Clinical outcomes and predictive factors of stent grafts treatment for symptomatic central venous obstruction in end stage kidney disease patients with arteriovenous access.

To assess the efficacy of stent grafts (SGs) in managing central venous obstruction disease (CVOD) in hemodialysis (HD) patients with arteriovenous (AV) access, and to identify predictive factors influencing the SG treatment outcomes. HD subjects with CVOD who underwent SGs placement at our center between August 2018 and June 2022 were enrolled. Survival curve analysis using the Kaplan-Meier method and log-rank test was performed. Cox proportional hazards regression analysis was employed to identify predictive factors associated with outcomes. A total of 59 SG implantation procedures for CVOD were analyzed, comprising 30 cases of stenosis and 29 cases of occlusion. The access circuit primary patency (ACPP) at 6, 12, and 24 months post-SG placement were 80.9%, 53.8%, and 31.4%, respectively, while, the target lesion primary patency (TLPP) were 91.3%, 67.6%, and 44.5%, respectively. Subgroup analysis revealed higher TLPP in the stenosis group compared to the occlusion group, although the difference was not statistically significant (P = 0.165). The TLPP was significantly improved by SG placement in those who had antecedent balloon dilations (P < 0.001). Cox proportional hazards regression identified target lesion length ≥ 30 mm and procedure defects as independent predictors of lower TLPP after SG treatment for CVOD in HD patients. SG placement demonstrates safety and efficacy in managing CVOD among HD patients, leading to improved TLPP of endovascular therapy (EVT) for CVOD. Notably, long target lesions (≥ 30 mm) and procedure defects emerged as predictive factors influencing TLPP.

A review of arterial thoracic outlet syndrome.

Arterial thoracic outlet syndrome (TOS) is a condition in which anatomic abnormalities in the thoracic outlet cause compression of the subclavian or, less commonly, axillary artery. Patients are usually younger and typically have an anatomic abnormality causing the compression. The condition usually goes undiagnosed until patients present with signs of acute or chronic hand or arm ischemia. Workup of this condition includes a thorough history and physical examination; chest x-ray to identify potential anatomic abnormalities; and arterial imaging, such as computed tomographic angiography or duplex to identify arterial abnormalities. Patients will usually require operative intervention, given their symptomatic presentation. Intervention should always include decompression of the thoracic outlet with at least a first-rib resection and any other structures causing external compression. If the artery is identified to have intimal damage, mural thrombus, or is aneurysmal, then arterial reconstruction is warranted. Stenting should be avoided due to external compression. In patients with symptoms of embolization, a combination of embolectomy, lytic catheter placement, and/or therapeutic anticoagulation should be done. Typically, patients have excellent outcomes, with resolution of symptoms and high patency of the bypass graft, although patients with distal embolization may require finger amputation.

Management of thoracic outlet syndrome in patients with hemodialysis access.

Patients with threatened arteriovenous access are often found to have central venous stenoses at the ipsilateral costoclavicular junction, which may be resistant to endovascular intervention. Stenoses in this location may not resolve unless surgical decompression of thoracic outlet is performed to relieve the extrinsic compression on the subclavian vein. The authors reviewed the management of dialysis patients with central venous lesions at the thoracic outlet, as well as the role of surgical decompression with first-rib resection or claviculectomy for salvage of threatened, ipsilateral dialysis access.

Patients, healthcare providers, and general population preferences for hemodialysis vascular access: a discrete choice experiment.

