Vascular Mapping Research Articles

Abstract 16982: Baseline Diameter Does Not Predict Growth Rate in Ascending Thoracic Aortic Aneurysm

Introduction: Patients with ascending thoracic aortic aneurysm (aTAA) are recommended to undergo routine imaging surveillance. While maximal diameter is the primary metric of disease severity, recent AHA/ACC guidelines emphasize the importance of aortic growth in determining surgical candidacy and risk of complications. Increasing diameter is often assumed to confer higher aortic growth rate (GR) due to increased wall tension; however, this relationship is poorly studied. Goal: To investigate the relationship between aTAA diameter and GR using Vascular Deformation Mapping (VDM), a validated technique for 3D growth mapping with sub-millimeter accuracy. Methods: We identified 122 patients with ascending aortic dilation (≥4.0 cm) and serial gated CT angiograms (CTA) with an interval of ≥2 years. Ascending GR was defined as the 90th percentile of wall deformation (radial direction) by VDM, normalized by interval (mm/y). Maximal diameter measurements were taken from the baseline CTA report. Aortic height index (AHI, cm/m) and aortic cross-sectional area/height ratio (CSAH, cm^2/m) were calculated. Ascending aortic length (AL, mm) was measured from the annulus to the origin of the innominate artery. Results: 122 patients (60.7% male, mean age 62.8 ± 10.9 y, 0% connective tissue disease) showed a mean baseline diameter of 44.7 ± 3.7 mm and mean GR of 0.30 ± 0.44 mm/y. No correlation was noted between GR and baseline diameter (r= -0.02, p= 0.86), AHI (r= -0.06, p= 0.54), CSAH (r= -0.04, p= 0.70), or AL (r= 0.08, p= 0.41). Diameter was modestly correlated with GR (r = 0.65, CI 95%: 0.11-0.89, p = 0.02) among the small subgroup with diameter ≥50mm (n=12). GR was not significantly correlated to age (r= -0.13, p= 0.17) and did not differ by sex (p= 0.91) or hypertension (p= 0.51). No demographic or anatomic variables were predictive of GR on multivariable analysis. Conclusions: Maximal aortic diameter is not predictive of aortic GR, especially at sizes under surgical thresholds (<50 mm).

Standardization of Pre-operative Evaluation to Improve the Outcome of Arteriovenous Fistula for Vascular Access of Hemodialysis: A Review of 700 Cases.

Background With the advent of COVID-19, mortality rates of end-stage kidney disease (ESKD) rose by 37% which makes its treatment an important part of healthcare. Arteriovenous fistula (AVF) is linked to higher patient survival rates. Cimino-Brescia fistula is the most effective vascular access technique, but it has a high rate of primary failure (PF) and a several-week maturation period before it can be used. The current study aims to verify the preoperative evaluation in improving survival among AVF patients. Methodology The current study is a retrospective analysis of the hospital database from Jan 2022 to July 2023, with patients of a mean age of 60.2 years. The sample size was around 700, including the patients indicated for long-term hemodialysis (HD) with an estimated GFR of less than 20 mm/min/1.73m². Following AVF surgery, post-operative outcomes, PF, and maturation time were considered. Results Among the 757 AVF procedures, 588 (82%) were new cases, and 112 (16%) had prior AVF history on the same side. PF was observed in 126 (18%) AVFs, while 574 (84%) achieved maturation. Age at surgery did not correlate with PF. Male sex and brachiocephalic AVF (BCAVF) had lower PF rates, while female gender, non-BCAVF, and vascular chronic kidney disease (CKD) were independent predictors. Proximal fistulas had a higher failure risk (32%). During surgery, the PF occurred six times more frequently in patients with veins and arteries under 2 mm and without a bruit. Conclusion AVF maturation aims to achieve a functional AVF for easy dialysis, requiring meticulous vein selection, doppler vascular mapping, and a standardized process to reduce PF rates. Factors determining PF include thrill and bruit, flow rates, and comorbidities. These findings can help clinicians make informed decisions and improve outcomes for patients undergoing fistula surgery.

Handheld Doppler Detection and Light Illumination for Vascular Mapping in Nasal Reconstruction.

