Arterial Caliber Research Articles

Tmem100-BAC-EGFP mice to selectively mark and purify embryonic endothelial cells of large caliber arteries in mid-gestational vascular formation.

Embryonic vascular development is achieved through the complex arrays of differentiation, proliferation, migration and mutual interaction of different cell types, and visualization as well as purification of unique cell populations are fundamental in studying its detailed mechanisms using in vivo experimental models. We previously demonstrated that Tmem100 was a novel endothelial gene encoding a small transmembrane protein, and that Tmem100 null mice showed embryonic lethality due to severe impairment of vascular formation. In the present study, we generated an EGFP reporter mouse line using a 216 kb genomic region containing mouse Tmem100 gene. A novel line designated as Tmem100-BAC-EGFP mice precisely recapitulated the Tmem100 expression profile at the mid-gestational stage, which was highly enriched in endothelial cells of large caliber arteries in mouse embryos. FACS experiments demonstrated that Tmem100-BAC-EGFP mice served to selectively purify a specific population of arterial endothelial cells, indicating their usefulness not only for the research concerning Tmem100 expression and function but also for comparative analysis of multiple endothelial cell subgroups in embryonic vascular development.

Wide-Field Swept-Source Optical Coherence Tomography Angiography Analysis of the Periarterial Capillary-Free Zone in Branch Retinal Vein Occlusion.

PurposeTo investigate the characteristics of the retinal periarterial capillary-free zone (paCFZ) with wide-field swept-source optical coherence tomography angiography (SS-OCTA) in eyes with branch retinal vein occlusion (BRVO).MethodsSeventy treatment-naïve eyes with BRVO and 35 healthy eyes were included. The paCFZ areas, artery calibers, and areas of the major arteries in the unaffected quadrants of BRVO eyes were measured in 12 × 12-mm SS-OCTA images and compared with those of the contralateral eyes and healthy eyes. Other multimodal imaging data were collected.ResultsThere were no significant differences in the unaffected artery caliber or area among the three groups (all P > 0.05). The unaffected paCFZ areas and the ratios of the unaffected paCFZ area to the counterpart artery area (paCFZ/artery area) of the major arteries were significantly larger than those in the contralateral or healthy eyes (all P < 0.05). Subgroup analysis revealed that the paCFZ/artery area value differed significantly between ischemic and nonischemic BRVO eyes (P < 0.01). The paCFZ/artery area value was positively correlated with logMAR best-corrected visual acuity, symptom duration, central macular thickness, and retinal nonperfusion area in BRVO.ConclusionsQuantitative SS-OCTA measurements confirmed enlarged paCFZs along the unaffected major retinal arteries in BRVO eyes. The paCFZ parameters were correlated with symptom duration, retinal ischemia, and visual function.Translational RelevanceRetinal periarterial capillary-free zones in BRVO can be non-invasively measured by SS-OCTA, assisting in clinically identifying retinal ischemia and evaluating visual function.

Effect of preoperative exercise on vascular caliber and maturation of arteriovenous fistula: the physicalfav trial, a randomized controlled study.

Autologous arteriovenous fistula (AVF) is the best vascular access for hemodialysis. Distal forearm radiocephalic fistula is the best option, although the primary failure rate ranges from 20% to 50%. The main objective of the PHYSICALFAV trial was to evaluate the effect of preoperative isometric exercise on vascular caliber, percentage of distal arteriovenous fistula, and primary failure rate. The PHYSICALFAV trial (NCT03213756) is an open-label, multicenter, prospective, randomized, controlled trial (RCT). A total of 138 patients were randomized 1:1 to the exercise group (exercises combining a handgrip device and an elastic band for 8weeks) or the control group (no exercise) and followed up with periodic Doppler ultrasound (DU) examinations. After 8weeks of preoperative isometric exercise, in the exercise group,significant increases were detected in venous caliber (2.80 ± 0.95mm vs 3.52 ± 0.93mm [p < 0.001]), arterial caliber (2.61 ± 0.82mm vs 2.74 ± 0.80mm [p = 0.008]), arterial peak systolic velocity (66.34 ± 19.2cm/s vs 71.03 ± 21.5cm/s [p 0.043]), and maximum strength (28.35 ± 9.16kg vs 32.68 ± 10.8kg [p < 0.001]). Distal radiocephalic fistulas were performed in 75% of the exercise group patients compared with 50.8% in the control group (p = 0.030). The global primary failure rate was very low in both groups (7% exercise group vs 14% control group [p = 0.373]). Isometric preoperative exercise can improve vascular caliber and increase the possibility of performing distal arteriovenous fistula, with no significant differences in primary failure rate.

