ARG ablation demonstrated a greater systolic BP-lowering effect than RDN (-29.6±12.0 vs -15.3±6.9 mmHg, P=0.018, Figure 2D). No complications were found during the procedure or follow-up. Conclusion Our study suggests that ARG ablation could lead to a more efficient BP-lowering effect compared to RDN, which provides a novel paradigm for autonomic modulation in the treatment of hypertension.Figure 1Figure 2

A novel, proof-of-concept radiofrequency renal denervation strategy to improve procedural efficiency: 12-month results from the SPYRAL DYSTAL pilot study

BackgroundCatheter-based renal sympathetic denervation (RDN) reduced blood pressure (BP) in multiple randomized sham-controlled trials of patients with uncontrolled hypertension (HTN). We tested proof-of-concept for a more selective treatment strategy, exclusively targeting these areas to improve the efficiency of the procedure. MethodsThe SPYRAL DYSTAL Pilot study was designed to mirror the SPYRAL HTN-OFF MED Pivotal study, enabling comparison with a propensity score adjusted active-control group. Patients were antihypertensive medication-free for one month before undergoing BP assessment. Those with office BP of 150–180/>90 mmHg and with an ambulatory systolic BP of 140–170 mmHg were selected to undergo open label treatment, delivering energy only to the distal main renal arteries and first order branches. Patients from DYSTAL were compared with patients who underwent maximized RF RDN treatment in the prior randomized OFF MED trial at 3 months. After 3 months, patients resumed antihypertensive medications as indicated. Safety and efficacy outcomes were assessed post hoc through 12 months. ResultsThe SPYRAL DYSTAL Pilot study treated 56 HTN patients. Baseline office systolic BP (OSBP) and 24-h ambulatory systolic BP (ASBP) were similar between DYSTAL and OFF MED patient groups. The number of ablations (32.3 ± 8.0 vs 46.6 ± 15.3, p < 0.001), procedure time (67 ± 21 min vs 99 ± 36 min; p < 0.001), and contrast volume (173 ± 77 cc vs 208 ± 96 cc; p = 0.014) were significantly lower with the simplified treatment strategy. OSBP and ASBP changes compared with baseline were −9.0 and −1.4 mmHg at 3 months, −20.3 and −13.9 mmHg at 6 months, and −20.3 and −16.6 mmHg at 12 months, respectively. During the medication up-titration phase, BP reductions among DYSTAL patients were similar to reductions observed in OFF MED through 12 months, with comparable number of drugs (1.4 and 1.5 medications, respectively (P=NS)). Two adverse events related to guidewire placement were reported. ConclusionIn this pilot study, focusing ablation treatment on the distal main and proximal branch renal arteries was performed, resulting in fewer RF lesions, and reduced contrast volume and procedure time. Whether BP reductions are similar between a selective vs. maximized RDN approach requires further prospective study.

Immediate post-ablation renal nerve stimulation predicted blood pressure reductions 6 months following renal denervation

Abstract Background Renal denervation (RDN) has been recognized as an alternative treatment strategy for blood pressure (BP) control. There is no consensus on which intra-procedural parameters could reliably predict BP-lowering responses following RDN, which usually occur months later. Purpose This study aimed to evaluate systolic BP (SBP) changes induced by renal nerve stimulation (RNS) during RDN and its associations with BP-lowering responses 6 months following RDN. Methods Seventeen patients with hypertension who underwent radiofrequency RDN between February 2019 and March 2021 were prospectively included. RNS was performed immediately before and after RDN in bilateral proximal and distal main renal arteries under general anesthesia. The responder was defined as 24-hour SBP reduction of ≥10 mmHg 6 months following RDN. Results RNS-induced SBP changes significantly decreased after RDN in all 4 sites of bilateral main renal arteries (all p&amp;lt;0.05). The mean 24-hour SBP were 144±16 mmHg and 131±15 mmHg at baseline and 6 months after RDN, respectively. Nine (53%) patients were responders. Compared to non-responders, the responders had significantly lower RNS-induced SBP changes in proximal main renal arteries immediately after RDN (right, 15.3±9.6 mmHg vs. 31.6±9.6 mmHg, p=0.005; left, 11.6±6.9 mmHg vs. 27.9±10.2 mmHg, p=0.002). All 7 patients with RNS-induced SBP increases of &amp;lt;20 mmHg after RDN in bilateral proximal main renal arteries were responders. Conclusions An RNS-induced SBP increase of &amp;lt;20 mmHg in bilateral proximal main renal arteries immediately after RDN was associated with significant 24-hour SBP reductions 6 months following RDN. Whether RNS-induced SBP changes could predict or even guide RDN strategies awaits further verifications.

