First-in-human feasibility study of the aXess graft (aXess-FIH): 6-Month results.

OBJECTIVE: The creation of an arteriovenous fistula (AVF) is considered the most effective hemodialysis (HD) vascular access. For patients who are not suitable for AVF, arteriovenous grafts (AVGs) are the best access option for chronic HD. However, conventional AVGs are prone to intimal hyperplasia, stenosis, thrombosis, and infection. Xeltis has developed an AVG as a potential alternative to currently available AVGs based on the concept of endogenous tissue restoration. The results of the first 6-month follow-up are presented here. METHODS: The aXess first-in-human (FIH) study [NCT04898153] is a prospective, single-arm, multicenter feasibility study that evaluates the early safety and performance of the aXess Hemodialysis Graft. A total of 20 patients with end-stage renal disease were enrolled across six European investigational sites. RESULTS: At 6-months follow-up, all grafts were patent with primary and secondary patency rates were 80% and 100%, respectively. Three patients required a re-intervention to maintain graft patency, while one re-intervention was required to restore patency. One graft thrombosis and zero infections were reported. CONCLUSION: The expected advantages of the novel aXess Hemodialysis Graft over conventional AVGs would be evaluated by the analysis on long-term safety and effectiveness during the 5-year follow-up of the currently ongoing trial.

Oxygen Saturation Increase in Ischemic Wound Tissues after Direct and Indirect Revascularization.

BACKGROUND: The primary approach for treating ischemic wounds is restoring oxygen supply to the ischemic region. While direct angiosomal revascularization is often associated with better post-operative wound healing and limb salvage, its superiority over non-angiosomal revascularization remains controversial. This study aimed to compare intraoperative tissue oxygen saturation changes in ischemic zones following either direct or indirect revascularization in below-the-knee arteries. METHODS: This prospective observational study included patients undergoing direct and indirect below-the-knee endovascular revascularizations. Assignment to the groups was not randomized. Near-infrared spectroscopy was used to monitor rSO2 changes near the ischemic wounds intraoperatively. The changes were compared between the groups. RESULTS: 15 patients (50%) underwent direct angiosomal revascularization, while an equal number of patients underwent indirect revascularization. Overall, a statistically significant increase in regional oxygen saturation was observed after revascularization (p = 0.001). No statistically significant difference was found between the direct and indirect revascularization groups (p = 0.619). CONCLUSIONS: This study revealed a minor difference in the oxygen saturation increase between the angiosomal and non-angiosomal revascularization groups. Such a finding indicates that the clinical significance of angiosomal revascularization is negligible and might be concealed by confounding factors, such as the vessel diameter and outflow impact on the restenosis rate.

Validation of the Lithuanian Version of the Walking Impairment Questionnaire in Patients with Peripheral Arterial Disease.

Background and Objectives: The Walking Impairment Questionnaire (WIQ) is a short and simple tool to measure walking impairment for patients with peripheral arterial disease requiring no special equipment or trained staff. The aim of this study was to assess the validity and reliability of the culturally adapted Lithuanian WIQ version in patients with intermittent claudication. Materials and Methods: In total, 40 patients with intermittent claudication and ankle-brachial index < 0.90 participated in this study. Reliability and internal consistency of the questionnaire were assessed by the intra-class correlation coefficient (ICC) and Cronbach's alpha (α), respectively. Validity was determined by correlations between the WIQ scores and a subjective test (Quality of Life 5 Dimension Questionnaire 3 Level Version (EQ-5D-3L)) and objective tests (6 min walk test (6MWT), treadmill test, and ankle-brachial index). Results: The test-retest reliability was assessed as excellent with an intraclass correlation coefficient of 0.90. The values of Cronbach's alpha were 0.957 (I time) and 0.948 (II time) and indicated an excellent internal consistency. Statistically significant Spearman correlations were detected between the WIQ and walking distances on the 6MWT (rho 0.514, p < 0.001) and treadmill test (rho 0.515, p < 0.001). Higher WIQ scores were associated with longer walking distances and duration. Moderate negative and low negative correlations were found between the WIQ and EQ-5D-3L scores. Conclusions: The Lithuanian version of culturally adapted WIQ demonstrates reliability and validity for patients with intermittent claudication, supported by two different walking tests showing statistically significant moderate Spearman correlations.

Abdominal Aortic Aneurysm Diameter versus Volume: A Systematic Review.

