Improved Patency Rates Research Articles

Influence of Perioperative Factors on Patency After Endovascular and Hybrid Treatments of TASC II D Aortoiliac Occlusive Lesions

Treatment of Trans-Atlantic Inter-Society Consensus (TASC) II D aortoiliac occlusive disease (AIOD D) remains a controversial topic. Although current recommendations support conventional surgical treatment, several recent studies have reported promising results with endovascular and hybrid strategies. The purpose of this work was to describe the outcomes of endovascular and hybrid management of AIOD D and to investigate the influence of perioperative factors on patency. This was a retrospective single-center study covering the period from 2016 to 2021. The primary end point was primary patency at 12months. Secondary endpoints included technical success rate, 30-day mortality, early major complication rate, primary assisted and secondary patency at 12months, and primary patency at 24months. After descriptive statistical analysis, a survival analysis was conducted using the Kaplan-Meier method. Eighteen perioperative factors potentially associated with primary patency were studied by univariate and multivariate analysis adjusted by a Cox regression model. In all, 82 patients (112 limbs) had undergone an attempt at endovascular (n=55, 67%) or hybrid (n = 27, 33%) treatment for AIOD D over the study period. The technical success rate was 99%. The 30-day mortality rate was 3%. The early major complication rate was 11%. The primary patency rates at 12 and 24months were 87.9% [80.3; 96.3] and 77% [66.3; 89.3], respectively. The primary assisted and secondary patency rates at 12months were 92.6% [86.3; 99.2] and 96% [91.4; 100]. Among the perioperative factors studied, the heavily calcified nature of the target lesions was the only variable significantly associated with primary patency loss in the multivariate analysis (P=0.021). Although the results of endovascular and hybrid treatment of AOID D are acceptable, future studies should focus on improving patency rates in heavily calcified lesions. Specific tools of endovascular preparation (intravascular lithotripsy, atherectomy) may represent interesting ways of research.

8mm Conduit Outperforms 6mm Conduit in Extra-anatomic Bypass

Extra-anatomic bypass is an important tool in relieving supra-inguinal occlusive disease. These bypasses are frequently conducted with prosthetic material, commonly available in 6-mm and 8-mm sizes. Previous studies have demonstrated infra-inguinal bypass has improved patency when graft size is 6 mm or greater. This study aimed to examine outcomes of 6-mm vs 8-mm prosthetic graft use in extra-anatomic bypasses. A retrospective analysis of the Vascular Quality Initiative supra-inguinal database (2010-2022) was conducted. Patients undergoing either axillary-femoral or femoral-femoral prosthetic bypass with available conduit size data were included. Primary endpoints included graft patency and major adverse limb events (MALE). A logistic regression analysis was performed of demographic and operative variables to determine if any factors contributed to the selection of graft size. Then, multivariable Cox regression analysis was conducted in groups based on prosthetic diameter (6 mm vs 8 mm), controlling for these factors. Seven mm was excluded from formal regression analysis due to small sample size but included in survival curves to demonstrate the stepwise impact of graft size. A total of 6463 patients were included for analysis; 2355 axillary-femoral bypasses and 4128 femoral-femoral bypasses. Of these, 1071 patients underwent bypass with 6-mm graft, and 5392 patients underwent bypass with 8-mm graft. Significant predictors (P < .05) of 8-mm graft use in both types of extra-anatomic bypass included male gender, body mass index (BMI) of 25-35 kg/m2, and common femoral as distal target when compared to profunda, superficial femoral artery, and other distal vessels. The most significant predictor (P < .001) of improved primary patency in both types of extra-anatomic bypass examined was larger conduit diameter (8 mm vs 6 mm axillary-femoral hazard ratio [HR], 0.5; femoral-femoral HR, 0.66). Cox regression curves by graft size were generated for both axillary-femoral and femoral-femoral bypasses (Figs 1 and 2), which demonstrated significantly higher primary patency in patients with 8-mm bypasses over time. Improved performance in 8-mm graft compared with 6-mm graft was additionally demonstrated in primary-assisted patency, secondary patency, and MALE regression curves with P < .001 for both axillary-femoral and femoral-femoral bypasses. In this retrospective analysis of extra-anatomic bypasses, 8-mm grafts had significantly improved patency rates and fewer MALE when compared with 6-mm grafts over time. Male sex and body mass index were associated with larger diameter bypass use; after controlling for these preoperative factors, 8-mm grafts still outperformed 6-mm grafts. Vascular surgeons should be cognizant of the potential implications in limb salvage when selecting prosthetic graft for extra-anatomic bypass.Fig 2Primary patency of axillary-femoral bypass over time by graft size.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Ten-year Experience of Surgical Management of Paget-Schroetter Syndrome

