Long-term survival after endovascular and open repair of unruptured abdominal aortic aneurysm

Background

The aim of this study was to examine patterns of 10-year survival after elective repair of unruptured abdominal aortic aneurysms (AAAs) in different patient groups.

Methods

Patients having open repair or endovascular aneurysm repair (EVAR) in the English National Health Service between January 2006 and December 2015 were identified from Hospital Episode Statistics data. Postoperative survival among patients of different age and Royal College of Surgeons of England (RCS) modified Charlson co-morbidity score profiles were analysed using flexible parametric survival models. The relationship between patient characteristics and risk of rupture after repair was also analysed.

Results

Some 37 138 patients underwent elective AAA repair, of which 15 523 were open and 21 615 were endovascular. The 10-year mortality rate was 38·1 per cent for patients aged under 70 years, and the survival trajectories for open repair and EVAR were similar when patients had no RCS-modified Charlson co-morbidity. Among older patients or those with co-morbidity, the 10-year mortality rate rose, exceeding 70 per cent for patients aged 80 years. Mean survival times over 10 years for open repair and EVAR were often similar in subgroups of older and more co-morbid patients, but their survival trajectories became increasingly dissimilar, with open repair showing greater short-term risk within 6 months but lower 10-year mortality rates. The risk of rupture over 9 years was 3·4 per cent for EVAR and 0·9 per cent for open repair, and was weakly associated with patient factors.

Conclusion

Long-term survival patterns after elective open repair and EVAR for unruptured AAA vary markedly across patients with different age and co-morbidity profiles.

Population-based study of mortality and major amputation following lower limb revascularization

Background

The aim of this study was to estimate separate risks of major lower limb amputation and death following revascularization for peripheral artery disease (PAD) using competing risks analysis.

Methods

Routinely collected data from Hospital Episode Statistics (HES) were used to identify patients who underwent endovascular or open lower limb revascularization for PAD in England from 2005 to 2015. The primary outcomes were major lower limb amputation and death within 5 years of revascularization. Cox proportional hazards and Fine–Gray competing risks regression were used to examine the competing risks of these outcomes.

Results

Some 164 845 patients underwent their first lower limb revascularization for PAD during the study interval. Most were men (64·6 per cent) and the median age was 71 (i.q.r. 62–78) years. Following endovascular revascularization, the 5-year cumulative incidence of amputation was 4·2 per cent in patients with intermittent claudication and 18·0 per cent in those with a record of tissue loss. The corresponding rates were 10·8 and 25·3 per cent respectively after open revascularization, and 8·1 and 25·0 per cent after combined procedures. The 5-year cumulative incidence of death varied from 24·5 to 39·8 per cent, depending on procedure type. Competing risks methods consistently produced lower estimates than standard methods.

Conclusion

The 5-year risk of major amputation following lower limb revascularization for PAD appears lower than estimated previously. Patients undergoing revascularization for tissue loss and those who require an open procedure are at highest risk of limb loss.

Weekend effect in non-elective abdominal aortic aneurysm repair

Background

The ‘weekend effect’ describes the phenomenon where patient outcomes appear worse for those admitted at the weekend. It has been used recently to justify significant changes in UK health policy. Recent evidence has suggested that the effect may be due to a combination of inadequate correction for confounding factors and inaccurate coding. The effects of these factors were investigated in patients with acute abdominal aortic aneurysm (AAA).

Methods

Patients undergoing non‐elective AAA repair entered into the UK National Vascular Registry from January 2013 until December 2015 were included in a case–control study. The patients were divided according to whether they were treated during the week (Monday 08.00 hours to Friday 17.00 hours) or at the weekend. Data extracted included demographics, co‐morbidities, preoperative medications and baseline blood test results, as well as outcomes. Coding issues were investigated by looking at patients treated for ruptured, symptomatic or asymptomatic AAA within the non‐elective cohort. The primary outcome was in‐hospital mortality. Secondary outcomes included length of inpatient stay, and cardiac, respiratory and renal complications.

Results

The mortality rate appeared to be higher at the weekend (odds ratio (OR) 1·69, 95 per cent c.i. 1·47 to 1·94; P < 0·001), but this effect disappeared when confounding factors and coding issues were corrected for (corrected OR for ruptured AAA 1·09, 0·92 to 1·29; P = 0·330). Differences in outcomes were similar for prolonged length of hospital stay (uncorrected OR 1·21, 95 per cent c.i. 1·06 to 1·37, P = 0·005; corrected OR for ruptured AAA 1·06, 0·91 to 1·10, P = 0·478), and morbidity outcomes.

Conclusion

After appropriate correction for confounding factors and coding effects, there was no evidence of a significant weekend effect in the treatment of non‐elective AAA in the UK.

A systematic review of postoperative cognitive decline following open and endovascular aortic aneurysm surgery

OBJECTIVES Postoperative cognitive decline (POCD) is a well-recognised neurological phenomenon following major surgery. Most commonly seen in elderly patients, it has direct links to increased long-term morbidity and reduced quality of life. Its incidence following open and endovascular abdominal and thoracic aneurysm surgery is unclear. The purpose of this systematic review is to collate available evidence for POCD following abdominal and thoracic aortic surgery, and to identify continuing controversies directing future research. METHODS A MEDLINE search was conducted following the recommendations of the PRISMA guidelines. Terms searched for included but were not limited to: aortic surgery, delirium, postoperative cognitive decline/dysfunction thoracic aortic surgery, abdominal aortic surgery. Reference lists were searched for additional studies. RESULTS Five observational studies were identified from the literature search. Variation in study methods, cognitive test batteries and thresholds set by the study coordinators did not allow for pooled results. In those studies that did find evidence of decline, risk was linked to age over 65 years, presence of postoperative delirium and decreased years in education. CONCLUSIONS Evidence thus far suggests that POCD can affect patients following major aortic, non-cardiothoracic as well as cardiothoracic surgery. Future research should focus on using a validated repeatable battery of cognitive tests and a single defined threshold for POCD to allow pooled analysis and more robust conclusions. Larger, adequately powered studies are required to re-evaluate the effect of aortic aneurysm surgery on postoperative cognitive function.

