Preoperative Vascular Mapping Research Articles

#858 The efficacy of preoperative ultrasound mapping prior to arteriovenous fistula creation: a meta-analysis and systematic review

Abstract Background and Aims Current literature presents conflicting evidence regarding the benefits of Color Doppler Ultrasound (DUS) in the preoperative vascular mapping of arteriovenous fistula (AVF) for haemodialysis. Thus, we conducted a systematic review and meta-analysis of RCTs to evaluate differences in primary AVF failure between patients randomly assigned to routine preoperatory DUS and those randomly assigned to physical examination assessment alone or combined with DUS when physical examination provides limited information. Method We systematically searched PubMed, Google Scholar, Web of Science, and Scopus databases from their inception to November 30, 2023. The accessible text search terms were: “fistula” AND “arteriovenous” AND “dialysis” OR “haemodialysis” AND “Doppler” OR “ultrasound” OR “ultrasonography” AND “preoperative” OR “perioperative” OR “mapping”. No language restriction was applied. We also reviewed references from original papers and review articles to identify additional suitable studies not covered by our original database searches. Exclusion criteria were: (1) meeting abstracts, case reports, reviews, practice guidelines, case-control or cross-sectional or longitudinal studies; (2) RCTs that did not report any estimates of the outcomes of interest; (3) RCTs conducted in the paediatric population (<18 years of age). Two authors independently extracted data from eligible RCTs. Disagreements at this level were resolved by consensus and a third author if needed. The outcome was categorized into three groups: primary AVF failure within 48 hours, within six weeks or 40 months from the vascular procedure. AVF Failure was defined as intraoperative inadequate vessels, incomplete surgical procedure, absence of thrill, thrombosis detection, AVF unsuitability for cannulation at 90 days, inability to achieve Qb 200-300 ml/min at six months, or lack of maturation at 40 months. Statistical analysis was performed using STATA 17.0 software with the metanalysis package and R (version 4.2.2.) for all statistical analyses. This study was performed according to the updated Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Results We included 6 RCTs involving 802 patients. Fig. 1 summarizes the results of the literature search and study selection. Table 1 shows the main clinical characteristics of RCTs. Compared to controls, the use of routine preoperative DUS was associated with a reduction in the risk of AVF failure within 48 hours [5 RCTs; OR 0.27, confidence interval 95% 0.16-0.45 for the common effect model (CEM); OR 0.27, CI 95% 0.16-0.46 for the random effects model (REM), no heterogeneity (I2 = 0%)]; within six weeks [2 RCTs (OR 0.33, CI: 95% 0.18-0.61 for CEM, and OR 0.34, CI 95% 0.18-0.63 for REM with I2 = 0%]; and within 40 months [4 RCTs, OR 0.51, CI 95% 0.35-0.75 for CEM; and OR 0.51, CI 95% 0.35-0.76 for the REM, with I2 = 0%] from surgical intervention (Figs 2–4). Conclusion Routine use of DUS in preoperative vascular mapping improves the survival AVF in the immediate to 40 months post-surgery, compared to relying solely on physical examination or using DUS only in cases of insufficient physical examination.

#806 Predicting arteriovenous fistula success using ferumoxytol-enhanced MRI (Fe-MRI) and computational flow dynamics (CFD)

Abstract Background and Aims Arteriovenous fistula (AVF) failure is common and is invariably associated with preexisting anatomic problems of the inflow and outflow circuit. Ferumoxytol, an iron oxide nanoparticle, provides a safe alternative to gadolinium contrast material for MR angiography in chronic kidney disease (CKD). Computational fluid dynamics (CFD) has been utilised to virtually demonstrate the haemodynamics within AVFs using high-quality vascular mapping obtained with ferumoxytol-enhanced MRI (Fe-MRI). Using Fe-MRI and CFD we aimed to assess AVF haemodynamics and identify flow patterns and geometries associated with AVF success. Method In this pilot study we used Fe-MRI datasets of CKD patients who had vascular mapping 6 weeks after AVF creation. Using CFD methods we performed vessel segmentation to construct three-dimensional (3D) patient-specific geometries from images obtained with Fe-MRI (Fig. 1). We then completed a detailed CFD analysis for each AVF geometry to establish the associations of haemodynamic (mean wall shear stress (WSS), oscillatory shear index (OSI), blood flow velocity, and areas of abnormal flow) and anatomical parameters (anastomosis angle, feeding artery diameter, feeding artery curvature, draining vein diameter, and draining vein curvature) with AVF outcomes. The primary outcome was AVF success defined as AVF use (assisted or unassisted) for dialysis for a minimum of 3 months. ROC analysis was used to assess anatomical predictors of AVF flows of ≥1000 ml/min. Results The study included 17 patients with CKD who had AVF creation between 2018 and 2020. From these, 13 AVFs were successfully used for dialysis and 4 failed to mature or were used for dialysis for <3 months before failure. Compared to failed fistulas, successful AVFs had higher mean WSS and OSI. Failed AVFs were characterised by different haemodynamic patterns including lower flow rates with less helical flows. On ROC analysis the three metrics with the highest area under the curve (AUC) values were the feeding artery curvature (0.82), feeding artery diameter (0.76), and draining vein diameter (0.74) with a combined AUC value of 0.83 (Fig. 2). Conclusion Using Fe-MRI and CFD in the post-surgical juxta-anastomotic environment higher mean WSS and OSI were predictive of AVF success. In addition, the feeding artery curvature, feeing artery and draining vein diameters are strongly correlated with high venous flow rates, one of the key factors of AVF success. Although vessel diameters are routinely measured as part of pre-operative vascular mapping, a greater emphasis should be given on mean WSS, OSI and feeding artery vessel curvature when selecting vessels for AVF creation.

