Hybrid and total endovascular repair of the aortic arch.

BACKGROUND: Recent advances in endovascular technology have enabled minimally invasive repair of the aortic arch, with specifically designed stent-grafts. This article reviews hybrid and total endovascular repair in the management of aortic arch pathology. METHODS: Studies relating to aortic arch management were identified using MEDLINE and Embase, focusing on endovascular repair. RESULTS: Hybrid arch repair is associated with an early mortality rate of some 12 per cent, and carries significant risk of stroke (up to 15 per cent), paraplegia (up to 6 per cent), retrograde dissection (up to 6·5 per cent) and proximal endoleak (6 per cent). Despite patients being of overall higher perioperative risk, hybrid repair has morbidity and early mortality rates comparable to those of open arch replacement. However, rates of freedom from aortic rupture or reintervention are significantly lower in the longer term, owing to the incidence of endoleak. Total endovascular arch repair may be achieved by the use of parallel stents or in situ fenestration in the emergency setting, or use of custom-made devices (scalloped, fenestrated or branched stent-grafts) in the elective setting. Reports of these relatively novel technologies suggest acceptable short-term outcomes, but long-term data are still awaited. CONCLUSION: Repair of aortic arch pathology presents a formidable challenge for endovascular technology. Open aortic arch repair remains the standard in younger, fitter patients, but endovascular technology and experience continue to evolve with encouraging early outcomes and expanding indications.

Early outcomes of patients transferred with ruptured suprarenal aneurysm or dissection.

Objective Despite centralisation of the provision of vascular care, not all areas in England and Wales are able to offer emergency treatment for patients with acute conditions affecting the aorta proximal to the renal arteries. While cardiothoracic centres have made network arrangements to coordinate care for the repair of type A dissections, a similar plan for vascular care is lacking. This study investigates early outcomes in patients with ruptured suprarenal aortic aneurysm or dissection (rSRAD) transferred to a specialist centre. Methods Retrospective observational study over a five-year period (2009-2014) assessing outcomes of patients with ruptured sRAD diagnosed at their local hospital and then transferred to a tertiary centre capable of offering such treatment. Results Fifty-two patients (median age 73 years, 32 male) with rSRAD were transferred and a further four died during transit. The mean distance of patient transfer was 35 miles (range 4-211 miles). One patient did not undergo intervention due to frailty and two died before reaching the operating theatre. A total of 23 patients underwent endovascular repair, 9 hybrid repair and 17 open surgery. Median follow-up was 12 months (range 1-43 months). Complications included paraplegia (n = 3), stroke (n = 2), type IA endoleak (n = 4); 30-day and in-hospital mortality were 16% and 27%. For patients discharged alive from hospital, one-year survival was 67%. Conclusions Although the number of patients with rSRAD is low and those who are transferred alive are a self-selecting group, this study suggests that transfer of such patients to a specialist vascular centre is associated with acceptable mortality rates following emergency complex aortic repair.

Cerebral embolization, silent cerebral infarction and neurocognitive decline after thoracic endovascular aortic repair.

