Maintenance of Hemodialysis Vascular Access and Prevention of Access Dysfunction: A Review

Hemodialysis nurses' knowledge, attitude, and practices in managing vascular access: A cross-sectional study in Saudi Arabia

Hemodialysis continues to be the primary approach for renal replacement therapy. Vascular access (VA), particularly arteriovenous fistula or arteriovenous graft, is the preferred technique for establishing hemodialysis access due to its lower risk of infection and central venous stenosis compared to catheters. The aim of this cross-sectional investigation was to examine hemodialysis nurses' knowledge, confidence, and practices in managing VA in Saudi Arabia. This is an online cross-sectional survey study that was conducted in Saudi Arabia between June and August 2023. This study utilized a previously validated questionnaire. Examined dialysis nurses' knowledge, attitude, practice, and self-efficacy pertaining to VA cannulation and evaluation. Binary logistic regression analysis was used to identify predictors of better knowledge of dialysis VA. A total of 197 participants were involved in this study. Around one-third of the study participants (37.0%) reported that they have received specialized training in managing VA. Participants agreement (answered agree or strongly agree) on statements that examined attitudes toward dialysis VA cannulation and management was high and ranged between 75.0% and 93.0%. The majority of participants (97.5%) reported that they perform this assessment. Most nurses (65%) preferred the rope-ladder technique. Participants agreement on statements that examined self-efficacy on dialysis VA cannulation and management was high and ranged between 72.1% and 98.0%. The most commonly agreed upon statement was that "they have confident in performing hemodialysis access (arteriovenous fistula and arteriovenous graft) assessment before cannulation." With 98.0% (answered agree and strongly agree). The mean knowledge score for our study sample was 6.4 (SD: 2.0) out of 12 (53.3%); which reflects marginal-level of knowledge on dialysis VA. Binary logistic regression analysis identified that nurses who have undergraduate degree are 92% more likely to be knowledgeable on dialysis VA compared to others (P < .05). Concerning VA, the level of knowledge among hemodialysis nurses working in Saudi Arabia was inadequate. Nurses who hold an undergraduate degree are presumed to have a more extensive understanding of dialysis VA. Further education programs are necessary for HD nurses to enhance their knowledge of VA, thereby optimizing their professional practices and enhancing the outcomes for their patients.

Early arteriovenous fistula failure associated with mortality and major adverse cardiovascular events in patients undergoing incident hemodialysis

BACKGROUND

Arteriovenous fistula (AVF) patency is important for patients undergoing hemodialysis. The association between early AVF failure and the prognosis, including all-cause mortality and major adverse cardiovascular events (MACE), has not been fully investigated. The present study was performed to investigate the association between early AVF failure and 3-year mortality, cardiovascular disease (CVD) mortality, and MACE.

METHODS

We analyzed 358 patients who started hemodialysis in our institution from October 2008 to February 2020. We defined early AVF failure as cases requiring percutaneous transluminal angioplasty or reoperation within 1 year after AVF surgery. The patients were divided into two groups according to the presence or absence of early AVF failure, and the prognosis of each group was examined. The association between early AVF failure and outcomes (3-year all-cause mortality, CVD mortality, and MACE) was determined using Cox proportional hazards regression analysis.

RESULTS

During the 3-year follow-up, 75 (20.9%) patients died (cardiovascular death: n = 39) and 145 patients developed MACE. According to the multivariable analysis, the early AVF failure group had a significantly higher risk of 3-year all-cause mortality (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.09-1.83; p = 0.009), CVD mortality (HR, 1.54; 95% CI, 1.29-2.08; p < 0.001), and MACE (HR, 1.68; 95% CI, 1.25-2.26; p < 0.001). When the patients were stratified by age, early AVF failure was associated with 3-year all-cause mortality in all groups except for the younger group (<65 years of age).

CONCLUSIONS

Early AVF failure was associated with an increased risk of 3-year all-cause mortality, CVD mortality, and MACE.

