Epidemiology and diagnosis of endograft infection.

Endograft infection is reported to occur in between 0.2 and 0.7 of patients and in general presents either within four months of endograft implantation of after more than 12 months. Review of all cases reported to date reveals three modes of presentation: approximately one third of patients present with evidence of an aorto-enteric fistula (although less than half of these present with gastrointestinal haemorrhage), one third present with non specific signs of low grade sepsis (malaise, weight loss) and the remainder with evidence of severe systemic sepsis. Infection is most commonly attributed to Staphylococcus aureus. Diagnosis relies on a high index of suspicion, imaging of the aorta and periaortic tissues (computed tomography or magnetic resonance imaging) and bacteriological culture. This paper presents a detailed analysis of the features of all cases reported to date and examines the aetiology, pathogenesis and imaging of endograft infection and aorto-enteric fistula.

Spleno-renal bypass facilitating endovascular stenting of a juxta-renal aortic aneurysm in a high risk patient.

The management of juxta-renal abdominal aortic aneurysms (AAA) is challenging. Open surgical repair is associated with significant morbidity (predominantly renal) and the absence of an adequate length of normal infra-renal aorta precludes the placement of a standard endograft. In high-risk patients who are unsuitable for standard open repair the endovascular options include fenestrated or branched stent grafts, which are complex, expensive and not widely available, especially in the acute setting. In this report, we describe a case of a hybrid endovascular graft utilising a spleno-renal bypass to facilitate the supra-renal fixation of an aorto-bi-iliac endovascular stent graft in a high-risk patient.

Chronic venous disease in a cohort of healthy UK Asian men.

OBJECTIVES: This group has previously reported that UK Asians are significantly less likely to undergo surgery for lower limb venous disease than age and sex matched Caucasians. The aim of the present study was to estimate the prevalence of lower limb chronic venous disease (CVD) in the UK Asian male population. DESIGN: A prospective, epidemiological survey. MATERIALS AND METHODS: 100 unselected Asian men attending a local Mosque were assessed for the evidence of lower limb CVD, involving the collection of data on history and clinical signs and objective assessments of venous pathophysiology using lower limb venous ultrasonography and venous photoplethysmography (PPG). RESULTS: On clinical examination, 80 limbs (in 50 subjects) had clinical evidence of CVD, the majority of cases consisting of varicose veins (CEAP C2). No limbs had either healed or active ulceration (C5/6), and only 2 limbs had thread veins (C1). Eight subjects had had previous venous surgery. The venous refill time (vRT) measured by PPG was lower in limbs with CVD. On venous ultrasound, reflux was present in 73/200 limbs, affecting primarily the GSV system, with only 7 limbs having deep venous reflux. CONCLUSIONS: Present data strongly suggest that the low rates of superficial venous surgery in UK Asians is not because they are inherently less likely to develop CVD.

The low incidence of surgery for non-cardiac vascular disease in UK Asians may be explained by a low prevalence of disease.

AIMS: Firstly, to compare rates of surgery for non-cardiac vascular disease in Caucasians and Asians and secondarily to assess the prevalence of peripheral arterial disease (PAD) and abdominal aortic aneurysm (AAA) in the male UK Asian population. METHODS: Analysis of a prospective database followed by an epidemiological survey of 100 unselected Pakistani males, in which demographic and anthropometric data were collected alongside aortic ultrasonography and measurement of ankle: brachial pressure index (ABPI). RESULTS: Although 14.1% of our catchment area is Asian, after correction for age, they only accounted for 64/2268 (2.8%) of procedures for PAD and AAA. Specifically, Asians were 10 times less likely to undergo AAA repair and 3 times less likely to undergo procedures for lower limb peripheral bypass, amputation and endovascular intervention. In the epidemiological study, 26 subjects had a significant history of ischaemic heart disease, 21 were diabetic, 32 had hypertension and 60 were current or ex-smokers. Median aortic diameter [IQR] was 17.6 mm [16.3-19.1 mm] and no subject had an AAA. In 200 limbs, median ABPI [IQR] was 1.12 [1.04-1.21]. Only 2 patients had an ABPI < 0.9. CONCLUSION: Despite a high prevalence of cardiovascular risk factors and ischaemic heart disease, the prevalence of PAD and AAA is much lower than would have been expected in an age- and sex-matched Caucasian population. These data suggest that the reduced incidence of surgery for PAD and AAA in UK Asians is due to a low prevalence of disease.

Peri-operative myocardial injury in patients undergoing surgery for critical limb ischaemia.