Paget-Schroetter syndrome (PSS) or effort-induced thrombosis, is an acute (< 14 days) venous thrombosis of the axillosubclavian vein. Early catheter-directed thrombolysis is required, to improve patency rate and avoid post thrombotic syndrome. This study aimed to report the management of Paget-Schroetter syndrome in our center across 10 years and to compare it to the established guidelines. Some of the selected patients were treated with catheter-directed thrombolysis (CDT) if the diagnosis of acute vein thrombosis was established 6 weeks after the appearance of the first symptoms and if a vascular surgeon was involved in the care and management of the patient. Patients underwent first rib removal 6 weeks after the CDT. Some patients with primary upper-limb venous thrombosis were not immediately referred to a vascular surgeon after the initial diagnosis. They were instead discharged home with the prescription of oral anticoagulation therapy (OAT) alone for at least 3 months. Between 2010 and 2020, 426 first rib removal procedures were performed for 338 patients with TOS at our center. Among them, eighteen (4.2%) patients with PSS were identified. Five (27.8%) patients underwent catheter directed thrombolysis. Median duration between first symptoms and thrombolysis was 10 days (range 1 to 32). Thirteen (72.2%) patients were discharged home with oral anticoagulation therapy alone and referred to a vascular surgeon with a median time of 365 days (range 8 to 6422) for thoracic outlet syndrome diagnosis. Post-thrombotic syndrome was noticed in 5 (38%) patients in the OAT group and 1 (20%) patient in the CDT group. Despite the guidelines being in favor of early CDT in Paget-Schroetter syndrome, most patients are discharged home o, oral anticoagulation therapy alone. The study findings demonstrate that better information about this specific complication must be provided to the concerned practitioners who are likely to encounter such patients.

Three-Year Patency Results following Endovascular Transvenous Femoropopliteal Bypass

Background and Objectives: Peripheral artery disease is one of the most common vascular pathologies. There is an ongoing debate among specialists on whether open or endovascular revascularization is preferred in cases of complex superficial femoral artery (SFA) lesions. The purpose of this study was to assess patency results of a relatively new transvenous endovascular bypass device. This could add to existing evidence and aid in comparison between open and endovascular bypass. Materials and Methods: Patients with complex TASC-C and D SFA lesions who had indications for revascularization were identified. Prospective analysis of stent graft patency from 54 transvenous femoropopliteal bypass procedures was performed. Patency was assessed by Duplex ultrasound every six months. Kaplan-Meier analysis was performed to assess primary, primary-assisted, and secondary patency of transvenous bypass. Results: Following endovascular transvenous femoropopliteal bypass, 3-year graft primary, primary-assisted, and secondary patency was 43.8%, 66.3%, and 73.9%, respectively. Conclusions: Transvenous endovascular femoropopliteal bypass is a viable option for selected patients who lack adequate saphenous vein or have comorbidities that increase the risk of open femoropopliteal bypass. Strict post-operative follow-up is necessary to improve patency rates.

Choosing the right treatment for the right lesion, part I: a narrative review of the role of plain balloon angioplasty in dialysis access maintenance.