A cadaveric study of variations in the vertebrobasilar system

Introduction: The intracranial part of vertebral artery, basilar artery, and their branches together form the veretebrobasilar system. Identification of anomalies or variations in the vertebrobasilar system can be useful in diagnosing associated aneurysms, and in preventing complications during endovascular treatment. Materials and Methods: The study was conducted in 60 randomly selected brain specimens obtained from the cadavers used for dissection by the undergraduate medical students in the department of anatomy. The length of the basilar artery, variations in its course, level of formation and termination were noted. The variations in the caliber of right and left vertebral arteries and their symmetry were noted. Photographs were taken to document the variations. The results obtained were then tabulated. Results: In the present study variations in the origin of basilar artery was noted in 25% of specimens. Other variations like fenestration and button hole formation was also noted. Asymmetry of vertebral arteries were present in 14% of specimens. Hypoplasia of vertebral artery was also noted. Conclusion: Knowledge of variations in the vertebrobasilar system is helpful for the neurosurgeons to plan and execute surgeries for treatment of stenosis, aneurysms, and arteriovenous malformations in the posterior cranial fossa. Keywords: Vertebrobasilar system, Variations, Hypoplasia, Asymmetry, Posterior circulation, Vertebrobasilar ischemia.

Proximal and distal radial artery approaches for endovascular percutaneous procedures: anatomical suitability by ultrasound evaluation.

To describe the variability of the radial artery (RA) diameters at 2 levels, proximal (pRA), within 2cm to the styloid process, and distal (dRA) at the snuff box, both eligible accesses for percutaneous approach, and to correlate these diameters with population features. A total of 700 patients (377 females, 323 males) have been enrolled from July 2018 to March 2019. The diameters of left and right RA were measured using ultrasound (US) examination. Diameters of pRA and dRA were compared between different sex and CRF (tabagism, hypertension, hyperlipidemia, BMI > 30, diabetes) using multivariate analysis and unpaired t test; the feasibility of radial access was evaluated considering a diameter ≥ of 2mm as a cut-off or a vessel/sheath ratio >1. The time needed to perform each assessment of the four vessels was recorded. The average proximal diameter of pRA was 2.58mm (sd = 0.58mm). The caliber of the dRA resulted 19.5% lower than the proximal one, with an average diameter of 1.99mm (sd = 0.47mm). On unpaired t test, a significant difference was reported for two of the parameters taken into account: sex and a BMI > 30. Our results show that 88% of patients have an estimated radial artery caliber suitable for pTRA at US examination. Males and patients with BMI > 30 show a higher mean pRA and dRA; thus, they could be the ideal candidates for radial access.

The GEF Trio controls endothelial cell size and arterial remodeling downstream of Vegf signaling in both zebrafish and cell models

Arterial networks enlarge in response to increase in tissue metabolism to facilitate flow and nutrient delivery. Typically, the transition of a growing artery with a small diameter into a large caliber artery with a sizeable diameter occurs upon the blood flow driven change in number and shape of endothelial cells lining the arterial lumen. Here, using zebrafish embryos and endothelial cell models, we describe an alternative, flow independent model, involving enlargement of arterial endothelial cells, which results in the formation of large diameter arteries. Endothelial enlargement requires the GEF1 domain of the guanine nucleotide exchange factor Trio and activation of Rho-GTPases Rac1 and RhoG in the cell periphery, inducing F-actin cytoskeleton remodeling, myosin based tension at junction regions and focal adhesions. Activation of Trio in developing arteries in vivo involves precise titration of the Vegf signaling strength in the arterial wall, which is controlled by the soluble Vegf receptor Flt1.

Basic principles of ultrasound-assisted choice of strategy for targeted infusion therapy

Objective. Optimization of fluid therapy in emergency medicine.&#x0D; Materials and methods: 1) conceptual four-phase liquid resuscitation model; 2) conceptual approach of infusion therapy management is based on an assessment of the four main components of haemocirculation: a vascular content, tone and integrity, blood flow; 3) fast bedside ultrasound algorithm for differential diagnosis of shocks and infusion resuscitation protocol using ultrasound of the inferior vena cava (preload assessment) and lungs (early detection of extravascular fluid).&#x0D; Results. Using the selected methods, it is possible to clearly determine the optimal target-oriented infusion strategy depending on the volemic status and the state of hemodynamics, the parameters of which can be estimated using ultrasound: vascular content – inferior vena cava (caliber and breathing variations); vascular tone – caliber of the tibia artery; vascular integrity – loss assessment in the third space (physiological cavities and interstitium of the lungs); blood flow – Doppler Echo.&#x0D; Conclusions. The use of diagnostic ultrasound allows to optimize tissue perfusion, keeping the intravascular fluid volume in a certain range by sorting patients into three categories of fluid management: infusion resuscitation, tested infusion, limiting infusion and early use of vasopressors, which reduces the number of adverse effects and the incidence of complications.

