Ramon Lee Varcoe

Ramon Lee Varcoe
Prince of Wales Hospital and Community Health Services | POWH · Department of Vascular Surgery

MBBS, MS, FRACS, PhD MMed (ClinEpi)

About

135
Publications
14,578
Reads
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1,891
Citations
Citations since 2017
87 Research Items
1286 Citations
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2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
Additional affiliations
March 2008 - present
Prince of Wales Hospital and Community Health Services
Position
  • Vascular Surgeon
March 2008 - December 2015
UNSW Sydney
Position
  • Professor (Associate)

Publications

Publications (135)
Article
The transitional flow which initiates within the junction (anastomosis) of an arteriovenous fistula (AVF) is known to be a contributing factor in the onset of vascular disease. A novel treatment method involving the implantation of a flexible stent across the anastomosis has enabled the retention of a large proportion of functioning AVFs, despite t...
Article
Objective: To examine long-term outcomes after endovascular (EVAR) and open repairs (OAR) for intact abdominal aortic aneurysms (AAA) in Australia, Germany, and the US, using a unified study design. Summary background data: Similarities and differences in long-term outcomes after EVAR versus OAR across countries remain unclear, given differences...
Article
Full-text available
Objective: To compare rates of mortality, rupture and secondary intervention following endovascular repair (EVAR) of intact abdominal aortic aneurysms (AAA) using contemporary endograft devices from three major manufacturers. Design: Retrospective cohort study using linked clinical registry (Australasian Vascular Audit) and all payer administrat...
Chapter
Percutaneous transluminal angioplasty remains the cornerstone of endovascular therapy for the treatment of peripheral arterial disease. However, its fundamental action is to apply controlled and high-pressure barotrauma to the blood vessel wall. This may generate a dissection injury with the potential to lead to both short- and long-term complicati...
Article
Full-text available
Arterio-venous fistula creation is the preferred vascular access for haemodialysis, but has a large failure rate in the maturation period. Previous research, considering the remodelling mechanisms for failure-to-mature patients, has been limited by obtaining the patient-specific boundary conditions at only a few points in the patient history. Here,...
Article
Background There has been growing use of intravascular ultrasound (IVUS) during lower extremity arterial and venous revascularization. Observational data suggest that the use of IVUS can improve periprocedural and long-term outcomes, but largescale prospective data remain limited. Consensus opinion regarding the appropriate use of IVUS during perip...
Preprint
Full-text available
The transitional flow which initiates within the junction (anastomosis) of an arteriovenous fistula (AVF) is known to be a contributing factor in the onset of vascular disease. A novel treatment method involving the implantation of a flexible stent across the anastomosis has enabled the retention of a large proportion of functioning AVFs, despite t...
Article
Full-text available
The arteriovenous fistula (AVF) is the optimal form of vascular access for end-stage renal failure patients requiring haemodialysis. However, AVFs can fail to mature into a useable conduit or develop recurrent stenoses that result in high surgical re-intervention rates to maintain patency. Here, we performed a narrative review of literature on meth...
Article
This review details the utility of intravascular ultrasound (IVUS) for the management of peripheral artery and venous disease. The purpose of this document is to provide an update in the use of IVUS in peripheral arterial and venous pathology and demonstrate the use of IVUS as a practical diagnostic imaging procedure to evaluate and treat periphera...
Article
Full-text available
Introduction Carotid artery pseudoaneurysm is a rare but potentially morbid complication of central venous catheter insertion. Traditionally managed by open surgical or endovascular repair, this article describes a case that uses percutaneous thrombin injection. Delivered at the point of care under ultrasound guidance, it offers a less invasive and...
Article
Full-text available
Computational fluid dynamics (CFD) modelling has been a useful non-invasive measurement tool to analyse the effects of blood flow in diseased arteriovenous fistula (AVF). To translate CFD findings for clinical use, it is essential to model the AVF as closely as possible to the physiological conditions. The AVF geometry consists of three boundary no...