The majority of patients with end-stage renal disease (ESRD) requiring hemodialysis (HD) do so via an arteriovenous fistula (AVF) or graft. Both of these accesses are complicated by dysfunction related to neointimal hyperplasia (NIH) and subsequent stenosis. Percutaneous balloon angioplasty using plain balloons is the first line treatment for clinically-significant stenosis, with excellent initial response rates, however, with poor long-term patency and need for frequent reintervention. Recent research has sought to improve patency rates utilizing antiproliferative drug-coated balloons (DCBs), however, their role in treatment has not yet been fully determined. In part one of this two-part review, we aim to provide a comprehensive overview of the mechanisms of arteriovenous (AV) access stenosis, the evidence behind their treatment with high-quality plain balloon angioplasty techniques, and treatment considerations for specific stenotic lesions. An electronic search was performed on PubMed and EMBASE to identify relevant articles from 1980 to 2022. The highest available level of evidence regarding stenosis pathophysiology, angioplasty techniques, and approaches to treating different types of lesions within fistulas and grafts were included as part of this narrative review. NIH, and subsequent stenoses, develop via a combination of upstream events, causing vascular damage, and downstream events, representing the subsequent biologic response. The large majority of stenotic lesions can be treated utilizing high-pressure balloon angioplasty, with the addition of ultra-high pressure balloon (UHPB) angioplasty for resistant lesions and prolonged angioplasty with progressive balloon upsizing for elastic lesions. Additional treatment considerations must be taken into account when treating specific lesions, including cephalic arch and swing point stenoses in fistulas and graft-vein anastomotic stenoses in grafts, amongst others. High-quality plain balloon angioplasty, performed utilizing the available evidence-basis regarding technique and considerations for specific lesion locations, is successful in treating the large majority of AV access stenoses. While initially successful, patency rates remain non-durable. Part two of this review will discuss the evolving role of DCBs, which seek to improve angioplasty outcomes.

Abstract 15181: PET/CT Imaging for Evaluating Inflammation in Rapamycin Coated Tissue-Engineered Arterial Grafts Implanted in an Ovine Model

Introduction: Small diameter tissue-engineered arterial grafts (TEAGs) conjugated with rapamycin may improve TEAG outcomes by reducing early post-implant inflammatory responses, thereby improving rates of TEAG patency. Therefore, the objective of this study was to apply in vivo PET/CT imaging to compare inflammation and patency of TEAGs conjugated with or without rapamycin. We hypothesized that rapamycin-coated TEAGs would have reduced inflammation and improved patency rates that could be evaluated during a single imaging session using 18 F-FDG PET/CT imaging. Methods: Rapamycin coated (n=3) and non-rapamycin coated (n=3) TEAGs were unilaterally implanted in the carotid artery of juvenile lambs. Flourine-18 ( 18 F)-fluorodeoxyglucose (FDG) PET/CT imaging was performed 8 weeks after TEAG implantation to quantify inflammation of the graft, which was expressed as the maximum standardized uptake value (SUV max ) in the graft. Graft patency was assessed using co-registered CT angiography imaging. In vivo PET/CT imaging results were further evaluated by ex vivo gamma counting of 18 F-FDG uptake in TEAG tissue. Results: In vivo PET/CT detected qualitative and quantitative differences in inflammation between non-drug coated and drug coated TEAGs (SUV max : 6.18±1.67 vs, 4.25±0.81; p=0.1). Differences in inflammation between groups were significant when evaluating results of ex vivo gamma counting of 18 F-FDG uptake (% Injected dose/g: 0.86±0.10 vs, 0.50±0.010; p=0.003). Additionally, CT angiography demonstrated that all rapamycin-coated TEAGs were patent (3/3) at 8 weeks post-implant whereas only one non-drug coated TEAG remained patent (1/3). Conclusions: Conjugation of TEAGs with rapamycin prevents excessive inflammation in the early months after implantation and maintains graft patency. PET/CT offers a translatable imaging approach that allows for combined in vivo assessment of the functional and anatomical characteristics of TEAGs and may assist in optimizing scaffold design for next-generation TEAGs.