Renal Artery Stenosis due to Entrapment

Common etiologies of renovascular occlusive disease include atherosclerosis disease, developmental fibrotic conditions such as fibromuscular dysplasia, and vasculitis. Extrinsic compression of the renal artery is a rarely reported phenomenon but can lead to similar clinical manifestations. We report recent experience with 2 patients who presented with extrinsic renal artery compression due to entrapment. Diagnosis was made with a constellation of findings on computed tomography angiography, dynamic duplex sonography, and catheter angiography. Both patients had hypertension and 1 had downstream subsegmental renal infarcts. The patients, both with right-sided renal artery entrapment, were treated with open surgical decompression. Exposure was achieved via extended Kocher maneuver followed by mobilization of the right kidney and, in 1 patient, detachment of the right lobe of liver to allow circumferential exposure of the proximal right renal artery to the aorta. All entrapping tissue was circumferentially released. Both operations were uncomplicated. Intraoperative sonography was used to confirm luminal patency of the released segments. Follow-up of renal artery duplex in both patients demonstrated resolution of dynamic compression. Renal artery peak systolic velocity and accelerations indices were all within normal limits. In both patients, improvement in blood pressure control was noted and discontinuation of anticoagulation was possible in the patient who had recurrent episodes of renal infarct. Extrinsic compression of renal artery by diaphragmatic crura is rare but should be considered in younger patients or otherwise any patients with no vascular risk factors when renovascular hypertension workup yields no demonstrable intrinsic disease. A high index of suspicion should be raised when an anomalously high origin of the renal artery or proximity to the diaphragmatic crura is seen on cross-sectional imaging. Work-up should include dynamic imaging to assess compression of renal arteries during expiration. Open surgical or laparoscopic decompression of the involved renal arteries can be curative.

Virus and Autoimmunity: Can SARS-CoV-2 Trigger Large Vessel Vasculitis?

IntroductionViral infections can induce autoimmune diseases in susceptible patients. SARS-CoV-2 has been associated with the development of rheumatic disease, especially small vessel vasculitis and arthritis. Typically, onset occurs days to weeks after the antigenic challenge and in patients with mild COVID-19. We report a case of large vessel vasculitis (LVV) temporally related to SARS-CoV-2 infection.Case descriptionAn otherwise healthy 19-year-old woman presented with fatigue, malaise, and chest and low back pain. The symptoms had begun 5 weeks earlier and 1 month after mild SARS-CoV-2 infection. Serological work-up revealed a marked proinflammatory state and anaemia without signs of infectious or autoimmune disease. Computerized tomography revealed thickening and blurring of the perivascular fat of the descending thoracic and abdominal aorta, progressing along the proximal iliac and renal arteries. Fluorodeoxyglucose positron emission tomography confirmed inflammatory activity. Symptoms and laboratory values normalized after prednisolone treatment.DiscussionRecent SARS-CoV-2 infection may be a trigger for LVV, including Takayasu arteritis, as well as other rheumatic diseases. A prompt and thorough differential diagnosis is essential to exclude aortitis and LVV mimickers. Moreover, physicians should be aware of the potential spectrum of systemic and autoimmune diseases that could be precipitated by SARS-CoV-2 infection. This will allow timely diagnosis and treatment, with significant improvement in prognosis.LEARNING POINTSSARS-CoV-2 infection can trigger large vessel vasculitis and other rheumatic diseases.Awareness of the association between COVID-19 and autoimmune phenomena allows for timely diagnosis and treatment with significant improvements in prognosis.Vasculitis and other autoimmune diseases should be kept in mind in patients who develop proinflammatory states days to weeks after an initial antigenic challenge.

Non-Permanent Transcatheter Proximal Renal Artery Embolization for a Grade 5 Renal Injury with Delayed Recanalization and Preserved Renal Parenchymal Enhancement

&lt;p&gt;Super-selective renal artery embolization is an increasingly popular technique for the management of traumatic, low-grade renal trauma. When performed in distal arterial branches, this intervention enables tissue preservation and arrest of hemorrhage, but it may not be practical in cases of multifocal, high-grade renal injuries. In such cases, surgical nephrectomy remains the more common treatment modality to ensure hemodynamic control. We present the unique case of a patient who presented in hemorrhagic shock following a major trauma that resulted in a grade 5 renal injury treated with complete renal artery embolization using Gelfoam, resulting in hemodynamic stabilization. Interestingly, imaging 1 month after embolization revealed residual enhancement of the inferior pole of the kidney, suggesting reconstitution of flow and partial renal salvage. Ultimately, transcatheter “nephrectomy” with careful selection of a temporary embolic agent may serve as a safe and efficient alternative to surgical nephrectomy with the added possibility of preserving partial renal perfusion and function in the emergent setting.&lt;/p&gt;

