Snuffbox distal transradial access (dTRA) for arteriovenous fistuloplasty in Singapore: Going distal is safe.

AIM: Arteriovenous fistula (AVF) dysfunction resulting from stenosis or occlusion, is a prevalent issue in end-stage renal failure patients reliant on autogenous AVFs for dialysis. Recently, a distal transradial approach (dTRA) has emerged, offering advantages such as diminished access site complications, better patient comfort and reduced risk of radial artery occlusion. Our study seeks to assess the effectiveness, outcomes and complication rates of employing dTRA for arteriovenous fistuloplasty in Singaporean patients. METHODS: A retrospective review of all dTRA fistuloplasties performed on dysfunctional or slow to mature AVFs from 2017 to 2023 in our institution was performed. Patients with a distal radial artery measuring 2 mm or more with no evidence of occlusion or thrombosis were included. Patients who required central venoplasty or cutting balloon angioplasty were excluded. Outcome measures included technical success, mean procedure duration, complications and post-intervention primary patency at 1, 3 and 6 months. Patients were followed up for 12 months post-intervention. RESULTS: A total of 37 patients were included. 97.3% of patients undergoing dTRA fistuloplasty had radiocephalic fistulas while 2.7% had brachiobasilic fistulas. There was 100% technical success (defined as success in radial artery cannulation, sheath insertion and crossing of stenotic lesions) in our study as all patients successfully underwent fistuloplasty via dTRA approach. One-month patency rate was 97.4%, 3-month patency rate was 92.1% and 6-month patency rate was 86.8%. There were no immediate complications (haematoma, infection, bleeding, pseudoaneurysm, occlusion) of the radial artery post-intervention. CONCLUSION: Our paper illustrates the safety and efficacy of utilising dTRA for arteriovenous fistuloplasty. This approach offers distinct benefits in addressing non-mature or dysfunctional distal forearm arteriovenous fistulas and should be taken into account in anatomically suitable cases.

Risk Prediction of Diabetic Foot Amputation Using Machine Learning and Explainable Artificial Intelligence.

BACKGROUND: Diabetic foot ulcers (DFUs) are serious complications of diabetes which can lead to lower extremity amputations (LEAs). Risk prediction models can identify high-risk patients who can benefit from early intervention. Machine learning (ML) methods have shown promising utility in medical applications. Explainable modeling can help its integration and acceptance. This study aims to develop a risk prediction model using ML algorithms with explainability for LEA in DFU patients. METHODS: This study is a retrospective review of 2559 inpatient DFU episodes in a tertiary institution from 2012 to 2017. Fifty-one features including patient demographics, comorbidities, medication, wound characteristics, and laboratory results were reviewed. Outcome measures were the risk of major LEA, minor LEA and any LEA. Machine learning models were developed for each outcome, with model performance evaluated using receiver operating characteristic (ROC) curves, balanced-accuracy and F1-score. SHapley Additive exPlanations (SHAP) was applied to interpret the model for explainability. RESULTS: Model performance for prediction of major, minor, and any LEA event achieved ROC of 0.820, 0.637, and 0.756, respectively, with XGBoost, XGBoost, and Gradient Boosted Trees algorithms demonstrating best results for each model, respectively. Using SHAP, key features that contributed to the predictions were identified for explainability. Total white cell (TWC) count, comorbidity score and red blood cell count contributed highest weightage to major LEA event. Total white cell, eosinophils, and necrotic eschar in the wound contributed most to any LEA event. CONCLUSIONS: Machine learning algorithms performed well in predicting the risk of LEA in a patient with DFU. Explainability can help provide clinical insights and identify at-risk patients for early intervention.

A substantial number of patients with rest pain, ulceration or gangrene are unable to undergo current non-invasive perfusion testing-Could another modality be utilised?

Rest pain, ulceration and gangrene are hallmark features of chronic limb-threatening ischaemia (CLTI). Wound healing can be challenging, and this is compounded by an inability to measure lower limb perfusion via non-invasive tools such as toe pressure (TP). Novel perfusion tests, such as pedal acceleration time (PAT), may overcome some limitations. This study aimed to quantify the proportion of patients with CLTI that were unable to undergo TP measurement. Over a three-year duration, 344 consecutive patients with CLTI underwent PAT assessment (403 limbs). Overall, 32% of limbs were unable to undergo first toe TP, and 12.9% were unable to undergo first and second toe TP due to forefoot/digit amputation or tissue loss. Inability to measure first toe TP disproportionately impacted CLTI patients with diabetes compared to patients without diabetes (39.6% limbs (106/268); vs. 17% limbs (23/135); p < 0.001). Novel modalities may provide a useful tool for assessing perfusion in CLTI.