The application of the expanded forehead flap in nasal reconstruction has the advantage of being able to provide a sufficient amount of flap and can provide good aesthetic results. For an expanded forehead flap to survive, there must be adequate arterial supply and venous return. Despite this, limited studies have been conducted on preoperative vascular mapping and the design of the expanded forehead flap for nasal reconstruction. In this article, the authors present a technique of hand-held Doppler detection with light illumination for vascular mapping. The study included patients who underwent total nasal reconstruction with expanded forehead flaps between May 2016 and April 2021. The design of the flap was based on the result of preoperative vascular detection by hand-held Doppler detection assisted by light illumination. A total of 32 patients underwent total nasal reconstruction with an expanded forehead flap. The distal part of the flap became necrotic 1 week after the surgery in 2 patients. Following dressing changes and the administration of antibiotics, the distal flap in these patients survived well. No complications were reported in the long term. Hand-held Doppler detection combined with light illumination is a convenient and effective preoperative design method for nasal reconstruction with an expanded forehead flap. All flaps survived well in the long term. Level IV.

Three-dimensional super resolution ultrasound imaging with a multi-frequency hemispherical phased array.

High resolution imaging of the microvasculature plays an important role in both diagnostic and therapeutic applications in the brain. However, ultrasound pulse-echo sonography imaging the brain vasculatures has been limited to narrow acoustic windows and low frequencies due to the distortion of the skull bone, which sacrifices axial resolution since it is pulse length dependent. To overcome the detect limit, a large aperture 256-module sparse hemispherical transmit/receive array was used to visualize the acoustic emissions of ultrasound-vaporized lipid-coated decafluorobutane nanodroplets flowing through tube phantoms and within rabbit cerebral vasculature in vivo via passive acoustic mapping and super resolution techniques. Nanodroplets were vaporized with 55kHz burst-mode ultrasound (burst length=145μs, burst repetition frequency=9-45Hz, peak negative acoustic pressure=0.10-0.22MPa), which propagates through overlying tissues well without suffering from severe distortions. The resulting emissions were received at a higher frequency (612 or 1224kHz subarray) to improve the resulting spatial resolution during passive beamforming. Normal resolution three-dimensional images were formed using a delay, sum, and integrate beamforming algorithm, and super-resolved images were extracted via Gaussian fitting of the estimated point-spread-function to the normal resolution data. With super resolution techniques, the mean lateral (axial) full-width-at-half-maximum image intensity was 16±3 (32±6)μm, and 7±1 (15±2)μm corresponding to ∼1/67 of the normal resolution at 612 and 1224kHz, respectively. The mean positional uncertainties were ∼1/350 (lateral) and ∼1/180 (axial) of the receive wavelength in water. In addition, a temporal correlation between nanodroplet vaporization and the transmit waveform shape was observed, which may provide the opportunity to enhance the signal-to-noise ratio in future studies. Here, we demonstrate the feasibility of vaporizing nanodroplets via low frequency ultrasound and simultaneously performing spatial mapping via passive beamforming at higher frequencies to improve the resulting spatial resolution of super resolution imaging techniques. This method may enable complete four-dimensional vascular mapping in organs where a hemispherical array could be positioned to surround the target, such as the brain, breast, or testicles.

Association between Carotid Wall Shear Stress-Based Vascular Vector Flow Mapping and Cerebral Small Vessel Disease.

Wall shear stress (WSS) is the frictional force caused by viscous blood flowing along the vessel wall. Decreased WSS is associated with local vascular endothelial dysfunction and atherosclerosis. The vector flow mapping (VFM) technique detects the direction of intracardiac blood flow and WSS on the vessel wall with echocardiography. In this study, we examined carotid WSS by applying the VFM technique to the carotid arteries and evaluated its relationship with cerebral small vessel disease (SVD). This is a single-center, prospective, observational study. We investigated the association between carotid WSS and SVD imaging, and cognitive outcomes in consecutive 113 patients with acute lacunar infarction. Carotid WSS was negatively associated with age (r=-0.376, p＜0.001). Lower WSS was correlated with total SVD scores (ρ=-0.304, p=0.004), especially with enlarged perivascular space (EPVS) in the basal ganglia ＞10 (p＜0.001). The carotid intima-media thickness was not associated with the total SVD score (ρ=-0.183, p=0.052). Moreover, lower WSS was associated with executive dysfunction. EPVS has recently been reported as a marker of early SVD imaging, and executive dysfunction is common in vascular cognitive impairment. These results suggested that decreased carotid WSS based on vascular VFM, which can be measured easily, is associated with imaging and cognitive changes in the early stages of SVD.

