Maximal Luminal Diameter Research Articles

Determining risk factors for vascular and bleeding complications after TAVR using CT angiography

Abstract Funding Acknowledgements None. Introduction The use of pre-procedural computed tomography angiography (CTA) of the iliofemoral sector in the planning of transaortic valve replacement (TAVR) has demonstrated a reduction in the risk of vascular complications in patients undergoing TAVR. In this study, we aimed to characterise the clinical and radiological factors associated with bleeding and vascular complications after TAVR. Methods Patients undergoing transfemoral TAVR in a tertiary centre between 2017 and 2019 were included in this analysis. All patients underwent iliofemoral CTA before the procedure and classical CTA-derived data as well as iliofemoral calcium volume were collected. Clinical data and outcomes regarding bleeding events, as well as vascular complications according to Valve Academic Research Consortium 2 (VARC-2) criteria, were also collected. 207 patients were included in this analysis, of whom 53% were women. The median age was 82 years (IQR 76-86) and the median STS mortality risk score was 3.9% (IQR 2.59-5.99). In this population, vascular complications according to the VARC-2 criteria occurred in 33% of patients (19% with major complications). Patients with lower body mass index (BMI) were more likely to suffer vascular complications. Vascular access with fluoroscopy was associated with a higher prevalence of complications compared to ultrasound-guided vascular access (62% vs. 38%, p=0.037). When considering radiological criteria, smaller minimum luminal diameter and area of the common femoral and external iliac arteries were associated with a greater risk of vascular complications, as were increased sheath to external iliac artery ratios and luminal attenuation values (p<0.05 for all). Bleeding complications occurred in 20 patients, with a greater prevalence of bleeding events in female patients (77% vs. 23%, p=0.001). Patients with a lower BMI, a history of obstructive pulmonary disease or coronary artery disease, aortic insufficiency and fluoroscopic valvular access were more likely to have bleeding complications. Regarding radiological criteria, decreased maximal luminal diameter of the common femoral artery and smaller minimal luminal diameters and areas of the external iliac artery were associated with bleeding complications. Increased sheath-to-femoral artery ratios and luminal attenuation values were associated with an increased risk of vascular complications (p<0.05 for all). Conclusion Our study underscores the importance of pre-procedural CTA in TAVR planning and identifies separate risk factors for vascular and bleeding complications.

Abstract 2023: Plasminogen Activator Inhibitor-1 Deficiency Augments Angiotensin II-induced Cardiac Fibrosis, But Not Aortic Aneurysm Formation In Mice

Background: Plasminogen activator inhibitor-1 (PAI-1) is highly abundant in human thoracic aortic aneurysms (TAA). This high abundance is mimicked in TAAs created by chronic infusion of angiotensin II (AngII) into mice. The purpose of this study was to determine whether deletion of PAI-1 influenced the development of thoracic aortic aneurysms during AngII infusion. Methods and Results: To determine the role of PAI-1 in acute and chronic phases of AngII-induced pathology, whole-body PAI-1 deficient mice (PAI-1 -/-) and wild type littermates (PAI-1 +/+) were infused with AngII (1,000 ng/kg/min) for 7 or 28 days, respectively. Aortic diameters were measured by ultrasonography and in situ measurement. PAI-1 deficiency did not alter maximal luminal or external aortic diameters at 7 or 28 days of AngII. At 7 days of AngII, ventricular hemorrhage was visibly evident in PAI-1 -/- mice. Mid-ventricular heart sections were next examined by hematoxylin and eosin staining, and red blood cell accumulation was found primarily within the epicardium. Masson’s trichrome staining revealed interstitial fibrosis in the epicardium, myocardium, and posterior septum of PAI-1 -/- mice. At 28 days of AngII, PAI-1 -/- mice displayed primarily epicardial fibrosis evident by trichrome staining and gross appearance. The posterior septum presented less fibrosis after 28 days of AngII relative to 7 days of AngII. Conclusions: PAI-1 deficiency did not alter aortic dilatation, indicating that PAI-1 is not a key contributor to AngII-induced TAAs. Paradoxically, PAI-1 deficiency augmented AngII-induced cardiac fibrosis with distinct distributions between acute and chronic phases.

Impact of native iliac vein aspect ratio on initial clinical presentation and outcomes following stenting for symptomatic chronic iliofemoral venous obstruction

