Suprarenal Aorta Research Articles

Abstract 14780: Developing a Model for Abdominal Aortic Aneurysm in Swine

Introduction: Abdominal aortic aneurysms (AAA) are responsible for over 150,000 deaths worldwide annually. Attempts at producing a reliable large-animal model of AAA have proven challenging. We sought to create a reproducible swine model of AAA using enzymatic degradation of the aortic wall. Methods: A total of 9 male Yorkshire swine received periadventitial injections of type 1 collagenase (23.5 mg) and porcine pancreatic elastase (500 mg) into a 4 cm segment of infrarenal aorta. Aortic diameter growth was monitored at POD 7 and 14 using ultrasound. The animals were euthanized on POD 21, and the suprarenal (control) and infrarenal (treated) aorta was harvested for analysis, after gross measurement of aortic diameter under physiologic blood pressure. Sections of control and treated aorta were used to obtain tensile strength using a tensiometer. Additional segments of the aorta were collected for histopathological analysis (H&E, elastin, alpha smooth muscle actin). PCR of matrix metalloproteinases (MMP9) was conducted. Groups were compared with paired t-tests, or ANOVA for repeated measures, where appropriate. Results: Average percent growth of aortic diameter at POD 21 for treated segments was 27% +/- 16.5% versus 4.5% +/- 4% for control tissue. The average difference in aortic growth by subject, was 26.7% [14.6%-38.8%]; (p<0.001). Aortic medial thickness was decreased in treated tissue; 235 um +/- 208 um versus 645 um +/- 191 um (p<0.0001). Quantity of both medial elastin fibers, and vascular smooth muscles cells was decreased in treated tissue; 1.8% +/- 3.16%, compared to 9.9% +/- 6.85% (p<0.0001), and 24% +/- 6.8% versus 37.4% +/- 6.9%, respectively. Tensile strength was also decreased in treated tissue; 16.7 MPa +/- 7 MPa versus 29.5 MPa +/- 10.7 MPa (p=0.0002). A 12-fold increase in expression of MMP9 mRNA was also demonstrated in aneurysmal tissue (p=0.002) Conclusion: A reproducible, large-animal model of AAA, with anatomical, histopathological, and biomechanical properties that are clinically translatable, can be achieved with extraluminal enzymatic degradation.

Abstract P245: Therapeutic Effects Of Mir-29b-Chitosan On Hypertension And Diabetic Complications

MicroRNA miR-29 promotes endothelial function in human arterioles in part by targeting LYPLA1 and increasing nitric oxide production. Endothelial dysfunction is common in cardiovascular diseases such as hypertension and diabetic microvascular complications. In addition, miR-29 is a master inhibitor of extracellular matrix gene expression, which may attenuate fibrosis but could also weaken tissue structure. The goal of this study was to develop an effective miR-29 therapeutic for multiple cardiovascular diseases using mouse models. Substantial accumulation of miR-29b and effective knockdown of Lypla1 in mouse tissues were achieved using a chitosan-packaged, chemically modified miR-29b mimic (miR-29b-CH) injected systemically at 200 μg/kg body weight. miR-29b-CH, injected once every three days, significantly attenuated angiotensin II-induced hypertension over two weeks (mean arterial pressure of 128 ± 5 vs 149 ± 5 mmHg, N = 7 Scr-CH, 8 miR-29b-CH p<0.05). In db/db mice, miR-29b-CH treatment for 12 weeks decreased cardiac (0.98 ± 0.13 vs 1.55 ± 0.17 % fibrosis) and renal (2.85 ± 0.28 vs 4.85 ± 0.47 % fibrosis) fibrosis and urinary albuminuria 0.0051 ± 0.0004 vs 0.0069 ± 0.0005 albumin/creatinine, N = 12 Scr-CH, 9 miR-29b-CH, p<0.05). In uninephrectomized db/db mice, the miR-29b-CH treatment for 20 weeks significantly improved myocardial performance index (0.36 ± 0.02 vs 0.57 ± 0.05) in addition to attenuating proteinuria (0.015 ± 0.004 vs 0.033 ± 0.005 protein/creatinine) (N = 8 Scr-CH, 8 miR-29b-CH, p<0.05). miR-29b-CH did not worsen abdominal aortic aneurysm in ApoE knockout mice treated with angiotensin II (33.7 ± 8.2 vs 29.8 ± 6.7% increase in suprarenal abdominal aorta diameter from baseline, N = 8 Scr-CH and 7 miR-29b-CH). miR-29b-CH caused aortic root fibrotic cap thinning (13.8 ± 2.5 vs 20.8 ± 1.8 % of total plaque area) in ApoE knockout mice fed a high cholesterol and high fat diet but did not worsen the necrotic zone (15.2 ± 1.4 vs 12.5 ± 1.0 % of total plaque area) or the mortality (11/12 control mice survived until end of study vs 10/12 miR-29b-CH treated, N = 8 Scr-CH, 7 miR-29b-CH). In conclusion, systemic delivery of low dose miR-29b-CH is an effective therapeutic for several forms of hypertension and diabetic complications in mice.