Background: A patient-centered dialysis treatment option requires an understanding of patient preferences for alternative vascular accesses and nephrologists often face difficulties when recommending vascular access to end-stage kidney disease (ESKD) patients. We aimed to quantify the relative importance of various vascular access characteristics to patients, healthcare providers and general population, and how they affect acceptability for patients and healthcare providers. Methods: In a discrete choice experiment, patients with maintenance hemodialysis (MHD), healthcare providers, and individuals from the general population were invited to respond to a series of hypothetical vascular access scenarios that differed in five attributes: cumulative patency, infection rate, thrombosis rate, cost, and time to maturation. We estimated the respondents' preference heterogeneity and relative importance of the attributes with a mixed logit model (MXL) and predicted the willingness to pay (WTP) of respondents via a multinomial logit model (MNL). Results: Healthcare providers (n = 316) and the general population (n = 268) exhibited a favorable inclination toward longer cumulative patency, lower access infection rate and lower access thrombosis rate. In contrast, the patients (n = 253) showed a preference for a 3-year cumulative patency, 8% access infection rate, 35% access thrombosis rate and 1.5 access maturity time, with only the 3-year cumulative patency reaching statistical significance. Among the three respondent groups, the general population found cumulative patency less important than healthcare providers and patients did. Patients demonstrated the highest WTP for cumulative patency, indicating a willingness to pay an extra RMB$24,720(US$3,708) for each additional year of patency time. Conclusion: Patients and healthcare providers had a strong preference for vascular access with superior patency. While the general population preferred vascular access with lower thrombosis rates. These results indicate that most patients prefer autogenous arteriovenous fistula (AVF) as an appropriate choice for vascular access due to its superior patency and lower complications than other vascular access types.

Infrapopliteal Bypass In Patients On Dialysis: Patency And Survival.

INTRODUCTION: Portugal has one of the highest prevalence of patients on a regular dialysis program. This population has a higher incidence of peripheral arterial disease with higher rates of postoperative morbidity and mortality. Our goal was to compare outcomes between dialysis and non-dialysis patients with chronic limb threatening ischemia (CLTI) submitted to infrapopliteal bypass. MATERIALS AND METHODS: A retrospective single-center study of infrapopliteal bypass for CLTI was performed between 2012 and 2019. Patients were divided in two groups based on dialysis status (group 1 incorporated patients on dialysis). Primary end point was 1-year freedom from CLTI. Secondary end points were limb-salvage, survival and primary (PP) and tertiary patency (TP) rates at 3 years of follow-up. RESULTS: A total of 352 infrapopliteal bypasses were performed in 310 patients with CLTI. Fourteen percent of the revascularizations were performed on dialysis patients (48/352). Median age was 73 years (interquartile range - IQR 15) and 74% (259/352) were male. Median follow-up was 26 months (IQR 42). Overall, 92% (325/352) had tissue loss and 44% (154/352) had some degree of infection. The majority of revascularization procedures were performed with vein grafts (61%, 214/352). The 30-day mortality was 4% (11/310), with no difference between groups (p = 0.627). Kaplan-Meier analysis showed no difference between groups regarding freedom from CLTI (76% vs. 79%; HR 0.96, CI 0.65-1.44, p=0.857), limb-salvage (70% vs. 82%; HR 1.40, CI 0.71-2.78, p=0.327) and survival (62% vs. 64%; HR 1.08, CI 0.60-1.94, p=0.799). PP rates were 39% in group 1 and 64% in group 2 (HR 1.71, CI 1.05-2.79, p=0.030). TP rates were not different between groups (57% and 78%; HR 1.79, CI 0.92-3.47, p=0.082). CONCLUSION: Infrapopliteal bypass for CLTI, on dialysis patients, resulted in lower PP rates. No differences were observed in freedom from CLTI, TP, limb salvage and survival.

Randomized Trial Comparing a Stent-Avoiding With a Stent-Preferred Strategy in Complex Femoropopliteal Lesions.