Optical coherence tomography angiography allows longitudinal monitoring of angiogenesis in the critical-sized defect model

Purpose: This study aims to evaluate the capability of optical coherence tomography angiography (OCTA) for imaging the microvasculature within a critical bone defect, to longitudinally observe vascular alterations, and quantify the microvascular density and morphology in a model of a critical-sized defect.Methods: An OCTA system was used to longitudinally monitor angiogenesis in four rat models presenting critical-sized defects with observations recorded on days 7, 14, and 28 post-defect creation. Simultaneously, angiogenesis in three additional rat models was evaluated through a conventional histological analysis involving hematoxylin and eosin staining.Results: OCTA was successful in acquiring in vivo 3D vascular perfusion mapping within the critical-sized defect, and it allowed for quantitative analysis of the microvasculature’s density and morphology. The OCTA imagery of the blood microvasculature revealed a noticeable augmentation in the number and size of vessels, with more extensive vessel convergence observed on day 14 compared to both days 7 and 28. Complementing these observations, quantitative analysis demonstrated that the vessel area density (VAD) and maximum vascular diameter index (MVDI) were significantly larger on day 14 in comparison to measurements taken on days 7 and 28.Conclusion: Leveraging its ability to capture high-resolution images, OCTA facilitated longitudinal monitoring of angiogenesis in models of critical-sized defects. Therefore, it potentially serves as a non-invasive experimental tool beneficial for bone regeneration research.

Indocyanine green (ICG) angiography-guided thyroidectomy: description of surgical technique.

Postoperative hypoparathyroidism is the most common complication after total thyroidectomy and, when becomes permanent, lead to a myriad of clinical symptoms, long-term need of calcium and vitamin D supplementation and negative impact on the patient's health-related quality of life. Any surgical innovation that could reduce complications and improve outcomes of patients undergoing total thyroidectomy deserves to be considered. Angiography-Guided Thyroidectomy has been proposed as a modification of the standard technique of thyroidectomy aimed to identifying the vascular pattern of the parathyroid glands to maximize efforts for preserving functioning glands at the time of operation. Our aim is to provide a technical description of this procedure based on the use of indocyanine green (ICG) angiography to standardize this technique. The surgical steps that are followed during a total thyroidectomy are modified due to previous visualization of the feeding vessels of the parathyroid glands according to fluorescence of the vascular mapping obtained by ICG angiography prior to thyroidectomy. The first step is to perform an ICG angiography to assess anatomical features of the feeding vasculature of the parathyroid glands, which allows precise surgical dissection for preservation of the glands. Once the viability of the parathyroids has been evaluated angiographically, thyroidectomy is performed in a second step. ICG angiography-guided thyroidectomy may be effective to preserve the largest number of better perfused parathyroid glands, which would contribute to reduce the risk of postoperative and permanent hypoparathyroidism. It can be successfully and safely implemented in thyroid surgery and standardization of the technique is necessary to homogenize this procedure in the future, allowing a better comparation of the results to be published.

Three-Dimensional Characterization of Aortic Root Motion by Vascular Deformation Mapping

The aorta is in constant motion due to the combination of cyclic loading and unloading with its mechanical coupling to the contractile left ventricle (LV) myocardium. This aortic root motion has been proposed as a marker for aortic disease progression. Aortic root motion extraction techniques have been mostly based on 2D image analysis and have thus lacked a rigorous description of the different components of aortic root motion (e.g., axial versus in-plane). In this study, we utilized a novel technique termed vascular deformation mapping (VDM(D)) to extract 3D aortic root motion from dynamic computed tomography angiography images. Aortic root displacement (axial and in-plane), area ratio and distensibility, axial tilt, aortic rotation, and LV/Ao angles were extracted and compared for four different subject groups: non-aneurysmal, TAA, Marfan, and repair. The repair group showed smaller aortic root displacement, aortic rotation, and distensibility than the other groups. The repair group was also the only group that showed a larger relative in-plane displacement than relative axial displacement. The Marfan group showed the largest heterogeneity in aortic root displacement, distensibility, and age. The non-aneurysmal group showed a negative correlation between age and distensibility, consistent with previous studies. Our results revealed a strong positive correlation between LV/Ao angle and relative axial displacement and a strong negative correlation between LV/Ao angle and relative in-plane displacement. VDM(D)-derived 3D aortic root motion can be used in future studies to define improved boundary conditions for aortic wall stress analysis.

Preoperative assessment for vascular access: Vascular mapping and handgrip strength.