Histological and SEM Assessment of Blood Stasis in Kidney Blood Vessels after Repeated Intra-Arterial Application of Radiographic Contrast Media.

Background: After application of iodinated contrast media (CM), a pronounced deterioration of the microcirculation in skin and myocardium was reported. Clinically, the repeated application of CM, especially, led to an increase of the renal resistance index (RRI). With respect to the transiency of the RRI increase, it is reasonable to assume that the deterioration of blood flow could be due to transient blood stasis caused by reversible morphologic cell alterations due to osmotic discrepancies between CM and human blood. Therefore, the hypothesis was investigated whether CM are able to induce in vivo such blood stasis and cell deformations in the renal vasculature of well-hydrated pigs. Methods: The in vivo study was performed as a prospective randomized examination to compare the effects of two different CM in 16 pigs (German Landrace). Pigs were randomized to receive either Iodixanol (n = 8), or Iopromide (n = 8). Each animal received 10 injections separated by 5-min intervals via the suprarenal aorta at a rate of 10 mL/s according to the usual procedure during a cardiac catheter examination. Finally, the kidneys were explanted and processed for histology (H & E staining and fibrin staining according to Weigert) as well as for scanning electron microscopy (SEM) with regards to morphologic correlates explaining the changes in the microcirculation. Results: In each of the predefined four categories of vascular diameters, blood stasis were found, but clearly more often after application of Iopromide than after application of Iodixanol (p < 0.001). In addition, Iopromide induced more blood stasis in all of the examined kidney regions compared to Iodixanol (p = 0.0001). There were no obstructive events in the middle cortex following the application of Iodixanol. Except for the region around a puncture channel of a placed-in catheter probe, no fibrin was detected in Weigert’s fibrin-stained samples, neither around the histologically assessed thrombi nor in vessels with blood stasis. Complementary SEM analyses revealed in a few cases only a slight generation of fibrin and thrombi and deformations, such as echinocyte and “box-like” deformations. Conclusions: According to previous in vitro studies, pathological erythrocyte deformations, such as echinocyte and box-like formation of erythrocytes, were observed also in vivo. In addition, blood stasis and/or thrombi could be detected in histological samples from explanted kidneys from young pigs after repeated in vivo administration of CM. In only a few cases, mural platelet aggregates within minimal fibrin meshes occurred only after the application of Iopromide.

Effect of Stent Graft Active Fixation and Oversizing on Aortic Neck Degeneration After Endovascular Aneurysm Exclusion for Infrarenal Aortic Aneurysm

Aortic neck degeneration after endovascular aneurysm repair (EVAR) has been implicated in the long-term development of endoleak and the subsequent reintervention. Optimal endograft sizing is a vital aspect to successful repair. This study looked at percentage of graft oversizing as well as type of fixation on aortic neck degeneration. We retrospectively evaluated all EVARs completed at Loyola University from 2006 to 2015 after Institutional Review Board approval. Exclusion criteria were patients without follow-up scans within a year. We collected demographics, comorbidities, graft type, size, aortic neck diameter, and maximum sac size diameters from the preoperative and follow-up scans. We reviewed and collected data of 432 patients but analyzed 154. We measured the largest aortic diameter on axial images 1 cm above and 1 cm below the renal arteries. Change in suprarenal and infrarenal aortic measurements were evaluated by calculating the millimeter difference from each scan compared with the preoperative scan. Linear mixed effects models were used to estimate patients’ mean differences over time. We compared three groups of neck fixation grafts. Those with active suprarenal fixation had a significant change in suprarenal aortic diameter at 4-year follow-up (1.86 mm; confidence interval [CI], 0.65-3.06) compared to those with active infrarenal (0.22 mm; CI, −0.67 to 1.11) or passive suprarenal fixation (1.52 mm; CI, −0.11 to 3.15; Fig 1). Those with active suprarenal fixation were the only ones to have significant increase in suprarenal aortic diameter (P = .0026). Degree of oversizing was also divided into three groups. Oversizing by <10% had less impact on the suprarenal aorta than >15% oversizing at 4 years (0.41 mm [CI, −0.31 to 1.14] vs 3.26 mm [CI, 1.63-4.88]; P < .001; Fig 2). Oversizing had a more pronounced effect on the infrarenal aorta: 4.43 mm [CI, 2.79-6.08], 5.57 mm [CI, −0.25 to 11.38], and 6.48 mm [CI, 2.99-9.97] for <10%, 10% to 15%, and >15% oversizing at 4 years, respectively. Stent grafts with active fixation below the renal arteries as well as oversizing by <10% seem to have the least effect on aortic neck degeneration over time. These factors should be considered in performing EVARs as aortic neck degeneration could lead to endoleaks. Further research defining the optimal stent graft type and oversizing is warranted.Fig 2Suprarenal aortic diameter change over time for each stent graft type. CI, Confidence interval.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Refractory heart failure and intermittent claudication secondary to supra-renal coral reef aorta