BACKGROUND: Limited comparative data exist on different interventional strategies for endovascular revascularization of complex femoropopliteal interventions. OBJECTIVES: In this study, the authors aimed to compare a stent-avoiding (SA) vs a stent-preferred (SP) strategy, promoting optimal lesion preparation and the use of drug-eluting technologies in both arms. METHODS: Within a prospective, multicenter, pilot study, 120 patients with symptomatic complex femoropopliteal lesions (Rutherford classification 2-4, mean lesion length 187.7 ± 78.3 mm, 79.2% total occlusions) were randomly assigned in a 1:1 fashion to endovascular treatment with either paclitaxel-coated balloons or polymer-coated, paclitaxel-eluting stents. Lesion preparation including the use of devices for plaque modification and/or removal was at the operators' discretion in both treatment arms. RESULTS: In the SA group, lesion preparation was more frequently performed (71.7% SA [43/60] vs 51.7% [31/60] SP; P = 0.038) with a high provisional stenting rate (48.3% [29/60]). At the 12-month follow-up, primary patency was 78.2% (43/55) in the SA group and 78.6% (44/56) in the SP group (P = 1.0; relative risk: 0.995; 95% CI: 0.818-1.210). Freedom from major adverse events was determined in 93.1% (54/58) in the SA group and in 94.9% (56/59) in the SP group (P = 0.717; relative risk: 0.981; 95% CI: 0.895-1.075), with all adverse events attributable to clinically driven target lesion revascularization. CONCLUSIONS: Both endovascular strategies promoting lesion preparation before the use of drug-eluting devices suggest promising efficacy and safety results in complex femoropopliteal procedures with a high proportion of total occlusions through 12 months. Ongoing follow-up will show whether different results emerge over time. (Best Endovascular Strategy for Complex Lesions of the Superficial Femoral Artery [BEST-SFA]; NCT03776799).

Drug-Coated Balloons in the Management of Coronary Artery Disease.

Drug-coated balloons (DCBs) are specialized coronary devices comprised of a semicompliant balloon catheter with an engineered coating that allows the delivery of antiproliferative agents locally to the vessel wall during percutaneous coronary intervention. Although DCBs were initially developed more than a decade ago, their potential in coronary interventions has recently sparked renewed interest, especially in the United States. Originally designed to overcome the limitations of conventional balloon angioplasty and stenting, they aim to match or even improve upon the outcomes of drug-eluting stents without leaving a permanent implant. Presently, in-stent restenosis is the condition with the most robust evidence supporting the use of DCBs. DCBs provide improved long-term vessel patency compared with conventional balloon angioplasty and may be comparable to drug-eluting stents without the need for an additional stent layer, supporting their use as a first-line therapy for in-stent restenosis. Beyond the treatment of in-stent restenosis, DCBs provide an additional tool for de novo lesions for a strategy that avoids a permanent metal scaffold, which may be especially useful for the management of technically challenging anatomies such as small vessels and bifurcations. DCBs might also be advantageous for patients with high bleeding risk due to the decreased necessity for extended antiplatelet therapy, and in patients with diabetes and patients with diffuse disease to minimize long-stented segments. Further studies are crucial to confirm these broader applications for DCBs and to further validate safety and efficacy.

Factors contributing to patency after aneurysmorrhaphy and outflow repair in arteriovenous fistula aneurysm treatment.

INTRODUCTION: Vascular access-related aneurysms (VARA) are a complication of arteriovenous fistulas. Repair techniques have been described in the literature with varied outcomes. MATERIALS AND METHODS: We conducted a prospective cohort study on patients who had VARA repair over 41 months. The indication for repair was an aneurysmal arteriovenous fistula (AVF) at risk of haemorrhage or difficulty in cannulation. Pseudoaneurysms, infected AVF and bleeding VARA were excluded. All patients underwent outflow stenosis treatment when present, followed by aneurysmorrhaphy. They were monitored periodically over 12 months, measuring functional primary and cumulative patency and access flow. We studied the patient demography, access flow and presence of outflow stenosis. Access flow was measured from the brachial artery (Qa) as a surrogate using ultrasonography. A Kaplan-Meier survival analysis was used to predict the primary and cumulative patency at 12 months and factors contributing to 12-month patency were analysed. RESULTS: A total of 64 patients were recruited for this study, of whom 58 completed the study. Most of the participants were male (67%) with a median age of 45 years. Forty-six patients (79.3%) had brachiocephalic fistula (BCF) aneurysms. Thirty-nine (67.2%) had preexisting outflow stenoses that required intervention. All patients underwent an aneurysmorrhaphy, of whom 12% had a cephalic arch vein transposition due to severe stenosis. Primary patency at 12 months was 86%, whereas the cumulative patency rate was 95%. Patency was significantly associated with younger age and showed a positive trend with higher preintervention Qa. Symptomatic recurrent stenosis developed in 17.2% of the cohort. CONCLUSION: Improving the patency of VARA entails the treatment of outflow stenosis and aneurysmorrhaphy. Surveillance is important to detect and treat recurrent outflow stenoses. The outcome is better among younger patients with pre-interventional access flow as measured in the brachial artery as a surrogate.