A prospective study on the efficacy of sequential treatment of technology Lipido-Colloid Impregnated with Silver and Technology Lipido-Colloid Nano-Oligosaccharide Factor in the management of venous leg ulcers.

Background and Aims: Venous leg ulcers (VLUs) are associated with significant morbidity and poor quality of life (QOL). Compression therapy and wound dressing are the mainstay treatment options. Technology Lipido-Colloid Impregnated with Silver (TLC-Ag) reduces bacterial load and Technology Lipido-Colloid Nano-Oligosaccharide Factor (TLC-NOSF) reduces elevated matrix metalloproteinases and improve wound healing. However, evidence is scarce on the role of sequential therapy. This study aims to evaluate if sequential treatment with TLC-Ag and TLC-NOSF improves VLU wound healing and QOL. Methods: This is a prospective cohort study from May 2020 to October 2021 on patients with VLUs who received sequential therapy, consisting of 2 weeks of TLC-Ag followed by two-layer compression bandage (2LB) with TLC-NOSF until complete wound healing. Participants were followed-up with weekly dressing changes. Our primary outcomes were wound area reduction (WAR) and Pressure Ulcer Scale of Healing (PUSH) score. Our secondary outcomes were QOL measures. Results: There were 28 patients with 57.1% males (n = 16) with a mean age of 65.3 years. Mean duration of VLU was 13.9 ± 11.7 weeks before the initiation of sequential therapy. Mean baseline wound area was 8.44 cm2. Median time to wound healing was 10 weeks. 57.1% of patients achieved complete wound closure at 3 months. There was significant WAR after 1 month (mean area 8.44-5.81 cm2, 31.2% decrease) and after 3 months (mean area 8.44-2.53 cm2, 70.0% decrease). Mean monthly WAR was 28.9%. PUSH score also decreased at 1 month (16.5% decrease, p < 0.001) and 3 months (63.3% decrease, p < 0.001) marks following the sequential therapy. EuroQol Visual Analog Scale (EQ-VAS) improved following sequential therapy (baseline: 69.0 ± 15.0, week 13: 80.2 ± 13.2, p < 0.001). Conclusion: Sequential therapy with TLC-Ag followed by TLC-NOSF and 2LB is feasible, with good wound healing and improvement in QOL of patients with VLUs.

Getting a Foothold on Diabetic Foot Disease-Outcomes of a Multidisciplinary Clinical Pathway for Inpatient Diabetic Foot Care: A 17-Year Institutional Review.

INTRODUCTION: Diabetes foot disease (DFD) contributes to poor quality of life, clinical and economic burden. Multidisciplinary diabetes foot teams provide prompt access to specialist teams thereby improving limb salvage. We present a 17-year review of an inpatient multidisciplinary clinical care path (MCCP) for DFD in Singapore. METHODS: This was a retrospective cohort study of patients admitted for DFD and enrolled in our MCCP to a 1700-bed university hospital from 2005 to 2021. RESULTS: There were 9279 patients admitted with DFD with a mean of 545 (±119) admissions per year. The mean age was 64 (±13.3) years, 61% were Chinese, 18% Malay and 17% Indian. There was a higher proportion of Malay (18%) and Indian (17%) patients compared to the country's ethnic composition. A third of the patients had end stage renal disease and prior contralateral minor amputation. There was a reduction in inpatient major lower extremity amputation (LEA) from 18.2% in 2005 to 5.4% in 2021 (odds ratio 0.26, 95% confidence interval 0.16-0.40, P < .001) which was the lowest since pathway inception. Mean time from admission to first surgical intervention was 2.8 days and mean time from decision for revascularization to procedure was 4.8 days. The major-to-minor amputation rate reduced from 1.09 in 2005 to 0.18 in 2021, reflecting diabetic limb salvage efforts. Mean and median length of stay (LOS) for patients in the pathway was 8.2 (±14.9) and 5 (IQR = 3) days, respectively. There was a gradual trend of increase in the mean LOS from 2005 to 2021. Inpatient mortality and readmission rate was stable at 1% and 11%. CONCLUSION: Since the institution of a MCCP, there was a significant improvement in major LEA rate. An inpatient multidisciplinary diabetic foot care path helped to improve care for patients with DFD.

