Anaesthetic specialisation leads to improved early- and medium-term survival following major vascular surgery.

OBJECTIVE: Vascular surgical specialisation is associated with improved outcomes. We aimed to assess the effect of anaesthetic specialisation on outcome following major vascular surgery. DESIGN: Retrospective cohort study. METHODS: Patients undergoing major vascular surgery (lower limb revascularisation, elective and ruptured abdominal aortic aneurysm repair, endovascular aneurysm repair and carotid endarterectomy) over a five-year period were identified from a prospective database. The primary outcomes were death within 30 days and death within two years of surgery. Potential risk factors for mortality were assessed using multivariate logistic regression modelling. RESULTS: The analysis cohort comprised 1155 patients followed up for a median of 583 days. Mortality within two years of surgery was 16%. For the overall cohort, care from vascular anaesthetists was independently associated with reduced 30-day (odds ratio 0.22; 95% CI 0.12-0.62) and medium-term mortality (0.31; 95% CI 0.18-0.55). For elective patients (n=851), vascular anaesthesia reduced two-year mortality (odds ratio 0.29; 95% CI 0.15-0.58; P=0.0004) though not 30-day mortality (odds ratio 0.55; 95% CI 0.15-1.95; P=0.35). For emergency patients, care by a vascular anaesthetist influenced neither 30-day mortality (odds ratio 0.33; 95% CI 0.08-1.41; P=0.13) nor medium-term mortality (odds ratio 0.45; 95% CI 0.17-1.21; P=0.11). CONCLUSIONS: Anaesthetic specialisation reduced early- and medium-term mortality rates following major vascular surgery. If replicated by prospective studies, these results suggest that vascular surgery services would benefit from specialised anaesthetic support.

Randomized clinical trial of folate supplementation in patients with peripheral arterial disease.

BACKGROUND: The aim was to determine whether folate supplementation improved arterial function in patients with peripheral arterial disease (PAD). METHODS: Individuals with PAD were randomly assigned to receive 400 microg folic acid (45 patients) or 5-methyltetrahydrofolate (5-MTHF) (48) daily, or placebo (40) for 16 weeks. Primary endpoints were changes in plasma total homocysteine (tHcy), ankle : brachial pressure index (ABPI) and pulse wave velocity (PWV). Secondary outcomes were changes in plasma inflammatory markers. RESULTS: Plasma tHcy was significantly reduced in folic acid and 5-MTHF groups compared with controls: median difference: - 2.12 (95 per cent confidence interval - 3.70 to - 0.75) micromol/l (P = 0.002) and - 2.07 (-3.48 to - 0.54) micromol/l (P = 0.007) respectively. ABPI improved significantly: median difference 0.07 (0.04 to 0.11) (P < 0.001) and 0.05 (0.01 to 0.10) (P = 0.009) respectively. Brachial-knee PWV (bk-PWV) decreased significantly in individuals receiving 5-MTHF and tended to be reduced in those taking folic acid compared with controls: median difference: - 1.10 (-2.20 to - 0.20) m/s (P = 0.011) and - 0.90 (-2.10 to 0.00) m/s (P = 0.051) respectively. Plasma levels of inflammatory markers were not affected. CONCLUSION: Folate administration reduced plasma homocysteine, and slightly improved ABPI and bk-PWV.

Homocysteine and peripheral arterial disease: systematic review and meta-analysis.