A microscope in your pocket: can smartphones be used to perform microsurgery?

PURPOSE: To evaluate the use of the latest generation smartphone camera in performing arterial microanastomosis in rats. METHODS: Ten Wistar rats were divided into 2 groups and underwent anastomosis of the right carotid artery with the aid of magnification from a microscope (group M) and a smartphone camera (group S), to compare patency in 72 hours, as well as to measure the weight of the animals, diameter of the carotid arteries and anastomosis time. RESULTS: There was no statistical difference between the weight of the animals or the diameter of the carotid arteries. There was a statistical difference for the time spent on anastomoses, which was greater in group S, with higher rates of thrombosis (p < 0.05). CONCLUSIONS: Although our patency and anastomosis time results were statistically lower in the smartphone group, there was success in some cases. As the segment continues to progress, it is likely that the results will improve in line with the evolution of camera technology.

Doppler ultrasound surveillance of recently formed haemodialysis arteriovenous fistula: the SONAR observational cohort study.

Background: Arteriovenous fistulas are considered the best option for haemodialysis provision, but as many as 30% fail to mature or suffer early failure. Objective: To assess the feasibility of performing a randomised controlled trial that examines whether, by informing early and effective salvage intervention of fistulas that would otherwise fail, Doppler ultrasound surveillance of developing arteriovenous fistulas improves longer-term arteriovenous fistula patency. Design: A prospective multicentre observational cohort study (the 'SONAR' study). Setting: Seventeen haemodialysis centres in the UK. Participants: Consenting adults with end-stage renal disease who were scheduled to have an arteriovenous fistula created. Intervention: Participants underwent Doppler ultrasound surveillance of their arteriovenous fistulas at 2, 4, 6 and 10 weeks after creation, with clinical teams blinded to the ultrasound surveillance findings. Main outcome measures: Fistula maturation at week 10 defined according to ultrasound surveillance parameters of representative venous diameter and blood flow (wrist arteriovenous fistulas: ≥ 4 mm and > 400 ml/minute; elbow arteriovenous fistulas: ≥ 5 mm and > 500 ml/minute). Mixed multivariable logistic regression modelling of the early ultrasound scan data was used to predict arteriovenous fistula non-maturation by 10 weeks and fistula failure at 6 months. Results: A total of 333 arteriovenous fistulas were created during the study window (47.7% wrist, 52.3% elbow). By 2 weeks, 37 (11.1%) arteriovenous fistulas had failed (thrombosed), but by 10 weeks, 219 of 333 (65.8%) of created arteriovenous fistulas had reached maturity (60.4% wrist, 67.2% elbow). Persistently lower flow rates and venous diameters were observed in those fistulas that did not mature. Models for arteriovenous fistulas' non-maturation could be optimally constructed using the week 4 scan data, with fistula venous diameter and flow rate the most significant variables in explaining wrist fistula maturity failure (positive predictive value 60.6%, 95% confidence interval 43.9% to 77.3%), whereas resistance index and flow rate were most significant for elbow arteriovenous fistulas (positive predictive value 66.7%, 95% confidence interval 48.9% to 84.4%). In contrast to non-maturation, both models predicted fistula maturation much more reliably [negative predictive values of 95.4% (95% confidence interval 91.0% to 99.8%) and 95.6% (95% confidence interval 91.8% to 99.4%) for wrist and elbow, respectively]. Additional follow-up and modelling on a subset (n = 192) of the original SONAR cohort (the SONAR-12M study) revealed the rates of primary, assisted primary and secondary patency arteriovenous fistulas at 6 months were 76.5, 80.7 and 83.3, respectively. Fistula vein size, flow rate and resistance index could identify primary patency failure at 6 months, with similar predictive power as for 10-week arteriovenous fistula maturity failure, but with wide confidence intervals for wrist (positive predictive value 72.7%, 95% confidence interval 46.4% to 99.0%) and elbow (positive predictive value 57.1%, 95% confidence interval 20.5% to 93.8%). These models, moreover, performed poorly at identifying assisted primary and secondary patency failure, likely because a subset of those arteriovenous fistulas identified on ultrasound surveillance as at risk underwent subsequent successful salvage intervention without recourse to early ultrasound data. Conclusions: Although early ultrasound can predict fistula maturation and longer-term patency very effectively, it was only moderately good at identifying those fistulas likely to remain immature or to fail within 6 months. Allied to the better- than-expected fistula patency rates achieved (that are further improved by successful salvage), we estimate that a randomised controlled trial comparing early ultrasound-guided intervention against standard care would require at least 1300 fistulas and would achieve only minimal patient benefit. Trial Registration: This trial is registered as ISRCTN36033877 and ISRCTN17399438. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR135572) and is published in full in Health Technology Assessment; Vol. 28, No. 24. See the NIHR Funding and Awards website for further award information.