Prospective study on the clinical and economic burden of venous leg ulcers in the tropics.

OBJECTIVE: Venous leg ulcers (VLUs) are both chronic and recurrent. The treatment of such ulcers often require multiple outpatient visits and dressing changes. Several reports on the costs of treating such VLUs have been reported in the west. We prospectively evaluated the clinical and economic burden of VLUs in a population of Asian patients in the tropics. METHODS: Patients from a prospective two-center study conducted at two tertiary hospitals in Singapore, as a part of the Wound Care Innovation in the Tropics program, between August 2018 and September 2021 were recruited. The patients were followed up for 12 weeks (visit 1 to visit 12), until index ulcer healing, death, or lost to follow-up (whichever came first). These patients were then followed up 12 weeks later to determine the longer term outcome of the wound (healed, recurrence, remained unhealed). The itemized costs derived from the medical service were retrieved from the relevant departments of the study sites. The patients' health-related quality of life was assessed at baseline and the last visit of the 12-week follow-up period (or until index ulcer healing), using the official Singapore version of the EuroQol five-dimension-5L questionnaire, which also includes a visual analog scale (EQ-VAS). RESULTS: A total of 116 patients were enrolled; 63% were men, and the mean patient age was 64.7 years. Of the 116 patients, 85 (73%) had a healed ulcer at 24 weeks (mean duration to ulcer healing, 49 days), and 11 (12.9%) had experienced ulcer recurrence within the study period. Within the 6-month follow-up period, the mean direct healthcare cost per patient was USD$1998. The patients with healed ulcers had significantly lower costs per patient compared with those with unhealed ulcers (USD$1713 vs USD$2780). Regarding health-related quality of life, 71% of the patients had a lower quality of life at baseline, which had improved at 12 weeks of follow-up, with only 58% of the patients reported to have a lower quality of life. Also, the patients with healed ulcers scored higher for both utilities (societal preference weights) and EQ-VAS at follow-up (P < .001). In contrast, patients with unhealed ulcers only scored higher EQ-VAS at follow-up (P = .003). CONCLUSIONS: The findings from this exploratory study provide information on the clinical, quality of life, and economic burden of VLUs in an Asian population and suggest the importance of healing VLUs to reduce the effects on patients. The present study provides data as a basis for economic evaluation as a consideration for the treatment of VLUs.

Diabetic foot in primary and tertiary (DEFINITE) Care: A health services innovation in coordination of diabetic foot ulcer (DFU) Care within a healthcare cluster - 18-month results from an observational population health cohort study.

Diabetic Foot in Primary and Tertiary (DEFINITE) Care is an inter-institutional and multi-disciplinary team (MDT) health systems innovation programme at a healthcare cluster in Singapore. We aim to achieve coordinated MDT care across primary and tertiary care for patients with diabetic foot ulcers (DFU), within our public healthcare cluster - an integrated network of seven primary care polyclinics and two acute care tertiary hospitals (1700-bed and 800-bed) with a total catchment population of 2.2 million residents. Results from prospective DEFINITE Care is referenced against a retrospective 2013-2017 cohort, which was previously published. Cardiovascular profile of the study population is compared against the same population's profile in the preceding 12 months. Between June 2020 and December 2021, there were 3475 unique patients with DFU with mean age at 65.9 years, 61.2% male, mean baseline HbA1c at 8.3% with mean diabetes duration at 13.3 years, mean diabetes complication severity index (DCSI) at 5.6 and mean Charlson Comorbidity Index (CCI) at 6.8. In the 12-months preceding enrolment to DEFINITE Care, 35.5% had surgical foot debridement, 21.2% had minor lower extremity amputation (LEA), 7.5% had major LEA whilst 16.8% had revascularisation procedures. At 18-months after the implementation of DEFINITE Care programme, the absolute minor and major amputation rates were 8.7% (n = 302) and 5.1% (n = 176), respectively, equating to a minor and major LEA per 100000 population at 13.7 and 8.0, respectively. This represents an 80% reduction in minor amputation rates (P < .001) and a 35% reduction in major amputation rates (P = .005) when referenced against a retrospective 2013-2017 cohort, which had minor and major LEA per 100000 population at 68.9 and 12.4, respectively. As compared to the preceding 12 months, there was also a significant improvement in cardiovascular profile (glycemic and lipid control) within the DEFINITE population, with improved mean HbAc1 (7.9% from 8.4%, P < .001), low-density lipoprotein (LDL) levels (2.1 mmol/L from 2.2, P < .001), total cholesterol (3.9 mmol/L from 4.1, P < .001) and triglycerides levels (1.6 mmol/L from 1.8, P = .002). Multivariate analysis revealed a history of minor amputation in the preceding 12 months to be an independent predictor for major and minor amputation within the study period of 18 months (Hazard Ratio 3.4 and 1.8, respectively, P < .001). In conclusion, within DEFINITE care, 18-month data showed a significant reduction of minor and major LEA rates, with improved medical optimisation and cardiovascular profile within the study population.