ObjectiveVenous stenting has become the first line of treatment for patients with symptomatic chronic iliofemoral venous obstruction (CIVO) in whom conservative therapy has failed. Intravascular ultrasound (IVUS) interrogation with the use of normal minimal luminal diameters or areas has become the standard to confirm the diagnosis and determine the adequacy of stenting. However, the aspect ratio (ratio between the maximal and minimal luminal diameters) has also been put forth as a possible metric for determining stent adequacy. This study explores the utility of the native iliac vein and stent aspect ratios in determining the initial presentation and outcomes after stenting. MethodsA retrospective analysis of contemporaneously entered data from patients who underwent stenting for quality of life (QoL)-impairing clinical manifestations of CIVO for whom conservative therapy had failed formed the study cohort. The limbs were grouped into three at the time of intervention using the IVUS-determined native vein aspect ratio: group I, those with a ratio of ≤1.4; group II, those with a ratio of 1.41 to 1.99; and group III, those with a ratio of ≥2. The characteristics appraised initially and after stenting included the venous clinical severity score, grade of swelling (GOS), visual analog scale (VAS) for pain score, and the CIVIQ-20 QoL score. Analysis of variance and paired and unpaired t tests were used for comparison of clinical and QoL variables, and Kaplan-Meier analysis was used to evaluate stent patency, with the log-rank test used to discriminate between different curves. ResultsThere were a total of 236 limbs (236 patients). The median age for the entire cohort was 62 years (range, 16-92 years). There were 161 women in the study, and left laterality was more common (137 limbs). Post-thrombotic obstruction was noted in 201 limbs (86%). The median body mass index was 36 kg/m2. There were 54 (23%), 64 (27%), and 118 (50%) limbs in groups I, II, and III, respectively. The median follow-up was 65 months. For the entire cohort, after stenting, the venous clinical severity score improved from 6 to 4 (P < .0001) at 3 months and remained at 4 at 6 months (P < .0001), 12 months (P < .0001), and 24 months (P < .0001). The GOS for the entire cohort improved from 3 to 1 (P < .0001) at 3 months and remained at 1 at 6 months (P < .0001), 12 months (P < .0001), and 24 months (P < .0001). The VAS for pain score for the entire cohort improved from 7 to 0 (P < .0001) at 3 months, increased to 2 (P < .0001) at 6 months, and remained at 2 (P < .0001) at 12 months. At 24 months, the VAS for pain score worsened to 3 (P < .0001). For the entire cohort, the CIVIQ-20 score improved from 62 to 40 (P < .0001). There was no difference in the GOS, VAS for pain score, or CIVIQ-20 score between the groups at baseline or at 6, 12, and 24 months after intervention. At 60 months, the primary stent patency was 89% for group I, 80% for group II, and 75% for group III (P = .85). The primary assisted stent patency was 100% for group I, 98% for group II, and 98% for group III (P = .5). Secondary patency was 100% for groups II and III (P > .5). Reintervention was pursued for QoL-impairing clinical manifestations in 53 limbs (22%) without a significant difference between the three groups (P = .13). ConclusionsThe native vein aspect ratio does not appear to determine the initial clinical presentation or QoL or impact the clinical or QoL outcomes after stenting for CIVO. Following stenting, no patient had an aspect ratio >2, with 97% of patients having an aspect ratio ≤1.4 and the remaining 3% having an aspect ratio of 1.41 to 1.99. IVUS-determined minimal cross-sectional luminal area and not the aspect ratios should be used for confirmation of the diagnosis of CIVO and to assess the adequacy of stenting.

Outcomes of Percutaneous Coronary Interventions for Long Diffuse Coronary Artery Disease with Extremely Small Diameter

The optimal percutaneous coronary intervention (PCI) strategy and clinical outcomes of long lesions with an extremely small residual lumen remain unclear. This study aimed to assess the efficacy of a modified stenting strategy for diffuse coronary artery disease (CAD) with an extremely small distal residual lumen. 736 Patients who received PCI using second-generation drug-eluting stents (DES) ≥38 mm long were retrospectively included and categorized into an extremely small distal vessel (ESDV) group (≤2.0 mm) and a non-ESDV group (>2.0 mm) according to the maximal luminal diameter of the distal vessel (dsDMax). A modified stenting technique was applied by landing an oversized DES in the distal segment with the largest luminal diameter and maintaining the distal stent edge partially expanded. The mean dsDMax and stent lengths were 1.7 ± 0.3 mm and 62.6 ± 18.1 mm in the ESDV group and 2.7 ± 0.5 mm and 59.1 ± 16.0 mm in non-ESDV groups, respectively. The acute procedural success rate was high in both the ESDV and non-ESDV groups (95.8% and 96.5%, p = 0.70) with rare distal dissection (0.3% and 0.5%, p = 1.00). The target vessel failure (TVF) rate was 16.3% in the ESDV group and 12.1% in the non-ESDV group at a median follow-up of 65 months without significant differences after propensity score matching. PCI using contemporary DES with this modified stenting technique is effective and safe for diffuse CAD with extremely small distal vessels.

Feasibility of Simple Oral Preparation Contrast-Enhanced CT Colonography (SOP-CE-CTC) Using Mannitol as a Neutral Oral Contrast Agent