Reliable vascular access (VA) is required for patients receiving chronic hemodialysis (HD) treatment. Vascular mapping using duplex doppler ultrasonography (DUS) can aid in planning VA construction. Greater handgrip strength (HGS) was found to be associated with more developed distal vessels both in chronic kidney disease (CKD) patients and healthy individuals, and patients with lower HGS had worse morphologic vessel characteristics and were, therefore, less likely to construct distal VA. This study aims to describe and analyze clinical, anthropometric, and laboratory characteristics of patients who underwent vascular mapping prior to VA creation. Prospective analysis. Adult patients with CKD referred for vascular mapping, at a tertiary center, between March 2021 and August 2021. Preoperative DUS by a single experienced nephrologist was carried out. HGS was measured using a hand dynamometer, and PAD was defined as ABI < 0.9. Sub-groups were analyzed according to distal vasculature size (<2 mm). A total of 80 patients were included, with a mean age of 65.7 ± 14.7 years; 67.5% were male, and 51.3% were on renal replacement therapy (RRT). Twelve (15%) participants had PAD. HGS was higher in the dominant arm (20.5 ± 12.0 vs 18.8 ± 11.2 kg). Fifty-eight (72.5%) patients had vessels smaller than 2 mm in diameter. There were no significant differences between groups concerning demographics or comorbidities (diabetes, HTN, PAD). HGS was significantly higher in patients with distal vasculature greater than or equal to 2 mm in diameter (dominant arm: 26.1 ± 15.5 vs 18.4 ± 9.7 kg, p = 0.010; non-dominant arm: 24.1 ± 15.3 vs 16.8 ± 8.6, p = 0.008). Higher HGS was associated with more developed distal cephalic vein and radial artery. Low HGS might be an indirect sign of suboptimal vascular characteristics, which might help predict the outcomes of VA creation and maturation.

Facial Doppler ultrasound in minimally invasive procedures

Color Doppler ultrasound (US) is an important ally in minimally invasive aesthetic procedures at the facial level. The three-dimensional images obtained make it possible to carry out a complete vascular mapping of the face, relate the different anatomical structures and observe the cutaneous and subcutaneous thickness. Knowing this information will make it easier for the professional to carry out safe planning in the injection of a "filler" in different dermal structures. Thus, this article intends to be a guide when carrying out such procedures, as well as in the management of possible complications. Knowledge of this information will allow the professional a safer procedure, with fewer possibilities of complications and clinical failures, making aesthetic and functional results compatible satisfactorily.

Does Preoperative Vascular Mapping Using Color-Doppler Ultrasound have a Role in the Success of Axial Nasolabial Flap?

Does Preoperative Vascular Mapping Using Color-Doppler Ultrasound have a Role in the Success of Axial Nasolabial Flap?

Preoperative mapping and multidisciplinary team are the key to success of arteriovenous access for hemodialysis

Introduction and objectivesFunctional and durable vascular access is needed for adequate hemodialysis. Arteriovenous fistula is preferred over prosthetic grafts or central venous catheters, but it is associated with high rates of primary failure and maturation failure.Preoperative mapping of arm vessels with color Doppler ultrasound (CDU) has been shown to be helpful in achieving better short and long-term outcomes. Unfortunately, is more time-consuming than a physical examination and requires an experienced examiner and special equipment; some authors defend that CDU should not be part of the routine preoperative assessment.We reported our experience in preoperative vessel mapping using color Doppler ultrasound to purpose a vascular access to the surgical team, surveillance of vascular access, and evaluation of main outcomes (primary failure, maturation failure, and patency). MethodsThis is a single-center retrospective study that includes patients who attended a specific appointment for vascular access planning consultation between January 2019 and December 2021. A nephrologist performed the physical exam and vascular mapping and proposed to the vascular surgeon team a specific type and location of vascular access. Patients were followed until one month after the first hemodialysis through functioning vascular access. ResultsIn this study, 167 patients were evaluated (114 incident patients – chronic kidney disease stage 4 or 5 – and 53 prevalent patients – under hemodialysis through central venous catheter). The vascular accesses proposed by nephrologist were radial-cephalic arteriovenous fistula in 70 patients (41.9%), brachio-cephalic arteriovenous fistula in 50 patients (29.9%), brachio-basilic arteriovenous fistula in 34 patients (20.4%), arteriovenous graft in 8 patients (4.8%) and central venous catheter in 2 patients (1.2%).Vascular access was constructed in 141 patients: distal arteriovenous fistula in 57 patients (40.4%), brachio-cephalic arteriovenous fistula in 54 patients (38.3%), brachio-basilic AVF in 27 patients (19.1%), and arteriovenous graft in 3 patients (2.1%). The created access corresponds to the proposed access in 129 patients (91.5%).Twenty-two (15.6%) primary failures were registered. Distal arteriovenous fistulas and diabetes mellitus were associated with a higher risk of primary failure (OR=3.929 (1.485–10.392), p=0.004; OR=3.867 (1.235–12.113), p=0.014, respectively).The incidence of maturation failure at eight weeks was 4.8%.The primary patency at 6, 12 and 24 months was 76.3%, 70.4% and 49.2%. Primary assisted patency was 84.8% at 6 and 12 months and 81.3% at 24 months. ConclusionsThis study demonstrates that the study of the entire vascular territory performed with color Doppler ultrasound, within a multidisciplinary team of nephrologists and vascular surgeons, is associated with high rates of autologous access and very low rates of primary failure and maturation failure (almost unprecedented in the literature).