Inconsistency in Graft Outcome of Bilayered Bioresorbable Supramolecular Arterial Scaffolds in Rats.

There is a continuous search for the ideal bioresorbable material to develop scaffolds for in situ vascular tissue engineering. As these scaffolds are exposed to the harsh hemodynamic environment during the entire transformation process from scaffold to neotissue, it is of crucial importance to maintain mechanical integrity and stability at all times. Bilayered scaffolds made of supramolecular polycarbonate-ester-bisurea were manufactured using dual electrospinning. These scaffolds contained a porous inner layer to allow for cellular infiltration and a dense outer layer to provide strength. Scaffolds (n = 21) were implanted as an interposition graft into the abdominal aorta of male Lewis rats and explanted after 1, 3, and 5 months in vivo to assess mechanical functionality and neotissue formation upon scaffold resorption. Results demonstrated conflicting graft outcomes despite homogeneity in the experimental group and scaffold production. Most grafts exhibited adverse remodeling, resulting in aneurysmal dilatation and calcification. However, a few grafts did not demonstrate such features, but instead were characterized by graft extension and smooth muscle cell proliferation in the absence of endothelium, while remaining patent throughout the study. We conclude that it remains extremely difficult to anticipate graft development and performance in vivo. Next to rational mechanical design and good performance in vitro, a thorough understanding of the mechanobiological mechanisms governing scaffold-driven arterial regeneration as well as potential influences of surgical procedures is warranted to further optimize scaffold designs. Careful analysis of the differences between preclinical successes and failures, as is done in this study, may provide initial handles for scaffold optimization and standardized surgical procedures to improve graft performance in vivo. Impact statement In situ vascular tissue engineering using cell-free bioresorbable scaffolds is investigated as an off-the-shelf option to grow small caliber arteries inside the body. In this study, we developed a bilayered electrospun supramolecular scaffold with a dense outer layer to provide mechanical integrity and a porous inner layer for cell recruitment and tissue formation. Despite homogenous scaffold properties and mechanical performance in vitro, in vivo testing as rat aorta interposition grafts revealed distinct graft outcomes, ranging from aneurysms to functional arteries. Careful analysis of this variability provided valuable insights into materials-driven in situ artery formation relevant for scaffold design and implantation procedures.

Actualidad en el diagnóstico y tratamiento de lesiones vasculares tipo Dieulafoy

Introducción: La lesión de Dieulafoy, constituye una causa rara de sangrado digestivo, pero potencialmente mortal, se produce, por la erosión de una arteria de calibre anormal, proveniente desde la capa submucosa y debe ser incluida, como una de las posibles causas de sangrado digestivo obscuro.&#x0D; Objetivos: Revisar la mejor evidencia médica publicada sobre sobre el manejo de las lesiones de Dieulafoy.&#x0D; Material y Métodos: Se realizó una revisión sistemática y crítica de la literatura científica sobre el manejo de las lesiones de Dieulafoy, la búsqueda se efectuó en la base de datos Medline de Pubmed utilizando las palabras clave: “Dieulafoy´s lesion”, “gastrointestinal bleeding”, “endoscopy” and treatment”.&#x0D; Resultados: La endoscopia, es el método inicial de diagnóstico; y el tratamiento endoscópico con métodos mecánicos, constituye la terapia de elección. &#x0D; Conclusiones: Las lesiones de Dieulafoy constituyen una causa infrecuente, pero potencialmente mortal de sangrado gastrointestinal, su identificación y correcto manejo se asocia con mejores resultados

Caliber of Intracranial Arteries as a Marker for Cerebral Small Vessel Disease.