Elevated Leukocyte Glucose Index Is Associated with Long-Term Arteriovenous Fistula Failure in Dialysis Patients.

(1) Background: Arteriovenous fistula (AVF) is the preferred type of vascular access for dialysis in patients with end-stage kidney disease (ESKD). However, the primary patency of AVF at one year is under 70% due to several risk factors and comorbidities. Leukocyte glucose index (LGI), a new biomarker based on blood leukocytes and glucose values, has been found to be associated with poor outcomes in cardiovascular disease. The aim of this study is to analyze the impact of LGI on the long-term primary patency of AVF following dialysis initiation. (2) Methods: We conducted a retrospective observational study in which we initially enrolled 158 patients with ESKD admitted to the Vascular Surgery Department of the Emergency County Hospital of Targu Mures, Romania, to surgically create an AVF for dialysis between January 2020 and July 2023. The primary endpoint was AVF failure, defined as the impossibility of performing a chronic dialysis session due to severe restenosis or AVF thrombosis. After follow-up, we categorized patients into two groups based on their AVF status: "functional AVF" for those with a permeable AVF and "AVF failure" for those with vascular access dysfunction. (3) Results: Patients with AVF failure had a higher prevalence of atrial fibrillation (p = 0.013) and diabetes (p = 0.028), as well as a higher LGI value (1.12 vs. 0.79, p < 0.001). At ROC analysis, LGI had the strongest association with the outcome, with an AUC of 0.729, and an optimal cut-off value of 0.95 (72.4% sensitivity and 68% specificity). In Kaplan-Meier survival analyses, patients in the highest tertile (T3) of LGI had a significantly higher incidence of AVF failure compared to those in tertile 1 (p = 0.019). Moreover, we found that patients with higher baseline LGI values had a significantly higher risk of AVF failure during follow-up (HR: 1.48, p = 0.003). The association is independent of age and sex (HR: 1.65, p = 0.001), cardiovascular risk factors (HR: 1.63, p = 0.012), and pre-operative vascular mapping determinations (HR: 3.49, p = 0.037). (4) Conclusions: In conclusion, high preoperative values of LGI are positively associated with long-term AVF failure. The prognostic role of the biomarker was independent of age, sex, cardiovascular risk factors, and pre-operative vascular mapping determinations.

Creating hemodialysis autogenous access in children and adolescents

ObjectiveEnd-stage renal disease (ESRD) in childhood and adolescence is rare, with relatively few published reports of pediatric ESRD vascular access. This study analyzes a 10-year experience creating arteriovenous fistulas (AVFs) in children and adolescents. Our goal is to review our strategy for creating functional autogenous vascular access in younger patients and report our results. MethodsWe retrospectively reviewed data and outcomes for consecutive vascular access patients aged ≤19 years during a 10-year period. Each patient had preoperative vascular ultrasound mapping by the operating surgeon in addition to physical examination. A distal forearm radiocephalic AVF was the first access choice when feasible, and a proximal radial artery inflow AVF was the next option. Demographic data, inflow artery, venous outflow target, and required transposition vs direct AVFs were variables included in the analysis. Primary and cumulative patency were calculated by Kaplan-Meier analysis. ResultsThirty-seven AVFs were created in 35 patients. No grafts were used. Ages were 6 to 19 years (mean, 15 years), and 20 were male. Causes of ESRD included glomerular disease (n = 18) and urinary obstruction or reflux (n = 7), among others. Three had previous AVFs, and 10 were obese. The proximal radial artery supplied AVF inflow in 25 patients and the brachial artery in only seven. Eleven individuals required a transposition and one a vein translocation to the contralateral arm. No patients developed hand ischemia, although two later required banding procedures for high flow. Eleven patients had successful transplants. A single patient died, unrelated to the vascular access. Five AVFs failed. Of these, two had new successful AVFs created, two regained renal function, one was transplanted, and one declined other procedures. Primary and cumulative patency rates were 75% and 85% at 12 months, 70% and 85% at 24 months, and 51% and 85% at 36 months, respectively. Median follow-up was 16 months. ConclusionsCreating an AVF for hemodialysis is a successful vascular access strategy for pediatric and adolescent patients. Proximal radial artery AVFs provided safe and functional access when a distal AVF was not feasible. Cumulative AVF patency was 85% at 36 months.