Imaging the Uterus in Placenta Accreta Spectrum Disorder.

Antenatal diagnosis of placenta accreta spectrum (PAS) improves maternal and neonatal outcomes by allowing for multidisciplinary planning and preparedness. Ultrasound is the primary imaging tool. Simplification and standardization of placental evaluation and reporting terminology allows improved communication and understanding between teams. Prior to 10 weeks of gestation, gestational sac position and least myometrial thickness surrounding the gestational sac help PAS diagnosis very early in pregnancy. Late first-, second-, and third-trimester evaluation includes comprehensive evaluation of the placenta, transabdominal and transvaginal with partially full maternal urinary bladder, and by color Doppler. Subsequently, the sonologist should indicate whether the evaluation was optimal or suboptimal; the level of suspicion as low, moderate, or high; and the extent as focal, global, or extending beyond the uterus. Other complementary imaging modalities such as 3D-power Doppler ultrasound, magnetic resonance imaging (MRI), and vascular topography mapping strive to improve antenatal placental evaluation but remain investigational at present. KEY POINTS: · Antenatal imaging, primarily using ultrasound with partially full maternal urinary bladder, is an essential means of evaluation of those at risk for PAS.. · Simplification and standardization of placental evaluation and reporting will allow improved communication between the multidisciplinary teams.. · Gestational sac location prior to 10 weeks of gestation and four markers after that (placental lacunae and echostructure, myometrial thinning, hypoechoic zone with or without bulging between placenta and myometrium, and increased flow on color Doppler)..

Lower extremity pseudoaneurysms and their interventional radiological management: a pictorial review.

Lower extremity pseudoaneurysms (PsAs) are mostly developed after traumatic or iatrogenic injury to the arteries. Unless treated, they can be complicated by adjacent mass effects, distal embolism, secondary infection, and rupture. Imaging helps in the diagnosis and planning of therapeutic intervention. Ultrasonography (USG) is often diagnostic, while CT angiography aids in vascular mapping required for intervention. Image-guided therapy offers to manage these pseudoaneurysms in a minimally invasive approach, obviating the need for surgery. A smaller, superficial, and narrow-necked PsA can easily be managed with local USG-guided compression or thrombin injection. When the percutaneous approach is not a feasible option, PsA from expendable arteries can also be managed with coiling or glue injection. Wide-necked PsA from an unexpendable artery necessitates stent graft placement, although coiling of the neck may be a viable and cheaper alternative for a long- and narrow-necked PsA. Presently, vascular closure devices are also used to seal a small arterial rent through a direct percutaneous approach. This pictorial review entails various techniques to deal with lower extremity pseudoaneurysms. An idea about the various intervention radiological approaches will help in choosing appropriate methods to tackle lower extremity pseudoaneurysms.

#3866 PREOPERATIVE ASSESSMENT FOR VASCULAR ACCESS: VASCULAR MAPPING AND HANDGRIP STRENGTH

Abstract Background and Aims A reliable vascular access (VA) is required for patients receiving chronic hemodialysis (HD) treatment. VA choice is complex and must consider patient characteristics, predicted patency and risk of primary failure. Vascular mapping (VM) by duplex doppler ultrasonography (DUS) can aid in the planning of which VA to place. Peripheral artery disease (PAD) is associated with higher AVF failure and can be assessed by calculating the ankle-brachial index (ABI). Muscle strength is independently associated with mortality risk and can be evaluated with handgrip strength (HGS). This study aims to describe and analyze clinical anthropometric and laboratory characteristics of patients referred for vascular mapping prior to VA creation and to correlate VM data, HGS, and ABI. Method Prospective analysis of all adult patients with CKD who were referred for VM, at a tertiary center, between March 2021 and August 2021. No patients were excluded. Preoperative DUS by a single experienced nephrologist was carried out. HGS was measured using a Hand Dynamometer and PAD was defined as ABI&amp;lt;0.9. According to distal vasculature size (&amp;lt;2mm) sub-groups were analyzed. Results 80 patients were included and 67.5% were male, mean age 65.7 ± 14.7 years and 51.3% were on Renal Replacement Therapy (RRT). Twelve (15%) participants had PAD. HGS was higher in dominant arm (20.5 ± 12.0 kg vs 18.8 ± 11.2 kg). Fifty-eight (72.5%) patients had vessels smaller than 2 mm in diameter. There were no significant differences between groups concerning demographic and comorbidities (diabetes, PAD). HGS was significantly higher in patients who had vessels greater than or equal to 2 mm in diameter (26.1 ± 15.5 kg vs 18.4 ± 9.7 kg, p = 0.010). Conclusion Greater HGS was associated with more developed distal vessels. Low HGS might be an indirect sign of poor vascular characteristics, which might help predict the outcomes of VA creation and maturation.