Single-centre experience with endovascular rotational thrombectomy for single session salvage of thrombosed arteriovenous fistulas and grafts.

OBJECTIVES: This paper documents our experience and outcomes of using a relatively new endovascular rotational thrombectomy device for salvage of thrombosed vascular access. METHODOLOGY: A retrospective study reviewing patients with thrombosed native AVF or AVG who underwent endovascular declotting using a rotational thrombectomy device between November 2018 and May 2020 at a tertiary university hospital in Southeast Asia. We evaluated demographics, procedural data, technical and procedural success, patency rates and complications. RESULTS: A total of 40 patients underwent single session endovascular declotting of thrombosed vascular access. The mean follow-up period was 21.6 months (range 13.4-31 months). The technical success was 92.5% and clinical success was 80%. About 50% of patients had concomitant thrombolysis for pharmacomechanical thrombectomy. One patient had a myocardial infarction during the post-operative period. There were no other major complications within 30 days. The primary patency was 45.5% at 6 months and 22.7% at 12 months. Assisted primary patency was 68.1% at 6 months and 61.6% at 12 months, which was maintained up to 2 years. The secondary patency was 84.1% at 6 and 12 months. CONCLUSION: Our study shows that rotational thrombectomy device for single session thrombectomy of thrombosed arteriovenous fistulas and grafts is safe and effective. A high technical and clinical success rate was achieved, with low complication rates and specific advantages compared to other techniques, including reduced length of hospital stay. Our reported mid-term outcomes are reasonable with an assisted primary patency of 62% at 12 and 24 months. The use of newer techniques and novel dedicated thrombectomy devices show promise.

Clinical validation of an artificial intelligence-enabled wound imaging mobile application in diabetic foot ulcers.

There is a lifetime risk of 15% to 25% of development of diabetic foot ulcers (DFUs) in patients with diabetes mellitus. DFUs need to be followed up on and assessed for development of complications and/or resolution, which was traditionally performed using manual measurement. Our study aims to compare the intra- and inter-rater reliability of an artificial intelligence-enabled wound imaging mobile application (CARES4WOUNDS [C4W] system, Tetsuyu, Singapore) with traditional measurement. This is a prospective cross-sectional study on 28 patients with DFUs from June 2020 to January 2021. The main wound parameters assessed were length and width. For traditional manual measurement, area was calculated by overlaying traced wound on graphical paper. Intra- and inter-rater reliability was analysed using intra-class correlation statistics. A value of <0.5, 0.5-0.75, 0.75-0.9, and >0.9 indicates poor, moderate, good, and excellent reliability, respectively. Seventy-five wound episodes from 28 patients were collected and a total of 547 wound images were analysed in this study. The median wound area during the first clinic consultation and all wound episodes was 3.75 cm2 (interquartile range [IQR] 1.40-16.50) and 3.10 cm2 (IQR 0.60-14.84), respectively. There is excellent intra-rater reliability of C4W on three different image captures of the same wound (intra-rater reliability ranging 0.933-0.994). There is also excellent inter-rater reliability between three C4W devices for length (0.947), width (0.923), and area (0.965). Good inter-rater reliability for length, width, and area (range 0.825-0.934) was obtained between wound nurse measurement and each of the C4W devices. In conclusion, we obtained good inter-rater and intra-rater reliability of C4W measurements against traditional wound measurement. The C4W is a useful adjunct in monitoring DFU wound progress.