Abstract Purpose This article prospectively assesses the feasibility of simple oral preparation contrast-enhanced computed tomography colonography (SOP-CE-CTC) using a large volume of oral 3% mannitol for good colonic distension along with mural and mucosal fold visualization. Methods A total of 100 patients in whom contrast CT abdomen was requested, recruited as per selection criteria, were advised to take mild oral bowel preparation for two nights, prior to the investigation. Then, after fasting overnight, they were asked to consume 1,500 to 2,000 mL of 3% mannitol solution in about an hour. Thirty minutes after completing the ingestion of oral mannitol, intravenous contrast was injected and SOP-CE-CTC was acquired at 55 seconds. Distension of six segments of the colon was evaluated by assigning scores 1 to 4 for qualitative assessment; and measuring the maximum luminal diameter of the colon, for quantitative assessment. Colonic mucosal and mural visualization were evaluated subjectively. All observations were recorded by two reviewers (with varying levels of experience) independently. Results On qualitative analysis, the colon showed optimal distension (score 4) in 58 to 89% cases on SOP-CE-CTC. There was agreement between both the reviewers in 89 to 99% cases (weighted kappa 0.820–0.979; p &lt; 0.001). On quantitative analysis, the mean of the maximum colonic diameter ranged between 3.4 and 5.2 cm; and both the reviewers agreed in 89 to 97% cases (weighted kappa 0.777–0.967; p &lt; 0.001). Mural and mucosal fold visualization in the proximal four segments of the colon was excellent (in 90–98%) but in the rectum and sigmoid it was 45 and 66%, respectively; both the reviewers agreed in 100% cases (weighted kappa 1.0 and p &lt; 0.001). Conclusion Good colonic distension, mural, and mucosal fold visualization can be achieved on SOP-CE-CTC using 1,500 to 2,000 mL of 3% oral mannitol and mild oral bowel preparation agents.

Adipocyte-Derived Serum Amyloid A Promotes Angiotensin II-Induced Abdominal Aortic Aneurysms in Obese C57BL/6J Mice.

Obesity increases the risk for human abdominal aortic aneurysms (AAAs) and enhances Ang II (angiotensin II)-induced AAA formation in C57BL/6J mice. Obesity is also associated with increases in perivascular fat that expresses proinflammatory markers including SAA (serum amyloid A). We previously reported that deficiency of SAA significantly reduces Ang II-induced inflammation and AAA in hyperlipidemic apoE-deficient mice. In this study. we investigated whether adipose tissue-derived SAA plays a role in Ang II-induced AAA in obese C57BL/6J mice. The development of AAA was compared between male C57BL/6J mice (wild type), C57BL/6J mice lacking SAA1.1, SAA2.1, and SAA3 (TKO); and TKO mice harboring a doxycycline-inducible, adipocyte-specific SAA1.1 transgene (TKO-Tgfat; SAA expressed only in fat). All mice were fed an obesogenic diet and doxycycline to induce SAA transgene expression and infused with Ang II to induce AAA. In response to Ang II infusion, SAA expression was significantly increased in perivascular fat of obese C57BL/6J mice. Maximal luminal diameters of the abdominal aorta were determined by ultrasound before and after Ang II infusion, which indicated a significant increase in aortic luminal diameters in wild type and TKO-TGfat mice but not in TKO mice. Adipocyte-specific SAA expression was associated with MMP (matrix metalloproteinase) activity and macrophage infiltration in abdominal aortas of Ang II-infused obese mice. We demonstrate for the first time that SAA deficiency protects obese C57BL/6J mice from Ang II-induced AAA. SAA expression only in adipocytes is sufficient to cause AAA in obese mice infused with Ang II.

Beyond Vessel Diameters: Non-invasive Monitoring of Flow Patterns and Immune Cell Recruitment in Murine Abdominal Aortic Disorders by Multiparametric MRI.

The pathophysiology of the initiation and progression of abdominal aortic aneurysms (AAAs) and aortic dissections (AADs) is still unclear. However, there is strong evidence that monocytes and macrophages are of crucial importance in these processes. Here, we utilized a molecular imaging approach based on background-free 19F MRI and employed perfluorocarbon nanoemulsions (PFCs) for in situ 19F labeling of monocytes/macrophages to monitor vascular inflammation and AAA/AAD formation in angiotensin II (angII)-treated apolipoproteinE-deficient (apoE−/−) mice. In parallel, we used conventional 1H MRI for the characterization of aortic flow patterns and morphology. AngII (1 μg/kg/min) was infused into apoE−/− mice via osmotic minipumps for 10 days and mice were monitored by multiparametric 1H/19F MRI. PFCs were intravenously injected directly after pump implantation followed by additional applications on day 2 and 4 to allow an efficient 19F loading of circulating monocytes. The combination of angiographic, hemodynamic, and anatomical measurements allowed an unequivocal classification of mice in groups with developing AAAs, AADs or without any obvious aortic vessel alterations despite the exposure to angII. Maximal luminal and external diameters of the aorta were enlarged in AAAs, whereas AADs showed either a slight decrease of the luminal diameter or no alteration. 1H/19F MRI after intravenous PFC application demonstrated significantly higher 19F signals in aortae of mice that developed AAAs or AADs as compared to mice in which no aortic disorders were detected. High resolution 1H/19F MRI of excised aortae revealed a patchy pattern of the 19F signals predominantly in the adventitia of the aorta. Histological analysis confirmed the presence of macrophages in this area and flow cytometry revealed higher numbers of immune cells in aortae of mice that have developed AAA/AAD. Importantly, there was a linear correlation of the 19F signal with the total number of infiltrated macrophages. In conclusion, our approach enables a precise differentiation between AAA and AAD as well as visualization and quantitative assessment of inflammatory active vascular lesions, and therefore may help to unravel the complex interplay between macrophage accumulation, vascular inflammation, and the development and progression of AAAs and AADs.