OBJECTIVE: To evaluate homocysteine (Hcy) levels in patients with peripheral arterial disease (PAD) as compared to unaffected controls, and to review the clinical effects of therapy aimed at lowering homocysteine in PAD patients. METHODS: MEDLINE, EMBASE and Cochrane databases were searched from 1950 to December 2007. We selected observational studies and trials that evaluated Hcy levels in patients with PAD compared to unaffected controls. We also included trials on the effect of Hcy-lowering therapy (folate supplementation) in PAD patients. Continuous outcomes were pooled in a random effects meta-analysis of the weighted mean difference between comparator groups. RESULTS: We retrieved 33 potentially suitable articles from our search. Meta-analysis of 14 relevant studies showed that Hcy was significantly elevated (pooled mean difference +4.31micromoll; 95% C.I. 1.71, 6.31, p<0.0001 with significant heterogeneity) in patients with PAD compared to controls. As all 14 studies consistently demonstrated raised plasma Hcy levels in PAD patients, the significant heterogeneity in this meta-analysis probably arises from differences in the degree of Hcy elevation. The effect of folate supplementation on PAD was tested in eight clinical trials but clinically important end points were inconsistently reported. CONCLUSION: Patients with PAD have significantly higher Hcy levels than unaffected controls. However, we did not find any robust evidence on clinically beneficial effects of folate supplementation in PAD.

Neonatal mycotic internal iliac aneurysm due to methicillin-resistant Staphylococcus aureus (MRSA) septicaemia successfully treated by coil embolisation.

A 12-day-old term male neonate presented with septic arthritis, multiple skin and intrabdominal abscesses and a mycotic aneurysm of the right internal iliac artery. He was diagnosed as having methicillin resistant staphylococcus aureus (MRSA) septicaemia and deemed unsuitable for surgical treatment of the aneurysm. Coil embolisation of the internal iliac artery was performed, followed by a successful recovery and with no evidence of residual or recurrent infection. The authors describe a method of treating internal iliac mycotic aneurysms in high-risk patients by endovascular means, which we believe has not been attempted in this precise scenario before.

Thrombolysis for acute deep vein thrombosis.

BACKGROUND: Standard treatment for deep vein thrombosis (DVT) aims to reduce immediate complications. Use of thrombolysis or clot dissolving drugs could reduce the long-term complications of post-thrombotic syndrome (pain, swelling, skin discolouration, or venous ulceration) in the affected leg. OBJECTIVES: To determine the efficacy and safety of thrombolysis for DVT. SEARCH STRATEGY: Publications describing randomised controlled trials (RCTs) of thrombolysis versus anticoagulation for acute DVT were sought through electronic searches of the Cochrane Peripheral Vascular Diseases trials register (last searched April 2004) and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched The Cochrane Library Issue 2, 2004). Additional trials were identified by reviewing reference lists of papers. There were no restrictions for language. SELECTION CRITERIA: RCTs examining thrombolysis versus anticoagulation for acute DVT and/or calf vein thrombosis were considered. DATA COLLECTION AND ANALYSIS: One reviewer (LIW) selected trials, extracted data and assessed study quality, with checking at all stages by the other reviewer (MPA). Where required, additional information was sought from trialists. MAIN RESULTS: Twelve studies were included. Complete clot lysis occurred significantly more often in the treatment group in early follow up, (relative risk (RR) 0.24; 95% confidence interval (CI) 0.07 to 0.82), and in late follow up, (RR 0.37; 95 % CI 0.25 to 0.54). A similar effect was also seen for any degree of improvement in venous patency. Significantly less post-thrombotic syndrome occurred in those receiving thrombolysis, (RR 0.66; 95 % CI 0.47 to 0.94). Leg ulceration was reduced although the data were limited by small numbers, (RR 0.53; 95 % CI 0.12 to 2.43). Venous function was improved at late follow up, but not significantly (RR 0.43; 95 % CI 0.06 to 3.17)Out of 668 patients, those receiving thrombolysis had significantly more bleeding complications, (RR 1.73; 95 % CI 1.04 to 2.88). Two strokes occurred in the treatment group (RR 1.70; 95 % CI 0.21 to 13.70). The incidence of bleeding appears to have reduced over time with the introduction of stricter selection criteria. There was no significant effect on mortality detected in either early or late follow up. Data on occurrence of pulmonary embolism (PE) and recurrent DVT were inconclusive. REVIEWERS' CONCLUSIONS: Thrombolysis appears to offer advantages in terms of reducing post-thrombotic syndrome and maintaining venous patency after DVT. Use of strict eligibility criteria has improved the safety and acceptability of this treatment. The optimum drug, dose and route of administration have yet to be determined.

