Effectiveness of a native vein arteriovenous fistula tracking system.

OBJECTIVE: This study aims to evaluate the effectiveness of a tracking program on the functional maturation rate of arteriovenous fistula (AVF). METHODS: Two major clinical outcomes (commencement of cannulation and functional maturation) of created AVFs were compared between two cohorts. (i) Cohort 1: historical cohort; (ii) Cohort 2: AVFs created after implementation of the tracking project. Multivariable Cox regression models were used to assess the association between cohort allocation and the two major clinical outcomes. RESULTS: Data of 114 and 141 patients were analyzed respectively from Cohorts 1 (historical data) and 2 (with AVF tracking). After adjustment of covariates in the multivariable analysis, the AVFs created in Cohort 2 were more likely to be cannulated earlier (adjusted HR: 2.82; 95% CI: 1.97-4.05; p < 0.001), compared to those in Cohort 1. Similarly, the AVFs of Cohort 2 patients had significantly higher probability of functional maturation (adjusted HR: 1.81; 95% CI: 1.31-2.48; p < 0.001) than fistulas in Cohort 1. Cannulation was commenced for half of the AVFs by 4.1 months post-creation in the historical cohort (Cohort 1), whereas in the post-tracking cohort, 50% of the AVFs were cannulated by 2.3 months after creation (p < 0.001). It took 5.5 and 4.3 months for 50% of the AVFs created in Cohort 1 and Cohort 2 patients to achieve catheter-free functional maturation, respectively (p = 0.06). CONCLUSION: An AVF tracking program with maturation target for the access surgeons, together with a standardized tracking, feedback, and clinical strategy adjustment system is able to improve the AVF functional maturation rate.

Experience from a Singapore tertiary hospital with restructuring of a vascular surgery practice in response to national and institutional policies during the COVID-19 pandemic.

Singapore was one of the first countries to be affected by COVID-19, with the index patient diagnosed on January 23, 2020. For 2 weeks in February, we had the highest number of COVID-19 cases behind China. In this article, we summarize the key national and institutional policies that were implemented in response to COVID-19. We also describe in detail, with relevant data, how our vascular surgery practice has changed because of these policies and COVID-19. We show that with a segregated team model, the vascular surgery unit can still function while reducing risk of cross-contamination. We explain the various strategies adopted to reduce outpatient and inpatient volume. We provide a detailed breakdown of the type of vascular surgical cases that were performed during the COVID-19 pandemic and compare it with preceding months. We discuss our operating room and personal protective equipment protocols in managing a COVID-19 patient and share how we continue surgical training amid the pandemic. We also discuss the challenges we might face in the future as COVID-19 regresses.

A Novel Endovascular Treatment for Recurrent Secondary Aorto-Enteric Fistula in a Patient With Prior Infra-Renal Aortic Ligation.

This report highlights the use of novel endovascular techniques in a 68-year-old male patient with massive hematemesis from a recurrent secondary aorto-enteric fistula (SAEF). With a prior history of infrarenal aortic ligation and the location of the SAEF being at the aortic sac, we explain the considerations for the techniques used and how we were able to stop the bleeding using percutaneous transarterial embolotherapy.

SIroliMus coated angioPlasty versus plain balloon angioplasty in the tREatment of dialySis acceSs dysfunctION (IMPRESSION): study protocol for a randomized controlled trial.