Article
Introduction Juxta-anastomotic stenosis (JXAS) is a common problem afflicting the arteriovenous fistula (AVF). This study aimed to evaluate the safety and long-term efficacy of an interwoven nitinol stent (Supera, Abbott Vascular, Santa Clara, CA, USA) in the treatment of radiocephalic AVF JXAS. Methods A single-center, retrospective, observationa...
Article
Full-text available
An arteriovenous fistula (AVF), a vascular structure surgically created to enable haemodialysis, is commonly affected by stenosis in the juxta-anastomotic region. A new treatment involving the implantation of a flexible stent has shown good potential for retaining healthy AVFs. Since vascular disease in the AVF is known to be related to the haemody...
Article
Objectives The aim of this study was to seek expert consensus regarding the features that predict adverse outcomes in order to develop a dedicated angiographic classification system for femoropopliteal artery dissection. Background Dissection of the femoral and popliteal arteries is common after percutaneous angioplasty. Its classification is impo...
Article
Objective: Compare long-term mortality, secondary intervention and secondary rupture following elective endovascular aneurysm repair (EVAR) and open surgical repair (OSR). Background: EVAR has surpassed OSR as the most common procedure used to repair abdominal aortic aneurysm (AAA), but evidence regarding long-term outcomes is inconclusive. Met...
Article
Introduction The clinical utility of the native arteriovenous fistula (AVF) is limited by a prolonged time to maturation, low overall maturation rate, and subsequent abandonment. Endovascular intervention is increasingly accepted as first line therapy to treat AVF stenosis. The objective of this study was to evaluate AVF formation outcomes when ear...
Article
Background: Endovascular revascularization (ER) via percutaneous transluminal angioplasty (PTA) and stenting are viable options for revascularization in below-the-knee (BTK) peripheral arterial disease. Two-dimensional angiography has been the standard of practice for estimating vessel size and selecting treatment devices during ER. However, in ot...
Article
Full-text available
Introduction Venous leg ulcers (VLU) embody the most severe stage of the broad spectrum of chronic venous disease. Approximately 40% of patients with VLU present with the underlying deep venous disease (DVD). Although the data are scarce, these deep venous disease-related VLU (DRV) are thought to have higher recurrence rates and a substantial econo...
Article
Purpose: A late increased mortality risk has been reported in a summary level meta-analysis of patients with femoropopliteal artery occlusive disease treated with paclitaxel-coated angioplasty balloons and stents. However, at the longer follow up timepoints that analysis was limited by small trial numbers and few participants. The aim of this stud...
Article
Full-text available
Cyanoacrylate embolization has gained interest as a safe, effective and minimally invasive method to treat symptomatic saphenous reflux. The procedure is generally well tolerated by patients, and complications such as phlebitis, are minor and usually self-limiting. Post-procedural infections have been described, but occur infrequently and usually i...
Article
Objectives : This study aims to assess the use of drug-coated balloon (DCB) in a large patient population under real-world conditions and, specifically, analyse the impact of diabetes mellitus on long term outcomes following DCB utilisation. Methods : BIOLUX P-III is a prospective, international, multicentre, registry that was conducted at 41 cent...
Article
Background Carotid endarterectomy (CEA) and carotid artery stenting (CAS) reduce the risk of stroke in patients with severe carotid stenosis. The aim was to compare contemporary treatment trends and outcomes after CEA and CAS between states of Australia. Methods A retrospective analysis was conducted on data from the Australasian Vascular Audit be...
Article
Carotid endarterectomy (CEA) and carotid artery stenting (CAS) prevent stroke in selected patients. However, each intervention carries a risk of perioperative complications including stroke or death (S/D). We aimed to determine the relationship between operator volume, hospital volume, and the perioperative risk of S/D in carotid revascularization...