Coral reef aorta (CRA), a rare disease, is characterized by severe calcification of the juxta-renal and suprarenal aorta that grows into the lumen and leads to severe stenosis. A 70-year-old woman with refractory hypertension and lower limb claudication presented with hypertension and congestive heart failure. Treatment with vasodilators and diuresis led to oliguria and exacerbated kidney function, while her congestion remained. Abdominal computerized tomography showed a bulky, irregular localized supra-renal aortic calcification with stenosis. A peripheral artery ultrasound and angiography showed no occlusive lesions in the distal run-off vessels. Based on her medical history and the unique aspects of the localized calcified lesion, CRA was diagnosed. We suspected that the congestive heart failure, refractory hypertension, and renal failure resulted from the supra-renal aortic stenosis. Because she developed oliguria with diuretics and vasodilators, we performed an open graft replacement with a thoracoabdominal approach. The reddish-brown calcified mass came off easily and was very fragile. The postoperative course was uneventful, and her heart and renal failure were completely resolved. This is the first report showing the fragility of CRA. Considering its fragility, catheter treatment may need to be avoided to prevent distal embolism.<Learning objective: When we encounter a calcified lesion localized at the level of the juxta and supra-renal aorta with extensive growth into the lumen, coral reef aorta (CRA) should be suspected. Considering that CRA lesion can be very fragile in contrast to the usual atherosclerotic lesion, as shown in our case, CRA might possibly increase the risk of distal embolization. Therefore, open graft replacement could be safer than endovascular stent-graft placement.>

Intravascular Ultrasound–Guided Revascularization of Chronic Juxtarenal Aortoiliac Occlusion

Chronic juxtarenal aortoiliac occlusion (JRO) represents the most severe form of aortoiliac occlusive disease, classified under Trans-Atlantic Inter-Society Consensus (TASC II) as a TASC II D lesion with surgical treatment as the main recommendation. Although endovascular revascularization of other TASC II D lesions are routinely performed, JRO is often considered a contraindication for endovascular treatment due to the extensive nature, extending from the level of the renal arteries down to the iliac arteries. We hereby illustrate an intravascular ultrasound-guided re-entry based technique to facilitate endovascular reconstruction of a JRO. A 58-year-old man with JRO presented with an infected nonhealing forefoot ulcer. A transradial pigtail catheter was positioned at the level of the occlusion as an imaging catheter and landmark for re-entry. Subintimal wiring was performed through bilateral groin accesses to the level of the pigtail catheter. Intravascular-guided re-entry catheter was used to identify the true lumen guide firing of the needle catheter, allowing passage for a guidewire into the true lumen of the suprarenal aorta. The intimal fenestration was dilated using a 4-mm angioplasty balloon which allowed passage of the contralateral guidewire. Kissing stent grafts were deployed bilaterally, extending from the level of the infrarenal aorta down to the level of the distal external iliac arteries in overlapping fashion. Completion angiography showed brisk flow from the aorta through the stented portion into the femoral arteries. The patient underwent forefoot amputation 2 days later with successful wound healing and limb salvage at 6months.

Suppression of Vascular Macrophage Activation by Nitro-Oleic Acid and its Implication for Abdominal Aortic Aneurysm Therapy.

Abdominal aortic aneurysm (AAA) is one of the leading causes of death in the developed world and is currently undertreated due to the complicated nature of the disease. Herein, we aimed to address the therapeutic potential of a novel class of pleiotropic mediators, specifically a new drug candidate, nitro-oleic acid (NO2-OA), on AAA, in a well-characterized murine AAA model. We generated AAA using a mouse model combining AAV.PCSK9-D377Y induced hypercholesterolemia with angiotensin II given by chronic infusion. Vehicle control (PEG-400), oleic acid (OA), or NO2-OA were subcutaneously delivered to mice using an osmotic minipump. We characterized the effects of NO2-OA on pathophysiological responses and dissected the underlying molecular mechanisms through various in vitro and ex vivo strategies. Subcutaneous administration of NO2-OA significantly decreased the AAA incidence (8/28 mice) and supra-renal aorta diameters compared to mice infused with either PEG-400 (13/19, p =0.0117) or OA (16/23, p = 0.0078). In parallel, the infusion of NO2-OA in the AAA model drastically decreased extracellular matrix degradation, inflammatory cytokine levels, and leucocyte/macrophage infiltration in the vasculature. Administration of NO2-OA reduced inflammation, cytokine secretion, and cell migration triggered by various biological stimuli in primary and macrophage cell lines partially through activation of the peroxisome proliferator-activated receptor-gamma (PPARγ). Moreover, the protective effect of NO2-OA relies on the inhibition of macrophage prostaglandin E2 (PGE2)-induced PGE2 receptor 4 (EP4) cAMP signaling, known to participate in the development of AAA. Administration of NO2-OA protects against AAA formation and multifactorial macrophage activation. With NO2-OA currently undergoing FDA approved phase II clinical trials, these findings may expedite the use of this nitro-fatty acid for AAA therapy.