BACKGROUND: Silent cerebral infarction is brain injury detected incidentally on imaging; it can be associated with cognitive decline and future stroke. This study investigated cerebral embolization, silent cerebral infarction and neurocognitive decline following thoracic endovascular aortic repair (TEVAR). METHODS: Patients undergoing elective or emergency TEVAR at Imperial College Healthcare NHS Trust and Guy's and St Thomas' NHS Foundation Trust between January 2012 and April 2015 were recruited. Aortic atheroma graded from 1 (normal) to 5 (mobile atheroma) was evaluated by preoperative CT. Patients underwent intraoperative transcranial Doppler imaging (TCD), preoperative and postoperative cerebral MRI, and neurocognitive assessment. RESULTS: Fifty-two patients underwent TEVAR. Higher rates of TCD-detected embolization were observed with greater aortic atheroma (median 207 for grade 4-5 versus 100 for grade 1-3; P = 0·042), more proximal landing zones (median 450 for zone 0-1 versus 72 for zone 3-4; P = 0·001), and during stent-graft deployment and contrast injection (P = 0·001). In univariable analysis, left subclavian artery bypass (ß coefficient 0·423, s.e. 132·62, P = 0·005), proximal landing zone 0-1 (ß coefficient 0·504, s.e. 170·57, P = 0·001) and arch hybrid procedure (ß coefficient 0·514, s.e. 182·96, P < 0·001) were predictors of cerebral emboli. Cerebral infarction was detected in 25 of 31 patients (81 per cent) who underwent MRI: 21 (68 per cent) silent and four (13 per cent) clinical strokes. Neurocognitive decline was seen in six of seven domains assessed in 15 patients with silent cerebral infarction, with age a significant predictor of decline. CONCLUSION: This study demonstrates a high rate of cerebral embolization and neurocognitive decline affecting patients following TEVAR. Brain injury after TEVAR is more common than previously recognized, with cerebral infarction in more than 80 per cent of patients.

Content Validation and Evaluation of an Endovascular Teamwork Assessment Tool.

OBJECTIVE/BACKGROUND: To modify, content validate, and evaluate a teamwork assessment tool for use in endovascular surgery. METHODS: A multistage, multimethod study was conducted. Stage 1 included expert review and modification of the existing Observational Teamwork Assessment for Surgery (OTAS) tool. Stage 2 included identification of additional exemplar behaviours contributing to effective teamwork and enhanced patient safety in endovascular surgery (using real-time observation, focus groups, and semistructured interviews of multidisciplinary teams). Stage 3 included content validation of exemplar behaviours using expert consensus according to established psychometric recommendations and evaluation of structure, content, feasibility, and usability of the Endovascular Observational Teamwork Assessment Tool (Endo-OTAS) by an expert multidisciplinary panel. Stage 4 included final team expert review of exemplars. RESULTS: OTAS core team behaviours were maintained (communication, coordination, cooperation, leadership team monitoring). Of the 114 OTAS behavioural exemplars, 19 were modified, four removed, and 39 additional endovascular-specific behaviours identified. Content validation of these 153 exemplar behaviours showed that 113/153 (73.9%) reached the predetermined Item-Content Validity Index rating for teamwork and/or patient safety. After expert team review, 140/153 (91.5%) exemplars were deemed to warrant inclusion in the tool. More than 90% of the expert panel agreed that Endo-OTAS is an appropriate teamwork assessment tool with observable behaviours. Some concerns were noted about the time required to conduct observations and provide performance feedback. CONCLUSION: Endo-OTAS is a novel teamwork assessment tool, with evidence for content validity and relevance to endovascular teams. Endo-OTAS enables systematic objective assessment of the quality of team performance during endovascular procedures.

Percutaneous pharmacomechanical thrombectomy for acute iliofemoral deep vein thrombosis: A suitability study.

OBJECTIVES: Percutaneous pharmacomechanical thrombectomy is an emerging therapy for acute deep vein thrombosis and may reduce long-term incidence of post-thrombotic syndrome. This study investigates the proportion of patients presenting with lower limb deep vein thrombosis who are potentially suitable for percutaneous pharmacomechanical thrombectomy. METHODS: A retrospective review of all duplex ultrasound scans for lower limb deep vein thrombosis over two-year period at a regional vascular unit was conducted. All acute occlusive iliofemoral deep vein thrombosis were screened for percutaneous pharmacomechanical thrombectomy suitability according to predefined criteria. RESULTS: There were 2513 duplex ultrasound scans for suspected lower limb deep vein thrombosis in the two-year period. There were 120 cases of acute occlusive iliofemoral deep vein thrombosis. After application of inclusion and exclusion criteria 48 out of 120 (40%) patients were identified as potential candidates for percutaneous pharmacomechanical thrombectomy. CONCLUSIONS: This indicates that a large randomised trial of percutaneous pharmacomechanical thrombectomy is feasible given expected recruitment rates in a multicentre study.