Pulmonary vein stenosis – ballooning vs. stenting: a systematic review and meta-analysis

Abstract Background Pulmonary vein stenosis (PVS), which is often unrecognized, may arise from a variety of conditions resulting in major morbidity and mortality. In some patients, pharmacological therapy may help but more often in advance stages, mechanical treatment must be considered. Transcatheter approaches, both balloon angioplasty (BA) and stent implantation have been applied. While both may be effective, they continue to be limited by restenosis. Herein, we compare the outcomes following BA and stenting for PVS. Purpose PVS presents a challenge for both diagnosis and therapy, with BA and stenting being primarily limited by restenosis. Stenting is performed in most cases and is associated with improved patency rates. Historical comparisons of BA and stenting for PVS have yielded similar results. Our analysis incorporates more conventional studies (2010–2021) and provides a larger stent (N=361) versus BA (N=229) contemporary analysis of the current state of PV intervention practice. Methods From January 1, 2010 to August 2, 2021, studies, limited to English language and humans, were assessed in Ovid MEDLINE®, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus. Two independent reviewers screened articles including those in which balloon angioplasty or stenting was performed for pulmonary vein stenosis with reporting of restenosis outcomes and data was independently extracted. Systematic review was performed, and overall restenosis rates were reported across all included studies. Meta-analysis was then performed using RevMan 5.4 assessing rates of restenosis and restenosis requiring repeat intervention. Results Our systematic review yielded 34 studies reporting on BA and/or stenting for PVS. Of these, 7 studies (1–7), treating a total of 343 patients with 590 PV interventions (229 BA and 361 Stents) reported restenosis rates with mean follow-up ranging from 10 to 60 months. Stenting was associated with a lower risk of restenosis compared to balloon angioplasty [risk ratio 0.35, 95% CI (0.18, 0.64), p=0.0008] (Figure 1). Restenosis requiring repeat intervention was reported in 5 studies, including 303 patients with 502 PV interventions (160 BA and 342 Stents) with stenting similarly associated with a lower risk of restenosis requiring re-intervention [risk ratio 0.34, 95% CI (0.16, 0.72), p=0.005]. Conclusion Stenting for pulmonary vein stenosis is associated with reduced risk of restenosis and re-intervention as compared to balloon angioplasty. Funding Acknowledgement Type of funding sources: None.

Transjugular Intrahepatic Portosystemic Shunt

Transjugular intrahepatic portosystemic shunt (TIPS) is now a well established percutaneous means of decreasing portal hypertension. The major clinical indications for transjugular intrahepatic portosystemic shunt are refractory variceal hemorrhage and refractory ascites. The shunt itself is created by placing a stent between the portal vein and the hepatic vein. The resultant shunting of portal venous flow to the systemic circulation helps reduce the portosystemic gradient and alleviate bleeding and ascites without changing the extrahepatic anatomy. History and Development The transjugular intrahepatic portosystemic shunt was initially described in 1969, originally by prolonged balloon dilation of a percutaneously created tract between the portal and hepatic veins. Unfortunately, short patency of the track remained a major clinical hurdle to its widespread use. The development of balloon expandable metallic stents and the subsequent introduction of flexible bare-metal stents helped improve patency rates. Intimal hyperplasia within the stent, especially at the hepatic venous end, required frequent secondary interventions such as balloon dilation and re-stenting. Early thrombosis was felt to be secondary to placing the transjugular intrahepatic portosystemic shunt across a major bile duct. Advances in stent technology and the introduction of polytetrafluoroethylene-covered stents over a decade ago has led to further increase in clinical patency and improved long-term results with TIPS.

Atherectomy vs Other Modalities for Treatment During Peripheral Vascular Intervention.

Calcified atheroma is frequently encountered in peripheral vascular intervention. Standard treatment with balloon and/or stenting alone does poorly in these cases due to vessel recoil, suboptimal luminal gain, and inadequate stent expansion. In light of the above challenges with angioplasty and stenting for PAD, endovascular atherectomy has emerged as a novel technology for atheroma treatment and removal, offering the benefits of surgical endarterectomy in a minimally invasive percutaneous approach. This review outlines the endovascular atherectomy devices available in clinical practice to date, compares and contrasts their mode of action, summarizes the relevant published data on indication and role of atherectomy over other treatment modalities for PAD, and discusses the future prospective on this emerging technology. Currently, there are host of peripheral atherectomy devices available with unique mechanism of action and relative advantages and disadvantages. Despite these recent technological advancements, there remains a paucity of data from well-designed studies regarding the superiority of atherectomy as an adjunctive treatment versus standard treatment with balloon and stenting. Emerging data have supported its use to improve patency rates in conjunction with drug-coated balloons. Although associated risks, including distal embolization and perforation, are often marginal, the cost of these devices to the healthcare system necessitates further investment in to establishing level 1 data to support their use. Peripheral atherectomy has the potential to improve limb-related outcomes, potentially through reduced need for bail-out scaffolds and improved drug uptake. Nonetheless, further investment in the evidence foundation supporting these devices versus standard practices is required.