Background: The dilation of intracranial large arteries caliber, may transfer more hemodynamic burden to the downstream brain capillaries, which, in the long run, results in cerebral small vessel disease (CSVD). This study aimed to investigate the relationship between intracranial artery calibers and small vessel disease.Methods: Patients with first-ever ischemic stroke of lacunar infarction subtype were enrolled via Nanjing Stroke Registry Program. An intracranial arterial Z-score, named the brain arterial remodeling (BAR) score, was calculated by averaging the calibers of the seven main intracranial arteries. Among the enrolled patients, those with a BAR score < −1 SD were deemed to have small intracranial artery calibers; those with a BAR score >1 SD were deemed to have large intracranial artery calibers and those with a between BAR score were deemed to have normal intracranial artery calibers. Imaging markers of CSVD, including lacuna, white matter hyperintensity (WMH), enlarged perivascular spaces (EPVS) and cerebral microbleeds (CMBs) were rated and then summed to obtain a total CSVD score.Results: A total of 312 patients were involved in this study, patients with BAR score >1 SD were older (P = 0.039), and more prone to having a history of myocardial infarction (P = 0.033). The Spearman's rank correlation coefficient between the BAR score and total CSVD score is 0.320 (P < 0.001). Binary logistic regression found that BAR score >1 SD was correlated with lacuna (OR = 1.987; 95% CI, 1.037–3.807; P = 0.039); severe WMH (OR = 1.994; 95% CI, 1.003–3.964; P = 0.049); severe EPVS (OR = 2.544; 95% CI, 1.299–4.983; P = 0.006) and CSVD (OR = 2.997; 95% CI 1.182–7.599; P = 0.021). Ordinal logistic regression analysis found that age (OR = 1.028; 95% CI, 1.007–1.049; P = 0.009), hypertension (OR = 3.514; 95% CI, 2.114–5.769; P < 0.001) and BAR score >1 SD (OR = 2.418; 95% CI, 1.350–4.330; P = 0.003) were correlated with the total CSVD score.Conclusions: Patients with large intracranial arterial calibers may have heavier CSVD burden. The mechanisms of this association warrant further study.

Quantifying Intra-Arterial Verapamil Response as a Diagnostic Tool for Reversible Cerebral Vasoconstriction Syndrome.

There is mounting evidence supporting the benefit of intra-arterial administration of vasodilators in diagnosing reversible cerebral vasoconstriction syndrome. We prospectively quantified the degree of luminal diameter dilation after intra-arterial administration of verapamil and its accuracy in diagnosing reversible cerebral vasoconstriction syndrome. Patients suspected of having intracranial arteriopathy on noninvasive imaging and referred for digital subtraction angiography were enrolled in a prospective registry. Intra-arterial verapamil was administered in vascular territories with segmental irregularities. The caliber difference (Caliberpost - Caliberpre) and the proportion of caliber change ([(Caliberpost - Caliberpre)/Caliberpre] × 100%) were used to determine the response to verapamil. The diagnosis of reversible cerebral vasoconstriction syndrome was made on the basis of clinical and imaging features at a follow-up appointment, independent of the reversibility of verapamil. Receiver operating characteristic curve analysis was performed to determine the best threshold. Twenty-six patients were included, and 9 (34.6%) were diagnosed with reversible cerebral vasoconstriction syndrome. A total of 213 vascular segments were assessed on diagnostic angiography. Every patient with a final diagnosis of reversible cerebral vasoconstriction syndrome responded to intra-arterial verapamil. The maximal proportion of change (P < .001), mean proportion of change (P = .002), maximal caliber difference (P = .004), and mean caliber difference (P = .001) were statistically different between patients with reversible cerebral vasoconstriction syndrome and other vasculopathies. A maximal proportion of change ≥32% showed a sensitivity of 100% and a specificity of 88.2% to detect reversible cerebral vasoconstriction syndrome (area under the curve = 0.951). The Reversible Cerebral Vasoconstriction Syndrome-2 score of ≥5 points achieved a lower area under the curve (0.908), with a sensitivity of 77.8% and a specificity of 94.1%. Objective measurement of the change in the arterial calibers after intra-arterial verapamil is accurate in distinguishing reversible cerebral vasoconstriction syndrome from other vasculopathies. A proportion of change ≥32% has the best diagnostic performance.