Extended use of endovascular aneurysm sealing: Chimneys for juxtarenal aneurysms

Hostile infrarenal aortic neck anatomy presents a challenge for the endovascular treatment of abdominal aortic aneurysm. Open surgical repair has been seen as the gold standard treatment for juxtarenal abdominal aortic aneurysm; however, endovascular techniques are now becoming more prevalent, particularly in patients deemed high risk for morbidity and mortality with open repair. The morphology of an aneurysm is a determinant of long-term outcomes, and short aneurysm necks are associated with poorer outcomes and a higher rate of secondary reinterventions. Parallel grafts have been used in combination with endovascular aneurysm repair to elongate the sealing zone into the paravisceral segment of the aorta. This technique is associated with a risk of proximal Type I endoleak due to "guttering." This risk may be decreased when parallel grafts are used in combination with endovascular aneurysm sealing and, as such, this technique may represent an alternative to current techniques for the treatment of juxtarenal abdominal aortic aneurysm, such as the use of conventional bifurcated grafts (with or without parallel grafts) and fenestrated endovascular stent grafts.

Endovascular aneurysm sealing for infrarenal abdominal aortic aneurysms: 30-day outcomes of 105 patients in a single centre

OBJECTIVE

Endovascular aneurysm sealing (EVAS) has been proposed as a novel alternative to endovascular aneurysm repair (EVAR) in patients with infrarenal abdominal aortic aneurysms (AAA). The early clinical experience, technical refinements, and learning curve of EVAS in the treatment of AAA at a single institution are presented.

METHODS

One-hundred and five patients were treated with EVAS between March 2013 and November 2014. Prospective data were recorded on consecutive patients receiving EVAS. Data included demographics, preoperative aneurysm morphology, and 30-day outcomes, including rates of endoleak, limb occlusion, reintervention, and death. Postoperative imaging consisted of duplex ultrasound and computed tomographic angiography.

RESULTS

The mean age of the cohort was 76 ± 8 years and 12% were female. Adverse neck morphology was present in 72 (69%) patients, including aneurysm neck length <10 mm (20%), neck diameter >32 mm (18%), β-angulation >60° (21%), and conical aneurysm neck (51%). There was one death within 30 days. The incidence of Type 1 endoleak within 30 days was 4% (n = 4); all were treated successfully with transcatheter embolisation. All four proximal endoleaks were associated with technical issues that resulted in procedure refinement, and all were in patients with adverse proximal aortic necks. The persistent Type 1 endoleak rate at 30 days was 0% and there were no Type 2 or Type 3 endoleaks. Angioplasty and adjunctive stenting were performed for postoperative limb stenosis in three patients (3%).

CONCLUSIONS

EVAS appears to be associated with reasonable 30-day outcomes despite the necessity of procedural evolution in the early adoption of this technique. EVAS appears to be applicable to patients with challenging aortic morphology and endoleak rates should reduce with procedural experience. The utility of EVAS will be defined by the durability of the device in long-term follow-up, although the absence of Type 2 endoleaks is encouraging.

Carotid artery stenting: high-risk interventionist versus high-risk center

Carotid artery stenting (CAS) is a less invasive alternative to carotid endarterectomy (CEA) for the management of carotid artery stenosis. Although early multicenter randomized controlled trials reported inferior results for CAS compared with CEA, recent advances in technology and increasing CAS operator expertise have lead to improved results. As with any procedure, a high caseload translates into increased experience and better outcomes. This article discusses the current shortfalls of CAS, as well as the various options available to improve CAS results. The majority of studies suggest that there is an inverse relationship between caseload volume and CAS outcomes that defines high-risk interventionists and high-risk centers. Centralizing CAS procedures to high-volume centers is essential for optimization of CAS outcomes.

Symptomatic Renal Artery Stenosis and Infra-renal AAA

OBJECTIVES

To identify evidence to guide the vascular surgeon as to the relevance of renal artery stenting in a patient with symptomatic renal artery stenosis undergoing elective endovascular aortic aneurysm repair (EVAR).

METHODS

A comprehensive literature search of MEDLINE was performed without time limits. The following terms were used in the first instance: renal artery stenting and renal artery stenosis, and any other analogous terms identified during the search. Selection criteria were set to randomised control trials.

RESULTS

Despite several large, randomised controlled trials investigating renal artery stenting against medical treatment alone in symptomatic renal artery stenosis, there has been no significant benefit identified in terms of improvement in renal function, control of blood pressure, or need for dialysis. The stented populations were also more likely to suffer from complications caused by the procedure such as bleeding, cholesterol embolisation and flash pulmonary oedema.

CONCLUSION

There is no evidence for the use of renal artery stenting over optimal medical management in the treatment of patients with symptomatic atherosclerotic renal artery stenosis, irrelevant of the degree of stenosis. In the setting of EVAR, prevention of deterioration of renal function should be with involvement of the renal physicians, adequate hydration, and use of minimal contrast agent. Repair should be undertaken in centres with access to 24-hour haemofiltration services.

International validation of a risk score for complications and reinterventions after endovascular aneurysm repair

Background

Lifelong surveillance is considered mandatory after endovascular repair (EVAR) of abdominal aortic aneurysms to detect endograft complications and prevent aneurysm rupture. Current protocols are not cost-effective or clinically effective. The international validity of the St George's Vascular Institute (SGVI) score for EVAR complications was examined.

Methods

The ENGAGE registry recruited patients undergoing EVAR at 79 centres in 30 countries. Reinterventions and endograft complications were recorded for up to 3 years after surgery. Preoperative aneurysm morphology was extracted from the registry database, and used to predict whether patients would be at low or high risk of complications after EVAR based on the SGVI score. Kaplan–Meier analysis was used to compare the incidence of endograft complications and reinterventions in patients predicted to be at low risk compared with those predicted to be at high risk.