Clinical and economic outcomes of a multidisciplinary team approach in a lower extremity amputation prevention programme for diabetic foot ulcer care in an Asian population: A case-control study.

Present guidelines recommend a multidisciplinary team (MDT) approach to diabetic foot ulcer (DFU) care, but relevant data from Asia are lacking. We aim to evaluate the clinical and economic outcomes of an MDT approach in a lower extremity amputation prevention programme (LEAPP) for DFU care in an Asian population. We performed a case-control study of 84 patients with DFU between January 2017 and October 2017 (retrospective control) vs 117 patients with DFU between December 2017 and July 2018 (prospective LEAPP cohort). Comparing the clinical outcomes between the retrospective cohort and the LEAPP cohort, there was a significant decrease in mean time from referral to index clinic visit (38.6 vs 9.5 days, P < .001), increase in outpatient podiatry follow-up (33% vs 76%, P < .001), decrease in 1-year minor amputation rate (14% vs 3%, P = .007), and decrease in 1-year major amputation rate (9% vs 3%, P = .05). Simulation of cost avoidance demonstrated an annualised cost avoidance of USD $1.86m (SGD $2.5m) for patients within the LEAPP cohort. In conclusion, similar to the data from Western societies, an MDT approach in an Asian population, via a LEAPP for patients with DFU, demonstrated a significant reduction in minor and major amputation rates, with annualised cost avoidance of USD $1.86m.

Clinical validation of a machine-learning-based handheld 3-dimensional infrared wound imaging device in venous leg ulcers.

Chronic venous insufficiency is a chronic disease of the venous system with a prevalence of 25% to 40% in females and 10% to 20% in males. Venous leg ulcers (VLUs) result from venous insufficiency. VLUs have a prevalence of 0.18% to 1% with a 1-year recurrence of 25% to 50%, bearing significant socioeconomic burden. It is therefore important for regular assessment and monitoring of VLUs to prevent worsening. Our study aims to assess the intra- and inter-rater reliability of a machine learning-based handheld 3-dimensional infrared wound imaging device (WoundAide [WA] imaging system, Konica Minolta Inc, Tokyo, Japan) compared with traditional measurements by trained wound nurse. This is a prospective cross-sectional study on 52 patients with VLUs from September 2019 to January 2021 using three WA imaging systems. Baseline patient profile and clinical demographics were collected. Basic wound parameters (length, width and area) were collected for both traditional measurements and measurements taken by the WA imaging systems. Intra- and inter-rater reliability was analysed using intra-class correlation statistics. A total of 222 wound images from 52 patients were assessed. There is excellent intra-rater reliability of the WA imaging system on three different image captures of the same wound (intra-rater reliability ranging 0.978-0.992). In addition, there is excellent inter-rater reliability between the three WA imaging systems for length (0.987), width (0.990) and area (0.995). Good inter-rater reliability for length and width (range 0.875-0.900) and excellent inter-rater reliability (range 0.932-0.950) were obtained between wound nurse measurement and each of the WA imaging system. In conclusion, high intra- and inter-rater reliability was obtained for the WA imaging systems. We also obtained high inter-rater reliability of WA measurements against traditional wound measurement. The WA imaging system is a useful clinical adjunct in the monitoring of VLU wound documentation.

Effectiveness of Comanagement Model: Geriatric Medicine and Vascular Surgery.

