The Influence of Carotid Plaque Morphology on the Development of Cerebral Symptoms

Background: Large randomized trials such as the European Carotid Surgery Trial (ECST) and North American Symptomatic Carotid Endarterectomy Trial (NASCET) have defined a role for carotid endarterectomy in symptomatic patients with severe carotid artery stenosis. Data from the same trials also shows that a subgroup of patients with less severe stenosis with a higher risk of stroke might benefit form carotid endarterectomy. In recent years, it has become apparent that besides the degree of stenosis, the morphology of the plaque itself plays a significant role in its potential for development of symptoms, and noninvasive methods of assessing plaque morphology are currently being developed. This paper reviews the literature regarding the relationship between carotid plaque morphology and the potential for development of clinical symptoms.

Methods: A Medline search and a meta-analysis of the literature was carried out. Intraplaque hemorrhage and plaque ulceration were both found to be associated with a higher risk of stroke development (p = 0.001 and 0.0001, respectively). Intraluminal thrombus was not found to be associated with an increased risk of symptom development in the data analyzed. A possible explanation for this incongruous finding is discussed. In addition, the paper also discusses the role of noninvasive plaque characterization as a method of identifying unstable plaques in the future.

Conclusion: Certain characteristics of plaque morphology correlate with a higher risk of development of symptoms and better noninvasive identification of plaque characterization will lead to better patient selection and may be especially useful identifying patients with lower degrees of stenosis but with potentially unstable plaques who might benefit from carotid endarterectomy but do not qualify for surgery using currently accepted criteria.

A Quantitative Study of Long Saphenous Vein Morphology in Patients Undergoing Arterial Surgery

Objective:

To quantify the incidence and extent of structural changes present in the long saphenous vein of patients with arterial disease.

Design:

Observational study of saphenous vein morphology.

Setting:

Departments of Surgery and Pathology, Leicester Royal Infirmary.

Patients:

Sixty vein biopsies from patients undergoing arterial surgery.

Main outcome measures:

Intimal and medial thickness and morphology.

Results:

Smooth muscle cell hyperplasia, elastosis and fibrosis contributed to intimal thickening (> 10 μm) in 87% of veins. This was frequently associated with medial longitudinal muscle hypertrophy. Intimal thickness had a skewed distribution with a median (range) of 33 (8–381) μm, The upper limit of the normal range was 200 μm. The median (range) medial thickness was 293 (131–468) μm.

Conclusions:

Intimal thickening is common in the long saphenous vein of patients undergoing arterial surgery but is extensive in only a small proportion. The upper limit of the normal range was 200 μm.

Intravascular Stapler for “Open” Aortic Surgery: Preliminary Results

OBJECTIVES

The aim of this study was to assess the efficacy of a new stapling device using a pig model.

METHODS

Straight 12 mm Gore-Tex grafts were inserted end to end into the aorta of 12 pigs. One anastomosis was performed with the stapler and the other using 4/0 prolene sutures and 13 mm needles. The animals were sacrificed at one week, one and three months and all grafts underwent histological examination. Leakage from the anastomoses was assessed in a separate specially designed circulation model using saline as a perfusate.

RESULTS

The stapled anastomoses took 1.0+/-0.25 minutes to complete while suturing took 8.5+/-1.5 minutes. There was no difference in the histology between the two types of anastomosis. The leak rate was six times greater at the sutured compared to the stapled anastomosis.

CONCLUSION

The use of stapled anastomoses may allow a significant shortening of aortic cross clamping time, reduce anastomotic leakage and may be particularly useful in laparoscopic aortic repair. A randomised trial is required to assess the efficacy of this device.

Cerebral protection during open retrograde angioplasty/stenting of common carotid and innominate artery stenoses

Background

This was a retrospective study of the effectiveness of open, retrograde angioplasty/stenting of supra-aortic arterial stenoses combined with transcranial Doppler-directed dextran therapy in preventing perioperative embolization.

Methods

Eight patients underwent angioplasty/stenting of the proximal common carotid (synchronous carotid endarterectomy (CEA) in six), while four underwent angioplasty/stenting of the innominate artery (synchronous CEA in one). Open exposure of the carotid bifurcation enabled temporary carotid clamping to protect the brain from procedural embolization. Dextran was administered to patients with a high rate of embolization on transcranial Doppler after the operation.

Results

No emboli were recorded in the cerebral circulation during the actual angioplasty procedure when the internal carotid artery was clamped. After operation three patients developed high-rate embolization and received dextran. No strokes or deaths occurred within 30 days of treatment. One patient developed symptoms and a recurrent stenosis greater than 50 per cent during follow-up and was treated by redo angioplasty.

Conclusion

Retrograde angioplasty/stenting with or without synchronous CEA offers an alternative approach to treating patients with supra-aortic inflow disease.