Article
Full-text available
Postural orthostatic tachycardia syndrome (POTS) is a variant of cardiovascular autonomic disorder characterised by an excessive heart rate on standing and orthostatic intolerance. We present a rare case of a 38-year-old man who underwent open repair of a thoracoabdominal aortic aneurysm for a chronic Stanford type B aortic dissection whose recover...
Article
Previous studies on everolimus-eluting bioresorbable vascular scaffolds (BVS) have shown promising 1-year primary patency rates in infrapopliteal arteries. Literature from large cohorts on long-term outcomes with the infrapopliteal Absorb BVS (Abbott Vascular) is lacking. The aim of this study is to pool published and unpublished data to provide a...
Article
Objective: Definitive treatment techniques for symptomatic deep venous reflux have been relegated to complex and invasive open surgery which is rarely performed today. The BlueLeaf® System provides an endovenous method for the formation of deep venous valves without an implant, avoiding complications associated with permanent foreign materials. Th...
Article
Full-text available
The arteriovenous fistula (AVF), which is a vasculature created for end-stage renal disease patients who require haemodialysis, is susceptible to many vascular diseases. It is well known that disturbed hemodynamics is a factor in the initiation of vascular disease; however, only a limited number of experimental studies have been conducted to assess...
Article
Introduction: Different types of bioresorbable vascular scaffolds (BVSs) have been developed and used in below-the-knee (BTK) arterial diseases. This is the first study reviewing and analyzing the literature on BVS treatment for BTK arterial disease. Evidence acquisition: MEDLINE; Embase; and Cochrane were searched for studies published until Oc...
Article
Objectives: The aim of this study was to perform a long-term evaluation of an everolimus eluting, bioresorbable vascular scaffold (BVS) in the treatment of de novo atherosclerotic disease within crural arteries. Methods: A prospective, single-arm study was performed enrolling patients with chronic lower limb ischemia between 2013 and 2018. Resu...
Article
Background: Peripheral vascular devices (stents and balloons) coated with paclitaxel were developed to address suboptimal outcomes associated with percutaneous revascularization procedures of the femoral-popliteal arteries. In randomized controlled trials (RCT), paclitaxel-coated devices (PCD) provided increased long-term patency and reduced need...
Article
Objective Hospital and surgeon operative caseload is thought to be associated with peri-operative mortality following the non-elective repair of aortic aneurysms; however, whether such an association exists within the Australian healthcare setting is unknown. Methods The Australasian Vascular Audit was interrogated to identify patients undergoing...
Article
Arteriovenous fistula creation is the preferred vascular access for haemodialysis therapy, but has a large failure rate in the maturation period. This period generally lasts 6 to 8 weeks after surgical creation, in which the vein and artery undergo extensive vascular remodelling. In this review, we outline proposed mechanisms for both arteriovenous...
Article
Endovascular revascularization has been increasingly utilized to treat patients with chronic limb-threatening ischemia (CLTI), particularly atherosclerotic disease in the infrapopliteal arteries. Lesions of the infrapopliteal arteries are the result of 2 different etiologies: medial calcification and intimal atheromatous plaque. Although several de...
Article
Drug-coated balloons (DCB) are used widely as a form of endovascular treatment for peripheral arterial disease, to improve patency by reducing neointimal hyperplasia and re-stenosis. We present a rare case of acute coronary syndrome secondary to anaphylaxis following inflation of a paclitaxel coated DCB used to treat a recurrent superficial femoral...
Article
Purpose: To report an experience with the Absorb bioresorbable vascular scaffold (BVS) in an Asian cohort with chronic limb-threatening ischemia (CLTI) from the DISAPEAR ( Drug Impregnated Bioresorbable Stent in Asian Population Extremity Arterial Revascularization) registry. Materials and Methods: A retrospective analysis was conducted of 41 patie...