A Computational Framework Examining the Mechanical Behaviour of Bare and Polymer-Covered Self-Expanding Laser-Cut Stents.

Polymer covered stents have demonstrated promising clinical outcomes with improved patency rates compared to traditional bare-metal stents. However, little is known on the mechanical implication of stent covering. This study aims to provide insight into the role of a polymeric cover on the biomechanical performance of self-expanding laser-cut stents through a combined experimental-computational approach. Experimental bench top tests were conducted on bare and covered versions of a commercial stent to evaluate the radial, axial and bending response. In parallel, a computational framework with a novel covering strategy was developed that accurately predicts stent mechanical performance. Different stent geometries and polymer materials were also considered to further improve understanding on covered stent mechanics. Results show that stent covering causes increased initial axial stiffness and up to 60% greater radial resistive force at small crimp diameters as the cover folds and self-contacts. The incorporation of a cover allows stent designs without interconnecting struts, thereby providing improved flexibility without compromising radial force. It was also shown that use of a stiffer PET polymeric covering material caused significant alterations to the radial and axial response, with the initial axial stiffness increasing six-fold and the maximum radial resistive force increasing four-fold compared to a PTFE-PU covered stent. This study demonstrates that stent covering has a substantial effect on the overall stent mechanical performance and highlights the importance of considering the mechanical properties of the combined cover and stent.

Treatment of cephalic arch stenosis in dysfunctional arteriovenous fistulas with paclitaxel-coated versus conventional balloon angioplasty

BackgroundTreatment of cephalic arch stenosis (CAS) with standard plain old balloon angioplasty (POBA) in dysfunctional arteriovenous fistulas (AVF), is associated with early re-stenosis and higher failure rates compared to other lesions. Paclitaxel-coated balloons (PCB) may improve patency rates. This is a retrospective cohort study. Patients who underwent POBA or PCB for CAS over a 3-year period were included. Outcomes compared were circuit primary patency rates (patency from index procedure to next intervention), circuit primary assisted-patency rates (patency from index procedure to thrombosis), and target lesion (CAS) patency rates (stenosis > 50%) at 3, 6 and 12 months.ResultsNinety-one patients were included. Sixty-five (71.4%) had POBA, while 26 (28.6%) had PCB angioplasty. There were 62 (68.1%) de-novo lesions. CAS was the only lesion that needed treatment in 24 (26.4%) patients. Circuit primary patency rates for POBA versus PCB groups were 76.2% vs. 60% (p = 0.21), 43.5% vs. 36% (p = 0.69) and 22% vs. 9.1% (p = 0.22) at 3, 6 and 12-months respectively. Circuit assisted-primary patency rates were 93.7% vs. 92% (p = 1.00), 87.1% vs. 80% (p = 0.51) and 76.3% vs. 81.8% (p = 0.77), whilst CAS target lesion intervention-free patency rates were 79.4% vs. 68% (p = 0.40), 51.6% vs. 52% (p = 1.00) and 33.9% vs. 22.7% (p = 0.49) at 3, 6 and 12-months respectively. Estimated mean time to target lesion intervention was 215 ± 183.2 days for POBA and 225 ± 186.6 days for PCB (p = 0.20).ConclusionTreatment of CAS with PCB did not improve target lesion or circuit patency rates compared to POBA.

Contemporary coronary artery bypass graft surgery and subsequent percutaneous revascularization.