Duplex imaging immediately prior to carotid endarterectomy

INTRODUCTION

In this centre, angiography is used only in selected cases, whilst duplex ultrasound (DU) is the main imaging method prior to carotid endarterectomy (CEA). DU has no associated morbidity and so can be repeated immediately before surgery to detect changes in the carotid plaque or degree of stenosis.

PATIENTS AND METHODS

We retrospectively examined our Vascular Surgery Audit database for the last 500 patients admitted for CEA. In each case, the DU scan was repeated immediately before surgery.

RESULTS

From 500 admissions, repeat DU immediately prior to surgery detected 8 (1.6%) situations where CEA would no longer have been an appropriate intervention. In four cases, the degree of stenosis was found to be less than 70% on the repeat scan - in three cases the internal carotid artery (ICA) had occluded or sub-occluded and in one case there was a dissection of the ICA plaque.

CONCLUSIONS

DU can be repeated, with no associated morbidity, immediately prior to surgery. Such a practice changes management decisions in 1.6% of admissions for CEA, allowing surgery unjustified by current evidence to be avoided. This policy also serves several other important purposes: it is a method of internal validation, provides a means of improving training of vascular technologists and of achieving quality assurance in DU techniques.

HMG-CoA reductase inhibitors (statins) decrease MMP-3 and MMP-9 concentrations in abdominal aortic aneurysms

BACKGROUND

An imbalance in matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are implicated in AAA formation. 3-Hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors (statins) are known to reduce MMP levels. The aim of this study was to investigate the in vivo effect of statins on MMP levels in AAA.

METHODS

Infra-renal aortic biopsies were obtained from the anterior sac of 63 patients undergoing asymptomatic repair. Seventeen patients were taking a statin pre-operatively, while 46 were not. The concentrations of MMP-1, -2, -3, -8, -9, -13, TIMP-1 and TIMP-2 were quantified using ELISA.

RESULTS

There was no difference in the concentration of MMP-1, -2, -8, -13, TIMP-1 or -2 in patients taking versus not taking a statin pre-operatively. In contrast levels of MMP-9 and MMP-3 were significantly lower in patients taking a statin.

CONCLUSIONS

These data demonstrate that statins decrease MMP-9 and MMP-3 levels and represent a potential pharmacotherapy in established AAA.

Matrix metalloproteinase 8 (neutrophil collagenase) in the pathogenesis of abdominal aortic aneurysm

Background

Loss of elastin is the initiating event in abdominal aortic aneurysm (AAA) formation, whereas loss of collagen is required for continued expansion. The elastolytic matrix metalloproteinases (MMPs) 2 and 9 are well described, but the source of excessive collagenolysis remains undefined. The aim of this study was to determine the expression of MMP-8, a potent type I collagenase, in normal aorta and AAA.

Methods

Infrarenal aortic biopsies were taken from 40 AAA and ten age-matched normal aortas. The concentrations of MMP-8 protein and its inhibitors, tissue inhibitor of metalloproteinase (TIMP) 1 and TIMP-2, were quantified by enzyme-linked immunosorbent assay. Immunohistochemistry was used to localize MMP-8 expression.

Results

MMP-8 concentrations were significantly raised in AAA compared with normal aorta (active MMP-8: 4·5 versus 0·5 ng per mg protein, P < 0·001; total MMP-8: 16·6 versus 2·8 ng per mg protein, P < 0·001). Levels of TIMP-1 and TIMP-2 were significantly lower in AAA than in normal aortic samples (TIMP-1: 142·2 versus 302·8 ng per mg protein; P = 0·010; TIMP-2: 9·2 versus 33·1 ng per mg protein, P < 0·001). Immunohistochemistry localized MMP-8 to mesenchymal cells within the adventitia of the aortic wall.

Conclusion

The high concentration of MMP-8 in aortic aneurysms represents a potent pathway for collagen degradation, and hence aneurysm formation and expansion.

A comparison of methods for determining genotypes at the tumour necrosis factor-alpha-308, interleukin (IL)-1beta+3953, IL-6 -174 and IL-10 -1082/-819/-592 polymorphic loci

Induced heteroduplex genotyping (IHG) is one of many methods that can be used to determine single nucleotide polymorphisms (SNPs). It is relatively new in comparison to other polymerase chain reaction (PCR)-based techniques. The aim of this study was to compare the results of genotyping using IHG with the results of genotyping using either polymerase chain reaction-sequence-specific primers (PCR-SSP) or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for SNPs in the tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and IL-10 genes. Ninety patients who consented to participate in the study had their genotypes determined by IHG and either PCR-SSP (TNF-alpha-308 and IL-10 -1082/-819/-592) or PCR-RFLP (IL-1beta +3953 and IL-6 -174). Results for each locus were compared between techniques by calculating the Kappa statistic as a measure of agreement. The IHG and more traditional genotyping methods produced very similar results at all loci. The Kappa statistics for each locus were as follows: TNF-alpha -308, K = 0.727; IL-1beta +3953, K = 0.886; IL-6 -174, K = 0.909; IL-10 -1082, K = 0.876; IL-10 -592, K = 0.920. IHG is a valid method for the determination of genotypes at the loci examined in this study and produces comparable results to those of more traditional methods of genotyping.