Follow up coronary vessel evaluation of magnesium bioresorbable stents with coronary computed tomography angiography

Abstract Background Cardiac computed tomography angiography (CCTA) has already shown its ability to evaluate late results of polymer-based bioresorbable scaffolds (BVS) in different clinical scenarios. Recently, magnesium-based BVS (Mg-BVS) has emerged as an interesting alternative to these previous platforms due to its lower risk of thrombosis. Nonetheless, there is no systematic data about characterization of magnesium BVS with CCTA. Purpose To study the feasibility of Mg-BVS assessment with CCTA and to evaluate in-scaffold wall tissue characterization during the follow-up. Methods In this multicentre work, CCTA was performed in patients with a previously implanted Mg-BVS as a supplementary follow-up assessment. All studies were done after the theoretical resorption time of the scaffolds. A central core laboratory with an independent level 3 expert in CCTA blinded to the clinical and angiographic results analysed the studies. For this purpose, a dedicated software for coronary analysis was used to quantify coronary stenosis and evaluate coronary wall (Figure). Results Eight patients (55±6 years-old; 87.5% male) with a previously implanted Mg-BVS from 3 different centres in Spain and Italy were included. The presentation was equally distributed (2, 25%) among stable and unstable angina, NSTEMI and STEMI. Target vessels included 5 left anterior descending (62.5%), 2 left circumflex (25%) and 1 right coronary arteries (12.5%). CTCA was performed 13 [11.3–20] months after BVS implantation. In spite of the blinding, all scaffolds were accurately located through identification of proximal and distal radiopaque markers. Concordance of CCTA Mg-BVS sizing was good for diameter (ICC 0.66; p=0.09) and excellent for length (ICC 0.98; p&amp;lt;0,001) of the stents. Patency of all scaffolds was confirmed without significant diameter (0.14 [0–0.27]%) or area (0.39 [0.19–0.57]%) stenoses compared with proximal reference segments. Moreover, within the stent boundaries the maximum luminal diameter and area narrowing were 0.22 [0,12–0.3]% and 0.39 [0.23–0.5]% respectively, in keeping with mild in-scaffold late loss and/or underlying plaque growth. Regarding coronary wall tissue characterization of segments with BVS, there was a plaque burden of 0.37 [0.31–0.48]% and plaque volume of 87.6 [50.2–189.3] mm3. The most common component of the plaque was fibrous (69.5 [33.9–133.7]%), suggesting that Mg-BVS allows for stabilization of unstable culprit lesions (6/8 cases). Compared to the proximal and distal reference segments, there was no differences in plaque volume or composition, suggesting a good coronary vessel healing. Conclusions This short series shows for the first time the ability of CCTA to correctly locate and evaluate patency of Mg-BVS. Moreover, the lack of metal struts allows a detailed coronary plaque evaluation at treated segments. These preliminary results suggest plaque stabilization and a good coronary vessel healing with this novel scaffold. Funding Acknowledgement Type of funding sources: None. Mg-BVS in LCx with mixed plaque

Development and in vivo Assessment of a Rapidly Collapsible Anastomotic Guide for Use in Anastomosis of the Small Intestine: A Pilot Study Using a Swine Model.

Various conditions in human and veterinary medicine require intestinal resection and anastomosis, and complications from these procedures are frequent. A rapidly collapsible anastomotic guide was developed for small intestinal end-to-end anastomosis and was investigated in order to assess its utility to improve the anastomotic process and to potentially reduce complication rates. A complex manufacturing method for building a polymeric device was established utilizing biocompatible and biodegradable polyvinylpyrrolidone and polyurethane. This combination of polymers would result in rapid collapse of the material. The guide was designed as a hollow cylinder composed of overlaying shingles that separate following exposure to moisture. An in vivo study was performed using commercial pigs, with each pig receiving one standard handsewn anastomosis and one guide-facilitated anastomosis. Pigs were sacrificed after 13 days, at which time burst pressure, maximum luminal diameter, and presence of adhesions were assessed. Burst pressures were not statistically different between treatment groups, but in vivo anastomoses performed with the guide withstood 10% greater luminal burst pressure and maintained 17% larger luminal diameter than those performed using the standard handsewn technique alone. Surgeons commented that the addition of a guide eased the performance of the anastomosis. Hence, a rapidly collapsible anastomotic guide may be beneficial to the performance of intestinal anastomosis.

A clinical and radiographic model to predict surgery for acute small bowel obstruction in Crohn's disease.

For more than half of Crohn's disease patients, strictures will cause bowel obstructions that require surgery within 10years of their initial diagnosis. This study utilizes computed tomography imaging and clinical data obtained at the initial emergency room visit to create a prediction model for progression to surgery in Crohn's disease patients with acute small bowel obstructions. A retrospective chart review was performed for patients who presented to the emergency room with an ICD-10 diagnosis for Crohn's disease and visit diagnosis of small bowel obstruction. Two expert abdominal radiologists evaluated the CT scans for bowel wall thickness, maximal and minimal luminal diameters, length of diseased segment, passage of oral contrast, evidence of penetrating disease, bowel wall hyperenhancement or stratification, presence of a comb sign, fat hypertrophy, and small bowel feces sign. The primary outcome was progression to surgery within 6 months of presentation. The secondary outcome was time to readmission. Forty patients met the inclusion criteria, with 78% receiving medical treatment alone and 22% undergoing surgery within 6months of presentation to the emergency room. Multivariable analysis produced a model with an AUC of 92% (95% CI 0.82-1.00), 78% sensitivity, and 97% specificity, using gender, body mass index, and the radiographic features of segment length, penetrating disease, and bowel wall hyperenhancement. The model demonstrates that routine clinical and radiographic data from an emergency room visit can predict progression to surgery, and has the potential to risk stratify patients, guide management in the acute setting, and predict readmission.