Article
Purpose To assess periprocedural results and secondary endovascular procedure outcomes over 5 years in patients aged ≥80 vs <80 years undergoing endovascular aneurysm repair (EVAR). Materials and Methods Data from the Endurant Stent Graft Natural Selection Global post-market registry (ENGAGE) were used for the analyses. A total of 1263 consecutive...
Article
Purpose: To evaluate the midterm results of patients suffering from no-option chronic limb-threatening ischemia (CLTI) treated with a dedicated system for percutaneous deep venous arterialization (pDVA). Materials and Methods: Thirty-two consecutive CLTI patients (mean age 67±14 years; 20 men) treated with pDVA using the Limflow device at 4 centers...
Article
Introduction The native arteriovenous fistula may remain immature despite adequate arterial inflow after formation. This may occur when the puncturable vein segment (cannulation zone) is too small to be reliably punctured, occluded or too deep under the skin for needle access. We performed stenting (stent-assisted maturation) of arteriovenous fistu...
Article
Background Registry studies have shown the Endurant stent graft is associated with low rates of all-cause- and aneurysm-related mortality when used for the endovascular treatment of abdominal aortic aneurysm (AAA). However, many were limited by length of follow-up and all had a proportion of patients lost to follow-up. The aim of this study was to...
Article
Purpose To report the risk of all-cause mortality after treatment with paclitaxel-coated devices vs uncoated controls in patients with chronic limb-threatening ischemia (CLTI). Materials and Methods A search of the PubMed, Embase, Cochrane, CINAHL, DARE, and PROSPERO databases was made on 5 November 2019 to identify randomized controlled trials (R...
Article
Full-text available
Purpose: We report short-term patency outcomes of a proof of concept study conducted to determine the efficacy of drug-eluting stent (DES) for the treatment of arteriovenous fistula (AVF) stenosis in hemodialysis patients. Materials and methods: This is a single-center, retrospective observational study involving 10 patients with AVF dysfunction...
Article
Background and objective: The use of patient-specific CFD modelling for arteriovenous fistulae (AVF) has shown great clinical potential for improving surveillance, yet the use of imaging modes such as MRI and CT for the 3D geometry acquisition presents high costs and exposure risks, preventing regular use. We have developed an ultrasound based pro...
Article
Introduction High flow rates may develop in arteriovenous fistula (AVF), resulting in clinical syndromes of steal, aneurysmal fistula, or high-output cardiac failure. Various techniques with varying success have been advocated to treat this difficult problem. We present a hemodynamically validated novel banding technique. Methods We designed a com...
Article
Purpose: To report the risk of all-cause mortality in patients who underwent dialysis access treatment using paclitaxel-coated devices compared with percutaneous transluminal angioplasty (PTA) with an uncoated balloon. Materials and Methods: A systematic review and meta-analysis of randomized controlled trials were performed to investigate the mort...
Article
Purpose: To assess the incidence and predictors of severe, persistent postprocedural hypotension (PPH) after carotid artery stenting (CAS). Materials and Methods: A total of 146 patients (mean age 72.8 years; 104 men) who underwent 160 CAS procedures using a standardized protocol at 3 vascular centers were retrospectively analyzed. The primary endp...
Article
Full-text available
Considerable advances have been made over the last decade in the management of patients with peripheral artery disease. Historically, endovascular treatment has been the accepted approach for short lesions and surgical bypass for long, complex femoropopliteal lesions. However, bypass surgery holds significant risk of mortality and morbidity for the...
Article
Purpose: To report the use of directional atherectomy to treat venous in-stent restenosis (ISR) and subsequent histopathological analysis of retrieved intrastent tissue. Case Report: A 55-year-old man presented with recurrent symptoms of venous congestion following iliofemoral stenting. The stents were found to be occluded on imaging. Directional a...
Article
Introduction: Endovascular treatment below-the-knee is safe and effective but limited by poor patency. Coronary drug-eluting stents (DES) may play a role in providing mechanical scaffolding and deliver anti-proliferative drug to the site of vascular barotrauma to reduce the incidence of restenosis. Our aim was to evaluate and compare the use of co...