Patients who have undergone coronary artery bypass graft (CABG) surgery are susceptible to bypass graft failure and progression of native coronary artery disease. Although the saphenous vein graft (SVG) was traditionally the most-used conduit, arterial grafts (including the left and right internal thoracic arteries and the radial artery) have improved patency rates. However, the need for secondary revascularization remains common, and percutaneous coronary intervention (PCI) has become the most common modality of secondary revascularization after CABG surgery. Procedural characteristics and clinical outcomes differ considerably from those associated with PCI in patients without previous CABG surgery, owing to altered coronary anatomy and differences in conduit pathophysiology. In particular, SVG PCI carries an increased risk of complications, and operators are shifting their focus towards embolic protection strategies and complex native-vessel interventions, increasingly using SVGs as conduits to facilitate native-vessel PCI rather than pursuing SVG PCI. In this Review, we discuss the differences in conduit pathophysiology, changes in CABG surgery techniques, and the latest evidence in terms of PCI in patients with previous CABG surgery, with a particular emphasis on safety and long-term efficacy. We explore the subject of contemporary CABG surgery and subsequent percutaneous revascularization in this complex patient population.

A prospective randomized feasibility trial comparing angiography and angiography with intravascular ultrasound for treatment of hemodialysis access failures.

Hemodialysis accesses suffer from limited primary patency requiring frequent interventions, revisions, or even abandonment. Prolongation of access life and usability with minimization of these adverse events is paramount. Endovascular methods are established first-line interventions for failing arteriovenous access and treatment of venous outflow stenoses. The Primary goal of this feasibility study was to evaluate intravascular ultrasound (IVUS) during interventional treatments on outcomes in those undergoing angiography for failing hemodialysis access. Secondary goals were to determine differences between IVUS and angiography on vessel and lesion characteristics and impact on treatment. In this prospective, randomized controlled trial, patients scheduled for angiography to evaluate and treat a failing hemodialysis access were randomized to use of angiography (DSA) alone or angiography plus IVUS (DSA + IVUS). Patients were treated by a standardized protocol and seen in follow-up at 2weeks, and every 3months for 2 years or until a study endpoint was reached. Measurement of vessel diameters, % stenosis, lesion length, and study endpoints (AV access thrombosis, re-intervention, or surgical revision) were recorded. A total of 55 subjects were enrolled, 27 in the DSA cohort and 28 in the DSA + IVUS cohort. There were 41 treated lesions in each group. Freedom from the composite endpoint of AV access thrombosis or re-intervention was 46.3% in the DSA cohort and 61.0% in the DSA + IVUS cohort (p = 0.27). Diameter measurements matched between the two imaging modalities only 9 times out of 41 total comparison measures. In pre-treatment lesions with >80% stenosis, IVUS had a greater tendency than DSA to underestimate the severity of stenosis, whereas in pre-treatment lesions with 50-80% stenosis, DSA was more likely than IVUS to underestimate the severity of stenosis. Post-treatment % stenosis had mean difference of -7.5% between DSA versus DSA + IVUS cohorts. In five lesions with <30% stenosis measured by angiogram, IVUS led to treatment escalation. In the interventional treatment of failing angioaccess, IVUS and angiography differ in the vast majority of cases in measurement of vessel diameter. A significant number of patients were found to have suboptimal therapeutic response by IVUS only, which led to an escalation in treatment, and in over one-third of cases, the IVUS results led to a change in treatment plan. The improved patency rates in the IVUS group was not statistically significant in this small population but should be further investigated in a larger trial.