Patch Corrugation on Duplex Ultrasonography may be an Early Warning of Prosthetic Patch Infection

Four of 10 patients presenting with prosthetic patch infection after carotid endarterectomy (CEA) were noted to have Duplex evidence of 'corrugation' of the prosthetic patch, without false aneurysm formation. In three, corrugation preceded diagnosis of overt patch infection by up to 11 months. In the fourth patient, awareness of the potential significance of patch corrugation enabled timely treatment of an otherwise unrecognized patch infection. Even if other imaging modalities are normal, the presence of patch corrugation on Duplex should prompt the surgeon to (at least) consider the possibility of patch infection.

Impact of the volume of aneurysmal contents on intraaneurysmal pressure after endovascular grafting (experimental studies)

With the purpose of clarifying the nature and outlining certain constituents of such an undesirable condition designated as "endotension", that emerges after transluminal grafting of the aneurysmally changed aorta, a basic theoretical model was worked out for explanation of "endotension". Also, there was designed and constructed in vitro an original experimental model using which the authors carried out a study into the relationship between the pressure in the aneurysm after its complete exclusion from the blood flow by an endovascular graft and the volume of the aneurysmal contents. Some factors described in the literature as influencing the pressure level in the aneurysm were at the given stage purposefully excluded. The volume of the "aneurysm" reproduced in our model was equal to 675 ml; each of five vascular grafts implanted into the aneurysm measured 110 mm in length. The pulsating liquid flow was reproduced in the system using a serial appliance for extracorporeal circulation. The liquid was aspirated from the aneurysm by means of a syringe with concurrent pressure guidance in the sac. To start pressure lowering, it was necessary to evacuate 0.4-1.6 ml of the liquid. The real clinical situations were considered from the standpoint of our results.

Cytokines, their genetic polymorphisms, and outcome after abdominal aortic aneurysm repair

BACKGROUND

Excessive cytokine production has been implicated in the development of organ failure. Polymorphic sites in cytokine genes have been shown to affect levels of production in vitro and may influence cytokine production in vivo. The aims of this study were to determine if cytokines or their genetic polymorphisms were related to outcome after abdominal aortic aneurysm (AAA) repair.

METHODS

A prospective study of 135 patients undergoing open AAA repair. Plasma levels of TNF-alpha, IL-1beta, IL-6 and IL-10 were measured 24 h post-operatively and genotypes for the TNF-alpha -308, IL-1beta+3953, IL-6 -174, IL-10 -1082 and IL-10 -592 polymorphisms were determined for each patient.

RESULTS

After elective AAA high levels of IL-10 were associated with both prolonged critical care (P<0.001) and hospital stay (P=0.001). The presence of a G allele at the IL-6 -174 locus was associated with a higher incidence of organ failure (P=0.04) and an A allele at TNF-alpha -308 with prolonged critical care stay (P=0.03). After ruptured AAA the development of multi-organ failure was associated with high levels of IL-6 (P=0.01) and TNF-alpha (P=0.04). High TNF-alpha levels were also associated with mortality (P=0.01).

CONCLUSION

Post-operative cytokine levels are related to outcome after AAA repair. Cytokine gene polymorphisms may provide a method for determining which patients are at high risk of complications.

Unstable Carotid Plaques Exhibit Raised Matrix Metalloproteinase-8 Activity

BACKGROUND

The fibrous cap of atherosclerotic plaques is composed predominantly of type I and III collagen. Unstable carotid plaques are characterized by rupture of their cap, leading to thromboembolism and stroke. The proteolytic mechanisms causing plaque disruption are undefined, but the collagenolytic matrix metalloproteinase (MMP) -1, -8, and -13 may be implicated. The aim of this study was to quantify the concentrations of these collagenases in carotid plaques and to determine their relationship to markers of plaque instability.

METHODS AND RESULTS

Atherosclerotic plaques were collected from 159 patients undergoing carotid endarterectomy. The presence and timing of carotid territory symptoms were ascertained. Preoperative embolization was recorded by transcranial Doppler. Each plaque was assessed for histological features of instability. Plaque MMP concentrations were quantified with ELISA. Significantly higher concentrations of active MMP-8 were observed in the plaques of symptomatic patients (20.5 versus 11.4 ng/g; P=0.0002), in plaques of emboli-positive patients (22.7 versus 13.5 ng/g; P=0.0037), and in those plaques showing histological evidence of rupture (20.8 versus 14.7 ng/g; P=0.0036). No differences were seen in the levels of MMP-1 and MMP-13. Immunohistochemistry, in situ hybridization, and colocalization studies confirmed the presence of MMP-8 protein and mRNA within the plaque, which colocalized with macrophages.