Dialysis Access-Associated Steal Syndrome in High-Risk Patients Undergoing Surgery for Hemodialysis Access: A Systematic Review and Meta-Analysis of Preventive Operative Techniques

This systematic review and meta-analysis examine preventive operative techniques in high-risk patients undergoing surgery for hemodialysis access to mitigate the risk of Dialysis Access-Associated Steal Syndrome (DASS). Chronic kidney disease often leads to end-stage renal disease (ESRD), necessitating dialysis. Successful vascular access is crucial for efficient dialysis, but complications, such as DASS, pose significant challenges. DASS redirects arterial blood flow, affecting populations undergoing arteriovenous access surgery. This study aims to assess preventive strategies, including distal revascularization with interval ligation (DRIL) and extension techniques. A systematic search of PubMed, Cochrane Library, EMBASE, and Web of Science until 2022 identified 11 relevant studies. The inclusion criteria comprised non-pediatric hemodialysis patients reporting outcomes related to patency and complications. The data were analyzed using Review Manager 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen). Meta-analysis indicated a significant association between DASS and arteriovenous fistula (AVF) or arteriovenous graft (AVG) procedures. Radiocephalic AVF (RC-AVF) and distal endovascular AVF procedures were favored. Various interventions addressed venous narrowing, including simple plication and loop interposition. The Modified by Inserted Latex Link for Endovascular Repair (MILLER) technique, DRIL, Extension Technique, and Proximalization of Arterial Inflow (PAI) were assessed for arterial bypass graft and blood supply preservation. This study underscores the importance of individualized strategies in preventing DASS during hemodialysis access surgery. Prophylactic measures, such as the extension technique, show promise, while DRIL remains effective in treatment. Ongoing research is imperative for optimizing outcomes in this complex patient population.

Improving assessment and escalation of threatened haemodialysis access: results of a nursing-led program

BACKGROUND

Optimal vascular access is critical to successful haemodialysis. Acute thrombosis of haemodialysis access often leads to unplanned hospital admissions and interventions to restore patency. Western Health is a large health service in Victoria, Australia. During the period February 2019 to January 2020, the rate of arteriovenous fistula (AVF) and arteriovenous graft (AVG) at Western Health satellite dialysis units was 0.33 episodes per 1000 patient-days, higher than the reported rate in the literature of 0.24 events per 1000 patient-days, and was associated with a cumulative total of 139 days of inpatient stay (2.2 per 1000 patient-days).

METHODS

The above results prompted creation of an education and escalation pathway for threatened haemodialysis access, based upon clinical markers of vascular access stenosis or imminent thrombosis assessed by nursing staff in satellite haemodialysis centres. In the period February 2020 to January 2021, the education and escalation pathway was implemented. We assessed referrals via the pathway, rates of AVF/AVG thrombosis and associated hospital length of stay in the following 12-month period (February 2021 to January 2022).

RESULTS

Following introduction of the pathway, rates of AVF/AVG thrombosis declined to 0.15 per 1000 patient-days (p = 0.02), associated with a decline in attributable cumulative inpatient stay to 55 days (0.69 per 1000 patient-days).

CONCLUSIONS

Our program demonstrates that the majority of thrombosed vascular access can be predicted and potentially averted with vigilant and well-practiced routine clinical assessment by trained nursing staff. Our nursing-led education and escalation program successfully identified vascular access at risk of imminent thrombosis, reduced rates of acute thrombosis and associated healthcare costs. Despite these improvements, there are still disparities in outcomes for patients with thrombosed vascular access, with regards to length of stay and requirement for insertion of a temporary central venous catheter (CVC) for urgent dialysis whilst awaiting intervention, and these are areas for further investigation and improvement.

Dialysis nurses’ knowledge, attitude, practice and self-efficacy regarding vascular access: A cross-sectional study in Singapore

Introduction:

Dialysis nurses play a paramount role in vascular access (VA) management. The aim of this study is to evaluate dialysis nurses’ knowledge, attitude, practice and self-efficacy (KACP-SE) pertaining to VA cannulation and evaluation.

Method:

An anonymous self-administered survey was administered to dialysis nurses from two tertiary hospitals (four dialysis units) and two community dialysis centres from April to May 2022. The 37-items survey consists of four dimensions of questions relating to VA cannulation and management: knowledge, attitude, practice and self-efficacy. The content validity and face validity of the survey was reviewed by three experienced VA professionals and five dialysis nurses respectively. The internal consistency and construct validity of the survey have been assessed with psychometric tests.

