Folic acid administration reduces neointimal thickening, augments neo-vasa vasorum formation and reduces oxidative stress in saphenous vein grafts from pigs used as a model of diabetes.

AIMS/HYPOTHESIS: There is evidence that plasma homocysteine augments vein graft failure and that it augments both micro- and macro-angiopathy in patients with diabetes mellitus. It is therefore suggested that homocysteine may augment vein graft thickening, a major cause of vein graft failure, in diabetic patients, as well as impairing adaptive growth of a new vasa vasorum, possibly through overproduction of superoxide. In order to test these proposals, the effect of folic acid administration, which lowers plasma homocysteine, on vein graft thickening and microvessel density was studied in pigs used as a model of diabetes. METHODS: Non-ketotic hyperglycaemia was induced in Landrace pigs by intravenous injection of streptozotocin, and folic acid was fed daily for 1 month. Vein grafts were excised and the thickness of the neointima and media and microvessel density were assessed by planimetry and superoxide formation. RESULTS: Plasma total homocysteine was significantly reduced by folic acid in both control and diabetic pigs, whereas glucose was unchanged. Compared with controls, diabetic pigs showed increased neointimal thickness and superoxide formation and decreased adventitial microvessel density. Folic acid reduced neointimal thickness and superoxide formation and augmented microvessel density in diabetic but not in control pigs. CONCLUSIONS: Folic acid administration reduces neointimal thickening, augments vasa vasorum neoformation and reduces oxidative stress in saphenous vein grafts from diabetic pigs. Folic acid may therefore be particularly effective in reducing vein graft failure in diabetic patients.

Anomalous right subclavian artery and coarctation-related aneurysm repaired with bilateral subclavian-to-carotid transposition and exclusion stent-grafting.

INTRODUCTION: Aortic arch anomalies are common; however, the presence of concomitant pathology may present a complex management problem. REPORT: A 42 year old lady with anomalous right subclavian artery was found to have recurrent coarctation of the aorta and an aneurysm related to the previous repair. Management of the aneurysm was complicated by the proximity of subclavian artery origins. Bilateral subclavian-to-carotid transposition was undertaken to preserve antegrade vertebral artery flow, with subsequent exclusion stent-grafting of the aneurysm and coarctation. DISCUSSION: This case illustrates combined surgical and interventional radiological repair to deal with a complex thoracic aortic clinical problem.

The effect of acute normovolaemic haemodilution on the inflammatory response and clinical outcome in abdominal aortic aneurysm repair--results of a pilot trial.

OBJECTIVES: To determine the effect of acute normovolaemic haemodilution (ANH) on the inflammatory response and clinical outcome in elective open abdominal aortic aneurysm (AAA) repair. DESIGN: Randomised controlled clinical trial. METHODS: Thirty-six patients were randomised to undergo ANH or act as controls. Cell salvage was permitted in both groups. Heterologous blood was transfused according to pre-determined triggers. Outcome measures were markers of the systemic inflammatory response in serum and urine observed at multiple time points, and clinical recovery. RESULTS: Median 890 (range 670-1620) ml of blood was removed at ANH in 16 patients. There were no differences in peri-operative changes in neutrophil count ( P = 0.13), serum C-reactive protein ( P = 0.38), interleukin-6 ( P = 0.50), total antioxidant capacity ( P = 0.73), urinary secretion of albumin ( P = 0.97) or retinol binding protein ( P = 0.41). There were no differences in the mortality and morbidity rates, systemic inflammatory response syndrome, ITU or hospital stay. CONCLUSIONS: ANH, when used in combination with cell salvage, made no impact on systemic inflammatory response and clinical outcome when compared to cell salvage alone after AAA repair. ANH cannot be recommended for routine use in patients undergoing abdominal aortic aneurysm surgery when cell salvage is available.

Management of the near total internal carotid artery occlusion.

OBJECTIVES: The risk of stroke in patients with near total internal carotid artery (ICA) occlusion is perceived to be high as stroke risk increases with severity of the stenosis. The management of this entity has not been addressed specifically in the existing randomised trials and thus it remains controversial. METHODS: Systematic review of the relevant literature. RESULTS: The management of patients with near total ICA occlusion remains controversial: some favour intervention whereas others have condemned it as dangerous or of no benefit. A prospective multicentre randomised trial regarding intervention versus best medical treatment for patients with symptomatic near total ICA occlusion seems difficult because of the large number of patients required to power the study. Nevertheless, it appears hard to decline surgery based on the current evidence. CONCLUSIONS: Because of the current controversy over the best management of the near total ICA occlusion, prospective observational studies are needed to demonstrate its prevalence in the symptomatic and asymptomatic population and any associated excess stroke risk. Based on the current evidence, surgery is the treatment of choice in most centres but its validity over best medical treatment remains untested.

Haemodilutional effect of standard fluid management limits the effectiveness of acute normovolaemic haemodilution in AAA surgery--results of a pilot trial.