Atypical Moyamoya Disease Associated with Midaortic Syndrome

AbstractWe report a case of a 4-year-old boy who presented with moyamoya disease associated with midaortic syndrome. He had been treated for severe persistent hypertension until he suffered multiple episodes of seizure and cerebral ischemic attack. Cerebral angiography showed bilateral terminal internal carotid artery stenosis. Angiographic survey showed severe stenosis of abdominal aorta and bilateral proximal renal arteries. This is a very rare report of moyamoya disease with midaortic syndrome.

Patient-specific computational flow modelling for assessing hemodynamic changes following fenestrated endovascular aneurysm repair

ObjectiveThis study aimed to develop an accessible patient-specific computational flow modelling pipeline for evaluating the hemodynamic performance of fenestrated endovascular aneurysm repair (fEVAR), with the hypothesis that computational flow modelling can detect aortic branch hemodynamic changes associated with fEVAR graft implantation. MethodsPatients who underwent fEVAR for juxtarenal aortic aneurysms with the Cook ZFEN were retrospectively selected. Using open-source SimVascular software, preoperative and postoperative visceral aortic anatomy was manually segmented from computed tomography angiograms. Three-dimensional geometric models were then discretized into tetrahedral finite element meshes. Patient-specific pulsatile in-flow conditions were derived from known supraceliac aortic flow waveforms and adjusted for patient body surface area, average resting heart rate, and blood pressure. Outlet boundary conditions consisted of three-element Windkessel models approximated from physiologic flow splits. Rigid wall flow simulations were then performed on preoperative and postoperative models with the same inflow and outflow conditions. We used SimVascular's incompressible Navier-Stokes solver to perform blood flow simulations on a cluster using 72 cores. ResultsPreoperative and postoperative flow simulations were performed for 10 patients undergoing fEVAR with a total of 30 target vessels (20 renal stents, 10 mesenteric scallops). Postoperative models required a higher mean number of mesh elements to reach mesh convergence (3.2 ± 1.8 × 106 vs 2.6 ± 1.1 × 106; P = .005) with a longer mean computational time (10.3 ± 6.3 hours vs 7.8 ± 3.5 hours; P = .04) compared with preoperative models. fEVAR was associated with small but statistically significant increases in mean peak proximal aortic arterial pressure (140.3 ± 11.0 mm Hg vs 136.9 ± 8.7 mm Hg; P = .02) and peak renal artery pressure (131.6 ± 14.8 mm Hg vs 128.9 ± 11.8 mm Hg; P = .04) compared with preoperative simulations. No differences were observed in peak pressure in the celiac, superior mesenteric, or distal aortic arteries (P = .17-.96). When measuring blood flow, the only observed difference was an increase in peak renal flow rate after fEVAR (17.5 ± 3.8 mL/s vs 16.9 ± 3.5 mL/s; P = .04). fEVAR was not associated with changes in the mean pressure or the mean flow rate in the celiac, superior mesenteric, or renal arteries (P = .06-.98). Stenting of the renal arteries did not induce significant changes time-averaged wall shear stress in the proximal renal artery (23.4 ± 8.1 dynes/cm2 vs 23.2 ± 8.4 dynes/cm2; P = .98) or distal renal artery (32.7 ± 13.9 dynes/cm2 vs 29.6 ± 11.8 dynes/cm2; P = .23). In addition, computational visualization of cross-sectional velocity profiles revealed low flow disturbances associated with protrusion of renal graft fabric into the aortic lumen. ConclusionsIn a pilot study involving a selective cohort of patients who underwent uncomplicated fEVAR, patient-specific flow modelling was a feasible method for assessing the hemodynamic performance of various two-vessel fenestrated device configurations and revealed subtle differences in computationally derived peak branch pressure and blood flow rates. Structural changes in aortic flow geometry after fEVAR do not seem to affect computationally estimated renovisceral branch perfusion or wall shear stress adversely. Additional studies with invasive angiography or phase contrast magnetic resonance imaging are required to clinically validate these findings. (JVS–Vascular Science 2021;2:53-69.) Clinical RelevanceUsing a computational flow modelling for assessing the hemodynamic performance of fenestrated endovascular aneurysm repair (fEVAR), this real-world, patient-specific study included 10 participants and found that structural changes in aortic flow geometry after fEVAR did not seem to adversely impact estimated renal or visceral branch perfusion metrics (eg, peak and mean arterial pressure and flow rates) or wall shear stress. These findings overall support the ongoing clinical use of commercially available fEVAR devices for repair of juxtarenal aortic aneurysms, and provides a computational framework for future evaluation of fEVAR configurations in a preoperative or postoperative settings.