Results

Some 1207 patients underwent EVAR, with follow-up of up to 3 years. The SGVI score accurately discriminated freedom from reinterventions (90·5 versus 79·3 per cent in low- versus high-risk patients; P &lt; 0·001), freedom from endograft complications (77·9 versus 69·6 per cent in low- versus high-risk patients; P = 0·012), and freedom from a composite outcome measure of reinterventions or endograft complications (75·0 versus 66·1 per cent in low- versus high-risk patients; P = 0·006) during mid-term follow-up.

Conclusion

This study has provided international validation of a morphological risk score that predicts mid-term reinterventions and endograft complications. The results may enable risk-stratified surveillance after EVAR.

Rationalising cross-match requests in vascular surgery is safe and cost effective

This study describes how a vascular centre rationalised their blood transfusion policy. A multidisciplinary panel reviewed data for blood transfusion protocols and implemented improvements that were analysed. The number of units cross-matched fell from 272 to 183 over a six month period. Unused blood reduced from 80% to 61%. The study concluded that rationalisation of cross matching policies is safe and provides cost and resource benefits.

Current endovascular management of acute type B aortic dissection - whom should we treat and when?

Aortic dissection is the most common of the acute aortic syndromes, once initiated, intimal disruption can propagate in an anterograde or retrograde fashion, and the resulting false lumen may compress the ostia of aortic branches or cause aortic expansion and eventual rupture. Acute complicated type B dissection most often requires immediate interventional treatment, whereas uncomplicated dissection has classically been managed with medical therapy alone. The first line management of complicated acute and aneurysmal chronic type B dissections has shifted toward minimally invasive endovascular treatment. To give an overview of the contemporary management of acute type B dissection, clinical manifestations, aims of management, and therapeutic options are discussed in the context deciding which patients require intervention and when.

Transgene delivery to endothelial cultures derived from porcine carotid artery ex vivo

Carotid artery disease is a widespread cause of morbidity and mortality. Porcine models of vascular disease are well established in vivo, but existing endothelial systems in vitro (e.g. human umbilical vein endothelial cells, rat aortic endothelial cultures) poorly reflect carotid endothelium. A reliable in vitro assay would improve design of in vivo experiments and allow reduction and refinement of animal use. This study aimed (1) to develop ex vivo endothelial cultures from porcine carotid and (2) to test whether these were suitable for lentivector-mediated transgene delivery. Surplus carotid arteries were harvested from young adult female Large White pigs within 10 min post-mortem. Small sectors of carotid artery wall (approximately 4 mm×4 mm squares) were immobilised in a stable gel matrix. Cultures were exposed to HIV-derived lentivector (LV) encoding a reporter transgene or the equivalent integration-deficient vector (IDLV). After 7-14 days in vitro, cultures were fixed and labelled histochemically. Thread-like multicellular outgrowths were observed that were positive for endothelial cell markers (CD31, VEGFR2, von Willebrand factor). A minority of cells co-labelled for smooth muscle markers. Sensitivity to cytotoxic agents (paclitaxel, cycloheximide, staurosporine) was comparable to that in cell cultures, indicating that the gel matrix permits diffusive access of small pharmacological molecules. Transgene-expressing cells were more abundant following exposure to LV than IDLV (4.7, 0.1% of cells, respectively). In conclusion, ex vivo adult porcine carotid artery produced endothelial cell outgrowths that were effectively transduced by LV. This system will facilitate translation of novel therapies to clinical trials, with reduction and refinement of in vivo experiments.

Embolisation of type 2 endoleaks after endovascular aneurysm repair

Endovascular treatment has become the preferred method of repair of abdominal and thoracic aortic aneurysms, and comes with a unique complication in the form of endoleaks (type I-IV). Type II endoleaks are the focus of this review. They are the most common form of endoleak detected in CT surveillance following endovascular repair. They are observed in 9% to 30% of patients after abdominal endovascular repair (EVR), and 1.4% following thoracic endovascular aortic repair (TEVR). They are classified as primary or secondary, depending on when they are identified following EVR. Typically, retrograde filling of the aneurysm sac is caused by single or multiple, patent feeding vessels. Despite its relative frequency, there is a lack of consensus on the threshold at which treatment should be considered. The aims of treatment are to halt sac expansion or to prevent rupture. A majority of patients may be managed conservatively. In those that are treated, the most common form of management is single vessel embolization. As we will discuss here, there are several ways of performing this procedure, based on the site of endoleak, and causative vessel. Possible reasons for poor success rates will also be discussed. A general consensus on how to best manage these patients is yet to be reached. The aim of this review is to give an overview of type II endoleaks, their natural history and vessels most commonly involved, as well as different approaches to embolisation.

Are concerns about EVAR durability relevant with modern devices?

Endovascular aneurysm repair (EVAR) is now universally adopted as first-line therapy for the management of large abdominal aortic aneurysms (AAA). The applicability has broadened such that up to 80% of patients are morphologically suitable for EVAR. In-spite of the evidence base demonstrating improved early outcomes following EVAR compared to open surgery, and informed patients' preference, EVAR-sceptics remain. The doubters voice anxieties regarding the durability of an endovascular repair and cite evidence of graft failures from the EVAR-1 trial results. Historically, graft migration and endoleak development have been the Achilles heel of EVAR. However, EVAR is an evolving technology that over the last 10 years has seen significant development from industry, and greater experience among clinicians. This has combined with centralisation of expertise in larger vascular units, with increased case-volume, leading to more appropriate periprocedural and long-term care. Current devices offer a durable repair for patients with infra-renal aortic aneurysms. The risk of graft migration is minimised by devices with secure fixation systems, potentially limiting de-novo type 1 and 3 endoleaks. Appropriate surveillance and timely endovascular re-interventions are perhaps the most important factors to ensure robust long-term outcomes from endovascular repair, even when native vessel morphology changes. Industry registry evidence and large single unit case series are now generating a healthy evidence base of EVAR durability in contemporary endovascular practice, that affirms its role as first-line therapy in the majority of morphologically suitable patients.