INTRODUCTION: Although up to a half of patients undergoing abdominal aortic aneurysm (AAA) repair suffer myocardial injury, as indicated by a rise in cardiac troponin I (cTnI), this is infrequently accompanied by a rise in creatine kinase (CK)-MB fraction or electrocardiogram (ECG) changes. This study compares for the first time peri-operative cTnI, CK-MB and ECG changes in patients undergoing surgery for critical lower limb ischaemia (CLI). METHODS: Twenty-nine patients (20 men, median age 75 [range, 57-95] years) were studied prospectively. cTnI, CK/CK-MB ratio and ECG were performed pre-operatively and on post-operative days 1, 2 and 3. RESULTS: Eleven (38%) patients had an elevated cTnI >0.5 ng/ml. Five (17%) patients had an elevated CK-MB fraction >4% and all of these patients had an elevated cTnI. Eleven (38%) patients had ischaemic changes on ECG including seven of 11 (64%) patients with elevated cTnI and all five patients with elevated CK-MB fraction. There was no relationship between pre-operative cardiac status, antiplatelet use or type of anaesthesia and post-operative cTnI rise. Patients with a cTnI rise were younger (p=0.01), and were more likely to have presented with gangrene (p=0.04) and have a longer operation time (p=0.01) than patients who did not demonstrate a cTnI rise. Four patients developed clinically apparent cardiac complications: cardio-pulmonary arrest (n=1), cardiogenic shock (n=1), acute CCF (n=1) and rapid atrial fibrillation (n=1). Survival at 6 months was 26 of 29 (90%) patients. CONCLUSION: These data demonstrate that over a third of patients operated for CLI sustain peri-operative myocardial injury, many of which are not clinically apparent. Pre-operative medical optimisation may improve prognosis in this group of patients.

Manipulation of the renin angiotensin system in peripheral arterial disease.

The Heart Outcomes Prevention Evaluation (HOPE) study has provided evidence for the use of ramipril for secondary cardiac prevention for patients with peripheral arterial disease. Despite this many vascular surgeons and general practitioners are reluctant to prescribe ACE inhibitors in a group of patients perceived to have a high incidence of renal artery stenosis. This review aims to review the pathophysiology of the renin-angiotensin system and make evidence based recommendations for commencing ACE inhibitors as part of a comprehensive delivery of best medical therapy to patients with peripheral arterial disease.

ACE inhibitors increase type III collagen synthesis: a potential explanation for reduction in acute vascular events by ACE inhibitors.

INTRODUCTION: Large trials have shown that angiotensin converting enzyme inhibitor (ACE-I) therapy reduces the risk of myocardial infarction and stroke. Acute vascular events are thought to be initiated by plaque rupture. Animal models of atherosclerosis show an increase in extra cellular matrix when given ACE-I therapy. ACE-I therapy could influence collagen synthesis, one of the major constituents of the atherosclerotic cap. METHODS: A nested case-control study was performed within the Huntingdon Aneurysm Screening Project. Subjects were assessed for arterial disease, drug history and smoking. Blood samples were taken for a measure of collagen synthesis, the amino-terminal propeptide of type III procollagen (PIIINP), lipid levels, iron metabolism and cotinine levels. RESULTS: Information was available for 420 subjects. Thirty-five were taking ACE-I therapy and 385 were not. Mean serum PIIINP level was 3.5 microg/l (sd 1.3 microg/l, range: 1.7-16.5 microg/l. There was a marked increase in mean collagen turnover between subjects taking ACE-I therapy compared to those not. Mean PIIINP level for cases and controls was 4.26 microg/l (95% CI: 3.73-4.79 microg/l) versus 3.61 microg/l (95% CI: 3.48-3.75 microg/l). No differences were found for patients taking other antihypertensive drugs. After adjusting for age, weight, height, lipid levels and ferritin, PIIINP levels remained significantly higher in cases than controls: 4.14 microg/l (95% CI: 3.72-4.57 microg/l) versus 3.62 microg/l (95% CI: 3.49-3.75 microg/l) (P-value 0.02). DISCUSSION: These results suggest that ACE-I therapy up-regulates collagen synthesis, and could improve plaque stabilisation. This may provide an explanation for the decrease in acute vascular events observed in patients on ACE-I therapy.

LDL cholesterol is associated with small abdominal aortic aneurysms.

OBJECTIVE: To examine the relationship between serum lipids and abdominal aortic aneurysms (AAA). METHODS: Two hundred and six males (>50 years) with AAA (> or =30 mm) detected in a population based screening programme were compared with 252 age-matched male controls in a nested case-control study. Smoking status, previous medical and family histories, height, weight, blood pressure, ankle brachial pressure index (ABPI) and non-fasting lipid profile were recorded. RESULTS: Cases were found to have significantly higher LDL cholesterol than controls. LDL cholesterol was an independent predictor of the risk for aneurysms in a logistic regression model adjusting for smoking status, family history of AAA, history of ischaemic heart disease, presence of peripheral vascular disease, use of lipid lowering medication and treatment for hypertension. There was a linear effect with increased levels of LDL cholesterol increasing the risk of having a small aneurysm (test for trend p=0.03). CONCLUSION: The highly significant association between LDL cholesterol and small aneurysms suggests that LDL, possibly acting via inflammatory mediated matrix degeneration, could be an initiating factor in the development of AAA. The ability of statin therapy to prevent AAA formation requires further investigation.

Near patient cholesterol testing in patients with peripheral arterial disease.