Expansive carotid artery remodeling: possible marker of vulnerable plaque.

Accumulated findings in the pathophysiology of atherosclerosis have demonstrated that not only luminal narrowing but also plaque characteristics influence the risk of future ischemic events. The morphology of the carotid artery (CA) changes in response to atherosclerotic development by expansive remodeling (ER), the clinical significance of which remains unclear. This study aimed to define associations between ER and local risk factors, including CA geometry and traditional systemic risk factors for ischemic events, to determine whether ER could serve as a clinical marker of carotid vulnerable plaque. The authors retrospectively analyzed 66 patients with CA stenosis who were scheduled to undergo carotid endarterectomy or CA stenting. They calculated ER ratios in the internal CA (ICA) from long-axis MR images and as the maximal distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA/the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis. Relative overall signal intensity (roSI) was calculated to assess intraplaque hemorrhage and defined as the signal intensity of plaque on an axial T1-weighted image with maximal stenosis relative to that of the adjacent sternocleidomastoid muscle. The authors evaluated CA geometry by calculating the angles between the common CA (CCA) and ICA, and between the CCA and external CA (ECA) using digital subtraction angiography. The ER ratios, age, sex, percentage of stenosis, roSI, hypertension, hyperlipidemia, low-density lipoprotein, statin medication, diabetes, smoking habit, and ischemic heart disease were compared between 33 symptomatic and 33 asymptomatic patients. The authors also compared symptomatic status, age, sex, percentage of stenosis, ICA angle, ECA angle, roSI, and other traditional atherosclerotic risk factors between groups with extensive and slight ER. The ER ratio was significantly greater in symptomatic than in asymptomatic patients (1.91 ± 0.46 vs 1.68 ± 0.40, p < 0.05). The ICA angle was significantly larger in the group with extensive ER than in those with slight ER (33.9° ± 20.2° vs 21.7° ± 13.8°, p < 0.01). The roSI, ECA angle, percentage stenosis, or any other traditional vascular risk factors were not associated with ER. Carotid ER might be an independent indicator of carotid vulnerable plaque, which should be validated in a longitudinal study of patients with carotid atherosclerosis, including those with nonstenotic to moderate stenosis.

155 Therapeutic Oxygen for Gastrointestinal Atomy (TOGA) Pilot Trial: Management of Acute Colonic Pseudo-Obstruction and Ileus With Oxygen Supplementation

INTRODUCTION: Acute intestinal dysmotility can lead to bowel distension, which promotes hypoperfusion and further negates contractility in acute colonic pseudo-obstruction (ACPO) and ileus. Current medical treatment is supportive. When bowel distension worsens, endoscopic decompression or surgical intervention may be necessary to avoid mortality; Interventions are time-consuming and not without risk. New effective and safe management approaches are needed. Manipulation of partial pressures of oxygen trapped within the bowel has been shown in patients with ACPO and ileus to improve clinical and radiographic outcomes. Therapeutic oxygen for gastrointestinal atomy (TOGA) is a pilot study aimed to demonstrate the benefit of a six hour course of 100% oxygen by non-rebreather mask as an adjunctive treatment for patients with ACPO and ileus who have failed to respond to alternative medical therapy after 24 hours. METHODS: Eight patients with ACPO or ileus were enrolled in this pilot study (ClinicalTrials.gov Identifier: NCT03386136) between May 1, 2018 and March 1, 2019 and administered 100% oxygen by non-rebreather mask for 6 hours in conjunction with traditional medical management. Abdominal radiographs were examined before and after treatment. Patient demographics, maximum diameter of bowel lumen distension on radiography, and clinical symptoms were recorded. RESULTS: Of the 8 patients (mean age 53.6 ± 17.4 years; 37.5% female), 87.5% demonstrated clinical improvement of symptoms after 6 hours of 100% oxygen (Table 1). For 7 patients, maximum luminal diameter improved on average by 1.14 ± 0.87 cm, the percentage decrease in luminal diameter on average was 13.8 ± 7.1%. One patient failed to improve but was later determined to have malignant small bowel obstruction. Only one patient suffered a potential adverse event to the oxygen therapy (transient tachycardia). No patients developed complications from their underlying disease, such as ischemia or perforation. Responding patients also reported improvements in abdominal pain, distension, and bowel movements. CONCLUSION: TOGA demonstrates that high concentrations of supplemental oxygen is a feasible and tolerable intervention to improve the clinical status of patients with ACPO and ileus, which may shorten hospitalization and overall morbidity. Further prospective enrollment is needed to extrapolate these promising findings and ensure confidence of its incorporation into common clinical practice.

Hypoxia accelerates intraplaque neovascularization derived from endothelial progenitor cells in carotid stenosis.