Multimodality Imaging-Based Characterization of Regional Material Properties in a Murine Model of Aortic Dissection

Chronic infusion of angiotensin-II in atheroprone (ApoE−/−) mice provides a reproducible model of dissection in the suprarenal abdominal aorta, often with a false lumen and intramural thrombus that thickens the wall. Such lesions exhibit complex morphologies, with different regions characterized by localized changes in wall composition, microstructure, and properties. We sought to quantify the multiaxial mechanical properties of murine dissecting aneurysm samples by combining in vitro extension-distension data with full-field multimodality measurements of wall strain and thickness to inform an inverse material characterization using the virtual fields method. A key advance is the use of a digital volume correlation approach that allows for characterization of properties not only along and around the lesion, but also across its wall. Specifically, deformations are measured at the adventitial surface by tracking motions of a speckle pattern using a custom panoramic digital image correlation technique while deformations throughout the wall and thrombus are inferred from optical coherence tomography. These measurements are registered and combined in 3D to reconstruct the reference geometry and compute the 3D finite strain fields in response to pressurization. Results reveal dramatic regional variations in material stiffness and strain energy, which reflect local changes in constituent area fractions obtained from histology but emphasize the complexity of lesion morphology and damage within the dissected wall. This is the first point-wise biomechanical characterization of such complex, heterogeneous arterial segments. Because matrix remodeling is critical to the formation and growth of these lesions, we submit that quantification of regional material properties will increase the understanding of pathological mechanical mechanisms underlying aortic dissection.

Quantification of suprarenal aortic neck dilation after fenestrated endovascular aneurysm repair

ObjectiveSuprarenal aortic neck dilation (AND) after fenestrated endovascular aneurysm repair (FEVAR) with commercially available devices has not yet been well characterized. The aim of this study was to measure diameter changes in the supravisceral aorta after FEVAR. MethodsThis is a single-center retrospective review involving patients with juxtarenal aneurysms treated with Cook ZFEN devices (Cook Medical, Bloomington, Ind). Patients with at least 1 year of cross-sectional radiologic follow-up were included. AND was defined as ≥3 mm at any measured location. Aortic diameter, defined as the average outer to outer diameter on three-dimensional centerline imaging, was measured at seven locations along the length of the ZFEN device from the proximal fixation struts to the bottom of the second seal stent. The first postoperative CT scan (≤1 month) served as a baseline from which subsequent measurements at annual intervals were compared. ResultsA total of 43 patients who underwent FEVAR from 2012 to 2018 met inclusion criteria, with a total of 119 target vessels (83 renal stents, 41 superior mesenteric artery scallops or large fenestrations). Mean follow-up time was 30.3 months. Any AND was found to occur in 32 (74.4%) patients. Aortic diameter dilation at latest follow-up was found to occur at all measured locations from the top of the fixation struts (1.9 ± 2.4 mm; P < .0001) to the middle of the second seal stent (1.3 ± 3.8 mm; P < .01). Diameter growth was most pronounced in the middle of the first seal stent, with mean AND of 3.6 ± 3.2 mm. At this location, the aorta experienced nearly linear annual growth of 0.99 mm (95% confidence interval, 0.7-1.28 mm) per year. Increasing device oversizing relative to the native visceral aorta was the strongest predictor of postoperative neck diameter growth (1.34 mm per 10% increase in oversizing; P = .02), whereas increasing proximal seal length was protective of growth (−1.82 mm per 10-mm increase in seal length; P = .016). Proximal seal lengths ≥3 cm were associated with less neck dilation compared with <3 cm (2.6 mm vs 4.9 mm; P = .022). Type IA endoleak in this cohort was rare (n = 1) and not associated with AND (P = .256). ConclusionsDilation of the suprarenal aorta is a common finding in midterm follow-up after FEVAR and not associated with proximal endoleak. Aggressive device oversizing is predictive of dilation, whereas longer seal lengths are associated with less dilation along the suprarenal seal zone. These results support the continued use of FEVAR for juxtarenal aneurysms, particularly in patients in whom ≥3 cm of healthy seal length can be obtained.

Factor XII blockade inhibits aortic dilatation in angiotensin II-infused apolipoprotein E-deficient mice.