Spontaneous recanalization of occluded transplant renal artery: a rare case report

BackgroundTransplant renal artery stenosis (TRAS) is a serious vascular complication that occurs after renal transplantation and can result in hypertension, renal functional impairment, and graft loss. Endovascular treatment has become the first-line treatment for TRAS because of its low invasiveness and high success rate.Case presentationA 23-year-old female with end-stage renal disease of unknown cause received a living-donor kidney transplantation 10 months ago. Seven months after the transplantation, her blood pressure gradually deteriorated. Magnetic resonance angiography revealed bending and stenosis of the transplant renal artery, and the patient received endovascular treatment. A digital subtraction angiography revealed significant stenosis of 95% in the proximal transplant renal artery. The guidewire could not pass through the stenotic segment of the transplant renal artery even with repeated attempts by the surgeons; as a result, the transplant renal artery became occluded, and vasodilators were ineffective. After the operation, renal function gradually worsened, so she began to receive regular dialysis. Twenty-five days later, the patient’s urine volume was significantly higher than that before, and ultrasound showed that the proximal transplant renal artery was not completely occluded. A re-intervention was performed, and the stent was placed successfully in the stenotic segment. After the operation, renal function gradually recovered, and dialysis was no longer needed.ConclusionPatients with iatrogenic transplant renal artery occlusion may have the possibility of spontaneous recanalization, which can help prevent the need for re-transplantation.

O04 Large vessel vasculitis related to COVID-19 infection

Case report - IntroductionBy June 2020, 175,000 cases of COVID-19 had been identified in London alone. The most common symptoms include fever, headache, loss of smell, cough, myalgia, and sore throat. The major complication is acute respiratory distress syndrome (ARDS) but systemic complications such as cardiomyopathy, acute kidney injury, encephalopathy and coagulopathy are being identified. A delayed multi-system inflammatory syndrome in children has also been recognised and further complications are likely to be identified as our experience increases. Here, we report the case of a patient with large vessel vasculitis who initially presented with symptoms highly likely to be due to COVID-19 infection.Case report - Case descriptionA 36-year-old black African nurse presented in May 2020, with acute onset 7 days prior of high-grade fevers, rigors, nights sweats, generalised myalgia, sore throat, headache with photophobia, anosmia, dysgeusia and a widespread rash. She was a smoker with no other relevant medical, travel nor sexual history, and no drug use. A COVID-19 swab on day 2 had been negative and she had taken a course of Doxycycline.Examination revealed firm palpable subcutaneous nodules on lower limbs, upper back and forehead and cervical lymphadenopathy. She was photophobic with no meningism. The rest of her physical examination was normal. BP was 116/97 mmHg, heart rate 109 bpm and satO2 100%. Investigations demonstrated C-reactive protein 330mg/L, erythrocyte sedimentation rate 140, Ferritin 479, lymphopaenia 0.7x109, eGFR 54 with no haematoproteinuria, D-dimer 3.05 mg/L with INR 1.1, aPTT 1.3, fibrinogen 8.8 g/L. Hb, WCC, liver function, CK, serum ACE and triglycerides were normal. Infectious screen revealed negative blood cultures, HIV, Hepatitis B and C, EBV, CMV and Treponema pallidum serology. CT brain and CSF analysis were normal including bacterial culture and viral PCR. ANA, ENA, dsDNA, ANCA and aPL antibodies were negative with normal complement levels. Throat swab grew group A streptococcus and she was treated with broad spectrum antibiotics for 7 days maintaining fevers up to 39oC. Skin biopsy was non-specific with negative direct immunofluorescence but showed microvascular thrombi in the papillary dermis. COVID-19 PCR tests (three naso-pharyngeal swabs and one stool PCR) and IgG test (day 38) were negative. CT showed no pneumonitis but non-specific retroperitoneal stranding with medium/large vessel vasculitis involving both proximal renal arteries and a 6 cm segment of mid abdominal aorta on PET-CT. We started oral prednisolone 40mg with immediate resolution of her fevers, myalgia, and inflammatory markers, remaining well a month later.Case report - DiscussionTakayasu’s arteritis is the most common autoimmune large vessel vasculitis (LVV) affecting young females and involves inflammation of the arterial wall ultimately resulting in stenosis and obstruction of the vessel. However, it is rare in patients with African heritage and usually presents with a prolonged prodromal phase. Given the atypical presentation and symptoms consistent with COVID-19 infection we feel that this patients’ LVV may have been a complication of COVID-19 infection. The relationship between infections and vasculitis is complex. TB and syphilis cause aortitis and a relationship between infection and vasculitis has been proven in HBV associated PAN and HCV associated cryoglobulinemia.Experimental data supports a possible association between CMV and herpes virus and Takayasu arteritis. It could, therefore, be hypothesised that COVID-19 infection can trigger LVV. Our patient had a throat swab positive for Streptococcus pyogenes which is an uncommon cause of infective endocarditis and mycotic aneurism, but this patient had no evidence of either endocarditis or aneurism formation and so it was felt the throat swab finding was incidental. Our patient had repeated negative COVID-19 nasopharyngeal swabs and a negative antibody test at day 38.Although this argues against a diagnosis of COVID-19 related illness, the relative lack of information we currently have regarding sensitivities of the tests, at what point COVID-19 PCR becomes negative in the illness and when/if patients develop antibodies, means these negative tests in the presence of typical symptoms cannot exclude the diagnosis. We believe this case is extremely important to highlight a possible novel inflammatory complication of COVID-19 infection. We decided to treat this patient in line with guidance for the management of LVV, including the introduction of methotrexate, but it will be interesting to observe her long-term outcome. Case report - Key learning points Increasing numbers of COVID-19 related systemic inflammatory conditions are likely to be recognised over the coming months. We present the case of patient with large vessel vasculitis who initially presented atypically with symptoms consistent with COVID-19 infectionTo identify these complications, COVID-19 symptoms questioning should be part of any routine medical historyMore information is required regarding the sensitivity of COVID-19 PCR and antibody tests to aid the diagnosis of these conditionsThe long-term management of inflammatory conditions associated with COVID-19 infection is not clear and a discussion is warranted as to whether DMARDs should be initiated