Recently, AAA volume measurement has been proposed as a potentially valuable surveillance method in situations when diameter measurement might fail. OBJECTIVE: The aim of this systematic review was to analyze the results of previous studies comparing AAA diameter and volume measurements. METHODS: A systematic search in PubMed, Cochrane, and EMBASE databases was performed to identify studies investigating the use of diameter and volume measurements in AAA diagnosis and prognosis in English, German, and Russian, published until December 2022. The manuscripts were reviewed by three researchers and scored on the quality of the research using MINORS criteria. RESULTS: After screening 752 manuscripts, 19 studies (n = 1690) were included. The majority (n = 17) of the manuscripts appeared to favor volume. It is, however, important to highlight the heterogeneity of methodologies and lack of standardized protocol for measuring both volume and diameter in the included studies, which hindered the interpretation of the results. CONCLUSIONS: The clinical relevance of abdominal aortic aneurysm volume measurement is still unclear, although studies show favorable and promising results for volumetric changes in AAA, especially in follow-up after EVAR.

The use of near-infrared spectroscopy in the diagnosis of peripheral artery disease: A systematic review.

BACKGROUND: Peripheral arterial disease is a stenosis or occlusion of peripheral arteries that results in compromised blood flow and muscle ischemia. The available diagnostic methods are mostly used to measure and visualize blood flow and are not useful in the evaluation of perfusion, especially in diabetic patients, which is now considered to be a research priority by most of the vascular societies around the world as this is still a relatively poorly studied phenomenon. OBJECTIVE: The aim of this review is to explore the clinical significance of muscle tissue oxygenation monitoring in lower-extremity peripheral artery disease diagnosis using the near-infrared spectroscopy method. METHODS: A systematic search in PubMed, CINAHL, and Cochrane databases was performed to identify clinical near-infrared spectroscopy (NIRS) studies in English and Russian, published until September 2019, involving muscle tissue oxygenation in peripheral arterial disease (PAD). The manuscripts were reviewed by two researchers independently and scored on the quality of the research using MINORS criteria. RESULTS: After screening 443 manuscripts, 23 studies (n = 1580) were included. NIRS-evaluated recovery time seems to be more accurate than ankle-brachial index in diabetic patients to differentiate between moderate and severe claudication. Consistent findings across all the included studies showed that both the oxygenation and deoxygenation rates as well as the recovery times varied from patient to patient and therefore were not suitable for standardization. CONCLUSIONS: The clinical relevance of routine use of NIRS to diagnose PAD is unproven; therefore, its use is not currently part of standard-of-care for patients with PAD since the absolute values seem to vary significantly, depending on the outside conditions. More data need to be provided on the possible use of NIRS monitoring intraoperatively where the conditions can be more controlled.

Measurement of Revascularization Effect Using Near Infrared Spectroscopy in Below the Knee Arteries.

Background: Current methods evaluating tissue ischemia are based mainly on evaluating blood flow and not tissue perfusion. However, diabetes mainly affects small vessels and blood flow evaluation is insufficient. The aim of the trial was to evaluate the feasibility of NIRS in measuring perfusion changes during chronic total occlusion (CTO) revascularization in below the knee (BTK) arteries. Methods: A prospective observational study was performed. During the endovascular revascularization procedure, tissue oxygenation changes were measured using three NIRS sensors. Postoperative angiographies and 30 days wound healing was evaluated. Results: The study enrolled 30 patients with chronic limb threatening ischemia, occluded below the knee arteries, Rutherford 5. Mean age 74.7 ± 11.2 years, 16 (53%) of the patients had diabetes mellitus, 10 (33%) had end-stage renal disease. A statistically significant NIRS rSO 2 increase was observed on sensors near the wound after the revascularization, p = 0.001. Thirty days follow-up visits included 27 patients, because 3 patients had died. Comparing good wound healing group with poor wound healing group intraoperative NIRS rSO 2 increase difference was statistically significant, p = 0.017. Conclusions: The study confirmed tissue perfusion increase could be detected using NIRS during revascularization of below the knee arteries. An intraoperative increase of NIRS rSO 2 proved to predict wound healing results.

Aortic thrombosis after DVT and PE in a young COVID-19 patient.

A rare case of aortic thrombosis in a young COVID-19 positive patient is presented in this case report. Arterial thrombosis developed despite the administration of anticoagulants for treating DVT and PE. The patient underwent axillobifemoral bypass surgery. Limited surgical surveillance, administered steroids and critical health status resulted in wound site infection and consequent graft removal. Aortic endarterectomy and autovenous-patch plasty were performed after the patient's condition improved. Etiopathogenesis of arterial events in the setting of COVID-19 is not entirely understood. It has been suggested that SARS-CoV-2 infection strongly affects vascular endothelial glycocalyx (VEGLX), causes systemic inflammation - reactive microvascular endotheliosis (SIRME), and consequently results in arterial thrombosis.