CONCLUSIONS

These data suggest that the active form of MMP-8 may be partly responsible for degradation of the collagen cap of atherosclerotic plaques. This enzyme represents an attractive target for drug therapy aimed at stabilizing vulnerable plaques.

Subintimal angioplasty in lower limb ischaemia

Subintimal angioplasty has been suggested as a treatment option for occlusive disease and has become an established practice in some centres, reducing their operative workload considerably. Others have concerns about the safety and durability of the procedure. This review will focus on the evidence for the use of subintimal angioplasty in lower limb occlusive disease. A systematic review of the literature from a Medline search has been carried out. Despite a paucity of trial data, subintimal angioplasty is now an established technique for the treatment of lower limb occlusive disease. The results for femoro-popliteal disease are well documented, with excellent technical and clinical success rates and low complication rates. The results for iliac disease are less well documented and demand caution. For infra-popliteal disease with critical ischaemia, the technique is again safe with good short and long-term results in a group of patients in whom distal bypass surgery is often risky. Subintimal angioplasty has a definite learning curve and those wishing to take it up should visit an experienced centre first. To achieve widespread acceptance it is likely to require large scale randomised controlled trials.

An In Vitro Model to Compare the Antimicrobial Activity of Silver-Coated Versus Rifampicin-Soaked Vascular Grafts

In situ replacement of infected vascular grafts is an accepted alternative to total graft excision and extraanatomic replacement. Its success relies upon the ability of the newly inserted graft to resist recurrent infection. This study compares the efficacy of two methods used to reduce the risk of graft reinfection: rifampicin soaking versus silver bonding of grafts. The grafts' resistance to infection was tested in vitro in two protocols, each using a panel of seven common bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The length of time the grafts remained free of organisms was compared between the groups. Both the silver graft and the rifampicin-soaked graft were significantly better than control graft at preventing bacterial growth on the graft surface. The rifampicin inhibited the growth of the gram-positive organisms, including MRSA, significantly better than the silver graft on days 2 and 3 (p < 0.001). Conversely, the silver graft was significantly more effective against the gram-negative organisms until day 4 (p < 0.0001). Both types of graft inhibit the in vitro growth of bacteria more effectively than controls, with rifampicin being most effective against gram-positive organisms and silver being best against the gram-negative organisms.

Feasibility of preoperative computer tomography in patients with ruptured abdominal aortic aneurysm: a time-to-death study in patients without operation

INTRODUCTION

Despite advances in surgery, anaesthesia, and critical care, mortality from ruptured abdominal aortic aneurysms (AAAs) has not decreased over the last 20 years. Endovascular aneurysm repair (EVAR) of ruptured AAAs is an alternative to open repair, which may improve outcome. However, a computed tomography (CT) scan is usually required to assess the anatomic suitability of the aneurysm for EVAR. This may result in delay in transferring patients to the operating room. We evaluated all patients admitted to hospital with a ruptured AAA who died without undergoing surgery, to determine time to death after AAA rupture and thus the potential time available for obtaining a CT scan.

METHODS

A retrospective case note review was conducted of 56 patients admitted to a single center with ruptured AAAs who did not undergo surgery because of advanced age or associated comorbidity over 8 years from 1995 to 2003. Statistical analysis was performed with the Fisher exact test.

RESULTS

The 56 patients (33 men, 59%; 23 women, 41%) had a median age of 85 years (range, 71-98 years). Reasons for no operation being performed were shock (9%), cardiac arrest (11%), quality of life (29%), malignancy (7%), cardiac disease (15%), respiratory disease (16%) and age (14%). Median systolic blood pressure at admission was 110 mm Hg, heart rate was 88 beats per minute, and hemoglobin concentration was 10.5 g/dL. Patients were not aggressively resuscitated once a decision was made to not perform surgery. Death within 2 hours of hospital admission occurred in 7 (12.5%) patients, and 49 (87.5%) patients died more than 2 hours after admission. Median interval between onset of symptoms and admission to hospital was 2 hours 30 minutes (range, 44 minutes-36 hours), and the median interval between admission and death was 10 hours 45 minutes (range, 1 hour 1 minute-143 hours 55 minutes). The median total time to death from onset of symptoms was 16 hours 38 minutes (range, 2 hours 6 minutes-146 hours 50 minutes).

CONCLUSION

Most (87.5%) patients admitted to hospital with a ruptured AAA died after more than 2 hours. These data show that most patients with a ruptured AAA who reach the hospital alive are sufficiently stable to undergo CT and consideration of EVAR.

Elevation in Plasma MMP-9 Following Carotid Endarterectomy is Associated with Particulate Cerebral Embolisation

OBJECTIVES

To study plasma MMP-9 levels before and after carotid endarterectomy (CEA).

DESIGN

Observational study.