Article
Purpose: To determine the clinical outcomes in hemodialysis patients after implantation of a Supera stent to treat juxta-anastomotic stenosis in radiocephalic arteriovenous fistulas (AVF). Materials and methods: A single-center retrospective study was conducted of 42 consecutive patients (mean age 66.7 years, range 40-84; 26 men) who had a faili...
Article
Full-text available
Giant cell arteritis (GCA) is a well-known cause of cranial vasculitis often presenting with headache and jaw claudication. Here we report the case of a woman suffering GCA who presented with critical lower limb ischemia. Despite best medical therapy, she developed progressive calf claudication and ulceration of the right foot. The findings on work...
Article
Full-text available
Objectives Operative caseload is thought to be associated with peri-operative mortality following intact aortic aneurysm repair. The aim was to study that association in the Australian setting, which has a unique healthcare provision system and geographical population distribution. Methods The Australasian Vascular Audit database was used to captu...
Article
Full-text available
Purpose: To investigate the midterm performance of the everolimus-eluting Absorb bioresorbable vascular scaffold (BVS) for the treatment of symptomatic infrapopliteal atherosclerotic disease. Methods: A single-center study prospectively enrolled 48 symptomatic patients (mean age 82.1±8.0 years; 27 men) between September 2013 and February 2018 to...
Article
The population of Australia is ageing, with women being the primary beneficiaries of this increase in longevity. Increasingly older individuals are being diagnosed with different chronic illnesses such as peripheral arterial disease (PAD) which causes blockages of the blood vessels in the legs resulting in pain, non-healing ulcers, immobility and t...
Article
Purpose: To compare the total initial treatment costs for open surgery, endovascular revascularization, and primary major amputation within a single-payer healthcare system. Methods: A multicenter, retrospective analysis was undertaken to evaluate 1138 patients with symptomatic peripheral artery disease (PAD) who underwent 1017 endovascular proc...
Article
Full-text available
Purpose: To report midterm results of the "pave-and-crack" technique to facilitate safe and effective scaffolding of heavily calcified femoropopliteal lesions in preparation for delivery of a Supera interwoven stent. Methods: Data were collected retrospectively on 67 consecutive patients (mean age 71±8 years; 54 men) treated with this technique...
Article
Background/aims: We sought to determine if a modification to the peri-anastomotic vein configuration during end-to-side arteriovenous fistula (AVF) creation would achieve a favorable hemodynamic environment compared with the standard acute-angle AVF. Methods: Computational fluid dynamics (CFD) modelling of two end-to-side AVF geometries (smooth-...
Article
Objective: Surveillance techniques for arteriovenous fistulae are required to maintain functional vascular access, with two-dimensional (2D) duplex ultrasound the most widely used imaging modality. This article presents a surveillance method for an arteriovenous fistula (AVF) using a freehand three-dimensional (3D) ultrasound system. A patient-cas...
Article
Full-text available
Purpose: To report the initial clinical experience with percutaneous deep vein arterialization (PDVA) to treat critical limb ischemia (CLI) via the creation of an arteriovenous fistula. Methods: Seven patients (median age 85 years; 5 women) with CLI and no traditional endovascular or surgical revascularization options (no-option CLI) were recrui...
Article
Mid-aortic syndrome is a rare cause of hypertension in the paediatric population. We present here the sonographic findings of a 2 year old who presented with hypertension. Mid-aortic syndrome was diagnosed upon finding renal artery and infrarenal aortic stenoses on ultrasound. The clinical entity and interrogation of the paediatric renal and aortic...
Article
Digital subtraction venography is a readily available tool in the modern hybrid endovascular theatre. We review the utility of venography in the treatment of saphenous venous insufficiency, focusing on the benefits over standard ultrasound imaging to guide ablative treatments.