A Bleeding Uretero-Arterial Fistula: Open Repair After Unsuccessful Endovascular Treatment.

INTRODUCTION: Uretero-arterial fistula (UAF) poses major challenges in management and diagnosis due to the rarity of this condition and associated high morbidity/mortality rates. METHODS: We describe a case of a UAF associated with previous aorto-biiliac grafting, ureteric stenting and right nephrectomy because of chronic pielonephritis and complicated by surgical site infection. This case illustrates a very complex pathology, with a challenging diagnosis and multiple treatment options. RESULTS: A 72 year-old woman was referred to Vilnius Vascular Unit for open UAF repair. The patient had a history of open abdominal aortic aneurysm repair using a bifurcated graft 25 years ago. The right ureter was injured during the operation and a rigid indwelling ureteric stent was inserted. Six months prior to referral, she underwent a right nephrectomy due to a chronic pyelonephritis, complicated by surgical site infection, which was still present at the time of admission. Initial CTA demonstrated bilateral iliac aneurysms, but no signs of UAF. A further CTA revealed a UAF between the right ureteral stump and the right common iliac artery (CIA) para-anastomotic aneurysm. After unsuccessful attempts to embolize the UAF using both coils and glue, the patient was referred to Vilnius Vascular Unit for open repair. Left axillo-bifemoral bypass reconstruction was performed followed by UAF repair and bifurcated graft explantation. Follow-up after 2 years showed no recurrence of haematuria, good function of the remaining kidney and patent axillo-bifemoral bypass with no signs of infection around the prosthetic aortic stump. CONCLUSIONS: Uretero-arterial fistula is a uncommon condition in everyday clinical practice. The rarity of this condition may lead to delayed or missed diagnosis which can result in life-threating consequences. A multidisciplinary approach involving urologists, vascular surgeon and radiologist are crucial to both the diagnosis and managment of this rare entity.

Value of Routine Flexible Sigmoidoscopy and Potential Predictive Factors for Colonic Ischemia after Open Ruptured Abdominal Aortic Aneurysm Repair.

Background and Objectives: colonic ischemia (CI) after ruptured abdominal aortic aneurysm (rAAA) repair is associated with increased morbidity and mortality. CI may be detected by using flexible sigmoidoscopy, but routine use of flexible sigmoidoscopy after rAAA is not clearly proven. The objective of this study was to evaluate the efficacy of routine flexible sigmoidoscopy in detecting CI after rAAA repair, and to identify potential hemodynamic, biochemical, and clinical variables that can predict the development of CI in the patients who underwent rAAA surgery. Materials and Methods: we retrospectively included all rAAA cases treated in Viborg hospital from 1 April 2014 until 31 August 2017, recorded the findings on flexible sigmoidoscopy, and the incidence of CI. We collected specific hemodynamic, biochemical, and clinical variables, measured pre- and perioperatively, and the first three postoperative days. The association between CI and possible predictors was analyzed in a logistic regression model. Results: a total of 80 patients underwent open rAAA repair during the study period. Flexible sigmoidoscopy was performed in 58 of 80 patients (73.5%) who survived at least 24 h after open rAAA surgery. Perioperative variables lowest arterial pH (p = 0.02) and types of operations-aortobifemoral bypass vs. straight graft (p = 0.04) showed statistically significant differences between CI groups. The analysis of the postoperative variables showed statistically significant difference in highest lactate on postoperative day 1 (p = 0.01), and lowest hemoglobin on postoperative day 2 (p = 0.04) comparing CI groups. Logistic regression model revealed that postoperative hemoglobin and lactate turned out to be independent risk factors for the development of CI (respectively OR = 0.44 (95% CI = 0.29-0.67) and OR = 1.91 (95% CI = 1.2-3.05)). Conclusions: flexible sigmoidoscopy can identify patients being at higher risk of mortality after open rAAA repair. The postoperative lactate and hemoglobin were found to be independent risk factors for the development of CI after open rAAA repair. Further larger studies are warranted to demonstrate these findings.

Is Abdominal Aortic Aneurysm Behavior after Endovascular Repair Associated with Aneurysm Wall Density on Computed Tomography Angiography?