Results and clinical consequences of trials on thoracic endografting

Thoracic endovascular repair (TEVR) has developed from endovascular treatment of infrarenal aortic aneurysms, and is now considered first-line treatment for a variety of thoracic aortic pathologies. In contrast to infrarenal repair, there are no large randomized controlled trials to underpin this change in practice, and most of the existing data are from smaller trials designed to evaluate the safety of a particular device. The aim of this review was to describe these studies with respect to perioperative adverse events, occurrence of device failure, mid-term aortic death, mid-term overall survival and freedom from aortic reintervention. The implications of these results are discussed in the context of their implications for clinical practice, taking into account the relative strengths and weakness of the available data. Where the individual trial design allows, direct comparison is made between TEVR and open surgical controls, and the results of TEVR applied to particular pathology groups is discussed.

Aortic rupture and sac expansion after endovascular repair of abdominal aortic aneurysm

Background

Long-term concerns about the durability of endovascular aortic aneurysm repair (EVAR) remain after the publication of controlled trials. Increased expertise in endograft technology, case selection and postoperative reintervention has created a need for reappraisal of the longer-term efficacy of EVAR using contemporary data.

Methods

Patients undergoing infrarenal EVAR between 2004 and 2010 were studied prospectively. Morphological compliance with manufacturers' instructions for use (IFU) was established using three-dimensional computed tomography. The primary outcome measures were all-cause and aneurysm-related mortality, postoperative rupture, reintervention and sac expansion. These adverse events were reported using Kaplan–Meier survival analysis, with comparison within, or outside IFU by the log rank test.

Results

Some 478 patients of median age 76 years had a median aneurysm diameter of 62·9 mm. Median follow-up was 44 (range 11–94) months; 198 (41·4 per cent) were compliant with IFU. The 30-day mortality rate was 2·1 per cent (10 of 478 patients): nine (2·0 per cent) of 455 patients who had elective and one (4 per cent) of 23 patients who had non-elective surgery. Aneurysm-related mortality was 0·897 deaths per 100 person-years, and all-cause mortality was 8·558 deaths per 100 person-years, with significantly lower survival outside IFU (P = 0·012). Two patients had a late rupture (0·138 per 100 person-years), of whom one died. There were 6·120 reinterventions per 100 person-years, with no difference for aneurysms treated outside IFU (P = 0·136). Primary sac expansion occurred in 6·721 per 100 person-years and secondary sac expansion in 4·142 per 100 person-years.

Conclusion

In this series EVAR had a lower aneurysm-related mortality rate than demonstrated in early controlled trials, and with lower sac expansion rates than reported from image repositories. Data from earlier studies should be applied to current practice with caution.

The use of heparin in patients with ruptured abdominal aortic aneurysms

The use of systemic heparin in patients with ruptured abdominal aortic aneurysms (rAAAs) remains a contentious issue with no clear guidelines. This review reports the current understanding, at a molecular and clinical level, of the possible benefits and risks of heparin in emergency aneurysm repair (both open and endovascular). MEDLINE, EMBASE, AMED, SCOPUS, CINAHL and Cochrane Library were searched for all articles containing the keywords 'rupture', 'abdominal', 'aneurysm' and 'heparin'. Current experience, indications and outcomes were analyzed. Articles were searched for both endovascular and open repair of AAAs. A total of eight studies were included for analysis in the systematic review. Of these, only one paper focused specifically on heparin use in open repair of ruptures and suggested a benefit. Of the remaining seven, two were self-reporting retrospective studies assessing individual surgeons' practice, one was a case report and the remaining four included mention of heparin use but with no outcome data. The evidence available suggests that a pro-coagulable state exists in rAAAs. This may be responsible for the morbidity and mortality postprocedure, which arises predominantly from multiple organ failure and cardiac compromise rather than outright hemorrhage. This diathesis may respond well to heparin administration, suggesting that heparin administration in ruptured aneurysms is appropriate.

Provider volume and long-term outcome after elective abdominal aortic aneurysm repair

Background

Robust risk-adjusted analyses have demonstrated that a reduction in perioperative mortality is associated with the repair of an abdominal aortic aneurysm (AAA) in centres with a high operative caseload (volume). However, the long-term impact of this volume-related effect on mortality remains unknown.

Methods

Demographic and clinical data were extracted from UK Hospital Episodes Statistics for patients undergoing elective repair of an infrarenal AAA from 1 April 2000 to 31 March 2005. The long-term mortality of this cohort was investigated through linkage to the UK Office for National Statistics (ONS) registry. Risk-adjusted survival was analysed using Cox proportional hazards modelling to identify the effect of hospital volume on long-term mortality.

Results

A total of 14 396 patients with mean age of 72 years, of whom 85·7 per cent were men, underwent elective repair of an infrarenal AAA in England. They were linked to follow-up using ONS data. Risk-adjusted analysis of all-cause mortality by Cox proportional hazards modelling demonstrated a significant effect of hospital volume across all quintiles up to 2 years (P = 0·013). Remodelling the data after excluding in-hospital mortality still demonstrated the significant effect of hospital volume on late outcome.

Conclusion

There is a long-term benefit to patients who undergo elective AAA repair in a high-volume hospital.

Lower extremity amputations--a review of global variability in incidence

AIM

To quantify global variation in the incidence of lower extremity amputations in light of the rising prevalence of diabetes mellitus.

METHODS

An electronic search was performed using the EMBASE and MEDLINE databases from 1989 until 2010 for incidence of lower extremity amputation. The literature review conformed to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement standards.

RESULTS

Incidence of all forms of lower extremity amputation ranges from 46.1 to 9600 per 10(5) in the population with diabetes compared with 5.8-31 per 10(5) in the total population. Major amputation ranges from 5.6 to 600 per 10(5) in the population with diabetes and from 3.6 to 68.4 per 10(5) in the total population. Significant reductions in incidence of lower extremity amputation have been shown in specific at-risk populations after the introduction of specialist diabetic foot clinics.

CONCLUSION

Significant global variation exists in the incidence of lower extremity amputation. Ethnicity and social deprivation play a significant role but it is the role of diabetes and its complications that is most profound. Lower extremity amputation reporting methods demonstrate significant variation with no single standard upon which to benchmark care. Effective standardized reporting methods of major, minor and at-risk populations are needed in order to quantify and monitor the growing multidisciplinary team effect on lower extremity amputation rates globally.