The relationship between intraplaque hypoxia and intraplaque hemorrhage (IPH) has been reported, but the details remain obscure. In this study, the authors aimed to clarify the relationship among intraplaque hypoxia, endothelial progenitor cells (EPCs), and neovascularization, which causes IPH. The histological findings of specimens obtained from carotid endarterectomy were assessed. This study included 49 patients who underwent carotid endarterectomy. Magnetic resonance plaque imaging was performed to analyze the components of the carotid plaques, and surgical specimens were subjected to immunohistochemical analysis. The numbers of hypoxia-inducible factor-1 alpha (HIF-1α)-, CD34-, CD133-, and vascular endothelial growth factor receptor-2 (VEGFR-2)-positive cells in the carotid plaques were precisely quantified, as were the number and maximum diameter of CD31-positive microvessels. Plaque components were judged as fibrous in 7 samples, lipid-rich in 22, and IPH in 20. The number of CD34-, VEGFR-2-, and CD133-positive cells as an EPC-specific marker was significantly correlated with the number of HIF-1α-positive cells (r = 0.9, r = 0.82, and r = 0.81, respectively). These numbers varied among the 3 plaque components (IPH > lipid-rich > fibrous). The number and maximum luminal diameter of CD31-positive microvessels were also significantly correlated with the number of HIF-1α-positive cells (r = 0.85 and r = 0.89, respectively) and varied among the 3 plaque components (IPH > lipid-rich > fibrous). The present findings suggest that intraplaque hypoxia may accelerate abnormal microvessel formation derived from EPCs, which in turn promotes IPH. The results also suggest that microvessel enlargement is a pivotal characteristic of IPH and these enlarged microvessels are immature endothelial tubes with disorganized branching and are fragile and prone to rupture.

A Clinical and Radiographic Model to Guide Medical versus Surgical Management for Acute Small Bowel Obstruction in Crohnʼs Disease

Introduction: Crohn's disease is a chronic inflammatory condition that often leads to stricture formation. For more than half of Crohn's disease patients, the strictures will cause bowel obstructions that require a surgical bowel resection within 10 years of their initial diagnosis. Certain patients may benefit from surgery over prolonged medical management. We evaluated whether CT imaging and clinical criteria obtained at the initial emergency room visit for acute small bowel obstruction are able to predict progression to surgery and readmission. Methods: We performed a retrospective chart review of Crohn's disease patients with acute small bowel obstructions seen in the emergency room. Inclusion criteria included adults (>18 years) admitted with the ICD-10 diagnosis for Crohn's disease and a primary diagnosis of small bowel obstruction. Patients with other causes of small bowel obstructions (e.g. malignancy, adhesions or anastomotic strictures), or without an admission abdominal CT scan with intravenous contrast or a confirmed diagnosis of Crohn's disease were excluded. Two expert abdominal radiologists evaluated the CT scans for bowel wall thickness, maximal and minimal luminal diameters, length of diseased segment, passage of oral contrast, penetrating disease, bowel wall hyperenhancement or stratification, presence of a comb sign, fat hypertrophy, and small bowel feces sign. The primary outcome was progression to surgery (yes/no) and days to readmission. The clinical and radiographic data were analyzed using univariate and multivariable analysis. Results: Forty patients met the inclusion criteria with the majority receiving medical treatment alone (78%) and the minority (22%) underwent surgery. Univariate analysis identified a BMI<25 as a significant predictor for surgery (P=0.04). Multivariable analysis of BMI and radiographic features consisting of involved segment length, penetrating disease, and bowel wall hyperenhancement produced a model that predicted progression to surgery with an AUC of 91% (95%CI 0.80-1.01), 78% sensitivity, and 84% specificity. Kaplan-Meier curves of high-vs. low-risk patients revealed significant separation for the time to readmission (P=0.04). Conclusion: We describe a model based on clinical and radiographic data collected in an emergency room setting that predicts progression to surgery and readmission. The model has the potential to stratify patients, guide management in the acute setting, and assess future risk for readmission.613_A Figure 1 No Caption available.613_B Figure 2 No Caption available.

Abstract 102: Semi-Automatic Measurement of External and Luminal Diameter Predicts the Four-Year Prognosis of Small Abdominal Aortic Aneurysms

Objective: Predicting which abdominal aortic aneurysms (AAA) will require surgery and which may remain stable remains a challenge. We set out to evaluate whether semi-automatic diameter measurements and finite element analysis (FEA) might predict the four-year prognosis of AAAs more precisely than standard diameter measurements. Methods: From a retrospective dataset of 97 patients with aneurysm baseline diameter of 40-50 mm, 39 AAAs remained below 55 mm in diameter for four years whilst 58 expanded beyond 54 mm within four years, or were treated surgically. Standard diameters, measured by radiologists or vascular surgeons, were recorded at baseline and at follow-up. Maximal external and luminal diameters as well as total and luminal volume were semi-automatically re-measured from 3D models based on CT images. FEA, estimating the peak wall rupture index (PWRI), was subsequently performed. Further, in 94 patients from the dataset, standard diameter growth rates between baseline and follow-up were calculated. Results: Aneurysms that would require surgery within four years were identified with 100% specificity by semi-automatic diameter, n=13 (22%), luminal diameter, n=14 (24%), PWRI, n=7 (12%), and luminal volume, n=5 (8.6%). Neither standard diameter nor total volume could reach 100% specificity. AAA diameter growth rate correlated with baseline semi-automatic diameter (r=0.39, p=9.2e-5), luminal diameter (r=0.29, p=0.005) and luminal volume (r=0.23, p=0.027) but not with PWRI (r=0.17, p=0.094), total volume (r=0.16, p=0.13), nor standard diameter (r=0.14, p=0.17). Conclusion: In AAAs with small diameters, precise, semiautomatic measurement of the maximal external and luminal diameter is able to specifically identify aneurysms requiring surgery within four years.