Abdominal aortic aneurysm (AAA) is an important cause of mortality in older adults. Chronic inflammation and excessive matrix remodelling are considered important in AAA pathogenesis. Kinins are bioactive peptides important in regulating inflammation. Stimulation of the kinin B2 receptor has been previously reported to promote AAA development and rupture in a mouse model. The endogenous B2 receptor agonist, bradykinin, is generated from the kallikrein-kinin system following activation of plasma kallikrein by Factor XII (FXII). In the current study whole-body FXII deletion, or neutralisation of activated FXII (FXIIa), inhibited expansion of the suprarenal aorta (SRA) of apolipoprotein E-deficient mice in response to angiotensin II (AngII) infusion. FXII deficiency or FXIIa neutralisation led to decreased aortic tumor necrosis factor-α-converting enzyme (TACE/a disintegrin and metalloproteinase-17 (aka tumor necrosis factor-α-converting enzyme) (ADAM-17)) activity, plasma kallikrein concentration, and epithelial growth factor receptor (EGFR) phosphorylation compared with controls. FXII deficiency or neutralisation also reduced Akt1 and Erk1/2 phosphorylation and decreased expression and levels of active matrix metalloproteinase (Mmp)-2 and Mmp-9. The findings suggest that FXII, kallikrein, ADAM-17, and EGFR are important molecular mediators by which AngII induces aneurysm in apolipoprotein E-deficient mice. This could be a novel pathway to target in the design of drugs to limit AAA progression.

Chimney Technique to Preserve Visceral Flow in a Coral Reef Aorta

The coral reef aorta (CRA) is a rare phenomenon of extreme calcification in the juxtarenal and suprarenal aorta. Open revascularization has an overall in-hospital mortality rate of 13%. We present a patient with a suprarenal CRA with colon ischemia. She has an extensive past medical history of percutaneous transluminal angioplasty and stenting of the celiac trunk (CT) and superior mesenteric artery (SMA). The computed tomography angiography showed a CRA of the suprarenal aorta with occlusion of the CT stent and near occlusion of the SMA stent. Our case illustrates that the CRA in the suprarenal part of the aorta can be treated well by chimney graft procedure, although owing to lack of long-term follow-up, it might be reserved for high-risk candidates for (thoraco)abdominal aortic surgery.

Runx2 (Runt-Related Transcription Factor 2)-Mediated Microcalcification Is a Novel Pathological Characteristic and Potential Mediator of Abdominal Aortic Aneurysm

Abdominal aortic aneurysms (AAAs) are highly lethal diseases without effective clinical predictors and therapeutic targets. Vascular microcalcification, as detected by fluorine-18-sodium fluoride, has recently been recognized as a valuable indicator in predicting atherosclerotic plaque rupture and AAA expansion. However, whether vascular microcalcification involved in the pathogenesis of AAA remains elusive. Approach and Results: Microcalcification was analyzed in human aneurysmal aortas histologically and in AngII (angiotensin II)-infused ApoE-/- mouse aortas by fluorine-18-sodium fluoride positron emission tomography and X-ray computed tomography scanning in chronological order in live animals. AAA patients' aortic tissue showed markedly enhanced microcalcification in the aortic media within the area proximal to elastic fiber degradation, compared with non-AAA patients. Enhanced fluorine-18-sodium fluoride uptake preceded significant aortic expansion in mice. Microcalcification-positive mice on day 7 of AngII infusion showed dramatic aortic expansion on subsequent days 14 to 28, whereas microcalcification-negative AngII-infused mice and saline-induced mice did not develop AAA. The application of hydroxyapatite, the main component of microcalcification, aggravated AngII-induced AAA formation in vivo. RNA-sequencing analysis of the suprarenal aortas of 4-day-AngII-infused ApoE-/- mice and bioinformatics analysis with ChIP-Atlas database identified the potential involvement of the osteogenic transcriptional factor Runx2 (runt-related transcription factor 2) in AAA. Consistently, vascular smooth muscle cell-specific Runx2 deficiency markedly repressed AngII-induced AAA formation in the ApoE-/- mice compared with the control littermates. Our studies have revealed microcalcification as a novel pathological characteristic and potential mediator of AAA, and targeting microcalcification may represent a promising strategy for AAA prevention and treatment.

