A systematic review of three-dimensional printed template-assisted physician-modified stent grafts for fenestrated endovascular aneurysm repair.

OBJECTIVE: Fenestrated endovascular aneurysm repair has yet to gain widespread adoption owing to the technical complexity and increased risk of complications. Three-dimensional (3D) printed templates to guide fenestrated physician-modified stent grafts (PMSGs) are a novel technique that may have the potential to increase the accuracy of fenestration alignment, and to disrupt both the cost and timing of the current commercial fenestrated endograft supply chain. We have conducted a critical appraisal of the emerging literature to assess this. METHODS: A systematic literature search was performed using PubMed and OVID Medline as guided by the PRISMA statement on April 30, 2020. We used "3D printing" and "physician modified" or "surgeon modified" and all related search terms. We identified 50 articles which met our search criteria. None articles were included as being of direct relevance to 3D-printed template-assisted PMSGs for fenestrated endovascular aneurysm repair. Abstracts were screened individually by each investigator to ensure relevance. RESULTS: Nine relevant articles were identified for critical analysis. These included one technical report, five case reports or series, two prospective trials, and one letter to the editor. CONCLUSIONS: These 3D-printed templates are a promising new avenue to assist with the placement of fenestrations in PMSGs, particularly in urgent or emergent cases where custom fenestrated endografts are unavailable, with larger scale studies warranted. Further work to validate the key stages of the template workflow are required, as well as further investigation into the most suitable manufacturing and distribution methods before the mainstream implementation of this novel technique.

Open versus Endovascular Abdominal Aortic Aneurysm Repair in the Australian Private Sector Over Twenty Years.

PURPOSE: Over the past two decades, the proliferation of endovascular surgery has changed the approach to abdominal aortic aneurysm (AAA) repair. In Australia, close to two-thirds of surgical procedures are performed in the private healthcare system. We aimed to describe the trends in AAA repair in the Australian private sector throughout the early 21st century. MATERIALS AND METHODS: Medicare Benefits Schedule (MBS) statistics were accessed to determine the number of infrarenal open AAA repair (OAR) and endovascular AAA repair (EVAR) procedures performed between January 2000 and December 2019. Population data were extracted from the Australian Bureau of Statistics and used to calculate incidence per 100,000 population. Further analysis was performed according to age, gender, and state. RESULTS: During the study period, 13,193 (67.0%) EVARs and 6504 (33.0%) OARs were performed in the Australian private sector. OARs fell from 70.5% (n=567) of AAA repairs in 2000 to 15.7% (n=237) in 2019, while EVARs rose from 29.5% (n=151) to 84.3% (n=808). The frequency of EVAR surpassed OAR in 2004. The overall incidence of AAA repair varied minimally over the time period (range: 4.9-6.5 per 100,000 adults per year). AAA repair was more common in males than females (9.7 vs 1.7 per 100,000 population) and more common in older age groups. There was a 4-fold increase in EVAR among males older than 85 years (12.8-57.4 per 100,000 population), the largest rise of any group. The overall EVAR:OAR ratio increased from 0.4 to 5.4. There were considerable state-based discrepancies. CONCLUSION: The landscape of AAA repair in Australian private sector has drastically changed with a clear preference toward EVAR. EVAR saw increased use across all genders, age groups and states, despite stable rates of AAA surgery. Further research is necessary to compare our findings to national trends in the Australian public sector.

A Fine Needle Recanalization Technique for Iliac Artery Occlusions in Endovascular Surgery.

BACKGROUND: Endovascular intervention for chronic total occlusions (CTOs) in aortoiliac occlusive disease (AIOD) poses technical challenges. In this manuscript, our experience of fine needle recanalization for the treatment of iliac artery CTO is described. METHOD: A prospective database recorded treatment of 11 limbs in 11 patients since 2011 using this technique. The majority of these CTO were of the common iliac artery (n = 9). RESULTS: Technical success rate was 91% (n = 10). One failed case was due to tortuous iliac anatomy. There was no restenosis of the treated segments at 8 weeks and no major complications, perforations, major limb loss, or periprocedural mortality. CONCLUSIONS: This technique is a safe and viable adjunct for difficult CTO in AIOD with suitable anatomy. It benefits from being a simple, low-profile, low-cost coaxial system and should be part of the armamentarium with other advanced endovascular techniques.