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.

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?

Revascularization of the Nipple-Areola Complex following Nipple-Sparing Mastectomy.

Preoperative vascular mapping has been demonstrated to be an excellent adjunct to perforator flap surgery by reducing operative times and enhancing surgical precision. This study evaluated the benefit of preoperative vascular mapping using magnetic resonance imaging and Doppler ultrasonography to identify the different perforators to the breast and compared it to postoperative mapping. The authors' intent was to determine whether preoperative knowledge of the various vascular sources to the nipple-areola complex affected the outcome and vitality of the nipple-areola complex. A prospective study was performed on 15 patients undergoing 25 nipple-sparing mastectomies for breast cancer or genetic predisposition. Ten patients underwent bilateral mastectomy, and five underwent unilateral mastectomy. Mean age was 52 years (range, 30 to 76 years). The mean patient body mass index was 22.4 kg/m2 (range, 20 to 35 kg/m2). Inclusion criteria consisted of breast cancer or genetic predisposition and grade 1 or 2 breast ptosis. Exclusion criteria included prior breast surgery, grade 3 ptosis, and gigantomastia. All patients underwent immediate direct-to-implant reconstruction. Preoperative vascular mapping by magnetic resonance imaging and external Doppler ultrasonography was performed in all 15 patients. In all 25 breasts, the fifth anterior intercostal artery perforator was identified preoperatively and preserved intraoperatively. Postoperative imaging demonstrated patency of the fifth anterior intercostal artery perforator vessels in all patients. Nipple-areola viability was demonstrated in all breasts. This study demonstrates that preoperative magnetic resonance imaging and Doppler ultrasonography for mapping breast perforator vessels is a useful strategy and should be considered for select patients undergoing nipple-sparing mastectomy. Identification of dominant perforators to the breast allowed mastectomy planning with preservation of the important perforator to the mastectomy skin flaps and nipple-areola complex. Therapeutic, IV.

Comparison of Hand-Held Doppler and Indocyanine Green Angiography in Preoperative Design of Expanded Forehead Flaps for Nasal Reconstruction.

Despite the different approaches for detection of perforators, methods of vascular mapping of the expanded forehead flap for nasal reconstruction are rarely described. This article aimed to present our experience in the preoperative design of the expanded forehead flap for nasal reconstruction and to compare the clinical practice of hand-held Doppler and indocyanine green angiography (ICGA) in vascular mapping for nasal reconstruction with the expanded forehead flap. From October 2019 to April 2022, 26 patients underwent nasal reconstruction using expanded forehead flap. The authors performed preoperative vascular mapping on 16 patients by hand-held Doppler alone, and on 10 patients by hand-held Doppler and ICGA primary outcomes considered were the visualization of the main vascular course of the flap obtained by hand-held Doppler or ICGA, intraoperative observation of the flap, and its postoperative complications. Indocyanine green angiography provides a better detection in distal flap and the branches of the supratrochlear artery. Vein detection by ICGA generally corresponds to the results obtained by the combination of hand-held Doppler and transillumination test. In the group that only used hand-held Doppler, 2 patients presented hemodynamic complications in the margin of the flap and 1 patient presented partial necrosis postoperatively. No complication was found in the group that used ICGA. It is recommended to use the ICGA for preoperative planning, as it yields highly accurate vascular courses. As an alternative to other methods, hand-held Doppler is also an effective tool. IV.

Selective Angiographic Flat Detector Computer Tomography Blood Volume Imaging in Pre-Operative Vascular Mapping and Embolization of Hypervascular Intracranial Tumors-Preliminary Clinical Experience.