METHODS

Pre-operative (morning of surgery) and post-operative (48 h) plasma samples were obtained from 75 consecutive patients undergoing CEA. MMP-9 concentrations were quantified using ELISA. Transcranial Doppler monitoring was performed on each patient to detect particulate embolisation during the dissection phase of the CEA, until the application of carotid clamps.

RESULTS

The median post-operative plasma MMP-9 level of emboli-positive patients was significantly higher than their median pre-operative value (14.9 ng/ml vs. 8.8 ng/ml; p=0.038). However, no significant difference was seen in the plasma MMP-9 level of emboli-negative patients (7.7 ng/ml vs. 7.1 ng/ml; p=0.364). A greater rise was seen in the median plasma MMP-9 levels of those patients suffering >2 emboli (from 3.4 to 19.3 ng/ml; p=0.041) than those patients suffering 1 or 2 emboli (from 10.1 to 12.8 ng/ml; p=0.340).

CONCLUSIONS

Plasma MMP-9 only rises after CEA in patients with evidence of embolisation. This increase is more pronounced in those with high numbers of emboli. These data suggest that the increase in MMP-9 is due to cerebral damage caused by embolisation.

The Clinical Value of the Systemic Inflammatory Response Syndrome (SIRS) in Abdominal Aortic Aneurysm Repair

OBJECTIVES

The systemic inflammatory response syndrome (SIRS) is common after major surgery. We examine the dynamics of SIRS in AAA patients, and assess the impact of the number of SIRS criteria on patient outcome.

DESIGN

Prospective study of 151 consecutive patients with AAA, undergoing repair electively, urgently or with rupture.

METHODS

SIRS scores and organ failure scores were recorded prospectively each day for all patients. Outcome measures included length of stay, evidence of organ failure and mortality.

RESULTS

The majority of patients developed SIRS postoperatively. Elective patients with a cumulative SIRS score of > or =10 during postoperative days 1-4 were more likely to die, compared to patients with a SIRS score of <10 (p=0.02). The development of SIRS late in the postoperative period (day 5-10) was associated with adverse outcome (death) in elective patients (p=0.01). The actual number of SIRS criteria present did not significantly correlate with either outcome or the incidence of organ failure.

CONCLUSIONS

SIRS is common in patients undergoing AAA repair. The SIRS score provides useful information regarding a patient's physiological state. High SIRS scores, and the development of SIRS late in the postoperative period are associated with adverse outcome in elective patients, and can therefore be used as an indicator of potential problems.

The post-operative mortality of ruptured abdominal aortic aneurysm repair

INTRODUCTION

Late peri-operative death after ruptured abdominal aortic aneurysm (RAAA) repair is usually due to multiple-organ failure. The aim of this study was to identify any factors that are associated with mortality in this group of patients.

METHODS

A retrospective case-note review of a single decade's operative experience of RAAA repair in a single centre. Only those patients with confirmed rupture at laparotomy were included. Sixty-three pre- intra- and post-operative variables were recorded where possible for each patient who survived surgery and the initial 24-hours post-operatively. Multi-variate analysis was performed using stepwise logistic regression. The P-POSSUM, RAAA-POSSUM, RAAA-POSSUM (physiology only), V-POSSUM, and V-POSSUM (physiology only) models were all compared to determine how each performed in these patients.

RESULTS

Two hundred and twenty-three cases of confirmed RAAA were identified, of whom 139 survived the operation and initial 24-hours post-operatively. In-hospital mortality in this group of patients was 32.4%. Variables significantly associated with mortality after multi-variate analysis, were low intra-operative systolic blood pressure, the presence of a consultant anaesthetist at the initial operation and the development of cardiac, renal or gastro-intestinal complications. All POSSUM models except the V-POSSUM and P-POSSUM (physiology only) models demonstrated no significant lack of fit in this dataset.

DISCUSSION

Factors associated with delayed peri-operative death after RAAA are not the same as those previously found to be associated with overall peri-operative mortality after RAAA repair.

Does the Sequence of Clamp Application During Open Abdominal Aortic Aneurysm Surgery Influence Distal Embolisation?

BACKGROUND

Embolisation of atherosclerotic debris during abdominal aortic aneurysm (AAA) repair is responsible for significant peri-operative morbidity. Reports have suggested that preferential clamping of the distal vessel(s) before the proximal aorta may decrease the number of emboli passing distally and hence reduce complications.

METHODS

Forty patients undergoing AAA repair were randomised to have either first clamping of the proximal aorta or the iliac vessels. Emboli passing through the Superficial Femoral Arteries were detected with a Transcranial Doppler ultrasound system.

RESULTS

There was no difference between the two groups in the number of emboli detected (p=0.49) and no significant correlation between number of emboli and dissection time (r=0.0008). However, there was a significantly higher number of emboli in the patient sub-group that were current smokers (p=0.034).