Microdissection of the Human Renal Nervous System: Implications for Performing Renal Denervation Procedures.

Despite the use of renal denervation to treat hypertension, the anatomy of the renal nervous system remains poorly understood. We performed a detailed quantitative analysis of the human renal nervous system anatomy with the goal of optimizing renal denervation procedural safety and efficacy. Sixty kidneys from 30 human cadavers were systematically microdissected to quantify anatomic variations in renal nerve patterns. Contrary to current clinical perception, not all renal innervation followed the main renal artery. A significant portion of the renal nerves (late arriving nerves) frequently reached the kidney (73% of the right kidney and 53% of the left kidney) bypassing the main renal artery. The ratio of the main renal artery length/aorta-renal hilar distance proved to be a useful variable to identify the presence/absence of these late arriving nerves (odds ratio, 0.001 (95% CI, 0.00002-0.0692; P: 0.001) with a cutoff of 0.75 (sensitivity: 0.68, specificity: 0.83, area under ROC curve at threshold: 0.76). When present, polar arteries were also highly associated with the presence of late arriving nerve. Finally, the perivascular space around the proximal main renal artery was frequently occupied by fused ganglia from the solar plexus (right kidney: 53%, left kidney: 83%) and/or by the lumbar sympathetic chain (right kidney: 63%, left kidney: 60%). Both carried innervation to the kidneys but importantly also to other abdominal and pelvic organs, which can be accidentally denervated if the proximal renal artery is targeted for ablation. These novel anatomic insights may help guide future procedural treatment recommendations to increase the likelihood of safely reaching and destroying targeted nerves during renal denervation procedures.

Patient-Specific Computational Flow Modelling for Assessing Hemodynamic Changes Following Fenestrated Endovascular Aneurysm Repair