Percutaneous trans-ulnar versus trans-radial arterial approach for coronary angiography and angioplasty, a preliminary experience at an Egyptian cardiology center

BackgroundTrans-ulnar approach was proposed primarily for elective procedures in patients not suitable for trans-radial approach that was introduced two decades ago. The trans-ulnar approach is as safe and effective as the trans-radial approach for coronary angiography and intervention.AimThis study’s aim was to assess the feasibility and safety of the trans-ulnar approach in coronary procedures as a preliminary experience for operators experienced in trans-radial approach with no/minimal trans-ulnar approach experience at an Egyptian center.ResultsVascular access in 120 patients was selected randomly for coronary angiography and angioplasty—80 through radial and 40 through ulnar approach. Patients were examined for local complications and Doppler evaluation to both radial and ulnar arteries a day after the procedure was done. Ulnar approach success was 82.5% versus 93.7% in the radial group; failure of ulnar artery puncture was the only cause of crossover in the ulnar group, while occurrence of persistent spasm was the leading cause of crossover in the radial group followed by radial artery tortuosity. The procedure time of coronary angiography and percutaneous coronary intervention of the ulnar group was significantly higher than that of the radial group (P value = 0.011 and 0.034, respectively). The mean caliber of the right ulnar artery was 2.45 ± 0.38, slightly larger than that of the radial artery 2.33 ± 0.38 at the level of the wrist, but this difference was statistically non-significant.ConclusionOur study demonstrated that ulnar access with experienced radial operators and in our patients is a safe and practical approach for coronary angiography or angioplasty, without any major complications. Bearing in mind its high success rate, it can be used when a radial artery is not useful for the catheterization or as a default approach on the expense of slightly longer procedural time.

Variations of the Anatomy and Bony Landmarks of Deep Circumflex Iliac Artery in a Select Kenyan Population.

The deep circumflex iliac artery (DCIA) is a large caliber artery which branches laterally from the external iliac artery (EIA), directly opposite the origin of the inferior epigastric artery (IEA). Population variations have been reported in its origin, length, and branching patterns. These may alter its relationship to palpable surgical landmarks such as the anterior superior iliac spine (ASIS) and the pubic tubercle (PT) which are used to locate the artery preoperatively, thus predisposing it iatrogenic injury. Despite this, there is paucity of data from the Kenyan setting. Cross-sectional study design. To determine the variations of the anatomy and bony landmarks of the Deep circumflex iliac artery in a select Kenyan population. A total of 104 DCIA from 52 formalin fixed adult cadavers were dissected to expose the DCIA, following which its vessel of origin and distance from the ASIS and PT, relation to the inguinal ligament (IL), length and branching patterns were noted. The average of the measurements were calculated. All data were collected and analyzed using Microsoft Excel 2007 (Microsoft Corporation, Redmond, WA). Representative photos of the vessel and its variations were taken. The DCIA was found to be present and bilaterally symmetrical in all cadavers. In all cases observed, it originated as a lateral branch from the EIA (100%), opposite the IEA and directly behind the IL in 98% of the cases. Its average distance from the ASIS along the IL was 7.28 ± 0.99, while it was 5.91 ± 1.03 from the pubic tubercle to its origin. Its length ranged from 3.7 cm to 9.5 cm, with an average length of 3.86 cm in the right limb and 3.67 cm in the left limb. As regards its branching patterns, in 78% of the cases, it bifurcated into the horizontal and ascending branches, in 6%, it trifurcated and in 4%, it divided into more than 3, exhibiting a fine tree-like branching (arborization). The DCIA in our setting exhibited variations from other settings and an increase in awareness of these variations will probably reduce future iatrogenic lesions of the DCIA and its major branches in Kenya.

Comparative analysis of histological and morphometric changes of the arterial bed of the hind limbs of the rats in acute ischemia-reperfusion and correction with carbacetam