Results:

There were 23 and 47 nurses, working in the participated community and tertiary hospital dialysis centres respectively, responded to the survey. The internal consistency coefficients indicated acceptable reliability of the instrument (KR-20 coefficient was 0.55 and 0.76 for knowledge and practice domains; Cronbach’s α was 0.85 and 0.64 for self-efficacy and attitude domains). In the exploratory factor analysis for attitude and self-efficacy, the instrument could account for 64.0% and 53.0% of the total variance respectively. In the knowledge domain, five out of eight single-select multiple-choice questions were correctly answered by >70% of the participants. Overall, the mean (±SD) of participants’ total self-efficacy score was 24.3 (±3.1) over total score of 30. The majority of the participants (82.4%) either agreed or strongly agreed that ultrasound guidance is useful for cannulation.

Conclusion:

This KAP-SE instrument can be used to evaluate knowledge, attitude, practice and self-efficacy of dialysis nurses toward VA management. The participants demonstrated acceptable knowledge level, but with some knowledge gaps identified. It also revealed nurses’ good self-efficacy level and welcoming attitude towards adopting ultrasound in VA cannulation among the participants.

X-ray-guided and ultrasound-guided percutaneous transluminal angioplasty to treat arteriovenous fistula dysfunction in hemodialysis patients: A retrospective controlled study

PURPOSE

To compare the safety and efficacy of X-ray-guided and ultrasound-guided percutaneous transluminal angioplasty in treating arteriovenous fistula dysfunction.

MATERIALS AND METHODS

Data for 219 patients with arteriovenous fistula dysfunction between January 2016 and December 2018 were retrospectively analyzed. The primary endpoints were technical success, clinical success, and primary patency rates. The secondary endpoints were complications and secondary patency rates. Procedure outcomes and both endpoints were evaluated by propensity score analysis.

RESULTS

After the propensity score matching, 73 matched pairs of cases were created with 34 pairs of autogenous arteriovenous fistula cases and 39 pairs of prosthetic arteriovenous graft cases. There was no significant difference between the X-ray-guided and ultrasound-guided group, respectively, regarding the technical success rate (84.9% vs 87.7%, p = 0.630), clinical success rate (98.6% vs 97.3%, p = 0.999), and complications (10.9% vs 5.5%, p = 0.228). Although the 6- and 12-month secondary patency rates for the dialysis access between the two groups had significant difference (p < 0.05), there was no significant difference in primary and secondary patency curves between the two groups (p > 0.05).

CONCLUSION

The overall efficacy of ultrasound-guided versus X-ray-guided percutaneous transluminal angioplasty in treating arteriovenous fistula dysfunction might be comparable.

Repeated Endovascular Interventions Are Worthwhile, Even After Thrombosis, to Maintain Long-Term Use of Autogenous Dialysis Fistulas

OBJECTIVES

Patients often require multiple access re-interventions to improve fistula patency and the overall usable lifespan of autogenous arteriovenous fistula (aAVF). There is no consensus on the appropriate number of re-interventions after which an access should be abandoned and new access placed. We evaluated whether repeated endovascular interventions for failing/failed aAVF are worthwhile or futile.

METHODS

A retrospective review was performed on aAVFs created between 2009-2014. Fistula function was evaluated until January 2017. Functional fistula patency (FFP) was defined as the total time of functional fistula use for hemodialysis, from time of cannulation to time of measurement or fistula abandonment, including all interventions performed to maintain/reestablish patency. Primary outcomes were FFP duration and number of post-dialysis interventions.

RESULTS

The study included 163 patients. Mean age was 67 (SD = 15.03). The only variable statistically different between functional fistulas and abandoned fistulas was obesity (p = 0.03). At the end of the study period, 145 (89.0%) patients continued to have functional fistulas, and 73 (44.8%) patients died, but had functional fistulas at time of death. Median FFP for the functional group was 3.18 years (range 0.01-7.01 years) and median number of interventions was 1 (range 0-13). In 18 patients (11%), the fistula was abandoned, most commonly due to thrombosis (47.1%), followed by infection (23.5%). No fistula was abandoned because of an unacceptable rate of reintervention. Median FFP in the abandoned group was 0.91 years (range 0.03-5.30 years), and median number of interventions was 0 (range of 0-5).