For people with advanced kidney disease, haemodialysis is best provided by an 'arteriovenous fistula', which is created surgically by joining a vein onto an artery at the wrist or elbow. However, these take about 2 months to develop fully ('mature'), and as many as 3 out of 10 fail to do so. We asked whether we could use early ultrasound scanning of the fistula to identify those that are unlikely to mature. This would allow us to decide whether it would be practical to run a large, randomised trial to find out if using early ultrasound allows us to 'rescue' fistulas that would otherwise fail. We invited adults to undergo serial ultrasound scanning of their fistula in the first few weeks after it was created. We then analysed whether we could use the data from the early scans to identify those fistulas that were not going to mature by week 10. Of the 333 fistulas that were created, about two-thirds reached maturity by week 10. We found that an ultrasound scan 4 weeks after fistula creation could reliably identify those fistulas that were going to mature. However, of those fistulas predicted to fail, about one-third did eventually mature without further intervention, and even without knowing what the early scans showed, another third were successfully rescued by surgery or X-ray-guided treatment at a later stage. Performing an early ultrasound scan on a fistula can provide reassurance that it will mature and deliver trouble-free dialysis. However, because scans are poor at identifying fistulas that are unlikely to mature, we would not recommend their use to justify early surgery or X-ray-guided treatment in the expectation that this will improve outcomes.

Sharp needle reconstructs peripheral outflow for patients with malfunctional arteriovenous fistula.

OBJECTIVE: To investigate the feasibility and efficacy of combining ultrasound-guided sharp needle technique with percutaneous transluminal angioplasty (PTA) for treating outflow stenosis or dysfunction in arteriovenous fistula (AVF) among hemodialysis patients. METHODS: From October 2021 to March 2023, patients with occluded or malfunctional fistula veins not amenable to regularly angioplasty were retrospectively enrolled in the study. They underwent ultrasound-guided sharp needle intervention followed by PTA. Data on the location and length between the two veins, technical success, clinical outcomes, and complications were collected. Patency rates post-angioplasty were calculated through Kaplan-Meier analysis. RESULTS: A total of 23 patients were included. The mean length of the reconstructed extraluminal segment was 3.18 cm. The sharp needle opening was performed on the basilic vein (60.9%), brachial vein (26.1%), or upper arm cephalic vein (13%) to create outflow channels. Postoperatively, all cases presented with mild subcutaneous hematomas around the tunneling site and minor diffuse bleeding. The immediate patency rate for the internal fistulas was 100%, with 3-month, 6-month, and 12-month patency rates at 91.3%, 78.3%, and 43.5%, respectively. CONCLUSION: Sharp needle technology merged with PTA presents an effective and secure minimally invasive method for reconstructing the outflow tract, offering a new solution for recanalizing high-pressure or occluded fistulas.

Alternative vein bypass in octogenarians with chronic limb-threatening ischaemia.