Comparison of morphologic features of intact and ruptured aneurysms of infrarenal abdominal aorta.

INTRODUCTION: Endovascular aneurysm repair (EVAR) has been suggested as a technique to improve outcome of ruptured abdominal aortic aneurysm (AAA). Whether this technique becomes an established treatment will depend, in part, on the anatomy of ruptured AAA. METHODS: The anatomy of intact and ruptured AAA seen in a university department of vascular surgery over 5 years was reviewed. Aneurysm anatomy was assessed with spiral computed tomographic angiography. Suitability for EVAR was assessed from the dimensions of the proximal neck and common iliac arteries. Neck length less than 15 mm, neck width greater than 30 mm, and common iliac artery diameter greater than 22 mm were declared unsuitable for EVAR. RESULTS: Three hundred sixty-three patients with intact AAA and 46 with ruptured AAA were identified. Larger intact aneurysms were significantly associated with longer renal artery-bifurcation distance and more complex proximal neck architecture. In this sample, patients with ruptured AAA were more likely to have larger aneurysms with shorter and narrower proximal necks. Significantly more intact aneurysms were morphologically suitable for endovascular repair compared with ruptured AAA (78% vs 43%; P <.001). CONCLUSIONS: Ruptured AAA are less likely to be suitable for endovascular repair than are intact AAA, most probably because of larger diameter at presentation. Open repair will likely remain the treatment of choice in most patients with ruptured AAA, because of current morphologic constraints of endovascular repair.

Spiral CT angiography versus aortography in the assessment of aortoiliac length in patients undergoing endovascular abdominal aortic aneurysm repair.

PURPOSE: To compare measurements of aortoiliac length obtained with spiral computed tomographic angiography (CTA) and aortography in patients undergoing endovascular aneurysm repair. METHODS: The distances from the lower-most renal artery to the aortic bifurcation and from the aortic bifurcation to the common iliac artery (CIA) bifurcation were measured using both CTA and aortography in 108 patients with abdominal aortic aneurysms. RESULTS: The level of agreement between CTA and aortography was high, with 69% of aortic and 76% of iliac measurements within 1 cm and > 90% within 2 cm of each other. Mean differences were -0.35 +/- 1.20 cm and 0.25 +/- 1.10 cm, respectively, for aortic and iliac lengths. Aortography overestimated renal artery to aortic bifurcation length in comparison to CTA (p = 0.003), particularly in patients with large aneurysms (> 6.5 cm) and lumen diameters > 4.5 cm (p < 0.0001). Measurements of CIA length were shorter by aortography than CTA (p = 0.02). CONCLUSIONS: There is a high level of agreement between CTA and aortography in the measurement of aortoiliac length, but aortography overestimates renal artery to aortic bifurcation length in patients with large-diameter aneurysms and wide aneurysm lumens. CTA is sufficiently accurate in the majority of cases to be used as the sole basis for the construction of endovascular grafts.

Common iliac artery aneurysms in patients with abdominal aortic aneurysms.

OBJECTIVES: To determine the incidence of common iliac artery (CIA) aneurysms in patients with abdominal aortic aneurysms (AAA) and to evaluate the relationship between AAA and CIA diameter. METHODS: Spiral CT angiography was used to measure the maximum diameters of the abdominal aorta and the common iliac arteries of 215 patients with AAA. RESULTS: The median CIA diameter was 1.7 cm--significantly greater than the published mean of 1.25 (2 S.D. = 0.85-1.65) cm of an age-matched, non-vascular population. Thirty-four patients (16%) had unilateral and 26 patients (12%) bilateral CIA aneurysms > or = 2.4 cm diameter. Eight-six vessels (20%) were affected. Right CIA diameters were wider than left CIA diameters (p < 0.0001, Wilcoxon matched-pairs signed rank test). The correlation between AAA size and CIA diameter was weak. CONCLUSIONS: The AAA population has abnormally dilated common iliac arteries. In this population, common iliac artery aneurysms should be defined as those greater than 2.4 cm diameter. 20% of CIAs in patients with AAA are aneurysmal according to this definition.