First-year results of a national abdominal aortic aneurysm screening programme in a single centre

Background

The UK Multicentre Aneurysm Screening Study (MASS) demonstrated reduced mortality from screening for abdominal aortic aneurysm (AAA). As a result, the National Health Service AAA Screening Programme was introduced in England. This study reports the results from an early-implementation screening centre.

Methods

Men aged 65 years were invited to attend an ultrasound assessment. Data were analysed for 15 months from the onset of the screening programme.

Results

A total of 6091 men aged 65 years were invited between April 2009 and June 2010, of whom 2037 (33·4 per cent) failed to attend. There were 162 self-referrals (median age 71·3 years) so that 4216 men were screened. Of those scanned, 4146 (98·3 per cent) had an aortic diameter of less than 3·0 cm, 65 (1·5 per cent) had an aneurysm measuring 3·0–5·4 cm, and five (0·1 per cent) had an aneurysm with a diameter of 5·5 cm and above. The presence of an aneurysm was more common in those who self-referred than in the invited group (P &lt; 0·001). All 70 screen-detected aneurysms were found in white men.

Conclusion

The prevalence of AAA was lower than expected. This reflects the younger age of this cohort compared with those in published large multicentre studies and the diverse ethnic background of the local population. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.

A systematic review of mid-term outcomes of thoracic endovascular repair (TEVAR) of chronic type B aortic dissection

OBJECTIVE AND DESIGN

The role of Thoracic Endovascular Repair (TEVAR) in chronic type B aortic dissection remains controversial and its mid-term success as an alternative to open repair or best medical therapy remains unknown. The aim of the present study was to provide a systematic review of mid-term outcomes of TEVAR for chronic type B aortic dissection.

MATERIALS AND METHODS

Medline, trial registries, conference proceedings and article reference lists from 1950 to January 2011 were searched to identify case series reporting mid-term outcomes of TEVAR in chronic type B dissection. Data were extracted for review.

RESULTS

17 studies of 567 patients were reviewed. The technical success rate was 89.9% (range 77.6-100). Mid-term mortality was 9.2% (46/499) and survival ranged from 59.1 to 100% in studies with a median follow-up of 24 months. 8.1% of patients (25/309) developed endoleak, predominantly type I. Re-intervention rates ranged from 0 to 60% in studies with a median follow-up of 31 months. 7.8% of patients (26/332) developed aneurysms of the distal aorta or continued false lumen perfusion with aneurysmal dilatation. Rare complications included delayed retrograde type A dissection (0.67%), aorto-oesophageal fistula (0.22%) and neurological complications (paraplegia 2/447, 0.45%; stroke 7/475, 1.5%).

CONCLUSION

The absolute benefit of TEVAR over alternative treatments for chronic B-AD remains uncertain. The lack of natural history data for medically treated cases, significant heterogeneity in case selection and absence of consensus reporting standards for intervention are significant obstructions to interpreting the mid-term data. High-quality data from registries and clinical trials are required to address these challenges.

Patient-reported symptoms are independent of disease severity in patients with primary varicose veins

The objective of this paper is to explore patterns of incompetence and disease distribution in patients with chronic venous disorders and to correlate this with CEAP (Clinical, Etiologic, Anatomic and Pathologic) classification and presenting symptoms to determine which features of chronic venous disorder (CVD) could be used to guide a patient pathway for referral and treatment. Consecutive patients attending a one-stop venous clinic at a university teaching hospital were recruited over a 12-month period. Patients were clinically assessed, assigned CEAP scores, duplex-scanned and categorized. Data were analyzed to identify associations between symptomatology and disease. Four hundred twenty-four limbs were divided into groups A (C2–3) (339) and B (C4–6) (85). The number of men, mean patient age, varicose vein diameter and quality-of-life score (Aberdeen Varicose Vein Questionnaire – AVVS) were significantly higher in group B ( P < 0.01). Ache occurred more commonly in group A and in women ( P < 0.01). Ache and pain were seen more frequently with saphenofemoral junction reflux ( P < 0.05). Group A women were more likely to be offered surgical intervention while men were managed conservatively ( P < 0.05). In conclusion, CVD symptoms are independent of disease severity assessed by CEAP score. Advanced disease is associated with larger venous diameters, older age and corresponds to a poorer quality of life. Objective markers such as CEAP, Venous Clinical Severity Score and AVVS should be used in determining a patient pathway for referral and treatment of CVD.

Should the role of EVAR be re-evaluated in light of the 10 year results of EVAR-1?

EVAR-1 published its 10 year results in 2010. The principal finding of the study was that the endovascular group (EVR) had a significant reduction in early aneurysm related mortality compared to open surgery (OR), but the benefit was lost by the end of the study (adjusted hazard ratio [HR], 0.92; 95% confidence interval [CI] 0.57-1.49; P=0.73). By the end of follow-up, there was no significant difference between the OR and EVR group in terms of death from any cause (HR 1.03; 95% CI 0.86-1.23; P=0.72). Despite these findings the uptake of EVR continues to increase. EVR is driving improved surgical outcomes in elective abdominal aortic aneurysm (AAA) surgery, and may yet establish itself as an essential tool in the emergency setting. Elective AAA mortality may be reducing in the U.K. as a consequence of broader application of EVR. This article presents and examines the EVAR-1 data and reports the additional wealth of evidence supporting EVR from prospective registries. It proposes that EVR should be re-evaluated, but not as a consequence of the long-term EVAR-1 results. Clinicians' expertise, understanding and the technology of EVR have progressed significantly since the establishment of the EVAR-1 trial, such that the results, though valuable, may not translate to modern practice. It is essential to maintain excellence in vascular surgery and the evidence-base now demonstrates that best practice in AAA management is in specialist vascular centres, performing high volume surgery offering EVR to all patients who are morphologically suitable.