A multicenter randomized controlled trial indicates that paclitaxel-coated balloons provide no benefit for arteriovenous fistulas

The role of paclitaxel-coated balloons has been established in the coronary and peripheral arterial circulations with recent interest in the use of paclitaxel-coated balloons to improve patency rates following angioplasty of arteriovenous fistulas. To assess the efficacy of paclitaxel-coated angioplasty balloons to prolong the survival time of target lesion primary patency in arteriovenous fistulas, we designed an investigator-led multi-center randomized controlled trial with follow up time variable for a minimum of one year. Patients with an arteriovenous fistula who were undergoing an angioplasty for a clinical indication were included but patients with one or more lesions outside the treatment segment were excluded. Following successful treatment with a high-pressure balloon, 212 patients were randomized. In the intervention arm, the second component was insertion of a paclitaxel-coated balloon. In the control arm, an identical procedure was followed, but using a standard balloon. The primary endpoint was time to loss of clinically driven target lesion primary patency. Primary analysis showed no significant evidence for a difference in time to end of target lesion primary patency between groups: hazard ratio 1.18 with a 95% confidence interval of 0.78 to 1.79. There were no significant differences for any secondary outcomes, including patency outcomes and adverse events. Thus, our study demonstrated no evidence that paclitaxel-coated balloons provide benefit, following standard care high-pressure balloon angioplasty, in the treatment of arteriovenous fistulas. Hence, in view of the benefit suggested by other trials, the role of paclitaxel-coated angioplasty balloons remains uncertain.

Message from the East About Anticoagulation After Deep Venous Stenting: The Agent Matters in Accomplishing the Mission

The study by Zhang et al.1 compares the outcomes when rivaroxaban or warfarin is administered for the first year after venous stenting for post-thrombotic syndrome (PTS). The data from well matched groups provide useful safety and efficacy endpoints. We see that at one year there was no difference between the anticoagulants in complication rates but an apparent improved patency rate for patients on rivaroxaban. In addition, those patients on rivaroxaban had better ulcer healing, lower Villalta scores, lower symptom recurrence and a reduced need for re-intervention.

Patency of ePTFE Arteriovenous Graft Placements in Hemodialysis Patients: Systematic Literature Review and Meta-Analysis.

Arteriovenous grafts (AVGs) are an appropriate option for vascular access in certain hemodialysis patients. Expanded polytetrafluoroethylene (ePTFE) has become the dominant material for such grafts, due in part to innovations in graft design and surgical interventions to reduce complications and improve patency rates. Comprehensive evidence syntheses have not been conducted to update AVG performance in an era in which both access choice and ePTFE graft functioning may have changed. We conducted a systematic review and meta-analysis summarizing outcomes from recent studies of ePTFE AVGs in hemodialysis, following PRISMA standards. Literature searches were conducted in multiple databases to identify observational and interventional studies of AVG patency and infection risk. Primary, primary-assisted, and secondary patency rates were analyzed at 6, 12, 18, and 24 months postplacement. Kaplan-Meier graft survival plots were digitized to recreate individual patient-level data. Patency rates were pooled using a random effects model. We identified 32 studies meeting our selection criteria that were published from 2004 through 2019. A total of 38 study arms of ePTFE grafts were included, representing 3381 AVG accesses placed. The mean primary, primary-assisted, and secondary patency rates at 1 year were 41% (95% CI, 35% to 47%), 46% (95% CI, 41% to 51%), and 70% (95% CI, 64% to 75%), respectively. Mean 24-month patency rates were 28% (95% CI, 22% to 33%), 34% (95% CI, 27% to 41%), and 54% (95% CI, 47% to 61%), respectively. A high degree of heterogeneity across studies was observed. Overall risk of infection was not consistently reported, but among available studies the pooled estimate was 9% per patient-year (95% CI, 6% to 12%). This meta-analysis provides an up-to-date estimate of the performance of ePTFE AVGs, within the context of improved graft designs and improved interventional techniques.

Artery to vein configuration of arteriovenous fistula improves hemodynamics to increase maturation and patency.