Thrombus distribution and changes in aneurysm size following endovascular aortic aneurysm repair.

OBJECTIVES: To determine (a) changes in aneurysm size following endovascular repair, (b) the significance of collateral lumbar artery blood flow and (c) the relationship between thrombus distribution within the aneurysm sac and the development of a "lumbar endoleak". MATERIALS AND METHODS: 72 patients treated with endovascular stent-grafts were followed up with spiral computed tomography for a median of 11 (range 3-27) months. The cross-sectional area of the aneurysm was measured at the point of maximum diameter pre- and post-operatively. The distribution and quantity of thrombus was recorded pre-operatively and this was related to changes in aneurysm size and the development of lumbar endoleaks post-operatively. RESULTS: An increase in aneurysm size occurred in 22 patients, of whom 10 had endoleaks. Fifteen aneurysms did not change in size, including four with endoleak, and 35 aneurysms decreased in size with no endoleaks. There was a significant difference between the endoleak and no endoleak groups (Chi-squared test = 17.1 with 2 degrees of freedom (d.f.), p < 0.001). Nine endoleaks were from patent lumbar arteries. No patients with thick circumferential or posteriorly placed thrombus developed an endoleak arising from lumbar vessels (0/23 cases) compared to those with minimal or anteriorly placed thrombus (9/49 cases) (Chi-squared test with Yate's correction = 3.17 with 1 d.f., p < 0.1). CONCLUSIONS: Aneurysms do not decrease in size in the presence of a lumbar endoleak, and some expand significantly. A number of aneurysms increase in size despite no evidence of an endoleak on computed tomography (CT). Patterns of thrombus distribution may be able to predict patients at risk from persistent endoleak via lumbar vessels.

Influence of abdominal aortic aneurysm size on the feasibility of endovascular repair.

PURPOSE: To assess the effect of abdominal aortic aneurysm (AAA) size on overall aneurysm morphology with special attention to possible relationships among various anatomic variables that determine the feasibility of endovascular repair. METHODS: One hundred sixty-eight patients were assessed with spiral computed tomographic angiography to measure the length and diameter of the AAA, the proximal neck, and the common iliac arteries. Anatomic variables were correlated with aneurysm size using Spearman's rank order correlation coefficients (rS); comparisons among small, intermediate, and large aneurysms were made using the Chi-square test. RESULTS: Correlations between aneurysm size and the anatomic variables above were weak. The strongest association was between aneurysm size and aortic length (rS = 0.41, p < 0.001). Subgroup analysis showed no difference in proximal neck length, neck diameter, or overall suitability for endovascular repair between aneurysms greater or smaller than 5.5-cm diameter. However, significantly more short (< 1.5 cm), wide (> 3 cm), and hence, unsuitable proximal necks were found in patients with aneurysms > 7 cm in diameter (chi 2 = 7.8, p < 0.01). CONCLUSIONS: Shortening and widening of the proximal neck seems to increase with aneurysm size but only after the aneurysm expands beyond 7 cm in diameter. Aneurysms with diameters in the 4.5- to 5.5-cm range are no more suitable for endovascular repair than those between 5.5 and 7 cm. The lack of any significant correlation between anatomic variables emphasizes the need for accurate preoperative assessment of the anatomy of each individual patient before endovascular repair.

The anatomy of abdominal aortic aneurysms: implications for sizing of endovascular grafts.