Background and objectives: Abdominal aortic aneurysm (AAA) growth is unpredictable after the endovascular aneurysm repair (EVAR). Continuing aortic wall degradation and weakening due to hypoxia may have a role in post-EVAR aneurysm sac growth. We aimed to assess the association of aortic wall density on computed tomography angiography (CTA) with aneurysm growth following EVAR. Materials and Methods: A total of 78 patients were included in the study. The control group consisted of 39 randomly assigned patients without aortic pathology. Post-EVAR aneurysm sac volumes on CTA were measured twice during the follow-up period to estimate aneurysm sac behavior. A maximum AAA sac diameter, aortic wall and lumen densities in Hounsfield units (HU) on CTA were measured. A relative aortic wall density (the ratio of aortic wall to lumen densities) was calculated. A statistical data analysis was performed using standard methods. Results: An increase in the AAA sac volume was observed in 12 (30.8%) cases. Median relative aortic wall density on CTA scores in both the patient and the control group at the level of the diaphragm were similar: 0.15 (interquartile range (IQR), 0.11-0.18) and 0.16 (IQR 0.11-0.18), p = 0.5378, respectively. The median (IQR) relative aortic wall density score at the level of the maximum AAA diameter in the patient group was lower than at the level below renal arteries in the control group: 0.10 (0.07-0.12) and 0.17 (0.12-0.23), p < 0.0001, respectively. The median (IQR) relative growing AAA sac wall density score was lower than a relative stable/shrinking AAA sac wall density score: 0.09 (0.06-0.10) and 0.11 (0.09-0.13), p = 0.0096, respectively. Conclusions: A lower aortic aneurysm wall density on CTA may be associated with AAA growth after EVAR.

Peripheral artery disease patients are poorly aware of their disease.

Objectives. We hypothesized, that patients with peripheral arterial disease (PAD) are less aware of risk factors and possible outcomes of the disease compared to patients with coronary artery disease (CAD), which are similar. Hence, the aim of this study was to evaluate awareness of and attitudes towards PAD and CAD among patients, who are already diagnosed with either disease. Design. A cross-sectional descriptive study was performed. Basic demographics, the presence and awareness of risk factors for PAD and CAD; perceived systemic and limb consequences, severity of PAD and CAD, self-reported knowledge about other non-vascular illnesses were assessed using an anonymous questionnaire. Results. 203 were invited and 157 (77%), 63 with PAD and 94 with CAD, patients agreed to take part in and completed the survey. Basic demographic characteristics were similar in both groups, except for the level of education: PAD patients were less educated compared to CAD patients (p = .002). Only 35% of PAD patients were familiar with the definition of PAD (key words were registered) in contrast to 52% CAD definition awareness among CAD patients (p = .034). PAD patients were significantly less familiar with other common diseases (p = .002) and risk factors for both PAD (p < .001) and CAD (p = .003) in comparison to equivalent CAD group parameters. Conclusions. PAD patients are less aware of risk factors for PAD and atherosclerosis in general, other illnesses and have lower level of education, which may negatively affect overall management of this complex disease.

Aortic sac enlargement after endovascular aneurysm repair: volume-related changes and the impact of intraluminal thrombus.

PURPOSE: Abdominal aortic aneurysm (AAA) growth after endovascular aneurysm repair (EVAR) is still unpredictable. The issue of optimal frequency of computed tomography angiography for surveillance and its measurement method accuracy remain unclear. We aimed to assess the value of abdominal aneurysm sac volume measurement for detecting expansions and the association of preprocedural intraluminal thrombus (ILT) volume with aneurysm sac growth following EVAR. MATERIAL AND METHODS: A total of 107 patients underwent elective EVAR. Inclusion criteria provided a cohort of 39 patients. Changes of postoperative maximum aneurysm sac diameter and AAA volume were calculated. Volumetric AAA changes and demographic data of the cases with clinically irrelevant AAA diameter enlargement were evaluated. Preoperative ILT volumes were collected. ILT and AAA sac volume ratio was calculated. Statistical data analysis was performed using standard methods. RESULTS: The mean changes of maximum AAA diameter and volume in percentage after EVAR were -5.08 ± 8.20 mm and -13.39 ± 23.32%, respectively. A moderate positive linear correlation between those changes was found (R 2 = 0.731; p < 0.0001). The mean relative AAA volume increase in cases without clinically relevant diameter enlargement was 11.50 ± 8.27%. The means of ILT and AAA sac ratios were 0.59 ± 0.17 and 0.52 ± 1.8 in growing AAA sac and in stable or shrinking AAA sac groups, respectively (p = 0.308). CONCLUSIONS: Volumetric AAA measurement may be useful as an additional method to diameter measurement after EVAR to identify clinically relevant sac growth. Preoperative volume of ILT may not significantly affect the growth rate of AAA after EVAR.