Abstract 104: Aortic Dilation and Elasticity in Thoracic Aortic Aneurysm in a Marfan Model is Sexually Dimorphic

Objective: Meta-analysis of data derived from Marfan patients in the Genetically-Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC) consortium revealed that thoracic aortic aneurysms occur more frequently in men than in women. To determine the characteristics of sexual dimorphism in experimental thoracic aortic aneurysms of a Marfan model, we determined ascending aortic and aortic root morphology in male and female fibrillin-1 haploinsufficent (FBN1 C1041G/+) mice using ultrasonography. Method and Results: Aortas from 4 to 6 week old male and female FBN1 C1041G/+ mice and their wild type littermates were assessed by high frequency ultrasonography. Mice were anesthetized and maintained at a heart rate of 450-550 beats per minute. Ultrasound images were captured using a Vevo 3100 instrument with a 40 MHz tranducer. The maximal luminal diameter of ascending aortic between the sinotubular junction and the innominate artery, and the aortic root diameter at the sinus of valsalva, were measured in mid-systole and end-diastole by two independent observers who were blinded to mice identity. FBN1 C1041G/+ mice demonstrated greater ascending aortic dilation in male mice compared to female mice, whereas no difference in aortic root diameter were detected between male and female wild type littermates. In addition, modest ascending aortic dilation was detected before aortic root dilation in FBN1 C1041G/+ mice. Ascending aortas from FBN1 C1041G/+ mice also demonstrated loss of elasticity as evidenced by reduced expansion in systole. Interestingly, this difference was detected much earlier than expected. Conclusion: The fibrillin-1 haploinsufficent model of Marfan syndrome associated thoracic aortic aneurysm demonstrate sexual dimorphism in ascending aortic dilation. Loss of elasticity in the ascending aorta is also an early manifestation in this thoracic aortic aneurysm model.

Assessment of colonic contents in patients with chronic constipation using MRI.

Although chronic constipation is common, colonic functional evaluating tests are uncommon. This study examines whether chronic constipation and gastrointestinal symptoms are correlated with the lateral diameter of the colon measured from MRI images. We included chronic constipation patients in a prospective, cross-sectional study using MRI at three centers. We divided 3D MRI colorectal images into 6 segments using with specified sequences and selected the maximum luminal diameter from each segment. We used the GSRS questionnaire to evaluate gastrointestinal symptoms. We evaluated the correlation between luminal diameters and GSRS scores. We found the following positive correlations: descending colon and unsatisfactory defecation symptoms; sigmoid colon and diarrhea; and rectum and constipation. The sum and ratio of the ascending and sigmoid colon diameters correlated with nausea and diarrhea. The sum of the transvers to the sigmoid colon diameter also correlated with nausea and diarrhea. The sum of all segment diameters correlated with nausea and constipation. In conclusion, we showed cross-sectional study of colonic MRI correlate with gastrointestinal symptoms. MRI might be useful for colonic motility evaluations to determine appropriate constipation treatments (Clinical trial registry number UMIN 000021274).

Gross Morphological Variation of Luminal Diameter of the Trachea in Different Age and Sex Groups of Bangladeshi Cadavers

Background: The tracheobronchial tree is a branched distribution system that carries air from the trachea down to the acini which are the gas exchange units of the lung. In the trachea air speed is high and the airway is particularly vulnerable to obstruction by foreign bodies and tumors. The study of the morphological variations of luminal diameter of the trachea is of profound clinical importance as it may help the clinicians for smooth conduction of some maneuvers like endotracheal intubation and bronchoscopic procedure. It also helps the surgeons to deal with resection and reconstruction of the trachea.Objective: The present study was carried out to establish a Bangladeshi standard regarding the luminal diameter of the trachea and to minimize the dependency on foreign standards.Materials and Methods: This cross sectional descriptive study was performed on 70 post mortem human trachea (44 male and 26 female) to find out the difference in luminal diameter of the trachea of Bangledeshi people in relation to age and sex. The specimens were collected from the morgue in the department of Forensic Medicine, Mymensingh Medical College, Mymensingh by purposive sampling technique. All specimens were grouped into three groups according to age ? Group A, B and C. Dissection was performed according to standard autopsy techniques. The trachea was cut horizontally through the upper border of the 5th tracheal ring and the luminal diameter was measured. The average diameter was expressed in centimeter. All data were recorded in the predesigned data sheet and statistical analysis was done using computer based statistical package, SPSS to evaluate the significance of variance between the different findings.Results: In the present study the maximum luminal diameter of the trachea was 1.65 in Group A, 2.05 in Group B and 1.85 cm in Group C. The minimum luminal diameter of the trachea was 0.7 cm in Group A, 0.85 cm in Group B and in Group C 0.85 cm. The mean (±SD) luminal diameter of the trachea was 1.24 ± 0.3, 1.39 ± 0.3 and 1.29 ± 0.23 cm in Group A, B and C respectively. The maximum mean luminal diameter of the trachea was in Group B (1.39 cm) and minimum was in Group A (1.24 cm). The mean difference of luminal diameter of the trachea between groups was statistically non significant at p&gt;0.5 level. The maximum mean (±SD) luminal diameter of the trachea was 1.50 ± 0.3 cm in male in Group B and minimum mean (±SD) luminal diameter of the trachea was 1.17 ± 0.26 cm in female in Group C. The mean luminal diameter of the male trachea was found to be greater than that of the female trachea among the age group. Mean difference between sexes in Group B was statistically highly significant at p&lt;0.001 level but not significant in Group A and C.Conclusions: The study would help to increase the information pool on the luminal diameter of the trachea of Bangladeshi people.J Enam Med Col 2017; 7(3): 146-150