Pre-operative embolization of hypervascular intracranial tumors can be performed to reduce bleeding complications during resection. Accurate vascular mapping of the tumor is necessary for both the correct indication setting for embolization and for the evaluation of the performed embolization. We prospectively examined the role of whole brain and selective parenchymal blood volume (PBV) flat detector computer tomography perfusion (FD CTP) imaging in pre-operative angiographic mapping and embolization of patients with hypervascular intracranial tumors. Whole brain FD CTP imaging with a contrast injection from the aortic root and selective contrast injection in the dural feeding arteries was performed in five patients referred for tumor resection. Regional relative PBV values were obtained pre- and post-embolization. Total tumor volumes with selective external carotid artery (ECA) supply volumes and post-embolization devascularized tumor volumes were determined as well. In all patients, including four females and one male, with a mean age of 54.2 years (range 44–64 years), the PBV scans were performed without adverse events. The average ECA supply was 54% (range 31.5–91%). The mean embolized tumor volume was 56.5% (range 25–94%). Relative PBV values decreased from 5.75 ± 1.55 before embolization to 2.43 ± 1.70 post-embolization. In one patient, embolization was not performed because of being considered not beneficial for the resection. Angiographic FD CTP imaging of the brain tumor allows 3D identification and quantification of individual tumor feeder arteries. Furthermore, the technique enables monitoring of the efficacy of pre-operative endovascular tumor embolization.

MO773: The Impact of the Time on Dialysis and Kidney Transplantation on Arterial Ultrasound Characteristics

Abstract BACKGROUND AND AIMS Vascular accesses (VA) are essential for efficient haemodialysis and preoperative vascular mapping through ultrasound (US) may help surgical planning and improve its outcomes. Several factors can affect vascular quality, hampering the decision about which access to create and affecting VA patency and complications. Our study aims to identify the impact of time on dialysis and/or kidney transplantation in arterial US characteristics. METHOD Retrospectively, we analysed a cohort of patients with chronic kidney disease in whom a US vascular mapping was performed for preoperative planning of dialysis access from 2018 to 2019. Besides demographical characteristics, patients were characterized regarding the presence of diabetes, hypertension, vascular disease (including coronary, cerebrovascular, or peripheral arterial disease), obesity and smoking (present or past). Vascular indicators were analysed by Doppler US of the arteries in both upper arms, particularly the radial and brachial arteries. Arterial indicators analysed included mean diameter and peak wave velocity (PWV), doppler waveform (mono, bi or triphasic) and calcification on both arms (on a score of 0 to 6). Patients were divided into three groups regarding whether they had not been transplanted and/or started dialysis (group 1), or if one or both conditions were positive for ˂ 5 years (group 2), or 5 or ≥years (group 3). Appropriate tests were applied recurring to SPSS v21.0. RESULTS A total of 153 patients were included. The mean age was 64.54 ± 16 years, 80 (52.3%) were male, 124 (81.0%) were white, 27 (17.6%) were black and 2 (1.3%) were Asian. Most patients had hypertension (138, 90.2%), 70 (45.8%) had diabetes, 59 (38.6%) had arterial disease, 36 (23.5%) were smokers and 45 (29.4%) were obese. The majority of patients were attending for the first vascular access (102, 66.7%). Regarding time since dialysis and/or kidney transplant, most patients were on group 1 (91, 59.5%), 46 (30.1%) were on group 2 and 15 (9.8%) were on group 3. We found that there was a statistically significant correlation between the time since initiation of dialysis and/or kidney transplantation and radial and ulnar mean PWV (P-value 0.004 and 0.004, respectively), but not with their mean diameters. Moreover, this correlation was valid for radial mean PWV between patients on group 1 and group 3 (P-value 0.006, CI 95% 3.88–28.57), and for ulnar mean PWV between patients on group 1 and group 3 (P-value 0.003, CI 95% 6.06–34.69) and between group 2 and group 3 (P-value 0.022, CI 95% 2.02–32.45). No statistically significant correlation was found between the time since kidney transplantation and/or dialysis was started and vascular calcification. CONCLUSION Our results show that patients who have been transplanted and/or started dialysis for 5 or more years (and, in the case of ulnar mean PWV, for ˂ 5 years too) have lower radial and ulnar mean PWV than patients who did not. Moreover, there is no statistically significant difference in radial and ulnar mean diameters and calcification between these groups. End-stage kidney disease (ESRD) is associated with peripheral arterial disease, which has a great impact on patients’ morbidity and mortality and is mainly a manifestation of atherosclerosis. Besides the traditional risk factors, like hypertension or diabetes, some non-traditional risk factors contribute to the high prevalence of PAD in ESRD, like oxidative stress or uraemic retention solutes. Pathologically, this is usually associated with media thickness increase and media calcification. In this study, this phenomenon can be demonstrated by lower peripheral velocities, with less impact in calcification or arterial diameter. Furthermore, the arterial diameter should not be the sole US indicator when deciding which VA to create, especially in patients on dialysis or transplanted, since it does not reflect the changes in arterial flux that results from several cardiovascular changes.