The requirement for smart catheters for advanced endovascular applications

Endovascular techniques are well established in minimally invasive vascular surgery. Stent-graft technology is evolving. This will allow more complex aortic pathology to be treated. Current limitations in this equipment include the reliance on selective catheters along with trial and error to cannulate visceral or aortic arch branch vessels. This can lead to prolonged operations with increased radiation and contrast load to the patient with inevitable increase in peri-operative morbidity. A smart catheter that could expedite target vessel catheterization, minimize repeat catheter changes, and provide greater haptic feedback would enhance the endovascular surgeon's armamentarium. This would lead to broader and safer application of endovascular surgery.

Centralization harnessing volume-outcome relationships in vascular surgery and aortic aneurysm care should not focus solely on threshold operative caseload

There has been great interest in the setting of threshold operative volumes for safety to guide centralisation of vascular surgical services by healthcare commissioners. This editorial examines the evidence for designing services around a numeric safety threshold in the relationship between volume and outcome in vascular surgery. Thresholds should be aimed at the best outcomes and equity of care. Equity means access to the most up-to-date technology and all the relevant support services for elective and emergency cases. The relationship of volume and outcome with quality is complex, and demands a shift in focus to infrastructural and procedural improvements that drive high-quality services rather than the concentration of planning exclusively around an operative volume threshold.

The diagnosis and management of aortic dissection

Aortic dissection represents the most common aortic emergency, affecting 3 to 4 per 100,000 people per year and is still associated with a high mortality. Twenty percent of the patients with aortic dissection die before reaching hospital and 30% die during hospital admission. Aortic dissections may be classified in 3 ways: according to their anatomical extent (the Stanford or DeBakey systems), according to the time from onset (acute or chronic), and according to the underlying pathology (the European Society of Cardiologists' system). Advances in endovascular technology have provided new treatment options. Hybrid endovascular and conventional open surgical repair represent the mainstay of treatment for acute type A dissection. Medical management remains the gold standard for acute and uncomplicated chronic type B dissection, though endovascular surgery offers exciting potential in the management of complicated type B dissection through sealing of the intimal entry tear.

Risk of reintervention after endovascular aortic aneurysm repair

BACKGROUND

The role of symptomatic presentation in directing reintervention after endovascular aortic aneurysm repair (EVAR) was investigated.

METHODS

All patients undergoing infrarenal EVAR between 2001 and 2009 were studied. Those needing reintervention were divided into symptomatic and asymptomatic presentations. Kaplan-Meier survival curves were used to calculate freedom from reintervention, and log rank tests for subgroup analyses. Multivariable analysis identified risk factors for reintervention.

RESULTS

The study included 553 patients with a mean(s.d.) age of 75(7) years and aneurysm diameter of 65(13) mm. The 30-day mortality rate was 2.5 per cent. Median follow-up was 31 (range 1-97) months. There were 86 reinterventions in 69 (12.5 per cent) of 553 patients; 41 presented with symptoms and 28 were asymptomatic. Reintervention-free survival rates at 1, 3 and 5 years were 90.1, 85.3 and 81.2 per cent. The reintervention rate was higher in patients who needed an intraoperative adjunct during the index procedure (P = 0.014) and in those who did not have intraoperative computed tomography angiography (P = 0.024). Intraoperative adjuncts were an independent risk factor for future reintervention (hazard ratio 2.62, 95 per cent confidence interval 1.18 to 3.76; P = 0.012).

CONCLUSION

Most patients requiring reintervention presented symptomatically. A high-risk subgroup may be identifiable to rationalize a postoperative surveillance programme.

Screened individuals' preferences in the delivery of abdominal aortic aneurysm repair

Background

This study aimed to determine preferences for service attributes in a population screened for abdominal aortic aneurysm.

Methods

A questionnaire was designed to encompass various aspects of service provision. Questions were calibrated against the time an individual was willing to travel to access specific attributes. Subjects attending an aneurysm screening programme were asked to complete a questionnaire before their screening ultrasound scan. Statistical analysis was through pairwise analysis of the median travel times with the signed rank test. The Wilcoxon rank sum, analysed by the Kruskal–Wallis test, was used to compare preference ratings.

Results

A total of 262 individuals were asked to complete the questionnaire; the response rate was 98·5 per cent. Approximately 92 per cent of individuals stated a willingness to travel for at least 1 h beyond their nearest hospital in order to access services with a 5 per cent lower perioperative mortality rate, a 2 per cent lower amputation or stroke rate, a high annual caseload of aneurysm repairs, and routine availability of endovascular repair.

Conclusion

Patients attending aneurysm screening were willing to travel beyond their nearest hospital to access a service with better outcomes, higher surgical volumes and endovascular surgery.

Propensity scored analysis of outcomes after ruptured abdominal aortic aneurysm

Background

This study examined the population outcome of ruptured abdominal aortic aneurysm (rAAA) in England, the role of endovascular repair (EVAR), and the relationship between outcome and hospital workload.

Methods

Data were retrieved from Hospital Episode Statistics between 1 April 2003 and 31 March 2008. Propensity scoring was used to compare the outcomes of stratified patients undergoing EVAR and open repair. The relationship between workload and outcome was determined.

Results

Some 3725 urgent and 4414 rAAA repairs were included. Mortality rates were 21·3 per cent for urgent repair and 46·3 per cent for rAAA repair. EVAR was employed for 16·3 and 7·6 per cent of urgent and rAAA repairs respectively. EVAR was associated with significantly reduced mortality for urgent repair (odds ratio (OR) 0·531, 95 per cent confidence interval 0·415 to 0·680; P &lt; 0·001) and rAAA repair (OR 0·527, 0·416 to 0·668; P &lt; 0·001). A propensity scored analysis confirmed the benefit of EVAR for rAAA repair (P &lt; 0·001). Repair of rAAA at hospitals with a higher elective aneurysm workload was associated with lower mortality rates irrespective of the mode of treatment (P &lt; 0·001). Higher-volume hospitals were more likely to operate on rAAA (P = 0·033).

Conclusion

EVAR offered a survival advantage over open repair for non-elective aneurysm procedures. Services for the treatment of rAAA should incorporate access to EVAR and would benefit from being based in units with a high elective caseload.