CONCLUSIONS

There appears to be no difference in the numbers of emboli detected when the first vascular clamp is applied to the proximal aorta or iliacs.

Early and late outcome after carotid artery bypass grafting with saphenous vein

OBJECTIVES

This study was undertaken to determine outcome and durability of internal carotid artery bypass grafting with saphenous vein.

METHODS

Data for 50 patients undergoing serial clinical and ultrasound surveillance were collected prospectively and analyzed retrospectively.

RESULTS

Bypass grafting was performed in 50 patients between 1995 and 2002, the commonest reasons being excessive endarterectomy zone thinning or penetrating atheroma (n = 22), severe internal carotid artery coiling above the endarterectomy zone (n = 14), and patch infection (n = 5). Perioperative mortality was 2%, and death and stroke rate was 6%. Perioperative complications were associated with complex cardiovascular events, including hemorrhage after prosthetic patch infection, on-table thrombosis after endarterectomy, and synchronous carotid artery-cardiac reconstruction. One patient had a late ipsilateral stroke (10 months; normal scan). Cumulative stroke-free survival at 3 years (including operative events) was 91%. Cumulative freedom from recurrent stenosis greater than 70% or occlusion was 86% at 1 year and 83% at 3 years. Severe recurrent stenosis or occlusion developed in 7 patients, within 9 months of surgery in 6 patients and with 18 months in 1 patient. Angioplasty was performed without complication (no protection device, no stent) in 5 patients, 3 of whom required repeat angioplasty on at least one further occasion.

CONCLUSIONS

In common with venous conduits elsewhere, carotid artery bypass grafting with saphenous vein is associated with a high incidence of early graft stenosis. The long-term stroke risk, however, is low. Carotid artery bypass grafting is a safe and durable alternative when endarterectomy would prove hazardous or inadvisable, but regular surveillance is necessary.

The Excess of Strokes in Female Patients after CEA is due to their Increased Thromboembolic Potential—Analysis of 775 Cases

INTRODUCTION

Women suffer an excess of complications following arterial surgery, including an increased stroke risk following CEA. In order to investigate this further we studied men and women's thromboembolic potential following CEA.

METHOD

Analysis of prospectively collected data on 775 consecutive CEAs performed between October 1995 and October 2001, to identify the number of microembolic events detected following CEA.

RESULTS

Overall women had a 2.2 fold increase in the number of postoperative emboli detected (95% CI 1.2-3.3). Of those patients with significant numbers of postoperative emboli (>25), 68% were female against 22% for men (p=0.009). In order to prevent progression onto postoperative thrombotic stroke 9.7% of women were treated with intravenous Dextran-40 therapy, as opposed to only 2.7% of men (p=0.013). There were no significant differences between men and women's preoperative risk factors and/or factors relating to their operation.

CONCLUSION

It is possible that women's excess of postoperative complications following arterial surgery is related to their apparent increased thromboembolic potential following acute arterial injury.

Management of a "saddle" embolus at the popliteal bifurcation by a variation of the "push and park" approach. A case report

We present a modification of a previously reported endovascular technique where a large embolus was "pushed and parked" into a diseased artery. A saddle embolus at the bifurcation of the popliteal artery, which occurred as a complication after a percutaneous subintimal recanalization, was pushed and parked into the tibio-peroneal trunk. This was achieved using 2 balloon catheters, one to disengage the embolus from the anterior tibial artery, and the other to push the embolus into the tibio-peroneal trunk, thus establishing flow into the anterior tibial artery. Pushing and parking an embolus into a less useful vessel when all attempts at catheter embolectomy have failed is a simple and quick method which should be borne in mind by all vascular interventionalists.

Cytokine gene polymorphisms and the inflammatory response to abdominal aortic aneurysm repair

BACKGROUND

Cytokines are key mediators of the inflammatory response to surgery and polymorphic sites in their genes have been shown to affect cytokine production in vitro. The aim of this study was to determine whether cytokine gene polymorphisms affect cytokine production in vivo in patients undergoing abdominal aortic aneurysm (AAA) repair.

METHODS

One hundred patients admitted for elective AAA repair had plasma levels of interleukin (IL) 1beta, IL-6, IL-10 and tumour necrosis factor (TNF) alpha measured at induction of anaesthesia and 24 h after operation. Genotypes for each patient were determined using induced heteroduplex genotyping for the following loci: IL-1beta + 3953, IL-6 - 174, IL-10 - 1082/-592 and TNF-alpha - 308.

RESULTS

Patients with an IL-10 - 1082 A allele had a significantly higher IL-10 response to surgery than those without an A allele (P = 0.030) and there was also a significant difference in IL-10 response between patients with IL-10 - 1082 AA genotypes and those with GG genotypes (P = 0.030).

CONCLUSION

Elective AAA repair results in a measurable cytokine response. In this study the magnitude of this response was not affected by the individual patient's cytokine gene polymorphisms.