Abstract 462: Reductions of ApoB-containing Lipoproteins Prevented the Progression of Established Abdominal Aortic Aneurysms in AngII Infused Mice

Background and Objective: We have demonstrated that increased plasma apolipoprotein B (apoB)-containing lipoproteins augment development of AngII-induced abdominal aortic aneurysms (AAAs) in male mice. The purpose of this study was to determine whether plasma apoB-containing lipoproteins also influenced progression of established AAAs during chronic AngII-infusion. Methods and Results: Male LDL receptor -/- mice fed either a normal (Group 1) or Western (42% calories from saturated fat) diet were infused with AngII (1,000 ng/kg/min) for 28 days to induced AAAs. Maximal luminal diameters of the suprarenal region were compared with baseline after 4 weeks of AngII infusion to determine AAA presence. Mice fed Western diet were stratified by aortic lumen diameter into either a group maintained on Western diet (Group 2) or switched to a normal laboratory diet (Group 3). AngII infusion was continued for another 8 weeks in all 3 groups. Plasma cholesterol concentrations were determined at 4, 6, and 12 weeks of AngII infusion. Mice fed a Western diet for the initial 4 weeks were hypercholesterolemic (260 ± 13 to 1,469 ± 59 mg/dl). Two weeks after Group 3 were returned to normal laboratory diet, plasma cholesterol concentrations were profoundly reduced to 382 ± 22 mg/dl which was maintained for the remaining interval. These reductions were due to decreases in plasma cholesterol concentrations apoB-containing lipoproteins. Luminal diameters of suprarenal aortas were measured at 6 and 12 weeks of AngII infusion by ultrasonography. While luminal expansion progressed in mice fed Western diet, no continuous expansion was detected in mice with established AAAs that were fed normal laboratory diet. Ultrasonic measurements were confirmed at study termination by ex vivo measurements of maximal widths of suprarenal aortas (Group 1 verus 2 versus 3: 1.35 ± 0.04 mm, 3.32 ±0.34 mm, 1.91 ± 0.11 mm, respectively). Conclusions: Plasma apoB-containing lipoproteins contribute to the progressive expansion of established AAAs in AngII-infused mice.

The association between expansive arterial remodeling detected by high-resolution MRI in carotid artery stenosis and clinical presentation.

The purpose of the present study was to investigate the association between carotid artery (CA) expansive remodeling (ER) and symptoms of cerebral ischemia. One hundred twenty-two consecutive CAs scheduled for CA endarterectomy (CEA) or CA stent placement (CAS) were retrospectively studied. After excluding 22 CAs (2 were contraindicated for MRI, 8 had near-occlusion, 6 had poor image quality, and 6 had restenosis after CEA or CAS), there were 100 CAs (100 patients) included in the final analysis. The study included 50 symptomatic patients (mean age 73.6 ± 8.9 years, 6 women, mean stenosis 68.5% ± 21.3%) and 50 asymptomatic patients (mean age 72.0 ± 5.9 years, 5 women, mean stenosis 79.4% ± 8.85%). Expansive remodeling was defined as enlargement of the internal carotid artery (ICA) with outward plaque growth. The ER ratio was calculated by dividing the maximum distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA by the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis using long-axis, high-resolution MRI. The ER ratio of the atherosclerotic CA was significantly greater than that of normal physiological expansion (carotid bulb; p < 0.01). The ER ratio of symptomatic CA stenosis (median 1.94, interquartile range [IQR] 1.58-2.23) was significantly greater than that of asymptomatic CA stenosis (median 1.52, IQR 1.34-1.81; p = 0.0001). When the cutoff value of the ER ratio was set to 1.88, the sensitivity and specificity to detect symptoms were 0.6 and 0.78, respectively. The ER ratio of symptomatic patients was consistently high regardless of the degree of stenosis. There was a significant correlation between ER ratio and ischemic symptoms. The ER ratio might be a potential indicator of vulnerable plaque, which requires further validation by prospective observational study of asymptomatic patients.