A Lucky Case of Successful Free Fibula Osteocutaneous Flap Harvest in Peronea Arteria Magna.

The free fibula flap (FFF) is based on the peroneal artery (PA) system, and it is well known that several anatomical variations of the lower limb vascular system exist, including peronea arteria magna (PAM). PAM is a rare congenital variation in which both anterior tibial artery and posterior tibial artery are either aplastic or hypoplastic, and as a result, PA will be the dominant blood supply to the foot. This variation was described as type III-C in Kim-Lippert's Classification of the Infra-Popliteal Arterial Branching Variations. The awareness of its existence is crucial as it often precludes FFF from being harvested due to the risk of significant limb ischemia and limb loss. Despite some literature reporting donor site complications and impending limb loss following FFF harvest in PAM, preoperative vascular mapping before FFF transfer remains controversial among the microsurgeons. We present a case with an incidental intraoperative finding of PAM that had a successful FFF harvest by luck, without preoperative vascular mapping.

Midterm results of arteriovenous fistula patency at Dong Nai General Hospital

Background: End-stage renal disease (ESRD) has dramatically increased in number and hemodialysis remains the main therapy. Arteriovenous fistula plays a critical role for dialysis patients. &#x0D; Materials and Methods: We retrospectively reviewed the medical records of AVF operated in Dong Nai General Hospital (between 09/2017 and 08/2020). Outcomes were compared between two groups: With and without preoperative vascular lập bản đồ to assess the role of this method. Learning curves were analyzed based on the trend of mean operative time and surgical success rate over time, and the number of operations required to overcome the learning curve was calculated with the CUSUM method. &#x0D; Results: The study group consisted of 158 patients, with a mean age of 54.76 ± 26. Male/ female rate was nearly 1:1. Short-term outcomes: Success rate was 87.3%, failure rate was 12.7%, reoperation rate was 7.6%. At 3 months, 6 months, and 9 months follow–up, the AVF patency was 86.70%, 84.18%, and 80.38%, respectively. Vascular lập bản đồ has a better trend of the short-term outcome (83.8% vs. 90.4%; P = 0.231), as well as AVF patency at 3 months, 6 months, 9 months (83.54% vs. 89.87%; P = 0.174), (79.75% vs. 88.61%; P = 0.066) and (75.95% vs. 84.08%; P = 0.077), respectively. However, the difference was not significant. In case of preoperative vascular lập bản đồ, the number of operations required to overcome the learning curve was 75 cases. &#x0D; Conclusion: Arteriovenous fistula surgery at Dong Nai General Hospital has a good short term and mid-term outcome. Preoperative vascular mapping seemed to improve the outcomes.

Feasibility of Creation of an Endovascular Arteriovenous Fistula in Patients Undergoing Preoperative Vascular Mapping.

The first endovascular arteriovenous fistula (endoAVF) device (WavelinQ), a novel percutaneous technique of AVF creation, was approved by the Food and Drug Administration in 2018 and has been placed in a small number of United States patients on hemodialysis. It is unknown how often patients with advanced CKD have vascular anatomy suitable for WavelinQ creation. The goal of this study was to determine the proportion of patients with vascular anatomy suitable for WavelinQ creation and to assess patient characteristics associated with such suitability. All patients referred for vascular access placement at a large academic medical center underwent standardized preoperative sonographic vascular mapping to assess suitability for an AVF. During a 2-year period (March 2019 to March 2021), we assessed the suitability of the vessels for creation of WavelinQ. We then compared the demographic characteristics, comorbidities, and vascular mapping measurements between patients who were or were not suitable for WavelinQ. During the study period, 437 patients underwent vessel mapping. Of these, 51% of patients were eligible for a surgical AVF, and 32% were eligible for a WavelinQ AVF; 63% of those suitable for a surgical AVF were also suitable for a WavelinQ AVF. Patients with a vascular anatomy suitable for WavelinQ were younger (age 55±15 versus 60±14 years, P=0.01) but similar in sex, race, diabetes, hypertension, coronary artery disease, and peripheral artery disease. Among patients with CKD with vascular anatomy suitable for a surgical AVF, 63% are also suitable for a WavelinQ endoAVF. Older patients are less frequently suitable for WavelinQ.