BACKGROUND: Octogenarians are regarded as one of the frailest patient groups among the chronic limb-threatening ischaemia population with high perioperative morbidity and mortality rates. As a result, alternative vein bypass surgery in the absence of sufficient great saphenous vein is often not considered as a potential treatment option. The aim of this study was to compare the results of octogenarians undergoing alternative vein bypass surgery due to chronic limb-threatening ischaemia to younger patients. METHODS: A single-centre retrospective analysis of patients undergoing bypass surgery for chronic limb-threatening ischaemia with alternative autologous vein grafts between 1997 and 2018 was performed. Patients aged over 80 years were compared with those under 80 years. Graft patency rates were assessed and a risk factor analysis for limb loss was performed. RESULTS: In total, 592 patients underwent bypass surgery during the study interval. Twenty-one per cent (n = 126) of patients were 80 years or older. At 4 years, primary, primary-assisted and secondary patency as well as limb salvage rates were not significantly different between the two groups (46% versus 50%, 60% versus 66%, 69% versus 72%, 72% versus 77%, for octogenarians versus non-octogenarians respectively). Major amputations were performed in 27 (21%) octogenarians and 91 (20%) non-octogenarians (P = 0.190). No higher 30-day and long-term mortality rates nor morbidity rates were detected in the octogenarian group with a median follow-up time of 27 (interquartile range 12-56) months. Minor amputation, the reason for alternative vein grafts, as well as the profunda femoris artery as proximal origin of the bypass were risk factors for limb loss in the postoperative course. CONCLUSION: Alternative vein bypass surgery in octogenarians with chronic limb-threatening ischaemia is safe and effective in terms of patency rates, limb salvage and survival compared with younger patients in the absence of sufficient great saphenous vein. Age alone should not be a deterrent from performing bypass surgery.

Endovascular Transvenous versus Open Femoropopliteal Bypass.

Background and Objectives: Lower extremity arterial disease is one of the most prevalent manifestations of atherosclerosis. The results from numerous studies regarding the best revascularization method of an occluded superficial femoral artery have been conflicting. The aim of this study was to compare the patency of transvenous endovascular with open femoropopliteal bypass, both with vein and prosthetic grafts. To our knowledge, a direct patency comparison between transvenous endovascular and open femoropopliteal bypass has not been published. This could help elucidate which method is preferable and in which cases. Materials and Methods: Patients with complex TASC-C and D SFA lesions were offered endovascular transvenous or open bypass. A total of 384 consecutive patients with PAD requiring surgical treatment were evaluated for inclusion in this study. Three-year follow-up data were collected for 52 endovascular procedures, 80 prosthetic grafts, and 44 venous bypass surgeries. Bypass patency was investigated by Duplex US every 6 months. Kaplan-Meier plots were used to analyze primary, primary-assisted, and secondary patency for endovascular transvenous, autovenous, and prosthetic bypasses. Results: Primary, primary-assisted, and secondary patency in venous group at 3 years was 70.5%, 77.3%, and 77.3%, respectively. In the endovascular transvenous group, primary, primary-assisted, and secondary patency at 3 years was 46.2%, 69.2%, and 76.9%, respectively. The lowest patency rates at 3 years were noted in the prosthetic graft group with 22.5% primary, 26.6% primary-assisted, and 28.2% secondary patency. Conclusions: The saphenous vein is the best graft to perform in above-the-knee femoropopliteal bypass. Transvenous endovascular bypass is a viable option with comparable primary-assisted and secondary patency. Primary patency is substantially lower for endovascular transvenous compared to venous bypass. Patients treated with endovascular transvenous bypass will require a significant number of secondary procedures to provide optimal patency. Prosthetic grafts should only be used if no other option for bypass is available.

Lymphaticovenous anastomosis in rabbits: A novel live experimental animal model for supermicrosurgical training.