Three dimensional models in uro-oncology: a future built with additive fabrication.

PURPOSE: Three-dimensional (3D) printing was invented in 1983 but has only just begun to influence medicine and surgery. Conversion of digital images into physical models demonstrates promise to revolutionize multiple domains of surgery. In the field of uro-oncology, researchers and clinicians have recognized the potential of this technology and are working towards making it an integral part of urological practice. We review current literature regarding 3D printing and other 3D technology in the field of urology. METHOD: A comprehensive assessment of contemporary literature was performed according to a modified PRISMA analysis for the purposes of this narrative review article. Medical databases that were searched included: Web of Science, EMBASE and Cochrane databases. Articles assessed were limited only to English-language peer-reviewed articles published between 1980 and 2017. The search terms used were "3D", "3-dimensional", "printing", "printing technology", "urology", "surgery". Acceptable articles were reviewed and incorporated for their merit and relevance with preference given for articles with high impact, original research and recent advances. RESULTS: Thirty-five publications were included in final analysis and discussion. CONCLUSIONS: The area of 3D printing in Urology shows promising results, but further research is required and cost reduction must occur before clinicians fully embrace its use. As costs continue to decline and diversity of materials continues to expand, research and clinical utilization will increase. Recent advances have demonstrated the potential of this technology in the realms of education and surgical optimization. The generation of personalized organs using 3D printing scaffolding remains the 'holy grail' of this technology.

The academic tweet: Twitter as a tool to advance academic surgery.

Social media, Twitter in particular, has emerged as an essential tool for surgeons. In the realm of academic surgery, it enables surgeons to advance the core values of academic surgery, as outlined by the Association for Academic Surgery: inclusion, leadership, innovation, scholarship, and mentorship. This article details the ways in which surgeons are using Twitter to embody these values and how the Twitter account for the Association of Academic Surgeons accomplishes its goal of inspiring and developing young academic surgeons.

A Novel Technique for Sutureless Proximal Aortic Endograft Revision in Type 1A Endoleak.

Management of type 1A endoleaks can be challenging. In the endovascular era, this condition is expected to become more frequent. Conventionally, surgical explant of the endograft remains the "last-resort" surgical treatment when all endovascular or other open options are exhausted. Endograft removal is a difficult and morbid procedure. An alternative technique is described that involves cinching the endograft after disengagement of the proximal fixation hooks. The endograft is redeployed within a prosthetic aortic replacement graft with an overlapping zone. This can reduce complications such as from additional anastomoses, graft bleeding, prolonged clamping, operative time, and associated comorbidities.

Pulmonary embolism with endovascular thrombolysis for thrombosed hemodialysis arteriovenous access
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AIMS: Acute thrombosis of hemodialysis (HD) arteriovenous access is an urgent problem for HD patients and is commonly managed by endovascular thrombolysis. Pulmonary embolism (PE) is a recognized complication of HD access thrombosis and thrombolysis but the risk and outcomes are unclear. This study aims to determine the incidence, predictors, and outcomes of PE after endovascular thrombolysis of HD arteriovenous access in patients presenting with acute thrombosis. MATERIALS AND METHODS: A single-center retrospective study was performed for all adult chronic kidney disease patients undergoing arteriovenous access thrombolysis between January 1, 2012, and December 31, 2014. Investigation for PE with CT pulmonary angiography or ventilation/perfusion scintigraphy (V/Q scan) was performed as clinically directed by the managing clinicians. In cases diagnosed with PE, the pulmonary embolism severity index (PESI) was calculated. RESULTS: A total of 48 (median age 68) patients underwent 74 thrombolysis procedures. Thrombolysis techniques were divided into pharmacological (44.6%), mechanical (17.6%), or pharmacomechanical (37.8%). Clinical success was achieved in 56/74 (75.7%) of procedures. Five episodes of thrombolysis for access thrombosis (6.8%) were associated with clinically symptomatic PE. The PESI score ranged from 51 to 127. All patients with PE were managed with 3 - 6 months of anticoagulation and recovered clinically. There were no statistically significant differences in baseline characteristics, methods of thrombolysis, or clot burden in patients that developed a PE. CONCLUSION: There is a clinically significant risk of symptomatic PE after arteriovenous access thrombolysis for access thrombosis in HD patients.
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Multidetector (64+) Computed Tomography Angiography of the Lower Limb in Symptomatic Peripheral Arterial Disease: Assessment of Image Quality and Accuracy in a Tertiary Care Setting.