Arteriovenous fistulae (AVF) are the preferred mode of hemodialysis access, but 60% of conventional [vein-to-artery (V-A)] AVF fail to mature, and only 50% remain patent at 1 year. We previously showed improved maturation and patency in a pilot study of the radial artery deviation and reimplantation (RADAR) technique that uses an artery-to-vein (A-V) configuration. Here, we show that RADAR exhibits higher rates of maturation, as well as increased primary and secondary long-term patencies. RADAR is also protective in female patients, where it is associated with decreased reintervention rates and improved secondary patency. RADAR and conventional geometries were compared further in a rat bilateral carotid artery-internal jugular vein fistula model. There was decreased cell proliferation and neointimal hyperplasia in the A-V configuration in male and female animals, but no difference in hypoxia between the A-V and V-A configurations. Similar trends were seen in uremic male rats. The A-V configuration also associated with increased peak systolic velocity and expression of Kruppel-like factor 2 and phosphorylated endothelial nitric oxide synthase, consistent with improved hemodynamics. Computed tomography and ultrasound-informed computational modeling showed different hemodynamics in the A-V and V-A configurations, and improving the hemodynamics in the V-A configuration was protective against neointimal hyperplasia. These findings collectively demonstrate that RADAR is a durable surgical option for patients requiring radial-cephalic AVF for hemodialysis access.

Undersized stent graft for treatment of cephalic arch stenosis in arteriovenous hemodialysis access

Cephalic arch stenosis (CAS) is a common cause of AV dialysis access failure and is notoriously difficult to treat with conventional venoplasty. Although stent graft (SG) placement has improved patency rate, they are prone to stent failure caused by edge stenosis. We investigate the effect of SG diameter relative to cephalic vein on patency rate among hemodialysis patients with dysfunctional arteriovenous access caused by CAS. We identified 22 patients with recalcitrant cephalic arch stenosis or post-venoplasty vessel rupture and received SG placement. Patients were divided into two groups based on the stent-to-vessel diameter (S/V) ratio: undersized group, < 1; and apposed group, 1–1.2. Outcomes were assessed through follow-up angiography. S/V ratio was significant smaller in the undersized patient group (p < 0.001). Placement of undersized SG demonstrated higher primary stent (p = 0.001) and access patency rates (p = 0.021) and a reduced number of post-treatment reinterventions per access year (p = 0.021). A decreased number of lateral edge stenosis was noted in undersized SG (p = 0.005). Increased S/V ratio was significantly associated with lateral edge stenosis (OR = 5.19; p = 0.027). Undersized SG is associated with higher primary stent and access patency rate, and decreased number of post-SG interventions, and are suggested in the treatment of cephalic arch stenosis.

The Impact of Novel Oral Anticoagulants on Outcomes of Patients Undergoing Lower Extremity Bypass

There is no consensus on the efficacy of anticoagulation to improve patency rates of lower extremity bypass (LEB) grafts. Historical studies, focusing primarily on vitamin K and platelet antagonists, produced mixed results. The introduction of direct oral anticoagulants (DOACs) has changed the landscape and warrants renewed examination of this important clinical question. Therefore, we sought to compare the outcomes of different postoperative anticoagulation regimens of patients undergoing LEB.

Vasovasostomy: kinetics and predictors of patency

To assess the timing of patency and late failure (secondary azoospermia) after vasovasostomy (VV) using standardized kinetics definitions. Retrospective cohort study. University-affiliated hospital. Patients with obstructive azoospermia. Vasovasostomy. Univariate and multivariate logistic regression assessed predictors of patency and late failure. Patency was defined as any sperm return to the ejaculate; and >2 million total motile sperm (TMS) in ejaculate. Late failure after VV was defined as azoospermia; or <2 million TMS in ejaculate. 429 men underwent VV, with median follow up of 242 days. Mean time to patency was 3.25 months versus 5.29 months in the "any sperm" versus ">2 million TMS" groups. Finding sperm intraoperatively during VV significantly improved patency rates in multivariable analysis (odds ratio [OR] 4.22). This association was further boosted when sperm was found bilaterally (OR 6.70). Late failure rate (azoospermia) was 10.6% at mean time of 14.1 months and 23% for <2 million, at mean time of 15.7 months. When assessing predictors of late failure, intraoperative motile sperm bilaterally was a statistically significant protective factor on multivariate analysis (hazard ratio 0.22). Vasovasostomy remains highly efficacious in treating obstructive azoospermia. Young patients, shorter obstructive intervals, and sperm identified intraoperatively predict improved outcomes. Clinicians can expect VV patency in 3 months and late failure within the first 2 years after surgery. However, patency rates, late failure rates, and kinetics vary by definition.