Resume. Ischemic-repefusion injury is a complex multifactorial tissue damage as the result of restoration of blood circulation, after the period of ischemia or lack of the oxygen, accompanied by the local and systemic disorders. Recently, more and more attention in treatment and prevention of postischemic disorders is paid to nootropic medicine, which smooths the phenomena of hypo- and hyperperfusion, and also improves tissue microcirculation.The aim of the study was to establish the manifestations of morpho-functional remodeling of the vascular bed of the hind limbs of the rats during ischemia-reperfusion and under conditions of carbacetam correction using histological and morphometric іnvestigations methods.Materials and methods. There was histological and morphometric examination of the arterial bed of the hind limbs of 30 rats under conditions of ischemia-reperfusion injury (group I) and 30 rats in the simulation of ischemia-reperfusion injury, which in the post-ischemic period was administered carbacetam once a day (5 mg / kg) for 14 days (group II) was performed. There were 6 intact animals in the control group.Simulation of ischemia was performed by applying SWAT rubber tourniquets on the hind limbs for 2 hours, and reperfusion - by removing the tourniquet. The animals were divided into 5 subgroups with reperfusion terms after 1, 2 hours and 1 day, as well as after 7 and 14 days. Histological examination was performed according to generally accepted methods. The vascular bed in the middle third of the thigh and shin, below the level of the application of the tourniquet was examined by Bresser Trino Researcher 40x – 1000x microscope. The morphometric parameters were calculated using SEO Image Lab software from Sumy Electron Optics.Research results and their discussion. Analyzing of the obtained results, it was founded that after 1 hour of the repefusion the structural changes became systemic, and after 1 day they were the most significant. Histologically, the elastic membranes were thinned and torned up, the swelling became a total character. In the late reperfusion period, a gradual return of morphological changes to the initial state and the increased in the proliferative activity of the fibroblasts were revealed. Under the conditions of correction after 1 day, the positive dynamics became more pronounced and reached its maximum after 7 days of the study. Morphometrically, the differences between the groups are especially pronounced 7 days after the removal of the tourniquet. At the level of the femoral artery revealed a lower value of external (D1) by 1.9% (p&lt;0,005) and internal (D2) diameters by 3,0% (p&lt;0,005) and an increased in Vi by 3,54% (p&lt;0,005)) in the specified experimental period in the animals with the correction, compared with the group without it.In small-caliber arteries, on the contrary, there was a less pronounced vasoconstriction level, when applying the correction, because the value of T decreased by 5,4% (p&lt;0,005) and Vi by 20,28% (p&lt;0,005), but there were higher indicator of D1 by 1,89 % (p&lt;0,005) and D2 by 11.55% (p&lt;0,005) compared to the group of animals without the correction.Conclusions. Ischemia and repfusion cause vascular remodeling after 1 hour with a peak of manifestations after 1 day of reperfusion. Under the conditions of the correction, the acceleration of the remodeling with stabilization of the process and the most possible structural restoration after 7 days of the study was noted. Morphometric data indicate less pronounced vasodilation at the level of large caliber arteries and spasm of arteries of muscular branches during that experimental period in the group with correction.

Can we Rotate the Head Safely During Cervical Nerve Root Injection?

Objectives: Trans-foraminal epidural injections have been used successfully to aid in the management of cervicobrachialagia. The aim of this study was to assess the cross sectional area of the vertebral artery during transforaminal cervical nerve root injections (TFCNRI) when the head is typically rotated and to compare with the neutral position cross sectional area. We hypothesize that head rotation does not lead to a change of vertebral artery calibre at the neural foramen, thus this technique can be performed relatively safely during TFCNRI. Material and Methods: A pilot study involving a retrospective review of 16 computed tomography guided TFNRI was performed and cross sectional area of vertebral artery with head tilted and head in neutral position was performed. Results: There was no correlation between the degree of head rotation and change in the area of the ipsilateral or contralateral vertebral artery. Conclusion: We suggest that head can safely be rotated to varied degrees while performing TFCNRI.

Retinal oxygen saturation and vessel diameter in patients with chronic kidney disease.

To investigate changes in retinal oximetry and the diameter of retinal vasculature in patients with chronic kidney disease (CKD) and relationships between retinal vasculature and the estimated glomerular filtration rate (eGFR), provide a scientific basis for the early detection and diagnosis of CKD. Eighty-three patients with CKD and 103 healthy individuals were included after providing informed consent. All participants were examined using a noninvasive technology (Oxymap Inc., Reykjavik, Iceland) for measuring the arterial (SaO2 ) and venous (SvO2 ) oxygen saturation and the arteriovenous difference in oxygen saturation (Sa-vO2 ). The corresponding retinal vessel diameters of these arterioles (D-A) and venules (D-V) were measured. The eGFR of patients with CKD was calculated from the serum creatinine concentration. In general, patients with CKD had higher mean SaO2 values than healthy individuals (100.15±4.68% versus 97.14±4.22%; p<0.001, mean±SD). The mean SaO2 in the superior temporal, superior nasal and inferior nasal quadrants significantly increased. There was no significant difference measured in the SvO2 when patients with CKD (63.66±5.29%) and healthy individuals (62.70±5.27%) were compared. The mean Sa-vO2 of the CKD group (36.49±4.98%) was increased compared with normal subjects (34.44±4.76%) (p=0.005). The retinal arteriole diameter was narrower in patients with CKD than in normal individuals (117.53±14.88μm versus 126.87±14.98μm; p<0.001, mean±SD), and the arteriovenous ratio was smaller than in normal individuals (0.71±0.09 versus 0.77±0.09; p<0.001, mean±SD). Pearson's two-tailed correlation showed a significant correlation between the SaO2 and eGFR (R=-0.363, p=0.001), and narrower retinal arterial calibre was significantly associated with a lower eGFR (R=0.415, p<0.001). Based on our results, there were alterations in retinal oxygen saturation and vascular diameter in patients with CKD. Further studies are needed to determine whether such changes play a role in the development of CKD.