BACKGROUND: Percutaneous transluminal angioplasty is the current standard treatment for arteriovenous fistula (AVF) stenosis. The mid- and long-term patency with plain balloon angioplasty (PBA) is however far from satisfactory. While paclitaxel-coated balloon angioplasty has been shown to be superior to PBA, concern over its safety profile has recently arisen after a reported possible increased mortality risk with a meta-analysis of large lower limb studies. An angioplasty balloon with a new type of drug coating, the sirolimus-coated balloon (SCB), has been proven to improve patency in the coronary arteries. However, its effect on AV access has yet to be studied. METHODS/DESIGN: This is an investigator-initiated, prospective, multicenter, double-blinded, randomized controlled clinical trial to assess the effectiveness of SCB compared to PBA in improving the patency of AVF after angioplasty. A total of 170 patients with mature AVF that requires PTA due to AVF dysfunction will be randomly assigned to treatment with a SCB or PBA at a 1:1 ratio, stratified by location of AVF and followed up for up to 1 year. The inclusion criteria include [1] adult patient aged 21 to 85 years who requires balloon angioplasty for dysfunctional arteriovenous fistula [2]; matured AVF, defined as being in use for at least 1 month prior to the angioplasty; and [3] successful angioplasty of the underlying stenosis with PBA, defined as less than 30% residual stenosis on digital subtraction angiography (DSA) and restoration of thrill in the AVF on clinical examination. The exclusion criteria include thrombosed or partially thrombosed access circuit at the time of treatment, presence of symptomatic or angiographically significant central vein stenosis that requires treatment with more than 30% residual stenosis post angioplasty, and existing stent placement within the AVF circuit. The primary endpoint of the study is access circuit primary patency at 6 months. The secondary endpoints are target lesion primary patency; access circuit-assisted primary patency; access circuit secondary patency at 3, 6, and 12 months; target lesion restenosis rate at 6 months; total number of interventions; complication rate; and cost-effectiveness. The trial is supported by Concept Medical. DISCUSSION: This study will evaluate the clinical efficacy and safety of SCB compared to PBA in the treatment of AVF stenosis in hemodialysis patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT04409912 . Registered on 1 June 2020.

Assessment of Flow after Lower Extremity Endovascular Revascularisation: A Feasibility Study Using Time Attenuation Curve Analysis of Digital Subtraction Angiography.

OBJECTIVES: Endovascular revascularisation is the mainstay of the treatment of lower extremity peripheral arterial disease. Improvement in perfusion after treatment is often quantified by a corresponding increment in ankle or toe brachial indices. These measurements are difficult to obtain in patients with foot wounds, and have to be performed at a separate time and setting after revascularisation. This preliminary study aimed to evaluate the use of parametric colour coding and analysis of time attenuation curves as a real time quantitative measure of perfusion after endovascular revascularisation. METHODS: Forty-seven consecutive patients with critical limb ischaemia were retrospectively enrolled and analysed. Parametric colour coding and generation of time attenuation curves in the main pedal vessel was performed for pre- and post-intervention digital subtraction angiograms of each patient. The change in time attenuation curve parameters was compared with the change in ankle or toe brachial indices before and after intervention. RESULTS: Comparing before and after lower extremity endovascular intervention, there were significant changes in the washout parameters derived from the time attenuation curve. The percentage of contrast decay 4 seconds after peak (I 4s) demonstrated the strongest correlation (R = .482) with the change in ankle or toe brachial indices. CONCLUSIONS: Parametric colour coding and time attenuation curve analysis might be a helpful tool that can provide real time intra-procedural quantitative data on pedal perfusion which can improve clinical outcomes.

Successful Endovascular Management of a Case of Aorto-oesophageal Fistula Presenting as Life Threatening Upper Gastrointestinal Bleed.

INTRODUCTION: Aorto-oesophageal fistula is a rare but life threatening cause of upper gastrointestinal haemorrhage. Severity of presentation and complexity of subsequent management depends on the size of the defect on both the aortic side and oesophagus. REPORT: The patient was a 67 year old Chinese man, who presented initially with a Stanford type A dissection with caudal extension to the right common iliac artery. The patient underwent replacement of the ascending aorta and proximal arch with debranching of the right innominate artery and aortic valve replacement. A follow up computed tomography (CT) aortogram done in the post-operative period showed a stable appearance of the caudal extension of the aortic dissection. The patient was discharged with a plan for future stenting of the thoracic aorta. Three weeks later the patient re-presented with an upper gastrointestinal bleed from an aorto-oesophageal fistula. The patient underwent endovascular stenting of the descending aorta for management of the fistula. Repeat oesophagogastroduodenoscopy showed a small erosion 35 cm from the incisors where the previous bleeding site had been. No further bleeding was seen. DISCUSSION: The patient recovered uneventfully after the procedure. Follow up CT aortogram done at 6 weeks demonstrated thrombosis of the false lumen of the descending thoracic aorta. Aorto-oesophageal fistula related to chronic type B aortic dissection is an extremely rare clinical entity and presents a challenge to the treating surgeon. This case demonstrates that selected cases can be judiciously managed by thoracic endovascular aneurysm repair alone.