Endovascular aneurysm repair with preservation of the internal iliac artery using the iliac branch graft device

OBJECTIVES

Aortoiliac aneurysms comprise up to 43% of the specialist endovascular caseload. In such cases endovascular aneurysm repair (EVAR) requires distal extension of the aortoiliac endograft beyond the ostium of the internal iliac artery (IIA) and into the external iliac artery, conventionally necessitating the embolisation of one or both IIA. This has been associated with a wide range of complications, and the use of an Iliac Branch-graft Device (IBD) offers an appealing endovascular solution.

DESIGN

Medline, trial registries, conference proceedings and article reference lists were searched to identify case series reporting IBD use. Data were extracted for review.

RESULTS

Nine series have reported the use of IBD in a total of 196 patients. Technical success was 85-100%. Median operating times were 101-290min and median contrast dose was 58-208g, with no aneurysm-related mortality. Claudication developed in 12/24 patients after IBD occlusion. One type I endoleak and two type III endoleaks occurred and were managed endovascularly. Re-occlusion occurred in 24/196 patients.

CONCLUSION

IBD was performed with high technical success rates and encouraging mid-term patency. Formalised risk stratification and morphological data are required to identify the group of patients who will benefit most. Cost-effectiveness appraisals are needed for this technique.

Elevated tissue expression of thrombomodulatory factors correlates with acute symptomatic carotid plaque phenotype

OBJECTIVES

Thrombomodulatory factors have been implicated in plaque instability. The aim was to examine the relationship between thrombomodulatory gene expression, timing of clinical events and plaque histology.

DESIGN OF STUDY

Plaques were obtained from 40 consecutive patients undergoing carotid endarterectomy and divided into three groups (group 1, early symptomatic, within 1 month; group 2, late symptomatic, 1-6 months and group 3, asymptomatic). Total RNA was isolated to determine the expression of tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA), plasminogen activator inhibitor-1 (PAI-1), tissue factor (TF), tissue factor pathway inhibitor (TFPI), thrombomodulin (TM), CD68 and vascular endothelial-cadherin (VE-Cadherin).

RESULTS

Expression of t-PA, PAI-1, TF, TFPI, TM, CD68 and VE-cadherin were significantly increased in the early symptomatic group (p=0.019, 0.028, 0.018, 0.025, 0.038, 0.016 and 0.027 respectively), but the level of gene expression in the late symptomatic group was indistinguishable from the asymptomatic group. The incidence of plaque rupture and intraplaque haemorrhage was significantly increased in the early symptomatic groups (58% versus 18%/18% group 2/3, and 55% versus 6%/9% respectively, p<0.05 for both).

CONCLUSIONS

Expression of thrombomodulatory genes is increased in unstable plaques, though levels after 1 month are comparable to asymptomatic plaques. This transient rise may influence plaque instability, and rapid resolution mirrors the clinical reduction in risk of further thrombo-embolic events.

Model for the reconfiguration of specialized vascular services

Background

This article built on previous work to develop an algorithm for elective abdominal aortic aneurysm (AAA) repair and carotid endarterectomy (CEA), with the aim of improving patient survival by regionalization of services. Vascular procedures were used as an example of specialized surgical services.

Methods

A model was generated based on a national data set that incorporated the statistical demonstration of procedural safety, hospital annual surgical case volume, and travel distance and time. Elective AAA repair was used to construct a hub-and-spoke model that was tested against CEA. The impact of the model was quantified in terms of mortality rates, and travel distance and time.

Results

Only 48 vascular hubs were required to provide adequate coverage in England, with the majority of patients travelling for less than 1 h to access inpatient vascular surgery. The model predicted a reduction in the number of deaths from elective surgery for AAA (P &lt; 0·001) and CEA (P = 0·016).

Conclusion

Adoption of this strategic model may lead to improved outcome after AAA and CEA. It could be used as a model for the regionalization of specialized surgery. The model does not take into account the complexity of providing a comprehensive vascular service in every locality.

Elevated plasma MMP1 and MMP9 are associated with abdominal aortic aneurysm rupture

BACKGROUND

The role of matrix metalloproteinases (MMPs) in abdominal aortic aneurysm (AAA) formation is well established. However the changes in plasma MMP levels with AAA rupture have not been reported. The aim of this study was to determine circulating levels of MMPs in non-ruptured and ruptured AAA immediately prior to open repair.

METHODS

Concentrations of MMPs and their endogenous tissue inhibitors (TIMPs) were quantified using ELISA in pre-operative plasma samples from non-ruptured and ruptured AAA.

RESULTS

MMP1 and MMP9 were elevated in the plasma of ruptured AAA versus non-ruptured AAA. A four-fold elevation in pre-operative plasma MMP9 was associated with non-survival at 30 days from rupture surgery compared with those surviving for greater than 30 days.

CONCLUSION

In conclusion, these findings support the role of MMPs in AAA pathogenesis. Elevation of MMP9 was associated with ruptured aneurysm related 30-day mortality and may represent a survival indicator in this group.

Demonstrating safety through in-hospital mortality analysis following elective abdominal aortic aneurysm repair in England

Background

The aims were to assess the evidence that individual hospitals had mortality rates in excess of the national average after abdominal aortic aneurysm (AAA) repair and to develop an effective method for monitoring mortality using local data.

Methods

Hospital Episode Statistics identified patients undergoing elective infrarenal AAA repair. A technique was developed that compared individual hospital mortality rates with the mortality rate in the remainder of England. The strength of evidence that the death rate was less than elsewhere, and less than twice elsewhere, was quantified using a test of statistical significance. A moving average chart technique was devised using local data for mortality monitoring and comparison to the national average.

Results

For 30 hospitals, the mortality rate was significantly greater than elsewhere, and in three hospitals it was demonstrably greater than twice that in the remainder of England. The moving average chart appeared to provide a useful technique for local mortality monitoring.

Conclusion

Different mortality rates exist for AAA repair within England. Mortality can be monitored locally and compared with the national average.

The Relationship between Hospital Case Volume and Outcome from Carotid Endartectomy in England from 2000 to 2005

OBJECTIVES

To assess the outcome of carotid endarterectomy in England with respect to the hospital case-volume.