Overview of the principal results and secondary analyses from the European and North American randomised trials of endarterectomy for symptomatic carotid stenosis

OBJECTIVES

Review of the primary results and secondary analyses from the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET).

DESIGN

Review of 48 ECST and NASCET papers.

RESULTS

The simple assumption that all patients with a symptomatic stenosis >70% benefit from CEA is untenable. Approximately 70-75% will not have a stroke if treated medically. The ECST and NASCET have identified subgroups that should have expedited investigation and surgery (male sex, age >75 years, 90-99% stenosis, irregular plaque, hemispheric symptoms, recurrent events for >6 months, contralateral occlusion, multiple co-morbidity). Accordingly development of local protocols for patient selection/exclusion should involve surgeons and physicians and take account of the local operative risk. The ECST and NASCET have also shown that the ubiquitous "string sign" is not associated with a high risk of stroke, and emergency CEA is unnecessary.

CONCLUSIONS

Surgeons must quote their own results and be aware that a high operative risk reduces long-term benefit. Accordingly, in those centres with a higher operative death/stroke rate, some "lower risk" patients should probably be considered for best medical therapy alone. It is hoped that pooling of the ECST and NASCET databases will enable more definitive guidelines to be developed regarding who benefits most from CEA.

Seizures after carotid endarterectomy: hyperperfusion, dysautoregulation or hypertensive encephalopathy?

OBJECTIVES

Presentation, management and outcome following seizure after carotid endarterectomy (CEA). MATERIALS AND DESIGN: Prospective audit.

RESULTS

Eight patients (0.8%) suffered a seizure (three bilateral) <30 days following 949 CEAs. Seizure was not associated with age, gender or presentation. Seven were treated hypertensives but four had labile BP pre-operatively. Five had severe bilateral carotid disease and four had vertebral/subclavian stenoses. Six had a >50% drop in middle cerebral artery blood flow velocity (MCAV) with clamping. Only three had >100% increase in MCAV with flow restoration. Five required treatment for post-operative hypertension. Two suffered seizures <36 hrs of CEA, the remainder were at 3-8 days. All eight had significantly elevated blood pressure at onset of seizures. Four underwent immediate MCAV monitoring and each was elevated. Emergency CT scanning/autopsy showed normal scans (n = 3), white matter oedema (n = 3), oedema and diffuse haemorrhage (n = 1), intracranial haemorrhage (n = 1). Seven developed a post-ictal neurological deficit (stroke = 5, TIA = 2). Overall, two patients either died or suffered a disabling stroke.

CONCLUSIONS

Post-CEA seizure was associated with adverse outcome. Most were labile hypertensives with severe bilateral carotid/vertebral disease. MCAV changes suggested poor collateral recruitment, but no consistent pattern of early hyperperfusion emerged. It remains uncertain whether high MCAVs and severe hypertension after seizure onset are cause or effect. Clinicians treating these patients in acute medical units were generally unaware of the "post-CEA hyperperfusion syndrome" and tended to treat the hypertension less aggressively.

Does the risk of post-CABG stroke merit staged or synchronous reconstruction in patients with asymptomatic carotid disease?

The management of patients with combined carotid and coronary artery disease remains controversial, largely because of a lack of high quality natural history studies in patients with asymptomatic carotid disease undergoing isolated coronary artery bypass surgery. To date, practice ranges from never recommending additional intervention to a more aggressive policy of prophylactic carotid endarterectomy. For surgeons in the latter group, the only remaining debate is whether CEA should be staged or synchronous. This paper reviews the rationales and available evidence for managing the cardiac patient with asymptomatic carotid disease and is largely based on the findings of 2 recently published systematic re-views on the subject. These reviews suggest that a reappraisal of practice is necessary before the indiscriminate implementation of carotid angioplasty further complicates interpretation of the already poor quality data available.

A systematic review of outcomes following staged and synchronous carotid endarterectomy and coronary artery bypass

OBJECTIVES

to determine the overall cardiovascular risk for patients with combined cardiac and carotid artery disease undergoing synchronous coronary artery bypass (CABG) and carotid endarterectomy (CEA), staged CEA then CABG and reverse staged CABG then CEA.

DESIGN

systematic review of 97 published studies following 8972 staged or synchronous operations.

RESULTS

mortality was highest in patients undergoing synchronous CEA+CABG (4.6%, 95% CI 4.1-5.2). Reverse staged procedures (CABG-CEA) were associated with the highest risk of ipsilateral stroke (5.8%, 95% CI 0.0-14.3) and any stroke (6.3%, 95% CI 1.0-11.7). Peri-operative myocardial infarction (MI) was lowest following the reverse staged procedure (0.9%, 95% CI 0.5-1.4) and highest in patients undergoing staged CEA-CABG (6.5%, 95% CI 3.2-9.7). The risk of death+/-any stroke was highest in patients undergoing synchronous CEA+CABG (8.7%, 95% CI 7.7-9.8) and lowest following staged CEA-CABG (6.1%, 95% CI 2.9-9.3). The risk of death/stroke or MI was 11.5% (95% CI 10.1-12.9) following synchronous procedures versus 10.2% (95% CI 7.4-13.1) after staged CEA then CABG.