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

Determining Haemodynamic Wall Shear Stress in the Rabbit Aorta In Vivo Using Contrast-Enhanced Ultrasound Image Velocimetry

Abnormal blood flow and wall shear stress (WSS) can cause and be caused by cardiovascular disease. To date, however, no standard method has been established for mapping WSS in vivo. Here we demonstrate wide-field assessment of WSS in the rabbit abdominal aorta using contrast-enhanced ultrasound image velocimetry (UIV). Flow and WSS measurements were made independent of beam angle, curvature or branching. Measurements were validated in an in silico model of the rabbit thoracic aorta with moving walls and pulsatile flow. Mean errors over a cardiac cycle for velocity and WSS were 0.34 and 1.69%, respectively. In vivo time average WSS in a straight segment of the suprarenal aorta correlated highly with simulations (PC = 0.99) with a mean deviation of 0.29 Pa or 5.16%. To assess fundamental plausibility of the measurement, UIV WSS was compared to an analytic approximation derived from the Poiseuille equation; the discrepancy was 17%. Mapping of WSS was also demonstrated in regions of arterial branching. High time average WSS (TAWSSxz = 3.4 Pa) and oscillatory flow (OSIxz = 0.3) were observed near the origin of conduit arteries. In conclusion, we have demonstrated that contrast-enhanced UIV is capable of measuring spatiotemporal variation in flow velocity, arterial wall location and hence WSS in vivo with high accuracy over a large field of view.

Evaluating the origin of vascular structures in ectopic kidneys with multidetector computed tomography.

The purpose of this study is to investigate the origin of the vascular structures in ectopic kidneys with multidetector computed tomography (CT). The abdominal CT images of 96 cases with 106 ectopic kidneys were retrospectively reviewed. The ectopic kidney location, type of ectopia, and the origins of renal arteries and veins of the ectopic kidneys were evaluated. The origins of the renal arteries and veins were classified as suprarenal aorta/inferior vena cava (IVC), normal origin, infrarenal aorta/IVC, aortic/IVC bifurcation, common iliac artery/vein, iliac bifurcation, internal iliac artery/vein, and external iliac artery/vein. Finally, the ectopic kidneys were classified according to the most common combinations of artery and vein origins. The renal artery originated from the suprarenal aorta in 1 case, normal origin in 13 cases, the infrarenal aorta in 36 cases, aortic bifurcation in 50 cases, the common iliac artery in 17 cases, and the iliac artery bifurcation in 2 cases. The renal vein was of normal origin in 19 cases, originated from the infrarenal IVC in 44 cases, IVC bifurcation in 36 cases, the common iliac vein in 23 cases, the internal iliac vein in 1 case, and the external iliac vein in 1 case. We classified the artery and vein origins of the ectopic kidneys into 7 most common types and other less common types. A significant correlation was found between the level of the ectopic kidneys and the origin of the arteries and veins (P < 0.001). Our study shows that the majority of ectopic kidneys have various origins of arterial and venous supply. We described the most common vascular origins of ectopic kidneys. Prior knowledge of these vascular variations may have important implications in preventing iatrogenic hemorrhage during surgery of patients with ectopic kidney.

Clinical Characteristics and Long-Term Outcomes of Midaortic Syndrome

Midaortic syndrome (MAS) is a rare congenital or acquired condition marked by segmental or diffuse stenosis of the distal thoracic and/or abdominal aorta and its branches. The optimal approach to medical or interventional management of MAS and long-term outcomes in adults are not well defined. We reviewed MAS cases to characterize the natural history of aortic disease, identify prognostic factors, and evaluate the durability of invasive interventions. We conducted a retrospective review of patients with MAS who presented to Memorial Hermann Hospital and Baylor College of Medicine between 1997 and 2018. We categorized cases according to demographic and clinical manifestations, etiologies, the extent of aortic involvement, interventions, and vascular outcomes. We identified a cohort of 13 patients with MAS. The etiology of MAS was identified in 6 cases, including genetic syndromes (neurofibromatosis type 1 (2/13), Williams syndrome (1/13), fibromuscular dysplasia (2/13), and Takayasu arteritis (1/13)). Mean age at first documented clinical event was 25.2 (2-67) years, but cases with genetic etiologies presented significantly younger (18.2years). The most common primary anatomic site was the suprarenal and infrarenal aorta (zones 5-8). Extra-aortic locations involved the renal (4/13), celiac (3/13), and superior mesenteric (3/13) arteries. Clinical manifestations included hypertension (13/13), claudication (9/13), and postprandial abdominal pain (5/13). All patients with available follow-up data underwent at least one surgical or endovascular intervention (range: 1-8). Postoperative complications included renal failure requiring postdischarge hemodialysis and respiratory failure. There were no deaths in long-term follow-up. MAS is a complex vasculopathy with substantial variability in clinical presentation and anatomic distribution. Extensive disease frequently requires multiple invasive interventions and results in refractory hypertension, which may predict subsequent clinical events. A multidisciplinary approach with long-term monitoring is essential for preservation of end-organ function and quality of life in this debilitating disease.