Midterm results of arteriovenous fistula patency at Dong Nai General Hospital

Background: End-stage renal disease (ESRD) has dramatically increased in number and hemodialysis remains the main therapy. Arteriovenous fistula plays a critical role for dialysis patients. &#x0D; Materials and Methods: We retrospectively reviewed the medical records of AVF operated in Dong Nai General Hospital (between 09/2017 and 08/2020). Outcomes were compared between two groups: With and without preoperative vascular lập bản đồ to assess the role of this method. Learning curves were analyzed based on the trend of mean operative time and surgical success rate over time, and the number of operations required to overcome the learning curve was calculated with the CUSUM method. &#x0D; Results: The study group consisted of 158 patients, with a mean age of 54.76 ± 26. Male/ female rate was nearly 1:1. Short-term outcomes: Success rate was 87.3%, failure rate was 12.7%, reoperation rate was 7.6%. At 3 months, 6 months, and 9 months follow–up, the AVF patency was 86.70%, 84.18%, and 80.38%, respectively. Vascular lập bản đồ has a better trend of the short-term outcome (83.8% vs. 90.4%; P = 0.231), as well as AVF patency at 3 months, 6 months, 9 months (83.54% vs. 89.87%; P = 0.174), (79.75% vs. 88.61%; P = 0.066) and (75.95% vs. 84.08%; P = 0.077), respectively. However, the difference was not significant. In case of preoperative vascular lập bản đồ, the number of operations required to overcome the learning curve was 75 cases. &#x0D; Conclusion: Arteriovenous fistula surgery at Dong Nai General Hospital has a good short term and mid-term outcome. Preoperative vascular mapping seemed to improve the outcomes.

Assessment of Duplex Ultrasound Carried Out by the Vascular Surgeon After Locoregional Anesthesia for Preferred Arteriovenous Fistula Access

Preoperative vascular mapping by duplex ultrasound is required in construction of an arteriovenous fistula for hemodialysis (AVF). Due to venous vasospasm in cool temperatures and variability of the dialysis patient's blood volume, the conditions for performing this examination may be less than ideal. However, local regional anesthesia (LRA) resulting in vasodilation of the limb, can allow the use of veins considered to be of insufficient caliber during preoperative ultrasound mapping. The aim of this study was to assess the functionality of AVF when duplex ultrasound is performed by the surgeon following LRA. These results were compared with those from the preceding year, during which preoperative duplex ultrasound had been performed without LRA by vascular specialists, (Clinical Trial registration number: NCT04978155). This is a prospective study of all the patients having received AVF after systematic immediate preoperative ultrasound (US) under LRA (US-LRA group) in 2020. The initial surgical programming based on the Silva criteria was reported by a vascular medicine specialist. The change of AVF strategy following US-LRA was reported together with AVF usability and patency and compared to the results of the control group, in which AVF had been performed in 2019 without US-LRA. Ninety patients were included in the US-LRA group and 93 in the control group. Modified surgical planning was observed in 38% of cases (35/90) in the US-LRA group including more distal AVF in 28% of patients (26/90) and alternative target vein in 6.6% (6/90). AVF usability at 6 weeks was 80% (72/90) in the US-LRA group and 51.6% (48/93) in the control group (P < 0.001). Median follow-up was 12 months [IQR:9-15] in the US-LRA group and 13 months [IQR:9-18] in the control group. Primary patency at 6, 12, 18 months was significantly better in the US-LRA group (73.6% vs. 57.4%, 54.4% vs. 40.2%, 31.3% vs. 28.2%, respectively, P < 0.001). Assisted patency and secondary patency were comparable in the two groups. This study showed the benefit of having the surgeon perform US-LRA before starting the procedure, thereby allowing for more distal AVF, better usability and patency.

MO773THE VASCULAR REALITY BEHIND ULTRASOUND VASCULAR MAPPING: WHICH FACTORS PREDICT THE BEST CANDIDATES FOR RADIOCEPHALIC ARTERIOVENOUS FISTULA?