OBJECTIVE: To determine the full range of aorto-iliac anatomy of patients with abdominal aortic aneurysms (AAAs) and thence the range of endovascular graft sizes required to deal with the majority of AAAs. DESIGN: Analysis of preoperative spiral CT measurements. MATERIALS: One hundred and sixty-eight patients with AAAs. METHODS: Multiplanar reconstruction measurements were taken of proximal aortic neck diameter and length, lowermost renal artery to the aortic bifurcation distance and length and diameter of common iliac arteries. Based on these measurements a range of graft sizes that would fit the majority of AAAs was determined. RESULTS: Ranges of anatomical variables were as follows: proximal aortic neck diameter 18-30 mm, renal artery to aortic bifurcation distance 93-210 mm, common iliac artery length 13-108 mm, common iliac artery diameter 6-67 mm. Over 750 graft sizes would be required to cover all anatomical combinations using a one-piece aorto-uni-iliac graft. CONCLUSION: A wide variety of aorto-iliac anatomy exists in patients with AAAs. The large number of graft sizes required to deal with the majority of AAAs makes the production of one-piece endovascular grafts commercially impractical. A proposed two-piece modular graft would allow the majority of AAAs to be treated using only 16 graft sizes.

Anatomical suitability of abdominal aortic aneurysms for endovascular repair.

BACKGROUND: Aortic aneurysm anatomy is crucial when considering patients for endovascular repair. The aim of this study was to determine the proportion of patients with aortic aneurysm suitable for endovascular repair with three different graft-stent systems. METHODS: Spiral computed tomographic angiography was used to assess the anatomy of 154 abdominal aortic aneurysms. Measurements were made of aneurysm neck length and diameter, renal artery to aortic bifurcation length, common iliac artery diameter and length, and external iliac artery diameter. Aneurysms were assessed for anatomical suitability for currently available aortoaortic, aortobi-iliac and aortouni-iliac devices. RESULTS: Six patients (4 per cent) had a distal aortic neck suitable for implantation of a straight aortic graft. Fifteen patients (10 per cent) had arterial anatomy suitable for implantation of a bifurcated graft and 85 (55 per cent) patients were suitable for endovascular repair with an aortouni-iliac graft. The primary reasons for unsuitability were: proximal neck length less than 1.5 cm (44 patients), proximal neck diameter greater than 3.0 cm (12), and angulation of the proximal neck (three). A further ten patients were considered unsuitable for an aortouni-iliac graft because of bilateral common iliac artery aneurysms (four), tortuous iliac arteries (four) and narrow external iliac arteries (two). CONCLUSION: The aortouni-iliac device has the widest applicability of the currently available endovascular systems but open repair remains the only option for a large proportion of patients.

Results of 100 cases of pulse-spray thrombolysis for acute and subacute leg ischaemia.

BACKGROUND: Pulse-spray thrombolysis is a rapid technique for the treatment of limb ischaemia of recent onset. Early results have been published but the longer term results are not known. METHODS: This study consisted of a series of 100 legs with acute and subacute ischaemia treated using this method with a follow-up interval of up to 3 years. Eighty-three limbs were classified as Fontaine grade III or IV and 42 had a sensory or motor deficit. Sixty-seven limbs were treated with pulse spray alone and 33 had an additional low-dose infusion. In 71 cases an additional catheter-directed intervention was required. RESULTS: Median duration of lysis was 135 (range 35-1540) min and median dose of recombinant tissue plasminogen activator used was 18 (range 4-61) mg. Complete radiological patency was achieved in 79 limbs and the ankle:brachial pressure index improved from a median of 0 (range 0-0.8) to 0.8 (range 0-1.5) (P < 0.0001). At 30 days ten patients had died, eight needed amputation and a further 11 had rethrombosed. Cumulative limb salvage rate at 30 months was 79 per cent (standard error 8) and the estimated cumulative patency rate for successful cases was 72 per cent (standard error 10). The incidence of major bleeding was 7 per cent and of minor bleeding 24 per cent. There were no haemorrhagic strokes but three thrombotic strokes occurred within 30 days of thrombolysis. CONCLUSION: Pulse-spray thrombolysis achieves rapid and safe revascularization of acute and subacute leg ischaemia.