Supra-aortic Remodeling After EVAR During One-year Follow-up: Comparison Between Three Different Fixation Types of Endografts

Introduction -The remodeling of the supra-renal aorta after endovascular aortic aneurysm repair (EVAR) in relation to different endograft design has not been fully investigated. The aim of this study was to assess the anatomic changes in supra-renal aorta post-EVAR with the use of different types of endografts during the first year. Methods - In total 100 patients undergoing EVAR with 3 types of endografts having different proximal fixation system were retrospectively analyzed. Fifty consecutive patients were treated with Ovation (supra-renal fixation and infra-renal sealing with polymer ring; Endologix, Irvin, CA, USA), 25 with Endurant (supra-renal fixation; Medtronic Cardiovascular, Santa Rosa, Calif, USA), and 25 with Excluder (infra-renal fixation; W.L. Gore & Associates, Flagstaff, AZ, USA). Baseline calcification (0 to 2) and thrombus (0 to 2) at the neck, co-morbidities and anatomical variables were recorded. Anatomic variables were AAA maximum diameter, supra-renal neck angulation, and diameters of the supra-renal aorta at 5mm, 15mm, 25mm, and 35mm above the most cephalad renal artery. Computed tomography angiography (CTA) was obtained pre-operatively at 1 and 12 months post-EVAR. Results - The mean AAA diameter was 56.5mm, 57mm and 55mm in Ovation, Endurant and Excluder group, respectively. Co-morbidities were not different across the 3 groups. Presence and amount of neck calcification (p=0.139) and thrombus (p=0.116) was similar among groups. Maximum aortic diameter showed significant reduction from pre-operative to 12-month post-operative CT scan for all 3 groups. (Ovation group: 56.5mm to 53mm; p<0.001, Endurant group: 57mm to 51mm; p<0.001, Excluder group: 55mm to 50mm; p<0.001). Regarding supra-renal aortic diameter changes, only the Ovation group showed a significant increase at all levels (mean increase of 1mm), except at 15mm which remained stable. Changes in supra-renal angulation were also significant only in the Ovation group (100, 80, 70; p<0.001) and Excluder group (220, 200, 180; p=0.05). Among the three different endografts, maximum diameter decrease, was not different (p=0.99), supra-renal aortic diameter increase, was significantly higher only in Ovation group at levels of 5mm (p=0.02) and 25mm (p=0.01) while there were no differences observed at the level of 15mm (p=0.12) and 35mm (p=0.25) and supra-renal angulation reduction was not different (p=0.7). No migration or endoleak type I was observed in any patient. Endoleak type II was observed in 18/50, 6/25 and 7/25 in Ovation, Endurant and Excluder group, respectively, (p=0.532). Conclusion - The type of endograft fixation system appears to have different impact on supra-aortic anatomy in terms of supra-renal aortic diameter and anglulation, but without any clinical effect in the first post-EVAR year. Longer follow up is needed to clarify future remodeling and clinical impact of these observations and whether any type of endograft requires more intense follow up.

The Assessment of Carbon Dioxide Automated Angiography in the Type II Endoleaks Detection: Comparison with Contrast-Enhanced Ultrasound

Introduction - The presence of type II endoleak (ELII) after endovascular aortic repair (EVAR) can be investigated with different methods. Since intraoperative completion angiography (ICA) may underestimate their presence, particularly if they are at low flow, contrast-enhanced ultrasound (CEUS) has been proposed as the gold standard during EVAR follow-up. Intra-procedural carbon dioxide (CO2) angiography has been shown to be useful in this setting, however no comparative studies including these three techniques are currently available. Aim of our study is to investigate the accuracy of a new automated CO2 angiographic (CO2A) system in the detection of ELII, by comparing it with ICA and CEUS. Methods - A series of consecutive patients undergoing EVAR for Abdominal Aortic Aneurysm (AAA) were enrolled and submitted to ICA and CO2A during the procedure. The iodinate contrast media were delivered through an automatic injector connected to a pigtail catheter in the suprarenal aorta, with constant flow velocity and volume injection. The CO2 was delivered through a recently available automatic injector connected to a 10F, 11mm long sheet positioned in the external iliac artery, with constant CO2 injection in terms of flow velocity and volume rate. All patients were blindly evaluated by CEUS on postoperative day1. The presence of ELII was defined as contrast enhancement into the residual sac appearing with a ≥ 5 seconds delay from contrast injection. The ICA and CO2A ability to detect ELII was compared with that of CEUS through the Cohen's concordance Index (K).s Results - Twenty-one patients with a mean AAA size of 56±8mm, were entered in the study. There were no intra or peri-operative complications related to ICA or CO2A. No type I-III endoleak were detected by ICA or CO2A, as confirmed also by CEUS. One (5%), 7(33%) and 4(19%) ELII, were detected by ICA, CO2A and CEUS, respectively. The only ELII detected by ICA was also detected by CO2A and CEUS. Three cases of ELII detected by CO2A were not detected by CEUS. No cases of ELII undetected by CO2A were visualized by CEUS. A perfect agreement between CEUS and both ICA and CO2A was observed for type I/III endoleak (Cohen's K:1). CEUS and ICA showed a poor agreement for ELII detection (Cohen's K:0.35). A substantial agreement was observed between CEUS and CO2A for ELII (Cohen's K:0.65). Conclusion - CO2A is safe and effective method for ELII detection in EVAR, with a significantly higher agreement with CEUS if compared with ICA.