METHODS

Data were from English Hospital Episode Statistics (2000-2005). Admissions were classified as elective or emergency. Risk-adjusted data were analysed through modelling of death rate, complication rate and length of admission with regard to the year of procedure and annual hospital volume of surgery. Hospitals with elevated death rates were identified and the evidence quantified that they had outlying mortality rates.

RESULTS

There were 280,081 diagnoses of extra-cranial atherosclerotic arterial disease in which 18,248 CEA were performed. The mean mortality rates were 1.04% for elective and 3.16% for emergency CEA. A volume-related improvement in mortality (p=0.047) was seen for elective CEA. Length of stay decreased as annual volume increased for elective and emergency CEA (p<0.001). 20% of the operations were performed in 67.1% of the hospitals, each of which performed fewer than 10 CEA per annum. A number of hospitals had elevated death rates.

CONCLUSIONS

Volume-related improvements in outcome were demonstrated for elective CEA. Minimum volume-criteria of 35 CEA per annum should be established in England. Hospitals performing low annual volumes of surgery should consider arrangements to network services.

Simvastatin attenuates the activity of matrix metalloprotease-9 in aneurysmal aortic tissue

To investigate whether statins reduce the concentration of MMP-9 in the aortic wall, we randomised patients undergoing elective open repair of an abdominal aortic aneurysm (AAA) to a pre-operative course of either simvastatin or placebo. MMPs in aortic biopsies were measured using gelatin zymography. Although recruitment closed early because of increasing statin use among eligible patients, with only 21 patients we demonstrated a 40% reduction in MMP-9 levels in the AAA wall in patients randomised to simvastatin. This provides a possible molecular mechanism to explain the reportedly beneficial effects of statins to slow AAA growth.

Meta-Analysis and Systematic Review of the Relationship between Hospital Volume and Outcome Following Carotid Endarterectomy

OBJECTIVES

This study investigated the relationship between annual hospital volume and the outcomes in carotid endarterectomy and quantified critical volume threshold for this procedure.

DATA SOURCES

PubMed, EMBASE and the Cochrane library were searched for all articles on the volume-outcome relationship in CEA.

REVIEW METHODS

Articles were included if they presented data on post-operative mortality and/or stroke rates and annual hospital volume of CEA. The review conformed to the QUOROM statement. The data were meta-analysed and a pooled effect estimate of volume on the stroke and/or mortality rates from CEA quantified, along with the critical volume threshold.

RESULTS

Twenty-five articles, encompassing 936 436 CEA, were analysed. Significant relationships between mortality rate and stroke rate and annual volume were seen. Overall, the pooled effect estimate was odds ratio 0.78 [95% confidence interval 0.64-0.92], in favour of surgery at higher volume units, with a critical volume threshold of 79 CEA per annum.

CONCLUSIONS

Significantly lower mortality and stroke rates were achieved at hospitals providing a higher annual hospital volume of CEA. Hospitals wishing to provide CEA should adhere to minimum volume criteria.

Meta-analysis and systematic review of the relationship between volume and outcome in abdominal aortic aneurysm surgery

Background

This study investigated the volume–outcome relationship for abdominal aortic aneurysm (AAA) surgery and quantified critical volume thresholds.

Methods

PubMed, EMBASE and the Cochrane library were searched for articles on the operation volume–outcome relationship in elective and ruptured AAA surgery. UK Hospital Episode Statistics data were also considered. Elective and ruptured AAA repairs were dealt with separately. The data were meta-analysed, and the odds ratios (95 per cent confidence interval) for mortality at higher- and lower-volume hospitals were compared. Volume thresholds were identified from each paper.

Results

The analysis included 421 299 elective and 45 796 ruptured AAA operations. Significant relationships between mortality and annual volume were noted for both groups. Overall, the weighted odds ratio was 0·66 (0·65 to 0·67) for elective repair at a threshold of 43 AAAs per annum and 0·78 (0·73 to 0·82) for ruptured aneurysm repair at a threshold of 15 AAAs per annum, both in favour of high-volume institutions.

Conclusion

Higher annual operation volumes are associated with significantly lower mortality in both elective and ruptured AAA repair. This suggests that AAA surgery should be performed only at higher-volume centres.

Epidemiological study of the relationship between volume and outcome after abdominal aortic aneurysm surgery in the UK from 2000 to 2005

Background

The aim was to assess the relationship between hospital volume and outcome after abdominal aortic aneurysm (AAA) surgery in the UK.

Methods

Hospital Episode Statistics (2000–2005) were classified as elective, urgent or ruptured AAA repair. Analysis was by modelling of mortality rate, complication rate and length of hospital stay with regard to the annual operative volume, after risk adjustment.

Results

There were 112 545 diagnoses, or repairs, of AAAs, of which 26 822 were infrarenal aneurysms. The mean mortality rate was 7·4, 23·6 and 41·8 per cent for elective, urgent and ruptured AAA repair respectively. Elective AAA repair undertaken at high-volume hospitals showed volume-related improvements in mortality (P &lt; 0·001). Patients were discharged from hospital earlier (P &lt; 0·001). The critical volume threshold was 32 elective AAA repairs per year. For urgent repair, patients at high-volume hospitals had a reduced mortality rate (P = 0·017) with an increased length of stay (P = 0·041). There was no relationship between volume and outcome for ruptured AAA repairs.

Conclusion

Increased annual volumes were associated with significant reductions in mortality for elective and urgent AAA repair, but not for repair of ruptured AAAs.

Contemporary management of the infra-renal abdominal aortic aneurysm

Abdominal aortic aneurysms (AAAs) principally affect men over 60 years of age. Aneurysms are usually asymptomatic and detected coincidentally or following the onset of symptoms. Elective repair of an AAA is considered when the diameter reaches 5.5cm or annual expansion exceeds 1 cm. Rupture represents a catastrophic event and carries an unacceptably high mortality. The advent of endovascular repair heralds an improvement in operative outcome for this disease process. In this review we provide an overview of the recent trials investigating the management of non-ruptured and ruptured aneurysms and the strategies that may be invoked to lower the mortality of this disease process