CONCLUSIONS

Through repeated interventions on aAVFs, none of the patients in our study exhausted all hemodialysis access options prior to transplantation, death or loss to follow-up. These results may indicate repeated and/or more frequent revisions do not negatively affect the FFP nor do they increase the overall risk for abandonment of aAVFs.

Staged brachioradial artery to brachioradial vein arteriovenous fistula creation for hemodialysis access in three patients with a high origin of the radial artery

When patients lack suitable superficial veins in the upper extremity to create an arteriovenous fistula, surgeons are faced with a decision between a synthetic graft or autologous fistula using deep veins, such as a brachial artery to brachial vein arteriovenous fistula. In patients with a high radial artery origin (or brachioradial artery) and inadequate superficial veins, arteriovenous fistula creation will be even more challenging. In the present report, we describe a technique used in three such patients who underwent successful staged brachioradial artery to brachioradial vein arteriovenous fistula creation.

Aneurysm Excision With Arteriovenous Anastomosis Proximalization for Dialysis Fistula Aneurysm Treatment

INTRODUCTION

Dialysis fistula aneurysms are common complications, which require surgical revision in selective cases. The results of aneurysm excision with arteriovenous anastomosis proximalization for the treatment of dialysis fistula aneurysms have been described below.

METHODS

Patients qualified for the reconstruction of a dialysis fistula aneurysm underwent a duplex ultrasound examination. The diameter, length of the aneurysm, relations with the artery, thrombus presence and blood flow were determined. In the case of favorable anatomical conditions, we performed aneurysm excision with arteriovenous anastomosis proximalization as the procedure of choice. Patients, dialysis access, operative data and the results obtained during a median follow-up of 41 months were then analyzed.

FINDINGS

Since 2012, we have performed 20 aneurysm excision combined with primary anastomosis as dialysis fistula aneurysm treatment. In 18 patients, aneurysm excision was combined with simple re-anastomosis in the more proximal arterial segment. In 2 autogenous radio-cephalic forearm direct fistulas the aneurysm excision was combined with switching anastomosis type from side-to-end to end-to-end. The 12- and 24-month primary patency rates of corrected fistulas in the observed group were 94.7% and 82.4%, respectively. No early complications were noted. In 7 patients (35%) we observed late complications, which required reintervention or led to access failure. Dialysis fistula thrombosis as an indication for treatment was a significant risk factor for late re-occlusion.

DISCUSSION

A simple primary reconstruction by arteriovenous anastomosis proximalization and aneurysm excision for the surgical correction of dialysis fistula aneurysms has potential benefits compared to established methods-aneurysmorraphy and aneurysm excision with a vascular prosthesis bypass. The obtained data showed the efficiency, safety and excellent long-term results of this procedure.

Comparison between endovascular versus hybrid thrombectomy for arteriovenous graft under complete ultrasound guidance

BACKGROUND

Endovascular treatment of acute thrombosed arteriovenous grafts performed completely under ultrasound guidance has rarely been reported. We compared the efficacy of a new endovascular thrombectomy technique (percutaneous manual thromboaspiration through the introducer sheath) with classical hybrid thrombectomy (minimally invasive surgical thrombectomy combined with high-pressure angioplasty) performed completely under ultrasound guidance, for arteriovenous graft thrombosis.

METHODS

This was a retrospective cohort study involving patients receiving hemodialysis who underwent arteriovenous graft thrombectomy between January 2014 and December 2017. We divided 130 participants into an intervention (endovascular) group (N.=65) and a control (classical hybrid) group (N.=65) according to the thrombectomy technique. The procedural success rate, immediate outcomes and patency were compared between the groups.

RESULTS

There was no significant difference in the procedural success rate (92.31% vs. 89.23%, P=0.55) between the intervention and control groups, respectively. No major complications were noted, but two cases of vessel rupture occurred in the control group and three cases of vessel rupture occurred in the intervention group. The procedure time in the intervention group was significantly shorter than that in the control group (74±14.21 min vs. 109.05±19.20 min, respectively; P<0.05). During the 6-month follow-up, we found no significant difference in the postintervention primary patency rate (48.33% vs. 55.17%; P=0.51) or the postintervention second patency rate (83.33% vs. 84.49%; P=0.79) between the intervention and control groups, respectively. Dialysis clearance and ≥50% stenosis were predictors of postintervention primary patency (hazard ratio, 7.80; 95% confidence interval: 1.75-34.81; P=0.01; and hazard ratio, 6.43; 95% confidence interval: 2.43-17.03; P<0.001), respectively.