Abstract Objective This study aimed to develop an accessible patient-specific computational flow modelling pipeline for evaluating the hemodynamic performance of fenestrated endovascular aneurysm repair (fEVAR), with the hypothesis that computational flow modelling can detect aortic branch hemodynamic changes associated with fEVAR graft implantation. Methods Patients who underwent fEVAR for juxtarenal aortic aneurysms with the Cook ZFEN were retrospectively selected. Using open-source SimVascular software, preoperative and postoperative visceral aortic anatomy was manually segmented from computed tomography angiograms. Three-dimensional geometric models were then discretized into tetrahedral finite element meshes. Patient-specific pulsatile in-flow conditions were derived from known supraceliac aortic flow waveforms and adjusted for patient body surface area, average resting heart rate, and blood pressure. Outlet boundary conditions consisted of three-element Windkessel models approximated from physiologic flow splits. Rigid wall flow simulations were then performed on preoperative and postoperative models with the same inflow and outflow conditions. We used SimVascular's incompressible Navier-Stokes solver to perform blood flow simulations on a cluster using 72 cores. Results Preoperative and postoperative flow simulations were performed for 10 patients undergoing fEVAR with a total of 30 target vessels (20 renal stents, 10 mesenteric scallops). Postoperative models required a higher mean number of mesh elements to reach mesh convergence (3.2 ± 1.8 × 106 vs 2.6 ± 1.1 × 106; P = .005) with a longer mean computational time (10.3 ± 6.3 hours vs 7.8 ± 3.5 hours; P = .04) compared with preoperative models. fEVAR was associated with small but statistically significant increases in mean peak proximal aortic arterial pressure (140.3 ± 11.0 mm Hg vs 136.9 ± 8.7 mm Hg; P = .02) and peak renal artery pressure (131.6 ± 14.8 mm Hg vs 128.9 ± 11.8 mm Hg; P = .04) compared with preoperative simulations. No differences were observed in peak pressure in the celiac, superior mesenteric, or distal aortic arteries (P = .17-.96). When measuring blood flow, the only observed difference was an increase in peak renal flow rate after fEVAR (17.5 ± 3.8 mL/s vs 16.9 ± 3.5 mL/s; P = .04). fEVAR was not associated with changes in the mean pressure or the mean flow rate in the celiac, superior mesenteric, or renal arteries (P = .06-.98). Stenting of the renal arteries did not induce significant changes time-averaged wall shear stress in the proximal renal artery (23.4 ± 8.1 dynes/cm2 vs 23.2 ± 8.4 dynes/cm2; P = .98) or distal renal artery (32.7 ± 13.9 dynes/cm2 vs 29.6 ± 11.8 dynes/cm2; P = .23). In addition, computational visualization of cross-sectional velocity profiles revealed low flow disturbances associated with protrusion of renal graft fabric into the aortic lumen. Conclusions In a pilot study involving a selective cohort of patients who underwent uncomplicated fEVAR, patient-specific flow modelling was a feasible method for assessing the hemodynamic performance of various two-vessel fenestrated device configurations and revealed subtle differences in computationally derived peak branch pressure and blood flow rates. Structural changes in aortic flow geometry after fEVAR do not seem to affect computationally estimated renovisceral branch perfusion or wall shear stress adversely. Additional studies with invasive angiography or phase contrast magnetic resonance imaging are required to clinically validate these findings. (JVS–Vascular Science 2021;▪:1-17.) Clinical Relevance Using a computational flow modelling for assessing the hemodynamic performance of fenestrated endovascular aneurysm repair (fEVAR), this real-world, patient-specific study included 10 participants and found that structural changes in aortic flow geometry after fEVAR did not seem to adversely impact estimated renal or visceral branch perfusion metrics (eg, peak and mean arterial pressure and flow rates) or wall shear stress. These findings overall support the ongoing clinical use of commercially available fEVAR devices for repair of juxtarenal aortic aneurysms, and provides a computational framework for future evaluation of fEVAR configurations in a preoperative or postoperative settings.

Renal Artery Stenosis Presenting at Sudden Flash Pulmonary Edema in a Patient with Solitary Kidney

Flash pulmonary edema is characterized by a sudden episode of dyspnea resulting from acute pulmonary venous congestion, which resolves rapidly. We report a case of renal artery stenosis presenting as flash pulmonary edema in a patient with solitary kidney treated by angioplasty with stent implantation. A 75-year-old man with solitary kidney visited the emergency room with acute shortness of breath. His blood pressure had risen to 206/90 mmHg and a chest radiograph revealed pulmonary edema. Echocardiography and coronary arteriography showed no clear abnormalities, but abdominal computed tomography revealed severe focal stenosis in the left proximal renal artery. A captopril renal scan found that the time to peak and half-time of radioactivity were delayed in the left kidney. Percutaneous transluminal angioplasty was performed, followed by stent implantation. After this procedure, the stenotic segment was completely dilated and blood pressure returned to the normal range.

Is the frozen elephant trunk technique justified for chronic type A aortic dissection in Marfan syndrome?