#6037 VALUE OF ARTERIAL CALCIFICATION DETECTED BY UPPER LIMB DOPPLER ULTRASOUND IN ADVANCED CHRONIC KIDNEY DISEASE

Abstract Background and Aims Vascular calcification is a common complication of chronic kidney disease (CKD), particularly in end-stage-renal disease (ESRD) and is predictive of subsequent cardiovascular disease and mortality. The aim of the present study was to evaluate the relationship between arterial calcification assessed by doppler ultrasound (DUS) performed by the same observer and biochemical parameters of CKD-MBD as well as the standard-of-care therapy for CKD-MBD. Method We present a retrospective study of 454 patients who were evaluated by DUS for pre-surgical vascular mapping from 2018 to 2021. Both arms brachial, radial and cubital arteries were analyzed, and vascular calcification was classified as absent, mild or moderate/severe (presence of acoustic shadowing). Laboratory serum analysis of PTH, serum Calcium (sCa), serum phosphorous (sPi) and serum magnesium (sMg) were collected (with a maximum interval of 6 months from DUS evaluation). Mortality was also registered during follow-up period. Results The demographics and biochemistry of the study population are summarized in Table 1. Arterial calcification was observed in 91.6% (n = 416) of the patients, 62.3% (n = 259) had mild calcification and 37.7% (n = 157) presented moderate/severe calcification. In univariate analysis, male gender (OR 2.2, p &amp;lt; 0.023), age (OR 1.03, p &amp;lt; 0.003), phosphate binders (OR 0.55, p value &amp;lt; 0.03) and cinacalcet use (OR 0.28, p &amp;lt; 0.019) were independently associated with the presence of arterial vascular calcification. Presence of vascular calcification on DUS was associated to mortality. In patients with vascular calcifications, moderate/severe calcification was associated with diabetes mellitus (OR 2.85, p&amp;lt;0.000), male gender (OR 1.69, p &amp;lt; 0.012), PAD (OR 2.43, p &amp;lt;0.001) and hemodialysis therapy for more than 5 years (OR 3.00, p&amp;lt; 0.010). Cinacalcet, phosphate binders, serum calcium, phosphorous, PTH and mortality did not correlate with calcification severity. In the multivariate logistic regression analysis adjusted to age, gender, PAD and serum calcium and magnesium, we found that serum PTHi (OR 1.00, p&amp;lt;0.040), hemodialysis for more than one year (OR 4.44, p&amp;lt; 0.040) and diabetes mellitus (OR 3.95, p&amp;lt; 0.001) were associated with moderate/severe vascular disease. Conclusion Concerning CKD-MBD related markers our study showed that only phosphate binders and cinacalcet use were predictive of absence of vascular calcifications, however no causality could be advanced with these data. For serious calcification, in our multivariable model, only PTH had statistical significance. It is widely recognized the importance of monitoring serum PTH, calcium and Pi to reduce the adverse clinical events associated with CKB-MBD. Widespread implementation of DUS in pre-surgical mapping for VA construction is also an opportunity for vascular study and features as calcifications can be a surrogate of CKD-MBD and cardiovascular burden.

#5918 ENDOVASCULAR CREATION OF AN ARTERIOVENOUS FISTULA (ENDOAVF) FOR HEMODIALYSIS ACCESS: A RETROSPECTIVE MONOCENTRIC EXPERIENCE