AIMS: To assess the bias, precision and utility of the Bioscanner 2000 for near patient testing of total cholesterol (NPTC) in patients with peripheral arterial disease (PAD). METHODS: One hundred consecutive patients attending a hospital-based clinic with symptomatic PAD underwent non-fasting NPTC using finger prick blood sample and a laboratory total cholesterol (TC) using blood drawn from an antecubital fossa vein. RESULTS: The Bioscanner 2000 showed good precision with a coefficient of variation of 1.8-3.8%. NPTC was significantly lower than laboratory TC (mean (S.D.) 4.67 (1.1) vs. 5.12 (1.2) mmol/l), p < or = 0.01, paired Student's t-test. Comparing the two methods using Deming regression revealed a 15% negative bias for the Bioscanner 2000 compared to laboratory testing, which was demonstrated to be a systematic bias using a Bland-Altman plot. Almost half (46%) of the readings differed by > 0.5 mmol/l, 16% by > 1.0 mmol/l and 3% by > 2 mmol/l. This means that if the cut-off for statin treatment were taken as a TC of 5.0 or 3.5 mmol/l then, based on NPTC, alone 18 and 6% of patients, respectively, would not have received a statin. CONCLUSIONS: In the present study, NPTC significantly under-estimated TC when compared to laboratory testing. However, in the majority of cases, this would not have affected the decision to prescribe a statin and NPTC testing allows the immediate institution or titration of statin treatment.

The utilisation of superficial venous surgery for chronic venous insufficiency by the U.K. Asian population.

BACKGROUND: The epidemiology of superficial venous disease is relatively well defined in the U.K. Caucasian population. By contrast, there are currently no data available for Asians, who comprise 3.6% of the U.K., and 14.1% of this institution's catchment population. The aim of this study was to compare surgery for superficial venous disease in Caucasians and Asians in this institution, in the context of our local population. METHODS: A prospectively gathered database of all 2011 superficial venous operations performed between January 1997 and April 2002 was retrospectively analysed with regard to ethnicity. The ethnic, gender and age composition of our catchment area was determined from U.K. census data. The full institutional records of 100 Asian and 100 randomly selected age and sex-matched Caucasian patients were compared in a case control study. RESULTS: After adjusting for age and gender according to census data, Asians were 40% less likely to undergo superficial venous surgery (SVS). Considering the 2011 operated patients as a whole, Asians were significantly younger and more likely to be male. In the case control study, Asians were significantly less likely to be operated for recurrent disease and significantly more likely to be operated for advanced disease. CONCLUSIONS: Although Asians are significantly less likely to undergo SVS; those that do are more likely to be young, male and operated for skin changes and ulcers. This strongly suggests that the under-representation of Asians is due to cultural, genetic or environmental factors and unmet health care need, rather than a lower prevalence of clinically significant venous disease in the Asian population.

Smoking cessation strategies in patients with peripheral arterial disease: an evidence-based approach.

INTRODUCTION: Smoking is the single most important aetiological factor for the development and progression of atherosclerosis. Unfortunately, most patients receive little or no treatment for their nicotine addiction. This review aims to make evidence based recommendations for smoking cessation as part of a comprehensive delivery of best medical therapy to patients with peripheral arterial disease. METHODS: A search of MEDLINE (1966 to 2003) and the Cochrane library was undertaken for studies relating to smoking cessation. Major priority was given to meta-analyses of randomised controlled trials including Cochrane reviews. RESULTS: Physician advise, nicotine replacement therapy and Bupropion are all evidence based treatments that have success in increasing the likelihood of permanent smoking cessation. A basic understanding of the psychology of addictive behaviour is essential so that appropriate advice and treatment can be tailored to individual patients. CONCLUSIONS: Complete and permanent smoking cessation is by far the most clinically and cost effective intervention in patients with atherosclerosis. Greater awareness of smoking cessation strategies, by clinicians treating vascular patients, is essential for the effective delivery of best medical therapy.

Ethnicity and peripheral arterial disease.

INTRODUCTION: the prevalence of peripheral arterial disease (PAD) is relatively well defined for the Caucasian population. Given the susceptibility of Asians and Afro-Caribbeans to coronary heart disease and stroke respectively, and the high prevalence of cardiovascular risk factors in both groups, one would expect a high prevalence of peripheral arterial disease. METHODS: a search of MEDLINE (1966-2002) was undertaken for studies on the incidence and prevalence of PAD, abdominal aortic aneurysms (AAA) and cerebrovascular disease in different ethnic groups. RESULTS: there are very few population-based prevalence studies assessing PAD, AAA or cerebrovascular disease in non-Caucasians. A review of hospital-based series demonstrates different patterns of PAD between ethnic groups. Blacks and Asians have a tendency towards more distal occlusive disease and AAA appear to be predominantly a disease of Caucasians. It is not clear whether these studies provide a true representation of the prevalence of arterial disease in various ethnic groups or are the result of an unmet health care need. CONCLUSIONS: further studies are required to establish the prevalence, natural history and response to treatment of PAD, AAA and cerebrovascular disease in non-Caucasians. Only when this has been achieved, can clinically and cost-effective health care be delivered to affected individuals from different ethnic groups.