CONCLUSIONS

Completely ultrasound-guided percutaneous manual thromboaspiration through the introducer sheath can be used for thrombosed arteriovenous grafts. This approach has the advantage of shorter operative time compared with hybrid treatment.

A Multicenter Randomized Clinical Trial of Hemodialysis Access Blood Flow Surveillance Compared to Standard of Care: The Hemodialysis Access Surveillance Evaluation (HASE) Study

Introduction

Arteriovenous (AV) access thrombosis remains 1 of the most troubling AV access–related complications affecting hemodialysis patients. It necessitates an urgent and occasionally complicated thrombectomy procedure and increases the risk of AV access loss. AV access stenosis is found in the majority of thrombosed AV accesses. The routine use of AV access surveillance for the early detection and management of stenosis to reduce the thrombosis rate remains controversial.

Methods

We have conducted a multicenter, prospective, randomized clinical trial comparing the standard of care coupled with ultrasound dilution technique (UDT) flow measurement monthly surveillance with the standard of care alone.

Results

We prospectively randomized 436 patients with end-stage renal disease on hemodialysis with arteriovenous fistula (AVF) or arteriovenous graft (AVG) using cluster (shift) randomization to surveillance and control groups. There were no significant differences in the baseline demographic data between the 2 groups, except for ethnicity (P = 0.017). Patients were followed on average for 15.2 months. There were significantly less per-patient thrombotic events (Poisson rate) in the surveillance group (0.12/patient) compared with the control group (0.23/patient) (P = 0.012). There was no statistically significant difference in the total number of procedures between the 2 groups, irrespective of whether thrombectomy procedures were included or excluded, and no statistically significant differences in the rate of or time to the first thrombotic event or the number of catheters placed due to thrombosis.

Conclusion

The use of UDT flow measurement monthly AV access surveillance in this multicenter randomized controlled trial reduced the per-patient thrombotic events without significantly increasing the total number of angiographic procedures. Even though there is a trend, surveillance did not reduce the first thrombotic event rate.

Novel Approaches to Arteriovenous Access Creation, Maturation, Suitability, and Durability for Dialysis

Since the arteriovenous fistula (AVF) was first conceived over 50 years ago, the goal to create a vascular conduit with predictable and reproducible maturation and durability continues to elude caregivers. Recently, however, advances in the understanding of vascular biology and new technologies now provides us with some optimism; we are moving toward a viable solution. A quickly maturing, sustainable, and durable arteriovenous access may soon be attainable. This review will discuss these advances. There are novel approaches to AVF creation and devices to enhance maturation, advances in arteriovenous graft material(s), and devices to safely prolong the use of tunneled dialysis catheters. Although hemodialysis (HD) access remains a complex problem, these innovations may lead the way to optimizing the care and the quality of life of those patients who have no choice but to proceed with HD.

Endoscopic Superficialisation of Haemodialysis Arteriovenous Fistulas in Obese Patients - Safety, Feasibility, and Outcomes

OBJECTIVE

The aim was to evaluate the safety and feasibility of endoscopic superficialisation (ES) in patients with deeply located cephalic veins in well matured arteriovenous fistulae (AVF) and to present functional outcomes.

METHODS

All patients with cannulation difficulties due to a deep lying cephalic vein of more than 6 mm but with an otherwise matured AVF with a straight needle access segment of at least 6 cm were included in this retrospective study. Procedure related safety, defined as completion of ES with no need for conversion to open surgery, and feasibility in terms of cephalic vein depth reduction were assessed. The primary endpoint was three successfully performed haemodialysis sessions using the endoscopically superficialised AVF during a minimum follow up of 12 months.

RESULTS

From June 2013 to August 2017, 12 patients with a mean body mass index of 33.5 ± 3.9 kg/m² underwent ES as a second stage procedure following radiocephalic (n = 5) or brachiocephalic AVF (n = 7) creation. All procedures were conducted endoscopically. Ultrasound imaging 12 weeks post-operatively documented a reduction in the depth of the cephalic vein from a mean of 10.1 ± 1.4 mm to 4.3 ± 0.8 mm. The mean duration of the ES was 69 ± 26.0 min with 67% performed under locoregional anaesthesia. In all but one patient with a cephalic vein of poor wall quality leading to recurrent haematoma, haemodialysis was performed successfully following ES.