OBJECTIVES: Older surgical patients frequently develop postoperative complications due to their frailty and multiple comorbidities. Geriatric medicine consultation helps to optimize risk factors and improve outcomes in patients with hip fracture. This study aimed to evaluate patient outcomes before and after comanagement model implementation between geriatric medicine (Geriatric Surgical Service) and vascular surgery services. DESIGN: This was a case-control study involving emergency vascular surgical patients who were comanaged by vascular surgery, geriatric medicine, and geriatric nursing services. SETTINGS AND PARTICIPANTS: This study was conducted in a tertiary hospital in Singapore from 2015 to 2018 with acute vascular surgical patients aged older than 65 years. METHODS: A retrospective cohort of 135 patients from 2013 to 2014 (control group) who fulfilled the criteria for the comanagement model was compared with a prospective cohort of 348 patients who were comanaged by a geriatric surgical service from 2015 to 2018, and a further subgroup analysis of patients between 2015 and 2016 (n = 150) (early intervention group) and between 2017 and 2018 (n = 198) (late intervention group) was performed. RESULTS: Comanaged patients had a significantly shorter length of hospital stay (11.6 vs 20.8 days, P = .001), reduced nosocomial infections (3% vs 12% for urinary tract infection, P = .003) and decreased 30-day readmission rates (22% vs 34%, P = .011). A trend of a decreased incidence of fluid overload was noted in patients comanaged with the geriatric surgical service (3% vs 7%, P = .073). Subgroup analysis showed progressive reductions in the length of stay (15.4 vs 11.6 days, P = .001), 30-day readmission rate (35% vs 22%, P = .01), and nosocomial urinary tract infection (8% vs 3%, P = .003) between the early intervention group and the late intervention group. Although they were not statistically significant, reductions were also observed in the delirium rate (13% vs 11%) and other postoperative medical complications in the early intervention group and the late intervention group. CONCLUSION AND IMPLICATIONS: Despite having increasing comorbidities, older vascular surgical inpatients had a significantly shorter length of stay, reduced nosocomial infections, and decreased 30-day readmission rates through a comanagement model with vascular surgery and geriatric medicine services. Improvements in outcomes were observed over time as the model of care evolved. Geriatric medicine intervention in the perioperative period improves the outcomes of older acute vascular surgical patients.

Novel home use of mechanical negative pressure wound therapy in diabetic foot ulcers.

OBJECTIVE: Mechanical negative pressure wound therapy is an ultraportable, light weight and disposable single-use device that has been shown to promote wound healing. This study evaluated home use of a mechanically powered negative pressure wound therapy (NPWT) in diabetic foot wounds. METHODS: Patients underwent revascularisation and/or debridement or amputation before starting mechanical NPWT. Wound outcomes and images of the wounds were recorded at each follow-up visit by the wound nurse. Patients were followed up until wound closure or end of therapy. RESULTS: A total of 12 patients (each with one wound) were included in the study. Of the 12 wounds, 33.3% (n=4) of wounds achieved primary wound closure while the remaining 66.6% (n=8) of wounds demonstrated a mean wound size reduction of 37.5±0.13%. Of the closed wounds, mean time to healing was 4.75±2.50 weeks. There was 100% limb salvage with no further debridement or amputations, and no 30-day unplanned readmissions. Mean length of hospital stay before starting home NPWT was 9.75±6.31 days. Mean number of NPWT changes was 8.33±2.67 sessions, while mean duration of therapy was 4.0±1.54 weeks. Mean cost of home NWPT therapy was US$1904±731 per patient. CONCLUSION: The home use of mechanically powered NPWT in diabetic foot wounds demonstrated excellent wound healing rates and 100% limb salvage, with no complications.

Outcomes of Catheter-Directed Thrombolysis for Arteriovenous Fistula Thrombosis in Singapore: Is It Still Relevant Today?

Objective: To review the outcomes of catheter-directed thrombolysis (CDT) for salvage of thrombosed arteriovenous fistula (AVF) in a single centre in Southeast Asia. Methods: A retrospective study of CDT in AVF between January 2015 and July 2018 at a tertiary university hospital was carried out. Results: Within the study period, 85 patients underwent CDT for AVF thrombosis. Of these patients, 78% underwent CDT for 24 h and 12% required CDT for 48 h. Moreover, 14% of patients had bleeding during CDT and hence required a decrease in dosing or complete cessation. Incidence of intracranial haemorrhage was 1%, and technical success was 92%. Post CDT, primary patency rates at 12, 24 and 36 months were 87%, 62% and 36%, respectively; assisted primary patency rates at 12, 24 and 36 months were 96%, 82% and 69%, respectively; and secondary patency rates at 12, 24 and 36 months were 99%, 93% and 86%, respectively. Multivariate analysis did not identify any predictive factors for patency post CDT. Conclusion: Within our study population, CDT for AVF salvage conferred good technical results with low rates of complications. There was good primary patency at 12 months, and the results were sustained up to 36 months. It remains a useful modality for fistula salvage, avoiding surgical intervention.

Transradial access for arteriovenous fistuloplasty in Singapore.