Abstract Background and Aims Functioning vascular access is an essential element for life-saving hemodialysis therapy. Surgical creation of a radiocephalic arteriovenous fistula (AVF) is the gold standard of vascular access for hemodialysis. However an endovascular approach to arteriovenous fistula creation (endoAVF) has increasingly gained acceptance over the last years as an alternative to the conventional surgical method. It offers a minimally invasive method for the formation of arteriovenous shunts and allows the creation of fistulas with minimal vessel trauma. There are currently two technologies available for this purpose, the Ellipsys Vascular Access System (Medtronic, Avenu Medical, San Juan Capistrano, Calif) and the Wavelinq endoAVF System (BD Medical, Franklin Lakes, NJ). At our centre (Careggi University Hospital, Florence), we developed an integrated service, based on a multidisciplinary approach between Interventional Radiology and Interventional Nephrology for percutaneous arteriovenous fistulas utilizing both Ellipsys and Wavelinq. We describe our experience with a case series of 39 patients, showing feasibility and outcome of this treatment option. Method Between December 2020 and January 2023 we created an endoAVF in 39 patients. Patients were suitable for the procedure after a pre-therapeutic ultrasound vascular mapping showed adequate brachial, radial and ulnar vessels and no ipsilateral central venous stenosis. After procedure, we performed a regular clinical and ultrasound monitoring. Therefore, we collected data regarding patient characteristics, initial technical success rate, number of access lost and number of endoAVF meeting primary and secondary patency. Results Of the total of 39 patients treated with endoAVF, 29 (74.3%) were male, with a mean age of 60.1 ± 33.9 years. The Wavelinq procedure was performed in 32 patients (82.0%) and the Ellipsys procedure in 7 patients (17.9%). Initial technical success was achieved in 38 (97.4%) cases, while in 1 case we had a primary failure of the fistula (Figure 1). Among these 38 patients, 4 (10.5%) were lost to follow-up because of death from other causes (3 patients) and because of kidney transplantation (1 patient), while 2 other patients (5.2%) have not required hemodialysys yet. Of the remaining 32 patients, we had 2 fistulas lost because of complications and a cumulative functional patency of 93.7% (30 fistulas), with a primary patency rate of 76% (23 fistulas). Conclusion The endoAVF appears to be feasible and safe for the creation of arteriovenous fistula suitable for hemodialysis access. Our data show an high functional cumulative patency of the endoAVF and a good primary patency, reducing the necessity of further interventions. Furthermore, in the prevalent hemodialysis population, the minimally invasive endovascular arteriovenous fistula procedure should help improving long wait times for vascular access creation. Further studies with more patients and multicentric data are needed to assess long-term outcomes.

#5029 PERCUTANEOUS ARTERIOVENOUS FISTULA CREATION: A DUBAI HOSPITAL EXPERIENCE

Abstract Background and Aims Targeting to improve the quality of care for chronic kidney disease patients (CKD) a non -surgical creation of native arteriovenous fistulae (AVF) with potentially cosmetic advantages, was offered for CKD patients in Dubai. The procedure started in January 2021 and the follow up continued till January 2023. The goal of this report is to share the original first experience in Dubai for this technique using 4F WavelinQ EndoAVF System. Method Fourteen patients underwent sonographic vascular mapping for endovascular AVF creation using 4F WavelinQ EndoAVF System. Nine patients were deemed suitable for Endovascular AVF creation and underwent the procedure under regional anaesthesia. Concomitant ulnar artery and ulnar vein or the concomitant radial artery and radial vein was used for the procedure. Results In this case series, the patients have a mean age of 53 ± 17 years, majority of the cases were men (77.8%). All cases were hypertensives (100%) with 2 cases(22.2%) have biopsy proven Glomerulonephritis and 5 cases (55.5%) were diabetics. The technique succeeded (defined by blood flow from used artery to concomitant deep vein and through perforator vein to superficial vein) in all patients (100%). Maturation success (defined as estimated fistula flow rates exceeded 500 mL/min and access vessel diameter was more than 4 mm) with multiple venous outflows was achieved in 8 cases (88.1%). One case (11.1%) showed primary maturation failure. Five cases (55.5%) achieved successful cannulation with excellent blood flow and reliable arterial and venous pressure during dialysis. Time to maturation was 35 ± 17 days and time to successful cannulation averaged 63 ± 45 days. Among patients achieving maturation success, one patient requested AVF closure (using coil embolization) due to mild to moderate upper limb oedema that required reintervention, one case underwent pre-emptive kidney transplantation and did not require to use the AVF and one patient refused using the AVF. In our study 3 cases (33.3%) required reintervention to facilitate maturation. It worth mention that among the 3 cases underwent reintervention, one case requested closure of the fistula and one case refused to use the fistula and only one case of the successful cannulation group underwent single reintervention. Conclusion In our limited experience, AVF creation using Endovascular technique resulted in dependable haemodialysis access with reliable maturation time, achieving excellent patency in the successful cannulation group with high blood flow rate and accepted arterial and venous pressure during dialysis. It also showed that the procedure was safe with better cosmetic shape and no scars. However more studies with bigger sample size are needed for better evaluation of the technique and to confirm the endovascular AVF creation proper position in the guidelines for vascular access creation in haemodialysis.

