Factors Affecting Arteriovenous Fistula (AVF) Maturation

AVF requires postoperative maturation before cannulation to initiate hemodialysis treatment. AVF maturation usually takes about six weeks and depends on the development of vascular remodeling. However, AVF surgery is not always followed by successful maturation. Recent studies have shown that the rate of maturation failure in patients with chronic kidney disease undergoing AVF-type vascular access establishment is very high, ranging from 20% to 60%. The source search was carried out on the online portal of journal publications as many as 12 sources from Medscape, Google Scholar, National Center for Biotechnology Information (NCBI) with the keywords chronic kidney disease, hemodialysis, AVF, and maturation. Many factors are involved in the functional maturation of AVF, including age, sex, coagulation factors, lipid profile, hypoalbumin, venous diameter, diabetes, hypertension, peripheral vascular disease, smoking, obesity, and dialysis. Failure of AVF maturation results in insufficient blood flow to allow cannulation and initiation of hemodialysis.

New Hypertensive Retinopathy Grading Based on the Ratio of Artery Venous Diameter from Retinal Image

Medical research indicated that narrowing of the retinal blood vessels might be an early indicator of cardiovascular diseases; one of them is hypertensive retinopathy. This paper proposed the new staging method of hypertensive retinopathy by measure the ratio of diameter artery and vein (AVR). The dataset used in this research is the public Messidor color fundus image dataset. The proposed method consists of image resizing using bicubic interpolation, optic disk detection, a region of interest computation, vessel diameter measuring, AVR calculation, and grading the new categories of Hypertensive Retinopathy based on Keith-Wagener-Barker categories. The experiments show that the proposed method can determine the stage of hypertensive retinopathy into new categories.

The impact of the catheter to vein ratio on peripheral intravenous cannulation success, a post-hoc analyses

Background Intravenous cannulation is usually the first procedure performed in modern healthcare, although establishing peripheral intravenous access is challenging in some patients. The impact of the ratio between venous diameter and the size of the inserted catheter (catheter to vein ratio, CVR) on the first attempt success rate can be of added value in clinical. This study tries to give insight into the consideration that must be made when selecting the target vein and the type of catheter, and proved the null hypothesis that an optimal CVR would not be associated with increased first attempt cannulation success. Methods This was a post-hoc analyses on adult patients admitted for peripheral intravenous cannulation. Intravenous cannulation was performed according to practice guidelines, by applying the traditional landmark approach. The CVR was calculated afterwards for each individual patient by dividing the external diameter of the inserted catheter by the diameter of the target vein, which was multiplied by 100%. Results In total, 610 patients were included. The median CVR was 0.39 (0.15) in patients with a successful first attempt, whereas patients with an unsuccessful first attempt had a median CVR of 0.55 (0.20) (P<0.001). The optimal cut-off point of the CVR was 0.41. First attempt cannulation was successful in 92% of patients with a CVR<0.41, whereas as those with a CVR>0.41 had a first attempt success rate of 65% (P<0.001). Conclusion This first introduction of the CVR in relation to cannulation success should be further investigated. Although, measuring the venous diameter or detection of a vein with a specific diameter prior to cannulation may increase first attempt cannulation success.

POS0850 NAILFOLD CAPILLARY DILATIONS IN RAYNAUD’S PHENOMENON: QUANTIFYING A PREDICTIVE THRESHOLD FOR THE ‘SCLERODERMA PATTERN’

Background:Non-specific abnormalities could be detected by nailfold videocapillaroscopy (NVC) in subject with primary Raynaud’s Phenomenon (RP) several years before the clinical onset of connective tissue diseases (CTD)s [1]. Previous findings from our group proved that ≤30 μm capillary dilations in RP patients have a negative predictive value for developing the ‘scleroderma pattern’ during follow-up [2].Objectives:To investigate the role of NVC >30 μm capillary dilations as positive predictive factors of the ‘scleroderma pattern’ in RP patients later developing systemic sclerosis (SSc)-related RP.Methods:A 10-year retrospective NVC-based investigation evaluated the dataset of sequential NVCs of 18 RP patients later developing SSc (cases) and 19 sex- and age-matched RP patients later developing other CTDs (controls). Both cases and controls had ≥1 NVC performed before the ‘scleroderma pattern’/CTD diagnosis (basal NVC) showing >30 μm dilated capillaries. Each NVC was qualitatively and semi-quantitatively assessed, recording number of total capillaries, number and average/site-specific diameters (arterial, apical, venous) of >30 μm dilated capillaries [3]. Statistical analysis was performed to stratify the risk of developing the ‘scleroderma pattern’.Results:Significant differences of capillary diameters were observed between cases and controls both at basal NVC and during follow-up (p<0.001). The proportion of >30 μm dilated capillaries in basal NVC was the strongest predictor of ‘scleroderma pattern’ in a median 3-year time, with a 27% cut-off (PPV 0.79, 95%CI 0.54,0.94; p<0.001). Additional “Higher risk” NVC hallmarks for ‘scleroderma pattern’ development were apical diameter >40 μm (p<0.001), venous diameter >25 µm (p<0.05) and average diameter ≥35 µm (p<0.005). Conversely, CTDs patients showed a stable NVC ‘non-scleroderma pattern’ over a median 10-year time.Conclusion:This is the first study to show that NVC-detected homogeneous and progressive capillary loop dilations in RP patients significantly contribute to predict the ‘scleroderma pattern’ evolution within a median 3-year time, possibly providing a “very early” window of opportunity in SSc pre-clinical stages.References:[1]Cutolo M et al. Expert Rev Clin Immunol. 2019;15(7):753–64. [2] Trombetta AC et al. J Rheumatol 2016;43:599–606. [3] Smith et al. Autoimmun Rev 2020; 19(3):102458.Disclosure of Interests:None declared