OBJECTIVE: The aim of this study was to evaluate image quality and accuracy of 64+ detector multidetector computed tomography angiography (MDCTA) for hemodynamically significant (≥50%) stenosis in patients with symptomatic peripheral arterial disease (PAD) using digital subtraction angiography as the reference standard. METHODS: This is a retrospective study of 29 patients with PAD (19 men, 10 women) who underwent lower limb MDCTA (64- or 80-detector) and digital subtraction angiography. Image quality and accuracy of MDCTA for hemodynamically significant stenosis were assessed in the infrarenal aorta and 15 lower extremity segments. RESULTS: Four hundred fifty-three segments were adequately visualized at both modalities. Multidetector CTA had 84.8% sensitivity, 87.7% specificity, and 86.3% accuracy for significant stenosis. Accuracy was decreased in the calf when compromising arterial wall calcifications were present versus absent (55.9% vs 82.4%, P < 0.0001). CONCLUSIONS: 64+ MDCTA is accurate in patients with symptomatic PAD. However, diagnostic accuracy in below-knee vessels remains relatively poorer. Alternative imaging modalities should be considered where below-knee disease is suspected.

3D Printing in Liver Surgery: A Systematic Review.

BACKGROUND: Rapid growth of three-dimensional (3D) printing in recent years has led to new applications of this technology across all medical fields. This review article presents a broad range of examples on how 3D printing is facilitating liver surgery, including models for preoperative planning, education, and simulation. MATERIALS AND METHODS: We have performed an extensive search of the medical databases Ovid/MEDLINE and PubMed/EMBASE and screened articles fitting the scope of review, following previously established exclusion criteria. Articles deemed suitable were analyzed and data on the 3D-printed models-including both technical properties and desirable application-and their impact on clinical proceedings were extracted. RESULTS: Fourteen articles, presenting unique utilizations of 3D models, were found suitable for data analysis. A great majority of articles (93%) discussed models used for preoperative planning and intraoperative guidance. PolyJet was the most common (43%) and, at the same time, most expensive 3D printing technology used in the development process. Many authors of reviewed articles reported that models were accurate (71%) and allowed them to understand patient's complex anatomy and its spatial relationships. CONCLUSIONS: Although the technology is still in its early stages, presented models are considered useful in preoperative planning and patient and student education. There are multiple factors limiting the use of 3D printing in everyday healthcare, the most important being high costs and the time-consuming process of development. Promising early results need to be verified in larger randomized trials, which will provide more statistically significant results.

Perceived barriers to endovascular repair of ruptured abdominal aortic aneurysm among Australasian vascular surgeons.