BACKGROUND: Lymphaticovenous anastomosis is widely used in lymphedema management. Although its effectiveness in reducing edema in patients can be clinically observed, evaluating the long-term outcomes of this technique can be complex. This study established an animal model to assess the outcomes of lymphaticovenous anastomosis technique at 15 and 30-days post-surgery using indocyanine green lymphography, Patent Blue V dye injection, and histopathological examination. METHODS: An experimental model was established in the hindlimbs of 10 rabbits using the popliteal vein and afferent lymphatic vessels in the popliteal area. The subjects were divided into two groups: the first group (n = 5) underwent patency assessment at 0 and 15 days, and the second group (n = 5) at 0 and 30-days, resulting in 20 anastomoses. Patency was verified at 0, 15, and 30-days using indocyanine green lymphography and Patent Blue V injection. Histopathological examinations were performed on the collected anastomosis samples. RESULTS: The patency rate was 90% (19/20) initially, 60% (6/10) at 15 days post-surgery, and 80% (8/10) at 30-days. The average diameter of lymphatic vessels and veins was 1.0 mm and 0.8 mm, respectively. The median number of collateral veins was 3; the median surgical time was 65.8 min. Histopathology revealed minimal endothelial damage and inflammatory responses due to the surgical sutures, with vascular inflammation and thrombosis in a single case. Local vascular neoformations were observed. CONCLUSION: This study highlights the reliability and reproducibility of using rabbits as experimental models for training in lymphaticovenous anastomosis technique owing to the accessibility of the surgical site and dimensions of their popliteal vasculature.

In vivo evaluation of safety and performance of a tapered nitinol venous stent with inclined proximal end in an ovine iliac venous model.

A tapered stent with inclined proximal end is designed for fitting the iliac anatomically. The aim of the present study was to evaluate the safety and performance of the new stent in ovine left iliac veins. The experiment was performed in 30 adult sheep, and one nitinol-based VENA-BT® iliac venous stent (KYD stent) was implanted into each animal's left common iliac vein. Follow-up in all sheep consisted of angiographic, macroscopic, and microscopic examinations at Day 0 (< 24 h), Day 30, Day 90, Day 180 and Day 360 post-stenting (six animals per each time-point). 30 healthy ~ 50 kg sheep were included in this study and randomly divided into five groups according to the follow-up timepoint. All stents were implanted successfully into the left ovine common iliac vein. No significant migration occurred at follow-up. There is no statistically significant difference between the groups (p > 0.05), indicating no serious lumen loss occurred during the follow-up period. Common iliac venous pressure was further measured and the results further indicated the lumen patency at follow-up. Histological examinations indicated that no vessel injury and wall rupture, stent damage, and luminal thrombus occurred. There was moderate inflammatory cell infiltration around the stent in Day-0 and Day-30 groups with the average inflammation score of 2.278 and 2.167, respectively. The inflammatory reaction was significantly reduced in Day-90, Day-180 and Day-360 groups and the average inflammation scores were 0.9444 (p < 0.001, Day-90 vs Day-0), 1.167 (p < 0.001, Day-180 vs Day-0) and 0.667 (p < 0.001, Day-90 vs Day-0), respectively. The microscopic examinations found that the stents were well covered by endothelial cells in all follow-up time points. The results suggested that the KYD stent is feasible and safe in animal model. Future clinical studies may be required to further evaluate its safety and efficacy.

Association between diabetes mellitus and primary restenosis following endovascular treatment: a comprehensive meta-analysis of randomized controlled trials.

IMPORTANCE: Diabetes mellitus (DM) is thought to be closely related to arterial stenotic or occlusive disease caused by atherosclerosis. However, there is still no definitive clinical evidence to confirm that patients with diabetes have a higher risk of restenosis. OBJECTIVE: This meta-analysis was conducted to determine the effect of DM on restenosis among patients undergoing endovascular treatment, such as percutaneous transluminal angioplasty (PTA) or stenting. DATA SOURCES AND STUDY SELECTION: The PubMed/Medline, EMBASE and Cochrane Library electronic databases were searched from 01/1990 to 12/2022, without language restrictions. Trials were included if they satisfied the following eligibility criteria: (1) RCTs of patients with or without DM; (2) lesions confined to the coronary arteries or femoral popliteal artery; (3) endovascular treatment via PTA or stenting; and (4) an outcome of restenosis at the target lesion site. The exclusion criteria included the following: (1) greater than 20% of patients lost to follow-up and (2) a secondary restenosis operation. DATA EXTRACTION AND SYNTHESIS: Two researchers independently screened the titles and abstracts for relevance, obtained full texts of potentially eligible studies, and assessed suitability based on inclusion and exclusion criteria.. Disagreements were resolved through consultation with a third researcher. Treatment effects were measured by relative ratios (RRs) with 95% confidence intervals (CIs) using random effects models. The quality of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. MAIN OUTCOMES AND MEASURES: The main observation endpoint was restenosis, including > 50% stenosis at angiography, or TLR of the primary operation lesion during the follow-up period. RESULTS: A total of 31,066 patients from 20 RCTs were included. Patients with DM had a higher risk of primary restenosis after endovascular treatment (RR = 1.43, 95% CI: 1.25-1.62; p = 0.001). CONCLUSIONS AND RELEVANCE: This meta-analysis of all currently available RCTs showed that patients with DM are more prone to primary restenosis after endovascular treatment.