Congenital central pulmonary artery anomalies: Part 2.

There is a broad spectrum of congenital anomalies of the central pulmonary arteries including abnormalities of development, origin, course and caliber. These anomalies incorporate simple lesions such as isolated pulmonary valve stenosis to very complex anomalies with many associated abnormalities. Part 1 and Part 2 of this review describe the range of anatomical variations that are encountered as well as important aspects of anatomy, physiology and surgical correction. The authors summarize and illustrate both well-recognized and more complex anomalies to provide a broad and comprehensive understanding of these lesions and their appearances on CT and MR imaging. In Part 2 the authors review abnormalities in development, origin and course of the central branch pulmonary arteries as well as abnormal pulmonary artery caliber.

1467-P: Retinal Vascular Biomarkers in Diabetic Peripheral Neuropathy

Purpose: Studies have shown that individuals with retinal blood vessel abnormalities often present with other biomarkers associated with diabetic peripheral neuropathy (DPN). Existing software requires extensive manual intervention to measure structures in the retinal vasculature (e.g., arterial caliber, artery/vein ratios, fractals, etc.) for the purpose of studying the relationship of these structures to DPN. The goal of this study was to demonstrate an artificial intelligence (AI) software system for determining DPN risk based on retinal vascular abnormalities. Our approach circumvented the need to explicitly measure vessel characteristics by using AI as applied to a state-of-the-art methodology known as “convolutional neural networks” (CNN) to characterize the retinal vascular structures. CNNs have been demonstrated to be effective in a number of medical applications. This study is the first time CNNs have been used to extract retinal vascular features for DPN risk assessment. Methods: From a database of 25,000 cases previously labeled as healthy (controls), unaffected diabetes (DM), or DPN, we have identified 331 cases that fit the requirements for this study. Controls (N=103) had monofilament and vibration tests to confirm normal peripheral nerve function. DM patients (N=163) were classified based on their medical records and monofilament and vibration tests. DPN patients (N=65) were confirmed by clinical examination and their medical record. With these cases, an AI classifier was trained to identify individuals with DPN biomarkers based on spatial features extracted from the retinal abnormalities. Results: 80% of cohort data were used for training and 20% was used for testing. The resulting AI tool demonstrated 95% specificity and 78% sensitivity when using the clinical exam as the reference standard. Conclusions: AI-based CNN analysis of retinal vascular features show promise for identifying subjects with DPN and reduced human manipulation and measurement of tedious vessel geometries. Disclosure M.R. Burge: None. P. Soliz: None. J. Benson: None. V. Joshi: None. Funding National Institutes of Health (DK104578)

P1315PREDICTABILITY OF SONOGRAPHICALLY DETERMINED IMMEDIATE POST-OPERATIVE BLOODFLOW AND VEIN DIAMETER ON PRIMARY RADIOCEPHALIC FISTULA SHORT AND LONGTERM OUTCOMES