Treatment decisions for descending thoracic aneurysm: preferences for thoracic endovascular aneurysm repair or surveillance in a discrete choice experiment.

OBJECTIVE: To investigate and rank factors that influence endovascular treatment decisions by specialists for patients with descending thoracic aortic aneurysm (dTAA). METHODS: Specialists completed a diagrammatic survey describing uncertainty about the benefit of thoracic endovascular aneurysm repair (TEVAR) for dTAA with respect to age, sex, and aneurysm diameter. Subsequently, a detailed discrete choice experiment was designed. Specialists were recruited and asked to indicate treatment their preference (TEVAR or surveillance) in 25 hypothetical cases of dTAA, with variable patient attributes: age, sex, American Society of Anesthesiologists (ASA) grade, aneurysm diameter, adequate landing zone distal to left subclavian artery (LSA), and length of aortic coverage. Data were analysed using multiple logistic regression. RESULTS: The diagrammatic survey, based on 50 respondents, showed that uncertainty about the benefits of TEVAR was greatest for patients aged 80-85 years (up to 47% of respondents were "unsure") and that uncertainty increased with increasing aneurysm diameter (for an 80-year-old man, 7% were unsure at 5.5 cm and 33% were unsure at 7.0 cm). Seventy-one specialists (mainly from Europe and North America, 86% vascular surgeons and 98% working in units offering TEVAR) completed the discrete choice experiment. Preference for TEVAR increased greatly with enlarging diameter: adjusted odds ratios (OR) >5.5-6.0 cm = 15.8 (95% confidence interval [CI] 9.83-25.40); >6.0-6.5 cm = 393.0 (95% CI 202.00-766.00); >6.5-7.0 cm = 1829.0 (95% CI 400.00-4,181.00). TEVAR was less likely to be preferred in patients older than 75 years (>75-80 years OR 0.32, 95% CI 0.21-0.49; >80-85 years = 0.18, 95% CI 0.11-0.28); in women (OR 0.52, 95% CI 0.37-0.74); in patients classified as ASA grade 4 (OR 0.44, 95% CI 0.36-0.57); and in patients with aorta coverage >25 cm (OR 0.48, 95% CI 0.32-0.74). The proximal landing zone did not influence preference. CONCLUSION: Specialists' preferences for endovascular repair of degenerative dTAA vary widely, and demonstrate clinical uncertainty, especially in octogenarians, and a reluctance to offer TEVAR to women. Aneurysm diameter dominates treatment preferences, but patient fitness and length of aortic coverage (>25 cm) also were influential, although the landing zone distal to LSA was not.

Team training in ruptured EVAR.

Ruptured abdominal aortic aneurysms are almost always a fatal condition. The incidence of ruptured aortic aneurysms (rAAA) is declining, the number of teams is increasing and there is an increased focus on patient safety resulting in limited real life training opportunities to maintain or improve the technical and human factor skills required to manage this acute aortic pathology. The availability and experience of the multidisciplinary team together with accessibility of appropriate resuscitation and efficient logistics all influence the modality of rAAA repair. A standardised patient's pathway for rAAA management and reliable multidisciplinary team are the keys to improve patient outcomes. Whole rEVAR team training using high fidelity simulation may be the one answer to allow clinicians to learn, practice, rehearse, improve and maintain team-based knowledge, technical and human factor skills and team attitudes to manage this challenging pathology.

Variation in maximum diameter measurements of descending thoracic aortic aneurysms using unformatted planes versus images corrected to aortic centerline.