BACKGROUND: Endovascular balloon angioplasty is standard therapy for dysfunctional arteriovenous fistula in end-stage renal failure patients on hemodialysis. Venous antegrade or retrograde puncture of the fistula is typically performed to gain access for fistuloplasty. Transradial approach for brachiocephalic or brachiobasilic arteriovenous fistulas offers an alternative method of access with the advantage of addressing multi-focal juxta-anastomotic and venous stenosis from the same approach. We aim to review the efficacy, outcomes and complication rates of transradial access for arteriovenous fistuloplasty among patients in Singapore. METHODS: A retrospective review of 195 endovascular fistuloplasties from September 2017 to August 2019, at a tertiary university hospital Vascular Surgery unit. RESULTS: Of 195 fistuloplasties, 43 (22%) were transradial approach (23 brachiocephalic arteriovenous fistulas, 20 brachiobasilic arteriovenous fistulas) in 33 patients (67% male and mean age = 65 years). Of these 43 procedures, 11 (26%) were performed as balloon-assisted maturation fistuloplasties while 32 (74%) were performed for mature arteriovenous fistulas with multi-focal juxta-anastomosis and venous stenosis. Technical success rate was 95% with mean procedure duration at 43.5 ± 14.6 min. Mean pre- and post-fistuloplasty dialysis access flow rates increased from 502 to 952 ml/min (p < 0.001). Post-intervention primary patency was 100%, 66% and 20% at 1, 6 and 12 months, respectively. There were four patients with non-limb-threatening radial artery thrombosis (9.3%) while there was no radial artery pseudoaneurysm or post-procedural bleeding. CONCLUSION: Transradial approach for arteriovenous fistuloplasty is a safe and feasible option in patients requiring balloon-assisted maturation or with multi-focal juxta-anastomotic and venous stenosis.

Systematic review and meta-analysis of the prevalence of abdominal aortic aneurysm in Asian populations.

OBJECTIVE: The prevalence of abdominal aortic aneurysms (AAAs) is well reported in Western countries and AAA screening programs are well-established. However, although individual studies have reported that the prevalence of AAAs is lower in Asian populations, high-quality data on the prevalence of AAA in Asians are relative lacking. The present study aimed to systematically synthesize the data available in the literature and report the prevalence of AAAs in Asians. METHODS: An electronic search was performed using two major databases (PubMed and EMBASE) with no limitations imposed on the year of publication. The review conformed to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Studies that reported the prevalence of AAAs in Asians were selected, and the population characteristics, AAA definition, method of screening, target population, and total number of patients screened were recorded. RESULTS: Our search yielded 157 unique articles. After a full-text review, 17 articles were included in the present study. All 17 studies of fair quality. The overall AAA prevalence was 1.30% (95% confidence interval [CI], 1.01%-1.59%) in Asian populations. The prevalence of AAAs was 2.56% (95% CI, 1.81%-3.31%) in Asian populations selected for cardiovascular risk factors and 0.61% (95% CI, 0.37%-0.85%) in Asian populations not selected for cardiovascular risk factors. CONCLUSIONS: The prevalence of AAAs in the general Asian population is low. However, the prevalence in Asian populations selected for cardiovascular risk factors approaches the prevalence of AAAs in Western populations. As such, screening for AAAs in carefully selected Asian male populations with cardiovascular risk factors could potentially yield benefits. Opportunistic screening for AAAs during ultrasound examination of the abdomen or transthoracic echocardiography for other indications could also be considered. However, further studies are needed to evaluate the potential benefits of screening for AAAs in carefully selected Asian populations.

Iliac vein pathology and short-term stenting outcomes in a South-East Asian population: A single-centre experience.