Intraoperative Division of Left Renal Vein has No Impact on The Fate of Renal Function After the Open Surgery for Para- and Juxtarenal Abdominal Aortic Aneurysm

Introduction - Left renal vein (LRV) division is occasionally imperative for better access to the suprarenal aorta during open surgery (OS) for pararenal and juxtarenal abdominal aortic aneurysm (P/JRAA). However, its impact on the postoperative renal function remains controversial. Prior studies referred to the impact on acute kidney injury (AKI), but they have rarely evaluated longer-term renal function. This study focused on a chronic renal decline (CRD) during follow-up. Methods - A retrospective review of our series of P/JRAA treated with OS from June 2007 to January 2017. Patients on hemodialysis at the time of surgery were excluded. Preoperative renal function was estimated using the chronic kidney disease (CKD) staging system. Postoperative AKI was defined by the RIFLE criteria (Risk, Injury, Failure, Loss of function, End-stage renal disease). CRD was defined as progression in CKD stage or estimated glomerular filtration rate (eGFR) decline of >20%. The impact of LRV division on the postoperative renal function was investigated by a time-to-event analysis. Results - Among 469 elective OS, 119 underwent repair for P/JRAA. Three patients with preoperative hemodialysis and 1 in-hospital deaths were excluded from the analysis. Consequently, 115 patients were enrolled. Preoperatively, 42 patients (36.5%) had CKD stage 3 (eGFR < 60 mL/min/1.73 m2). Eight patients (8.7%) were in stage 4 (eGFR < 30 mL/min/1.73 m2). Proximal clamping was supraceliac (5 patients), suprarenal (38 patients), and inter-renal (72 patients). The median renal ischemic time was 33 minutes. LRVs were divided in 27 patients (group D), and stayed intact in 88 patients (group I). There was no significant difference in patients’ backgrounds between the groups. Group D tended to require higher proximal clamping (P=0.087) and related to significantly longer operation time (P<0.001). However, the median renal ischemic time was not significantly different between the groups (P=0.916). AKI seemed more common in group D, but not significant (P=0.103). During a median renal function follow-up for 13.8 months (interquartile range, 1.9-36.4), CRD was observed in 5 patients of group D and 14 patients of group I (18.5% and 16.1%, respectively). One patient in group I required hemodialysis 5 years after surgery. Kaplan-Meier curves to compare the freedom from CRD showed no significant difference between the groups (P=0.805; log-rank test). Risk-adjusted comparison, matching preoperative CKD stage and proximal clamp sites, did not change these findings. Conclusion - LRV division had no significant impact on CRD for up to 2 years during follow-up. Our result supported the safety of LRV division in terms of the mid-term outcomes.

O144 CALCIFICATION IN THE DESCENDING AORTA PREDICTS POSTOPERATIVE LEAKAGE OF INTRA-THORACIC ANASTOMOSIS AFTER OPEN ESOPHAGECTOMY FOR CANCER

Abstract Aim Postoperative anastomotic leakage is a major complication in the surgery of the esophagus. In this study, we aim to examine whether calcifications of the aortic segments can predict anastomotic leakage after open esophagectomy for cancer with intra-thoracic anastomosis of a gastric conduit. Background and methods All patients with esophageal cancer who underwent elective esophagectomy with an intra-thoracic anastomosis at Tampere University Hospital between 2007-2018 were evaluated. Preoperative data were associated to outcome. These included demographic, anamnestic, clinical, laboratory, and radiologic data. Preoperative staging thoraco-abdominal CT-scans were re-evaluated to document the presence of calcifications in the various aortic segments. Results A total of 97 patients (median age 64 (43-78) years, 20% female) were analysed, with anastomotic leakage occurring in 22 patients (23%). Median time from surgery to leakage was 10 (1-32) days, and follow-up time 28 (1-143) months. From all the factors that were evaluated in the univariate analysis, only the presence of calcification in the descending thoracic aorta was associated with a higher risk of anastomotic leakage (11% vs. 33%, HR 4.571; 95% CI 1.40-15.0; p=0.011). There was a trend for anastomotic leakage in the presence of calcification in the suprarenal abdominal aorta (13% vs. 29%, p=0.057). A higher leakage rate was documented when a calcification was present in the infrarenal abdominal aorta (8.3% vs. 25%, p=0.205), and in the ascending thoracic aorta (22% vs. 30%, p=0.559), without reaching statistical significance. Conclusion The presence of a calcification in the descending thoracic aorta is associated with higher risk of anastomotic leakage after open esophagectomy for cancer.