Abstract Background and Aims Vascular accesses (VA) are key components for efficient hemodialysis. Arteriovenous fistulas (AVF) are recommended over arteriovenous graft (AVG), but deciding the type and location of a VA is challenging. Preoperative vascular mapping before surgical creation of VA, especially trough ultrasound (US), is helpful in this decision, contributing to improve AVF e AVG outcomes. Our study aims to identify patient factors associated with appropriate arterial US parameters that predict feasibility for radiocephalic fistula creation. Method We analyzed a cohort of chronic kidney disease patients who underwent US vascular mapping for preoperative planning of dialysis access from 2019 to 2020, in a tertiary referral center. Patients were characterized based on its demographical characteristics, and the presence of diabetes, hypertension, obesity, and smoking. Arterial indicators were analyzed by ultrasound techniques in both upper arms, including radial, ulnar and brachial arteries. Those indicators included arterial diameter, calcification, doppler wave form, and pulse wave velocity. Continuous variables were recorded as means (±SD) for normally distributed data and as medians (interquartile ranges) for nonnormally distributed data. Comparisons were made using t tests or Wilcoxon rank sum tests as appropriate. Categorical variables were examined by frequency distribution and recorded as proportions. Comparisons were made using the x2 test. Unadjusted and adjusted multivariate logistic regression models were fitted to identify predictors for a good candidate for radiocephalic arteriovenous fistula. Results A total of 252 patients were included. The mean age was 65±16 years, 144 (57%) were male, 211 (84%) where white, 40 (16%) were black, and 1 (0.4%) was asian. Most had arterial hypertension (205, 81%), 98 (39%) had diabetes mellitus, 89 (35%) were smokers, and 72 (29%) were obese. The majority of patients were attending for the first VA (186; 74%). Most patients were considered appropriate candidates for arteriovenous fistula creation (207, 82%), whereas 45 (18%) were assigned to PTFE graft. Obesity and male sex were found to be predictors for being a good candidate for radiocephalic arteriovenous fistula in a multivariate logistic regression model adjusted for age, hypertension, and diabetes (OR 3.21, CI 95% 1.63-6.32, p-value 0.001 and OR 2.09, CI 95% 1.07-4.08, p-value 0.031, respectively). Figure 1 presents the arterial indicators analyzed during ultrasound mapping, including both upper limbs. Conclusion Our results show that obesity and male sex are predictors for radiocephalic arteriovenous fistula creation. While female sex has long been known to be a risk factor for VA failure, possibly because of worse arterial indicators, an association between obesity and higher probability of distal AVF creation has not been established yet. Comparison between arterial indicators in obese and nonobese patients shows that obese patients generally have better arterial indicators, especially higher pulse wave velocities, and less arterial calcification. Given that some studies show an association between obesity and shorter fistula survival (due to higher secondary failure rate), our results may come as. A possible explanation for this difference is that obesity may exert a physical protective effect of the forearm vascular bed against iatrogenic damage (blood sampling and vessel cannulation). Besides that, factors other than vascular indicators may contribute to ulterior VA failure, like the proinflammatory state in obese patients and its consequent myointimal hyperplasia. However, our conclusions are based on preoperative findings, and not on VA outcomes, especially its patency and complications. Moreover, which further help to determine the better location for a VA creation, were not evaluated in this study.

Cadaveric study of arterial renal anatomy and its surgical implications in partial nephrectomy.

Partial nephrectomy is gaining, nowadays, more interest in oncologic kidney surgery. This type of surgery requires the good knowledge of vascular renal anatomy to make it safe and to guarantee good functional and oncological outcomes. This paper exposes the clinical implication of the arterial renal anatomy in nephron-sparing surgery. This is a cadaveric study of 71 human kidneys performed at Charles Nicolle mortuary. The right and left kidneys with surrounding tissues were removed en bloc with the adjacent part of the aorta and inferior vena cava, cleared and studied. Colored resin was injected in each artery, vein, and urinary ducts, with a specific color code for each structure. Corrosion technique was used to eliminate the surrounding tissue, leaving only the colored resin matrix. The Ternon anatomic classification of the inferior polar artery, based on its emergence point was used. Multiple renal arteries were noted in 9.85% of casts. Anterior and posterior division of main renal artery was found in 95.7% of cases. Posterior segmental artery crossed posteriorly the upper caliceal infundibulum and the renal pelvis in 93% of cases. The upper renal pole was vascularized by an apical segmental artery in 16.9% of cases and a superior polar artery in one case (1.4%). The mid pole of the kidney was supplied by a unique anterior branch and a single posterior branch in 40% of cases. Inferior polar artery was found in 52 casts (73.23%). Type I of Ternon was found in 6 casts (11.53%), Type II in 25 cases (48.07%), Type III in 19 cases (36.53%), Type IV in 2 cases (3.84%), and type V in 13 casts (25%). Renal vascular anatomy presents large variations. Good knowledge of the segmental arterial anatomy of the kidney is a primordial to a safe partial nephrectomy. Good preoperative vascular mapping can be of great help for the surgeon.

Preoperative Vascular Mapping With Doppler Ultrasound—A Standardized Protocol in Vascular Access for Hemodialysis

Highlights Preoperative DU is recommended by international guidelines. Preoperative vascular mapping is of utmost importance for surgical planning. Standard protocols are needed to ensure reproducibility of methods and studies. We present our setting and describe in detail our standard protocol.