CONCLUSIONS

Endoscopic superficialisation of the cephalic vein is a safe and effective technique. Providing good functional results, ES represents an alternative approach for second stage superficialisation in obese patients.

Quality and management care improvement of patients with chronic kidney disease: from data analysis to the definition of a targeted clinical pathway in an Italian Region

BACKGROUND

Clinical Diagnostic Care Pathways (CDCP) are management tools widespread throughout the world to improve the quality of patient care through a well-organized care continuum and to enhance the patient's "risk-adjusted" outcomes; indeed they could optimize the management of resources. They are particularly effective in the management of patients with chronic degenerative diseases, such as chronic kidney disease, with increasingly incidence and prevalence, with an estimated 11-13% of the population being affected. The aim of this study is to apply the Health Services Research methods to estimate the relationship between need, demand and supply in patients with stage 5 Chronic Kidney Disease (CKD) for, then to describe the definition of a CDCP dedicated to patients in Lazio Region, so to allow an appropriate patient management, to reduce the likely complications and the patients' migration to facilities outside the region.

METHODS

The study was conducted in 2017 in collaboration between the National Institute of Health, the University of Messina and the S. Giovanni Addolorata Hospital.

RESULTS

We analyzed the data for the CKD in Roma and in the San Giovanni Addolorata Hospital Trust and we found a drop out in the patients' attendance towards other regions and/or hospitals. So we defined a CDCP to be adopted at the San Giovanni Addolorata hospital.

CONCLUSIONS

To define management and care tools to provide adequate, efficient and patient centered care is a nowadays "must", to ensure the sustainability of the Italian NHS, which today is comparable to a "ship that is heading towards a perfect storm".

Standardized Protocol for Hemodialysis Vascular Access Assessment: The Role of Ultrasound and ColorDoppler

Introduction: Ultrasound and colorDoppler technique, which is relatively inexpensive, rapid, non-invasive and repeatable is a powerful tool used for early diagnosis of vascular access (VA) complications in hemodialysis patients. To date a standard and widely comprehensible echocolorDoppler (ECD) protocol is not available. Materials and Methods: A simple step-by-step protocol based on anatomical and hemodynamic parameters of VA has been developed during a 3-years VA ECD follow-up. It consists of an ECD study scheme. The algorithm created involves the calculation of brachial artery flow, description of artero-venous and/or graft-vascular anastomosis and efferent vessel and/or graft. Results: The algorithm allows to formulate a medical report that takes into account both anatomic and hemodynamic parameters of the VA. Reduction of complications and the prevention of chronic complications as well as the early detection of acute problems were achieved. Discussion and Conclusion: The creation of a step-by-step protocol may simplify the multidisciplinary management of VA, its monitoring and the early diagnosis of its complications.

The formulation and characterization of 3D printed grafts as vascular access for potential use in hemodialysis

Arteriovenous graft (AVG) failure continues to be a life-threatening problem in haemodialysis. Graft failure can occur if the implanted graft is not well-matched to the vasculature of the patient. Likewise, stenosis often develops at the vein-graft anastomosis, contributing to thrombosis and early graft failure. To address this clinical need, a novel ink formulation comprised of ACMO/TMPTA/TMETA for 3D printing a AVG was developed (ACMO-AVG), in which the printed AVG was biocompatible and did not induce cytotoxicity. The ease of customizing the ACMO-AVG according to different requirements was demonstrated. Furthermore, the AVG displayed similar mechanical properties to the commercially available arteriovenous ePTFE graft (ePTFE-AVG). Unlike ePTFE-AVG, the ACMO-AVG displayed excellent anti-fouling characteristics because no plasma protein adsorption and platelet adhesion were detected on the luminal surfaces after 2 h of incubation. Similarly, exposure to human endothelial cells and human vascular smooth muscle cells did not result in any cell detection on the surfaces of the ACMO-AVG. Thus, the present study demonstrates a newly developed 3D printing ink formulation that can be successfully 3D printed into a clinically applicable vascular access used for haemodialysis.

An arteriovenous graft that was successfully 3D printed with a novel printing ink formulation that displayed excellent mechanical and anti-fouling properties.