Abstract Background and Aims Vascular access (VA) guidelines recommend radio-cephalic (RC) over upper arm autogenous arteriovenous fistulas (AVF) as first line VA for hemodialysis in end stage renal disease (ESRD) patients. RCAVFs generally have inferior maturation and patency rates predicated on a lower feeding arterial blood flow (BF) and outflow vein calibre (VC). However studies on postoperative BF and VC as predictors of AVF outcomes, so far are confounded by their focus on early outcomes only, heterogeneity of AVFs studied, variable timing of assessment and use of non-standardised outcome definitions. Our aim was therefore to assess the accuracy and influence of immediate post-operative BF and VC on both early and longterm outcomes in a homogenous cohort of primary RCAVFs using standardised definitions and outcome measures as mandated by VA guidelines. Method This was a prospective study conducted in multi-ethnic Asian ESRD patients who had their primary RCAVFs created between October 2013 and October 2014 under regional anesthesia at Khoo Teck Puat hospital Singapore. All AVFs were assessed immediately after surgery for brachial artery BF and outflow VC using doppler ultrasound. A 10MHz linear probe and GE Logic e R7 machine were used exclusively by a single operator. Receiver operating characteristic (ROC) curves were generated to determine the optimal BF and VC cut-off for AVF maturation. Maturation was defined as BF&amp;gt;600mL/min, VC&amp;gt;6mm and vein depth &amp;lt;6mm at 6 weeks post-op. An area under the curve (AUC)&amp;gt; 0.7 was considered clinically significant. Kaplan–Meier analysis was used to evaluate the AVF primary and secondary patency based on best BF and VC cut-offs. Cox regression statistics was used to determine AVF hazard factors. Results Fifty-seven primary RCAVFs were created and included in the study. The baseline characteristics are shown in Table 1. Sonography- based non-assisted maturation at 6 weeks was 56%. ROC identified 410 mL/min and 42mm as the best BF and VC cut-off respectively to most accurately predict 6-week maturation. The sensitivity, specificity, positive predictive value and negative predictive value were 75%, 61%, 44% and 86% for BF at 410 mL/min and 69%, 61%, 41% and 83% for VC at 42mm respectively. Survival analysis (Fig. 1 and 2) showed that AVFs with VC≥42 mm compared to &amp;lt;42mm had significantly greater 6 months, 1-year, 2-year and 4-year primary and secondary patency rates. There was no significant difference in patency rates between AVFs with BF≥410 and &amp;lt;410mL/min. Cox proportional regression hazard analysis showed that diabetes (HR 2.26, CI 1.02-4.99, p= 0.04) and maturation (HR 0.47, 95% CJ 0.24-0.89, p=0.02) as significant contributed to the variability of primary patency. Only VC (HR 0.28, 95% CI 0.13-0.063, p=0.002) impacted significantly towards secondary patency. Conclusion An immediate post-op BF≥410mL/min and VC≥42mm can predict early RCAVF outcome in the form of nonassisted maturation, but only VC accurately impact on longterm AVF survival. VA surveillance efforts should therefore target RCAVFs with post-op VC &amp;lt;42mm for timely intervention and maintenance of longterm patency.

Do body mass index and waist-to-height ratio over the preceding decade predict retinal microvasculature in 11-12 year olds and midlife adults?

Microvascular changes may contribute to obesity-associated cardiovascular disease. We examined whether body mass index (BMI) and waist-to-height ratio (WHtR) (1) at multiple earlier time points and (2) decade-long trajectories predicted retinal microvascular parameters in mid-childhood/adulthood. Participants/design: 1288 11-12 year olds (51% girls) and 1264 parents (87% mothers) in the population-based Child Health CheckPoint (CheckPoint) module within the Longitudinal Study of Australian Children (LSAC). LSAC exposure measures: biennial BMI z-score and WHtR for children at five time points from age 2-3 to 10-11 years and self-reported parent BMI at six time points from child age 0-1 years to 10-11 years. CheckPoint outcome measures: retinal arteriolar and venular caliber. BMI/WHtR trajectories were identified by group-based trajectory modeling; linear regression models estimated associations between BMI/WHtR at each time point/trajectories and later retinal vascular caliber, adjusted for age, sex, and family socioeconomic status. In time point analyses, higher child BMI/WHtR from age 4 to 5 years was associated with narrower arteriolar caliber at the age of 11-12 years, but not venular caliber. For example, each standard deviation higher in BMI z-score at 4-5 years was associated with narrower arteriolar caliber at 11-12 years (standardized mean difference (SMD): -0.05, 95% confidence interval (CI): -0.10 to 0.01); by 10-11 years, associations had doubled to -0.10 (95% CI: -0.16 to -0.05). In adults, these finding were similar, except the magnitude of BMI and arteriolar associations were similar across all time points (SMD: -0.11 to -0.13). In child and adult BMI trajectory analyses, less favorable trajectories predicted narrower arteriolar (p-trend < 0.05), but not venular (p-trend > 0.1), caliber. Compared with those in the average BMI trajectory, SMDs in arterial caliber for children and adults in the highest trajectory were -0.25 (95% CI: -0.44 to -0.07) and -0.42 (95% CI: -0.73 to -0.10), respectively. Venular caliber showed late associations with child WHtR, but not with BMI in children or adults. Associations of decade-long high BMI trajectories with narrowed retinal arteriolar caliber emerge in children, and are clearly evident by midlife. Adiposity appears to exert its early adverse life course impacts on the microcirculation more via arteriolar than venular mechanisms.