OBJECTIVE: Current literature regarding iliofemoral intervention and stenting is mostly based on Western populations. We present our experience of iliofemoral stenting for chronic venous disease within a South-East Asian population. METHODS: This is a single-centre retrospective review of a prospectively collected registry. Seventy-one patients with 105 limbs underwent iliac vein IVUS and stenting between 2016 and 2019. All patients underwent pre-procedure ultrasound venous scan and MRI venogram. Pre- and post-operative CEAP classification, Villalta score and Venous Clinical Severity Score (VCSS), technical results, stent patency rates and complication rates are documented. RESULTS: Seventy-six per cent of the cases are non-thrombotic iliac vein lesion, and 68% of patients have C4 to C6 disease. Ten percentage of patients had acute thrombosis on presentation. There was 100% technical success. A 6- and 7-point reduction in the mean VCSS and Villalta score, respectively, were noted post-stenting (baseline of 10 points and P < 0.001 in both categories). Post-stenting ulcer healing rate was 91% at 6 and 12 months. One-year ulcer recurrence and cellulites recurrence were at 8% and 7%, respectively. One unplanned 30-day readmission (not related to procedure) and no 30-day mortality were noted. Bleeding complication from anticoagulation was 3%. There was 10% in-stent non-flow limiting stenosis on surveillance. One-year primary patency was 91%, and secondary patency was 100%. CONCLUSION: Within our series, iliofemoral stenting has 100% technical success, with statistically significant reduction in VCSS and Villalta score, good wound healing rates, low ulcer and cellulites recurrence and good primary and secondary patency rates at 1 year.

Effect of Thoracic Endovascular Aortic Repair on Aortic Remodeling in Patients with Type B Aortic Dissection in an Asian Population.

BACKGROUND: Management of uncomplicated type B aortic dissection (TBAD) has traditionally been aggressive medical therapy. Recent studies brought about a paradigm shift with evidence to suggest benefits from early endovascular intervention to a high risk subgroup of acute uncomplicated TBAD patients. AIMS: We aim to review the effects of aortic remodeling in Asian patients with TBAD with and without endovascular intervention, including maximal aortic diameter, true lumen diameter, and false lumen thrombosis. METHODS: This is a single-center retrospective study of a prospective database. Patients who presented to our institution with acute TBAD from January 2008 to December 2015 (n = 44) were evaluated. Eighteen percent (8 patients) presented with complicated TBAD and underwent emergency thoracic endovascular aortic repair (TEVAR) while the remaining 82% (36 patients) were treated with optimal medical therapy (OMT). RESULTS: Six patients under the conservative arm crossed over to elective TEVAR after 6 weeks because of interval radiological progression of disease. There was no significant difference in the baseline demographics of the TEVAR group and the OMT group. At 24 months, mean maximal aortic diameter difference was -7.7 mm and +1.9 mm (P = 0.077), mean true lumen diameter difference was +10.0 mm and +2.6 mm (P = 0.049), and false lumen thrombosis was 100% and 20% (P = 0.012) for TEVAR and OMT, respectively. Kaplan-Meier analysis showed no significant difference in mortality between the 2 groups at 30 days and 2 years. CONCLUSIONS: Within an Asian population with TBAD, TEVAR with OMT has a significant positive effect on aortic remodeling, compared with OMT-only management.

Outcomes of incisional negative pressure wound therapy following brachiobasilic transposition arteriovenous fistula creation: A 1:2 propensity score matched study.

Incisional negative wound pressure therapy (iNPWT) use on closed incisions has been shown to improve wound outcomes, but no studies have evaluated the use of iNPWT following brachiobasilic transposition arteriovenous fistula (BBT-AVF). We aim to investigate the efficacy of iNPWT vs conventional wound therapy in reducing surgical site infections (SSIs) for BBT-AVF incisions. This is a retrospective cohort study of patients who underwent BBT-AVF creation between January 2010 and December 2017. A 1:2 propensity score matching (PSM) was performed to reduce selection bias and address for confounding factors. Study outcomes included SSI and haematoma incidence, 30-day readmission, and 30-day mortality. A total of 154 patients were reviewed in this study: 47 (30.5%) had iNPWT and 107 (69.5%) had conventional wound therapy. The overall median age was 60.5 (interquartile range 54-69). PSM with a 1:2 ratio resulted in a total of 117 patients (39 iNPWT and 78 conventional wound therapy). In the unmatched cohort, SSI incidence was lower in the iNPWT group (n = 1/47 [2.1%] vs n = 14/107 [13.1%], P = .035). However, incidence of SSI was comparable between iNPWT and conventional wound therapy after matching (n = 1/39 [2.6%] vs n = 9/78 [11.5%], P = .102). There was no significant difference in 30-day readmission and 30-day mortality. Within our study population of patients with BBT-AVF incisions, there is a non-statistically significant reduction in SSI incidence for patients who received iNPWT as compared with conventional wound therapy. Further prospective randomised controlled studies should be conducted to validate these findings.