Chronic type A aortic dissection (cTAAD) in Marfan syndrome (MFS) is rare. Surgical experience is limited and the role of frozen elephant trunk (FET) technique remains undefined. We seek to evaluate the safety and efficacy of the total arch replacement (TAR) and FET technique for cTAAD in MFS. The clinical data of sixty-eight patients with MFS undergoing FET and TAR for cTAAD were analyzed. Mean age was 35.8±9.7 years and thirty-nine were male (57.4%). Operative mortality was 10.3% (7/68). Stroke occurred in one (1.5%), re-exploration for bleeding in five (7.3%), low cardiac output in four (5.9%), and acute renal failure in two (2.9%). Follow-up was complete in 100% (61/61) at mean 7.3±4.0 years. The false lumen was obliterated in 73.5% across FET and 50.0% in unstented descending aorta (DAo). Distal dilation occurred in twenty patients, six of whom underwent thoracoabdominal aortic replacement, one abdominal aortic replacement and one thoracic endovascular aortic repair (TEVAR). Late death occurred in five. At ten years, 59.8% were free from distal aortic dilation, and the incidences were 23.2% for death, 14.4% for distal reoperation, and 62.4% for reoperation-free survival. Predictors for operative mortality were extra-anatomic bypass [odds ratio (OR), 229.592; P=0.036], preoperative maximal size (DMax) of aortic sinuses (mm) (OR, 1.134; P=0.032) and cardiopulmonary bypass (CPB) time (minute) (OR, 1.061; P=0.041). Risk factors for aortic dilatation included patent false lumen at diaphragmatic hiatus [hazard ratio (HR), 5.374; P=0.008], preoperative DMax (mm) of proximal DAo (HR, 1.068; P=0.001) and renal arteries (HR, 1.102; P=0.005) which also predicted distal reoperation (HR, 1.149; P=0.001). The time from onset to operation (day) (HR, 1.002; P=0.004) and CPB time (minute) (HR, 1.032; P=0.036) predicted late death. This study shows that the TAR and FET technique is a safe and durable approach to cTAAD in patients with MFS. The operation should be performed as early as possible to optimize clinical outcomes.

Renal artery stenosis presenting as preeclampsia

BackgroundRenal artery stenosis is a notorious cause of secondary hypertension which classically presents as chronic refractory hypertension, recurrent flash pulmonary edema or renal insufficiency after initiation of an angiotensin converting enzyme inhibitor. Rarely, there have been reported cases of pregnant patients presenting with new onset or superimposed preeclampsia secondary to renovascular hypertension. In this subset of patients, renovascular hypertension carries significantly higher risks including obstetric, fetal and medical emergencies and death. Prompt treatment is required. However, the teratogenic risks of radiological investigations and antihypertensive medications limit diagnostic and management options thus posing quite a dilemma.Case presentationA 38-year-old female, at 33 weeks of gestation, was hospitalized for preeclampsia with severe features. A viable neonate had been expeditiously delivered yet the patient’s post-partum blood pressures remained severely elevated despite multi-class anti-hypertensive therapy. Renal artery dopplers revealed greater than 60% stenosis of the proximal left renal artery and at least 60% stenosis of the right renal artery. Renal angiography showed 50% stenosis of the left proximal renal artery for which balloon angioplasty and stenting was performed. The right renal artery demonstrated less than 50% stenosis with an insignificant hemodynamic gradient, thus was not stented. Following revascularization, the patient’s blood pressure improved within 48 h, on dual oral antihypertensive therapy.ConclusionsPreeclampsia that is refractory to multi-drug antihypertensive therapy should raise suspicion for renal artery stenosis. Suspected patients can be screened safely with Doppler ultrasonography which can be then followed by angiography. Even if renal artery stenosis does not seem severe, early renal revascularization may be considered in patients with severe preeclampsia who do not respond to antihypertensive management.

AIUM Practice Parameter for the Performance of Duplex Sonography of Native Renal Vessels

AIUM Practice Parameter for the Performance of Duplex Sonography of Native Renal Vessels

Renal salvage using stent graft placement after acute renal artery occlusion with prolonged ischemic time

PurposeTo describe a patient with acute renal artery occlusion who underwent successful revascularization procedure after experiencing a protracted ischemic period, which resulted in successful retrieval of renal function.Case reportA 58-year-old male with a history of left renal artery stenosis and stent graft placement presented with symptoms of chest pain, shortness of breath, and flank pain. The patient was admitted to the Intensive Care Unit with the diagnosis of multiorgan failure and subsequent anuria that led to the initiation of hemodialysis. Computed tomography angiography demonstrated an aortic occlusion along with bilateral proximal renal artery occlusion with reconstitution of the mid to distal renal arteries via collateralization. The patient underwent angioplasty with bilateral renal artery stent-graft placement and successful revascularization of proximal renal arteries. Post-operatively, his renal function and urine output improved, and the patient was able to be weaned off hemodialysis along with the benefit of concurrent amelioration of his renovascular hypertension.ConclusionFor select patients with renal artery occlusion, revascularization of the renal arteries may result in dialysis independence and stabilization of renovascular hypertension, despite prolonged time of ischemia.