P1346PLANNING VASCULAR ACCESS CREATION FOR HEMODIALYSIS: IS THERE A ROLE FOR THE NEPHROLOGIST? A SINGLE-CENTER EXPERIENCE

Abstract Background and Aims Vascular access planning is a crucial step in the path to dialysis treatment. Although the vascular surgeon role is of undeniable importance on vascular access creation, the nephrologist’s view may be an added advantage on vascular access planning. Method A retrospective observational study of the vascular access appointments carried out at the Centro Hospitalar de Tondela-Viseu’s nephrology department between 1/1/2017 and 13/12/2019 was performed. Of the 173 consultations reviewed, 71 patients were referred to preoperative vascular mapping, which were selected. In those selected, 38 had a vascular access built. A descriptive and statistical analysis of the population and proposed vs constructed access was performed. Results Of those patients referred to the vascular access appointment for vessel mapping, the median age was 70 years, the majority were men (59.2%), most of them had Chronic Kidney Disease (CKD) stage 5 (57.7%) and most frequently had Diabetic Nephropathy (38.6%) or Chronic Glomerulonephritis (14.9%) as the cause of kidney disease. The majority were Diabetic (62%), Hypertensive (91.5%), Obese (63.4%) and had a history of stroke, coronary or peripheral arterial disease (63.4%). The vascular mapping was performed for creation of first access in 64.8% of the patients and the nephrologist most commonly proposed a radio-cephalic fistula (63.6%) as first line access creation, followed by brachio-cephalic (30.3%) and brachio-basilic (6%) fistulas. An arteriovenous graft was suggested in only 1 case and 4 patients were not referred to the vascular surgeon as they had no vascular patrimony to autologous vascular access creation. Regarding those patients who had already a vascular access at the time of this study (n=36), 58.33% coincided with the first line access suggested by the nephrologist. We found that the nephrologist most frequently proposed a brachio-basilic fistula in older patients (median age 77.5), while younger patients had proposed other fistulas (median age 77.5 years, p=0.031). Those patients without history of stroke, coronary or peripheral arterial disease had 4.57 times more odds of being proposed to a radio-cephalic fistula (p=0.007) and those with history of atherosclerotic events had 4.36 times more odds of being proposed for a brachio-cephalic fistula (p=0.003). Patients with more vascular calcification on the vessel mapping appointment had 7 times more odds of not being proposed for a distal fistula (p=0.000) and had instead 5.56 times more odds of being proposed to a brachio-cephalic fistula (p=0.003). Gender, etiology of CKD, smoking, diabetes, hypertension, heart failure and obesity were not significantly associated with vascular access proposed by the nephrologist. Conclusion In light of the results of this study, we conclude that there is an important place for ultrasound preoperative mapping by the nephrologist on planning the vascular access for haemodialysis.

Role of peribrachial fat as a key determinant of brachial artery dilatation for successful arteriovenous fistula maturation in hemodialysis patients

The functional quality of the inflow artery is one of the most important determinants of arteriovenous fistula (AVF) success. We evaluated the association of early optimal brachial arterial dilatation with a successful AVF maturation and assessed the role of peribrachial adipose tissue in determining brachial arterial distensibility. All patients underwent a preoperative vascular mapping with Doppler ultrasound (US), and only patients who had suitable vessels for AVF creation were enrolled (n = 162). Peribrachial fat thickness was measured using US. To evaluate the degree of brachial dilatation, follow-up US was performed at 1 month after surgery, and early brachial artery dilation was defined as the change in postoperative arterial diameter compared to the preoperative value. The primary outcome was failure to achieve a clinically functional AVF within 8 weeks. Nonfunctional AVF occurred in 21 (13.0%) patients, and they had a significantly lower brachial dilatation than patients with successful AVF during early period after surgery (0.85 vs. 0.43 mm, p = 0.003). Patients with a brachial dilatation greater than median level showed a 1.8-times higher rate of achieving a successful AVF than those without. Interestingly, the early brachial dilatation showed significant correlations with diabetes (r = −0.260, p = 0.001), peribrachial fat thickness (r = −0.301, p = 0.008), and the presence of brachial artery calcification (r = −0.178, p = 0.036). Even after adjustments for demographic factors, comorbidities, and baseline brachial flow volume, peribrachial fat thickness was an independent determinant for early brachial dilatation (β = −0.286, p = 0.013). A close interplay between the peri-brachial fat and brachial dilatation can be translated into novel clinical tools to predict successful AVF maturation.