Transit time flow measurement in off-pump surgery: is it a functional index of the biological graft integrity?

OBJECTIVE: Transit-time flow measurement (TTFM) represents a valid tool in the assessment of the quality of the anastomosis during coronary artery bypass graft (CABG). Nevertheless, a high variability limits its standardized use, lacking univocally accepted cut-off flow values. Our study analyzes TTFM data collected from a study population that underwent off-pump CABG (OP-CABG), with the aim to differentiate into subgroups according to the presence of diabetes mellitus. PATIENTS AND METHODS: Patients referred to the Cardiovascular Unit of S. Michele Hospital (Caserta, Italy) for coronary artery disease (CAD) and underwent OP-CABG between January 2015 and December 2019 were enrolled, and intraoperative TTFMs data were recruited and evaluated. Mean graft flow (MGF) and pulsatility index (PI) values were collected and analyzed. RESULTS: The study population was composed of 342 patients who underwent OP-CABG with TTFM data regarding 824 grafts. Diabetic patients shared a higher cardiovascular risk profile. The TTFM assessment showed better results for the use of the arterial grafts in diabetic patients, especially for those insulin-dependent; conversely, venous grafts showed worse data with lower MGF and higher PI values. In particular, the anastomoses of the saphenous vein graft with marginal obtuse (MO) coronary artery showed worse MGF results in the insulin-dependent rather than normoglycemic subgroup (28.66 vs. 38.44, p=0.003). CONCLUSIONS: Diabetic patients, especially in the insulin-dependent subgroups, have demonstrated lower MGF and higher PI values collected from venous anastomoses with, conversely, inverse results from the arterial one. These results might be correlated to an altered biological adaptability caused by the effects of the diabetic endocrine disorder.

Transient time flow measurement in arterial grafts.

Coronary artery bypass grafting (CABG) is one of the foundations of treatment for coronary artery disease. While it has improved substantially since its inception more than 50 years ago, including a rising use of multiple arterial grafting, intraoperative quality assessment is yet to be disseminated as an integral part of the procedure. Herein we review the fundamentals of intraoperative quality assessment in CABG using transient time flow measurement (TTFM) with a focus on its use in arterial grafting.

Vaso-Lock for sutureless anastomosis in a pig arteriovenous loop model.

A vascular anastomosis is a critical surgical skill that involves connecting blood vessels. Traditional handsewn techniques can be challenging and resource intensive. To address these issues, we have developed a unique sutureless anastomotic device called Vaso-Lock. This intraluminal device connects free vascular ends using anchors to maintain traction and enable a rapid anastomosis. We tested the anastomotic capability of Vaso-Locks in a pig common carotid-internal jugular arteriovenous model. The use of Vaso-Lock allowed us to accomplish this procedure in less than 10 min, in contrast to the approximately 40 min required for a handsewn anastomosis. The Vaso-Lock effectively maintained patency for at least 6 weeks without causing significant tissue damage. Histological analysis revealed that the device was successfully incorporated into the arterial wall, promoting a natural healing process. Additionally, organ evaluations indicated no adverse effects from using the Vaso-Lock. Our findings support the safety and effectiveness of the Vaso-Lock for arteriovenous anastomosis in pigs, with potential applicability for translation to humans. Our novel sutureless device has the potential to advance surgical practice and improve patient outcomes.