P4566Comparison of standard renal denervation procedure versus novel distal and branch vessel ablation with brachial arterial access

Abstract Objectives We assessed a novel approach to percutaneous renal denervation for uncontrolled hypertension consisting of ablation beyond the proximal main renal artery (Y-pattern), including the primary branches, and compared it to the standard procedure applied only within the main vessel. We also assessed the safety and practicality of a brachial access approach. Methods and results Renal denervation was performed on 119 consecutive patients (60±13 years). In 68 of the patients, femoral arterial vascular approach was used and in 51 brachial. In 80 patients treated with the standard ablation, 12.0±3.0 total ablations (both sides) were applied while 20.4±3.9 total ablations were delivered for the group of 39 patients with Y-pattern denervation (P&lt;0.001). Technically successful renal denervation was achieved in all patients. Office blood-pressure levels at baseline were 170±17/93±10 mm Hg for the standard group and 169±13/96±9 mm Hg for the Y-pattern group. No major adverse events occurred during the procedure or in the postprocedural in-hospital period. Renal denervation was associated with significant decreases in both office and ambulatory systolic and diastolic blood pressure in both groups. The reduction in 24-hour mean ambulatory systolic blood pressure at 6 months was significantly greater (P=0.002) for the Y-Pattern group (−22.1±15.4 mm Hg) compared to the Standard group (−11.8±16.2 mm Hg). Changes in diastolic office and ambulatory pressure were also significantly greater at 6 months in the Y-pattern ablation group. Indices of blood pressure variability improved in both groups. Between group comparison of blood pressure and other parameters at follow up Standard Y-Pattern P (Standard vs Y) Change in Office Diastolic Blood Pressure (mmHg) 1 Month −8.0±13.2* −9.8±8.5* 0.49 3 Months −6.3±6.9* −6.4±9.0* 0.96 6 Months −5.0±9.0* −9.9±10.8* 0.01 Change in Ambulatory Diastolic Pressure (mmHg) 24-Hour −5.2±8.4* −6.2±10.0* 0.61 Daytime −3.2±9.4* −5.6±10.0* 0.24 Night Time −7.6±8.4* −6.5±11.5* 0.56 Antihypertensive Medication Classes 4.9±1.1* 5.3±0.8* 0.07 otal Number of Lesions† 12.0±3.0 20.4±3.9 &lt;0.001 Conclusion Renal denervation using a Y-pattern ablation strategy combined with a greater number of lesions is safe and resulted in significant greater decreases in mean 24-hour ambulatory systolic and diastolic blood pressure compared to the conventional

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

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

Clinical application of renal autotransplantation in complex urological diseases

Objective: To summarize the experience of renal autotransplantation for severe iatrogenic proximal ureteral damage and renal artery aneurysms in eight patients and to explore the clinical application value of renal autotransplantation. Methods: Two patients of renal artery aneurysms and six patients of severe iatrogenic proximal ureteral damage between January 2010 and March 2018 in our center were retrospectively reviewed. Results: The procedures of eight cases were successful, with immediate return of renal function in the patients. The warm ischemia time was (3±1) minutes, the total operation time was (340±164) min, and the estimated blood loss was (180±60) ml, respectively. For renal artery anastomosis, six patients of severe iatrogenic proximal ureteral damage received end-to-end anastomosis between the internal iliac artery and renal artery, and two patients of renal artery aneurysms were treated with renal artery and internal iliac artery for reconstruction, then end-to-side anastomosis to recipien external iliac artery. A direct ureterovesical anastomosis was performed in seven patients, one patient was received pyeloureteroplasty. No serious complications of blood vessel and ureter were found during perioperative and long-term follow-up. All cases follow-up hitherto have normal renal function and blood pressure. Conclusions: Renal autotransplantation can be appropriate for patients with proximal ureteral loss and complex hilar renal artery aneurysms. In addition, it is able to protect renal functions to the most extent and provides a surgical alterative for complex renal diseases.