OBJECTIVE: Although endovascular abdominal aortic aneurysm (AAA) repair (EVAR) is widely accepted for elective surgery, the uptake of emergency EVAR for ruptured AAA (REVAR) has trailed behind. This study was intended to identify the barriers to widespread application of REVAR in Australia and New Zealand. METHODS: A cross-sectional survey of members of the Australia and New Zealand Society of Vascular Surgeons was performed in late 2013. Primary themes explored were (1) perceived barriers to performing REVAR and (2) advantages of REVAR compared with open repair. Secondary data measures were the volume of AAA surgery, standard protocol use, and staff accreditation among vascular units. RESULTS: A total of 85 surgeons responded to an anonymous online questionnaire (41% response rate); of these, 23 surgeons (27%) had no experience with REVAR, and 65% currently perform more EVAR than open repair for elective procedures, compared with 18% for ruptured AAA. Of the perceived barriers explored, respondents agreed that poor availability of endovascular facilities (73% agreed or strongly agreed) and ancillary staff (56%) were barriers to REVAR. Most surgeons agreed that the advantages of REVAR include reduced intraoperative blood loss, length of stay, and postoperative complications. Four of 11 vascular units performing REVAR had standard protocols in use, and four had mandatory staff accreditation. CONCLUSIONS: The most common barrier to REVAR identified by surgeons was the poor availability of endovascular facilities, many of which are not ideally suited for this type of procedure. Australian and New Zealand vascular units have low rates of standard protocol use and staff accreditation for REVAR, which may have implications for patient care.

Clinical outcomes after arteriovenous fistula creation in chronic kidney disease.

BACKGROUND: Optimal timing of arteriovenous fistula (AVF) surgery in chronic kidney disease (CKD) is uncertain. METHODS: A single-centre retrospective study of pre-dialysis CKD patients having first AVF surgery. RESULTS: The median estimated glomerular filtration rate (eGFR) at the time of AVF surgery in 100 patients was 15 ml/min/1.73 m(2), with patients classified as having an early AVF if eGFR was >15 ml/min/1.73 m(2) (n = 46) or a late AVF if eGFR was ≤15 ml/min/1.73 m(2) (n = 54). In the eGFR ≤15 group, 81% of patients started haemodialysis (HD), compared with 63% of the eGFR >15 patients (p = 0.04). The median time to starting HD was 30.3 months in the eGFR >15 group compared to 10.7 months for the eGFR ≤15 group (log rank p = 0.018). There were no differences in the requirements for a dialysis catheter (eGFR >15 24% vs. eGFR ≤15 11%, p = 0.20) or additional access procedures between the two groups. CONCLUSIONS: AVF surgery with an eGFR >15 ml/min/1.73 m(2) was associated with a higher risk of AVF non-use and a more prolonged time to the need for HD.

Aortic aneurysms - screening, surveillance and referral.

BACKGROUND: Aortic aneurysms are a common finding in elderly patients. Rupture of an aortic aneurysm is a catastrophic event associated with a very high mortality. OBJECTIVE: To review the current literature on aortic aneurysmal disease, including the recommended referral threshold, surveillance guidelines and treatment options. DISCUSSION: Screening of men aged 65 years and over has been shown to reduce aneurysm related mortality, however, no formal screening guidelines exist in Australia. In addition to the risk of aneurysm expansion and rupture, patients are at increased risk of cardiovascular morbidity and mortality. Small aneurysms should be managed with surveillance and cardiovascular risk factor modification. Large aneurysms should be referred promptly to a vascular surgeon for assessment and repair. Symptomatic and ruptured aneurysms require emergency assessment and treatment. Advances in endovascular techniques enable most patients with aortic aneurysms to be treated with minimally invasive stent grafts, which have lower perioperative complication rates than open repair.

Non-aortic aneurysms - natural history and recommendations for referral and treatment.

BACKGROUND: Non-aortic aneurysms constitute a collection of conditions where the same pathology presents in multiple anatomic locations. They are often detected incidentally and the aetiology, natural history, clinical presentation and treatment of non-aortic aneurysms may differ completely, depending on their site. OBJECTIVE: This article summarises current knowledge about non-aortic aneurysms in a structured manner, highlighting the natural history and recommendations for referral and treatment. DISCUSSION: Non-aortic aneurysms have an underestimated morbidity and mortality risk, and elective treatment has been demonstrated to prevent complications such as rupture or embolisation. Although endovascular repair has become increasingly popular, conventional open surgical repair has continued to play a substantial role in the treatment of non-aortic aneurysms. Treatment must be tailored to the patient and anatomic location, and early counselling and assessment by a vascular specialist is recommended.