The Use of Fiji Image J as an Image Analysis Tool for Measuring Retinal Vessel Diameter in Rodent Model of Diabetic Retinopathy

The purpose of this study was to evaluate the use of Fiji Image J application for digital fundus image analysis of retinal vessel diameter in diabetic retinopathy rat model. Male Sprague-Dawley rats, weighing 200-250 grams, were divided into two groups: normal and diabetic. The diabetes was induced by intraperitoneal (IP) injection of streptozotocin (STZ, 55 mg/kg body weight). Normal rats received IP citrate buffer. Fundus images were captured at week 0, 6 and 12 post-induction to observe changes in retinal veins and arteries. Images obtained were then analyzed using Fiji Image J software. Retinal venous diameter was increased in both groups at week 6 and 12 compared to baseline (p<0.05). However, no significant differences were seen in the retinal venous diameter at week 12 compared to week 6 in both groups. When comparing between the groups, retinal venous diameter in diabetic group was significantly greater compared to normal group at week 6 and 12 by 1.37- and 1.35-folds (p<0.001), respectively. For the retinal arterial diameter in diabetic group, an increase was observed at week 6 and 12 compared to baseline by 1.17- and 1.2-folds (p<0.05) respectively, however, similar changes were not observed in normal group. There was also no significant difference between the retinal arterial diameter of normal and diabetic group at week 6 and 12. In conclusion, retinal vessels diameter analysis of fundus images using Fiji Image J can be utilized to determine quantitative changes between normal and rats with STZ-induced diabetic retinopathy.

The effect of pelvic pathology on uterine vein diameters

Background Transvaginal ultrasound (TVS) is a sensitive tool for detecting various conditions that contribute to pelvic pain. TVS can be also used to assess blood flow and measure the size of pelvic veins. Pelvic venous congestion (PVC) is characterised by enlargement of the pelvic veins and has been recognised as a cause of chronic pelvic pain. The reference ranges for uterine venous diameter in women with normal pelvic organs have been established, but there is no information regarding the potential effect of pelvic pathology on the uterine venous diameters. The aim of this study was to examine the size of uterine venous plexus in women with evidence of pelvic abnormalities on TVS and to determine whether the reference ranges need to be adjusted in the presence of pelvic pathology. A prospective, observational study was conducted in our gynaecological outpatient clinic. Morphological characteristics of all pelvic abnormalities detected on TVS and their sizes were recorded. The uterine veins were identified and their diameters were measured in all cases. The primary outcome measure was the uterine venous diameter. Regression analyses were performed to determine factors affecting the uterine venous size in women with pelvic pathology. Results A total of 1500 women were included into the study, 1014 (67%) of whom were diagnosed with pelvic abnormalities. Women with pelvic pathology had significantly larger uterine venous diameters than women with normal pelvic organs (p < 0.01). Multivariable analysis showed that pre-menopausal status, high parity, presence of fibroids (p < 0.001) and Black ethnicity were all associated with significantly larger uterine vein diameters. Based on these findings modified reference ranges for uterine venous diameters have been designed which could be used for the diagnosis of PVC in women with uterine fibroids. Conclusions Our findings show that of all pelvic pathology detected on TVS, only fibroids are significantly associated with uterine venous enlargement. Factors known to be associated with enlarged veins in women with normal pelvic organs, namely parity and menopausal status, also apply in patients with pelvic pathology. Future studies of uterine venous circulation should take into account the presence and size of uterine fibroids when assessing women for the signs of PVC.

Morphometric Characterization of Human Coronary Veins and Subvenous Epicardial Adipose Tissue—Implications for Cardiac Resynchronization Therapy Leads

Subvenous epicardial fat tissue (SEAT), which acts as an electrical insulation, and the venous diameter (VD) both constitute histomorphological challenges for optimal application and lead design in cardiac synchronization therapy (CRT). In this study, we characterized the morphology of human coronary veins to improve the technical design of future CRT systems and to optimize the application of CRT leads. We retrospectively analyzed data from cardiac computed tomography (CT) of 53 patients and did studies of 14 human hearts using the postmortem freeze section technique and micro CT. Morphometric parameters (tributary distances, offspring angles, luminal VD, and SEAT thickness) were assessed. The left posterior ventricular vein (VVSP) had a mean proximal VD of 4.0 ± 1.4 mm, the left marginal vein (VMS) of 3.2 ± 1.5 mm and the anterior interventricular vein (VIA) of 3.9 ± 1.3 mm. More distally (5 cm), VDs decreased to 2.4 ± 0.6 mm, 2.3 ± 0.7 mm, and 2.4 ± 0.6 mm, respectively. In their proximal portions (15 mm), veins possessed mean SEAT thicknesses of 3.2 ± 2.4 (VVSP), 3.4 ± 2.4 mm (VMS), and 4.2 ± 2.8 mm (VIA), respectively. More distally (20–70 mm), mean SEAT thicknesses decreased to alternating low levels of 1.3 ± 1.1 mm (VVSP), 1.7 ± 1.1 mm (VMS), and 4.3 ± 2.6 mm (VIA), respectively. In contrast to the VD, SEAT thicknesses alternated along the further distal vein course and did not display a continuous decrease. Besides the CRT responsiveness of different areas of the LV myocardium, SEAT is a relevant electrophysiological factor in CRT, potentially interfering with sensing and pacing. A sufficient VD is crucial for successful CRT lead placement. Measurements revealed a trend toward greater SEAT thickness for the VIA compared to VVSP and VMS, suggesting a superior signal-to-noise-ratio in VVSP and VMS.