OBJECTIVE: Evaluation of variation in descending thoracic aortic aneurysm (dTAA) diameters measured on CT scans in different planes and by different observers and the potential impact on treatment decisions. METHODS: CT angiography of dTAA (N = 20) were assessed by three specialists, with measurements repeated after 1 month. Calliper measurements of maximum external diameters were made on unformatted images and perpendicular to the aneurysm centerline after image processing (corrected). Repeatability was assessed using Bland-Altman plots. RESULTS: Maximum corrected diameter measurements were smaller than axial measurements (66.3 ± 7.9 mm vs. 74.9 ± 20.9 mm, p < .001). Both intraobserver and interobserver variation were less for corrected than for axial measurements (mean intraobserver differences 5.0 ± 3.8 mm vs. 11.8 ± 9.3 mm, p < .001; mean interobserver differences 2.8 ± 2.5 mm versus 10.4 ± 14.0 mm, p < .001) and interobserver variation increased with aneurysm diameter for maximum axial but not corrected measurements. Using corrected rather than axial measurements could have changed treatment decisions in two patients (10%) using a treatment threshold diameter of 55 mm and 10 patients (50%) using a threshold of 65 mm. CONCLUSION: Corrected diameters were smaller than axial diameters, could be measured with higher repeatability, and were subject to less interobserver variability. Using corrected versus axial measurements would have changed management decisions in up to half of the cases in this study.

Planning for EVAR: the role of modern software.

Endovascular intervention has revolutionized the treatment of aortic disease, extending the cohort of patients eligible for repair. Accurate planning for endovascular aortic repair is essential. Recent advances in modern software have demonstrated potential for improving outcomes and enhancing the decision making process beyond 3D measurements and intraoperative navigation techniques. With increasing uptake and complexity of endovascular therapies requiring multidisciplinary collaborations, it has become apparent that planning must extend to the preparation of entire interventional teams and support the early identification and prevention of potentially harmful events. This paper will examine recent advances not only in morphological planning and computational modelling, but also the role of software in the preparation of teams and prevention of error.

Post-thrombotic syndrome: a clinical review.

Up to half of patients with proximal deep vein thrombosis (DVT) will develop post-thrombotic syndrome (PTS) despite optimal anticoagulant therapy. PTS significantly impacts upon quality of life and has major health-economic implications. This narrative review describes the pathophysiology, risk factors, and diagnosis, prevention and treatment of PTS, to improve our understanding of the disease and guide treatment. Relevant articles were identified through systematic searches of the PubMed, EMBASE and Cochrane databases between 1966 and November 2011. Studies were included for detailed assessment if they met the following criteria: published in English, human study participants, study population aged > 18 years, and lower limb post-thrombotic syndrome. All non-systematic reviews and single patient case reports were excluded. Recurrent thrombosis, thrombus location and obesity are major risk factors, whereas the importance of gender and age remain uncertain. The diagnosis of PTS is based on clinical findings in patients with a known history of DVT. Several clinical scales have been described, with the Villalta Score gaining increasing popularity. Adequate anticoagulation and use of elastic compression stockings (ECS) following DVT can reduce the incidence of PTS. Catheter-directed thrombolysis and mechanical thrombectomy of acute DVT may preserve valvular function. Studies to date of these techniques are encouraging, and have reported improved hemodynamics and a reduced incidence of PTS. The management of established PTS is challenging. Compression therapy, aimed at reducing the underling venous hypertension, remains the mainstay of treatment. This is despite a paucity of high-quality evidence to support its use. Pharmacologic and surgical treatments have also been described, with a number of studies citing symptomatic improvement.

Current practice of carotid endarterectomy in the UK.