A primer on cohort studies in vascular surgery research.

Vascular research questions can be answered using various study designs. Observational studies are used frequently to address a wide range of clinical questions when randomized clinical trials are not feasible or practical. One of the powerful vascular research tools is the cohort study. The cohort study is a reliable observational study design in which individuals who share a common characteristic (a cohort) are followed over time and their outcomes are assessed at various intervals. This review focuses on the essential characteristics, design, implementation, bias, validity, and clinical significance of cohort studies and provides illustrative examples. A cohort study can be either a prospective or a retrospective study, depending on whether the outcome occurred before or after the enrollment of the cohort. Each type has its advantages and disadvantages. Confounding, selection, and information biases can all occur in cohort studies. Applications of the cohort study design include studying the natural history of a disease, describing a condition's frequency, and investigating multiple outcomes simultaneously.

MRI in CFD for chronic type B aortic dissection: Ready for prime time?

OBJECTIVES: Better tools are needed for risk assessment of Type B aortic dissection (TBAD) to determine optimal treatment for patients with uncomplicated disease. Magnetic resonance imaging (MRI) has the potential to inform computational fluid dynamics (CFD) simulations for TBAD by providing individualised quantification of haemodynamic parameters, for assessment of complication risks. This systematic review aims to present an overview of MRI applications for CFD studies of TBAD. METHODS: Following PRISMA guidelines, a search in Medline, Embase, and the Scopus Library identified 136 potentially relevant articles. Studies were included if they used MRI to inform CFD simulation in TBAD. RESULTS: There were 20 articles meeting the inclusion criteria. 19 studies used phase contrast MRI (PC-MRI) to provide data for CFD flow boundary conditions. In 12 studies, CFD haemodynamic parameter results were validated against PC-MRI. In eight studies, geometric models were developed from MR angiography. In three studies, aortic wall or intimal flap motion data were derived from PC/cine MRI. CONCLUSIONS: MRI provides complementary patient-specific information in CFD haemodynamic studies for TBAD that can be used for personalised care. MRI provides structural, dynamic and flow data to inform CFD for pre-treatment planning, potentially advancing its integration into clinical decision-making. The use of MRI to inform CFD in TBAD surgical planning is promising, however further validation and larger cohort studies are required.

STABILISE; treatment of aortic dissection, a single Centre experience.

PURPOSE: To outline the process of the STABILISE technique and its use; reporting patient outcomes and midterm follow up for complicated aortic dissection. MATERIALS AND METHODS: Single centre retrospective analysis from January 2011 to January 2021 using the STABILISE technique which utilises balloon assistance to facilitate intimal disruption and promote aortic relamination. RESULTS: Sixteen patients underwent endovascular aortic repair with the STABILISE technique for aortic dissection over the study period. Fourteen patients (14/16; 88%) had acute dissection. Two of 16 (12%) were chronic. The median age of the patient cohort was 61 years (range 32-80 years) and consisted of a male majority (n = 11; 69%). The median time from diagnosis to intervention was 5 days (1-115 days; IQR 1-17.3). More than half (56%) had surgical repair of a acute type A aortic dissection prior to radiological intervention. The procedure was technically successful with no procedural mortality. Two patients were lost to follow up and two died in the post-operative period. Twelve patients had ongoing follow up with an average number of 2.9 ± 1.6 scans performed. Follow up was available in thirteen patients (81%) with a median follow up period of 1097 days (IQR 707-1657). The rate of re-intervention (n = 2/16; 13%) requiring additional stenting was in line with published re-intervention data (15%). Follow up showed a reduction in false lumen size following treatment with total luminal dimensions remaining stable over the follow-up period. CONCLUSION: The STABILISE technique as a procedure for complicated aortic dissection, either acute or chronic, appears safe with stable mid-term aortic remodelling and patient outcomes. LEVEL OF EVIDENCE: Level 3, Retrospective cohort study.