OBJECTIVE: To evaluate the impact of standard fluid management on the effectiveness of ANH as a blood conservation method in elective open AAA repair. DESIGN: Prospective randomised controlled study. METHODS: Thirty-four patients undergoing elective AAA repair were randomised to have ANH (16) or act as controls (18). Intra-operative cell salvage was permitted in both groups. Haemoglobin (Hb) concentrations were determined at variable intervals peri-operatively. Blood loss and the use of heterologous blood were recorded. RESULTS: The pre- and post-operative Hb concentrations, surgical blood loss and the use of cell salvage were similar in both groups. Hb concentration (median, range) decreased significantly from pre-operative to aortic clamping (with blood loss <100 ml) in ANH patients from 8.8 (7.5-10.2) to 5.7 (4.2-6.6)mmol/l following ANH but also in controls from 8.6 (7.5-9.7) to 7.0 (4.5-9.0)mmol/l due to fluid infusion (P<0.01 for every comparison). Bank blood requirements were similar: median 2 units in ANH and 2.5 units in control patients (P=0.68). CONCLUSIONS: Large volumes of fluids infused during AAA repair already conserve blood by the mechanism of hypervolaemic haemodilution. When cell salvage is used with standard fluid management during AAA repair, additional ANH is ineffective in saving blood.

Reoperation for neurological complications following carotid endarterectomy.

BACKGROUND: There remains a dilemma whether or not to re-explore the carotid artery when a neurological complication occurs after carotid endarterectomy. This study reviewed the indications for, findings and clinical outcomes following re-exploration. METHODS: Patients who experienced transient or permanent neurological events following carotid endarterectomy were identified from a prospectively compiled computerized database. Case notes were retrieved to determine time to onset of symptoms, use of carotid artery imaging and details about patients who had surgical re-exploration, and outcomes. RESULTS: Some 780 consecutive carotid endarterectomies were performed over 16 years, with an incidence of major stroke or death of 2.3 per cent (18 patients). Fifty-one patients experienced transient or permanent neurological events following surgery, 25 of whom underwent re-exploration. The findings included carotid thrombosis (ten patients), flap or other technical cause (three), haematoma (two) and no abnormality (ten). The neurological outcome after 30 days was similar, whether or not the carotid artery was re-explored. CONCLUSION: Carotid artery re-exploration was undertaken in approximately half of the patients who developed neurological complications following carotid endarterectomy. Although the cause was identified and a secondary procedure was undertaken in 14 of 25 patients, there was no improvement in clinical outcome at 30 days compared with that of patients managed non-operatively.

Pre-operative hand-held Doppler run-off score can be used to stratify risk prior to infra-inguinal bypass surgery.

OBJECTIVES: to investigate the relationship between calf vessel run-off assessed by hand-held Doppler, graft patency and patient survival following infra-inguinal graft surgery. DESIGN: prospective cohort study of 258 consecutive patients undergoing infra-inguinal bypass grafts in one centre between 1995-99. MATERIALS AND METHODS: ankle Doppler auditory waveform characteristics were documented for patients considered for infra-inguinal bypass grafting. Doppler signals from the anterior tibial, posterior tibial and dorsalis pedis arteries were scored triphasic/biphasic (2), monophasic (1) or absent (0). A total Doppler run off score (0-6) was calculated. Following surgery graft surveillance was undertaken using duplex ultrasound at 6, 12, 26 and 52 weeks. Graft and patient survival were analysed using Cox regression analysis. RESULTS: overall primary assisted graft patency at one year was 80%. With an increasing Doppler score from 0 to 6, primary assisted graft patency steadily rose from 50% to 100% (p = 0.0002), accompanied by a steady fall in patient mortality from 50% to 5% (p = 0.0003).

External supports and the prevention of neointima formation in vein grafts.

AIMS AND METHODOLOGY: the aim of this review is to provide an overview of the aetiology of neointima formation in vein grafts and to highlight the use of an external support to modulate this phenomenon. A systematic literature review was performed via computerised search on MEDLINE, OVID and the Cochrane Library. The search terms initially employed were broad-based; "vein graft", "neointima" and "external stent". Subsequently, more specific search terms were utilised; "perivenous mesh", "external prosthesis" and "varicose vein". Articles from indexed journals relevant to the objective, external venous supports, from the earliest reports in the 1960's to the latest in 2001 were included to obtain an exhaustive list. Reviews, abstracts and proceedings of scientific meetings, case reports and the results of both animal model investigations and human clinical trials in all languages were included. Articles describing an external support employed in both peripheral and aortocoronary bypass investigations were included.

A randomised, double blind, placebo-controlled study to determine the efficacy of immune modulation therapy in the treatment of patients suffering from peripheral arterial occlusive disease with intermittent claudication.

OBJECTIVES: this study examined the effect of immune modulation therapy (IMT) on claudication distances. MATERIALS AND METHODS: a double-blind placebo controlled trial was performed on patients with disabling intermittent claudication with randomisation stratified for short and long distance IC. For IMT, following exposure to UV light, oxidisation and 42.5 degrees C, 10 ml of citrated autologous blood was administered by intra-muscular injection. One course consisted of 6 injections in 3-weeks followed by 3-weeks rest. Patients received 2, 3 or 4 courses depending on response. The primary end-point was the number of responders (>50% increase in initial claudication distance (ICD)) in each group. Secondary end-points included percentage changes in ICD and change in quality of life. RESULTS: at week 24, there were more responders in the IMT group (20/31, 65%) compared to placebo (16/39, 41%) (p=0.06). In the subgroup of short distance claudicants this difference reached significance (IMT 17/26, 65%) (Placebo 12/33, 36%) (p=0.04). The median increase in ICD was significantly greater in the IMT group (81%) compared to placebo (44%, p=0.04). These results were supported by quality of life measurements. CONCLUSIONS; IMT is a safe and apparently effective treatment for patients with short distance claudication.