BACKGROUND: Carotid endarterectomy (CEA) reduces the risk of stroke in patients with internal carotid stenosis of 50-99 per cent. This study assessed national surgical practice through audit of CEA procedures and outcomes. METHODS: This was a prospective cohort study of UK surgeons performing CEA, using clinical audit data collected continuously and reported in two rounds, covering operations from December 2005 to December 2007, and January 2008 to September 2009. RESULTS: Some 352 (92·6 per cent) of 380 eligible surgeons contributed data. Of 19,935 CEAs recorded by Hospital Episode Statistics, 12,496 (62·7 per cent) were submitted to the audit. A total of 10,452 operations (83·6 per cent) were performed for symptomatic carotid stenosis; among these patients, the presenting symptoms were transient ischaemic attack in 4507 (43·1 per cent), stroke in 3572 (34·2 per cent) and amaurosis fugax in 1965 (18·8 per cent). The 30-day mortality rate was 1·0 per cent (48 of 4944) in round 1 and 0·8 per cent (50 of 6151) in round 2; the most common cause of death was stroke, followed by myocardial infarction. The rate of death or stroke within 30 days of surgery was 2·5 per cent (124 of 4918) in round 1 and 1·8 per cent (112 of 6135) in round 2. CONCLUSION: CEA is performed less commonly in the UK than in other European countries and probably remains underutilized in the prevention of stroke. Increasing the number of CEAs done in the UK, together with reducing surgical waiting times, could prevent more strokes.

Asymptomatic Carotid Surgery Trial-2 (ACST-2): rationale for a randomised clinical trial comparing carotid endarterectomy with carotid artery stenting in patients with asymptomatic carotid artery stenosis.

OBJECTIVES: To compare carotid endarterectomy with carotid artery stenting in the prevention of stroke in patients with asymptomatic carotid stenosis. DESIGN: A large, simple, pragmatic international trial of at least 5000 patients with asymptomatic carotid stenosis in whom intervention is thought to be needed but where there is substantial uncertainty about the appropriate choice of treatment. The trial is designed to fit in easily with normal clinical practice. MATERIALS & METHODS: A short (approximately 2 min) telephone call is made to randomise patients to either carotid endarterectomy (CEA) or stenting (CAS). Follow-up by the collaborator will be at one month after the procedure (simple 1-page form) and by the ACST office for 5-years post-procedure. Data will be analysed on an intention-to-treat basis; main outcomes will be 30-day myocardial infarction, stroke and death, and 5-year stroke rates. In addition, appropriate subgroup analyses will be undertaken, and health economic evaluation will consider procedural and stroke-related healthcare costs and quality of life. CONCLUSION: Collaborators who routinely undertake CEA and CAS are encouraged to participate in ACST-2. This trial, now funded and open for randomisation, will provide important evidence comparing the immediate and long-term safety and efficacy of carotid endarterectomy and stenting in patients with asymptomatic carotid stenosis.

Nucleus accumbens dopamine depletion impairs both acquisition and performance of appetitive Pavlovian approach behaviour: implications for mesoaccumbens dopamine function.

The involvement of mesoaccumbens dopamine in adaptive learning and behaviour is unclear. For example, dopamine may act as a teaching signal to enable learning, or more generally modulate the behavioural expression, or selection, of an already-learned response. The present study investigated the involvement of the mesoaccumbens dopamine system in a fundamental form of learning: Pavlovian conditioning. In this case, the temporal association of a previously neutral visual stimulus and a biologically significant unconditioned stimulus (US), subsequently led to the production of the conditioned response (CR) of discriminated approach behaviour directed toward the conditioned stimulus (CS+), relative to a control (CS-) stimulus. 6-hydroxydopamine lesions of the nucleus accumbens (NAcc), leading to approximately 80% reductions in tissue dopamine, were made at varying time points in four experimental groups of rats, either before or subsequent to the acquisition of the CR. NAcc dopamine depletion produced long-term neuroadaptations in dopamine function 2 months after surgery, and profoundly impaired discriminated Pavlovian approach regardless of when the lesion was made. Thus, NAcc dopamine not only plays a role in conditioned behavioural activation, but also in making the appropriate discriminated response i.e. the direction of response. Further, acquisition lesions produced a far greater impact on discriminated approach than performance lesions. This difference in lesion-induced impairment implies that mesoaccumbens dopamine may play differential roles in the learning and performance of preparatory Pavlovian conditioning.