#6848 DIABETES AND HEMODIALYSIS ARTERIOVENOUS ACCESS CONSTRUCTION – A RETROSPECTIVE STUDY IN A SINGLE CENTER

Abstract Background and Aims The preferred vascular access for patients with end-stage renal disease is native arteriovenous fistula (AVF). However, in some patients, given their co-morbidities, vascular access (VA) construction is not feasible. Diabetes Mellitus (DM) is described as one of the main factors associated with vascular access failure. The aim of this study is to characterize in a non-diabetic versus diabetic population the pre-surgical vascular mapping by doppler ultrasound (DUS), as well as analyze which VA could theoretically be constructed, what VA was effectively were constructed and its patency between the two groups. Method We present a retrospective study of a cohort of patients that were evaluated by DUS for pre-surgical planning and VA construction from 2018 to 2021. We collected demographic, clinical and DUS parameters. The feasibility for VA construction was classified in pre-surgical evaluation as possible, non-advisable or as borderline. The patency after surgery was observed until day 45. Results We analyzed a total of 355 patients. Almost half of the population had diabetes (n = 161, 45.4%). The demographics and clinical parameters are summarized in Table 1. Concerning pre-surgical vascular mapping, we observed that patients with diabetes had more severe calcifications than the non-diabetic group. Table 2 summarizes the doppler characteristics of right and left radial and brachial arteries in both groups. Regarding the feasibility of VA construction, the non-diabetic group was more likely to receive a radiocephalic fistula than the diabetic group (33% vs 23.6%, pvalue 0.12). Surprisingly, in our study the non-diabetic group had also more patients that could only sustain a prosthetic fistulas (15.5% vs 12.4%, pvalue 0.41). Diabetic patients showed more likelihood to construct proximal fistulaes (67.4% vs 56.8%, p = 0.06). In terms of what type of VA was effectively created, more radiocephalic fistulas were performed in the non-diabetic group (13.95% vs 7.5%, pvalue 0.17). In the diabetic group more brachiocephalic fistulas (65.6% vs 62.4%, pvalue 0.17) and more prosthestic fistulaes (19.4% vs 14.4%, pvalue 0.17) were constructed. Concerning VA patency at 45 days the diabetic group demonstrated higher rates but with no statistical significance (88.4% vs 83.2%, pvalue &amp;lt; 0.18). Only arterial hypertension, showed to be predictive for VA patency, in the univariate and multivariate analysis that included age, sex, diabetes and ethnicity (OR 0.3, pvalue &amp;lt;0.09 and OR 0.32, pvalue &amp;lt;0.019 respectively). Conclusion We found that diabetic patients had significantly more comorbidities (older age, obesity and peripheral artery disease). Regarding the construction of a VA, in diabetic patients there was a lower probability of creating a radiocephalic fistula but a similar possibility of constructing a proximal fistula. Besides that, after VA construction, no differences were found between the two groups in terms of vascular patency. Although diabetes status reduced the probability for radiocephalic fistulas, once VA construction was successful no differences in VA survival at 45 days was verified.

Preoperative visualization of midline-crossing subcutaneous arteries in transverse abdominal flaps using photoacoustic tomography

Photoacoustic tomography is a noninvasive vascular imaging modality that uses near-infrared pulsed laser light and ultrasound to visualize vessels. We previously demonstrated the utility of photoacoustic tomography for anterolateral thigh flap surgery involving body-attachable vascular mapping sheets. However, it was not possible to obtain clear separate images of arteries and veins. In this study, we tried to visualize subcutaneous arteries that cross the midline of the abdomen, since these arteries are known to be important for obtaining large perfusion areas in transverse abdominal flaps. Four patients scheduled to undergo breast reconstruction with abdominal flaps were examined. Photoacoustic tomography was performed preoperatively. The tentative arteries and veins were traced according to the S-factor, an approximate hemoglobin oxygen saturation parameter calculated using 2 laser excitation wavelengths (756 and 797nm). Intraoperatively, arterial-phase indocyanine green (ICG) angiography was performed after abdominal flap elevation. Images of vessels speculated to be arteries by preoperative photoacoustic tomography were merged with those of intraoperative ICG angiography and analyzed in an 8×4-cm2 area below the umbilical region. The S-factor was used to visualize the midline-crossing subcutaneous arteries in all 4 patients. A matching analysis compared preoperative tentative arteries according to photoacoustic tomography with ICG angiography results in the 8×4-cm2 area below the umbilical region and indicated a 71.3-82.1% match (average: 76.9% match). This study demonstrates that the S-factor, a noninvasive, label-free imaging modality, can be used to successfully visualize subcutaneous arteries. This information can aid in selecting perforators for abdominal flap surgery.