CONCLUSIONS

10-12% of patients undergoing staged or synchronous procedures suffered death or major cardiovascular morbidity (stroke, MI) within 30 days of surgery. Overall, there was no significant difference in outcomes for staged and synchronous procedures and no comparable data for patients with combined cardiac and carotid disease not undergoing staged or synchronous surgery.

The role of cytokine gene polymorphisms in the pathogenesis of abdominal aortic aneurysms: a case-control study

BACKGROUND

Cytokines are the primary mediators of inflammation and also influence matrix metalloproteinase expression, both of which are important in development of abdominal aortic aneurysm (AAA). A significant, but as yet unknown, familial factor contributes to the pathogenesis of AAA. Many cytokine genes contain polymorphic sites, some of which affect cytokine production in vitro. Cytokine gene polymorphisms may therefore influence the pathogenesis of AAA. The purpose of this study was to determine whether there is any association between cytokine gene polymorphisms and AAA.

METHODS AND RESULTS

This case-control study comprised 100 patients with AAA and 100 age-matched and sex-matched control subjects. For each case and control subject in the study, genotypes at the following cytokine gene polymorphic loci were determined: interleukin (IL)-1beta +3953, IL-6 -174, IL-10 -1082, IL-10 -592, and tumor necrosis factors-alpha -308. Allele and genotype frequencies were compared between AAA and control groups, and odds ratios (OR) were calculated for the presence of AAA with each allele at each locus examined as risk factors. The IL-10 -1082 A allele was significantly more common in the AAA group than the control group (P =.03). The OR for the IL-10 -1082 A allele as a risk factor for AAA was 1.8 (95% confidence interval, 0.9-3.6).

DISCUSSION

These associations suggest a significant role for IL-10 in the pathogenesis of AAA. This association of AAA with the IL-10 -1082 A allele is also biologically plausible; the IL-10 -1082 A allele is associated with low IL-10 secretion, and it may be that AAA develops in patients who are unable to mount the same anti-inflammatory response as those who do not have AAA.

The systemic inflammatory response syndrome, organ failure, and mortality after abdominal aortic aneurysm repair

BACKGROUND

Organ failure is a major cause of morbidity and mortality after abdominal aortic aneurysm (AAA) repair. The aim of this study was to determine the relationships between the systemic inflammatory response syndrome (SIRS), organ failure, and mortality after AAA repair and to determine whether the clinical monitoring of SIRS was a useful adjunct to clinical method.

METHODS

One hundred consecutive patients undergoing open AAA repair were prospectively studied. Patients were divided into three groups: those undergoing elective AAA repair, those with symptomatic but nonruptured AAA, and those with ruptured AAA. The presence of SIRS and organ failure was recorded on a daily basis for each patient until discharge or death.

RESULTS

Most patients had SIRS develop during the postoperative period: 89% of the elective group, 92% of the emergency nonruptured (urgent) group, and 100% of the ruptured group. Multiorgan failure occurred in 3.8% of the elective group, 38% of the urgent group, and 64% of the ruptured AAA group. After ruptured AAA repair, the concurrent absence of both SIRS and any organ failure for 48 hours had a sensitivity of 93% and a specificity of 91% as a predictive indicator of subsequent survival to hospital discharge. Patients in whom multiorgan failure developed after ruptured AAA repair had a significantly higher mortality rate (69%) than those who did not (0%; P =.001; 95% CI for the difference, 30.2% to 85.8%).

CONCLUSION

The differences in the incidence rate of multiorgan failure between the patient groups compared with the high incidence rate of SIRS in all patient groups supports the two-hit hypothesis of multiorgan failure. The presence of multiorgan failure after ruptured AAA repair is associated with poor outcome. The absence of SIRS and organ failure in these patients is a good predictive indicator of survival.

The acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in vascular patients

OBJECTIVE

the aim of this study was to establish at which point during a hospital admission MRSA acquisition occurs in vascular patients.

METHOD

a consecutive series of 100 patients undergoing arterial surgery were screened for MRSA carriage on admission to hospital, on exit from theatre, on discharge from ITU, weekly whilst an inpatient and on hospital discharge. Screening was with moistened swabs from nose, throat, perineum and open wounds that were pooled for microbiological culture.

RESULTS

four patients (4%) screened positive for MRSA on admission to hospital. Of the remaining 96, 16 (17%) acquired MRSA during their hospital stay as follows: exit from theatre, one; exit from ITU, six; on the ward postoperatively, nine. Comparing MRSA acquisition (n=16) with non acquisition (n = 80) the following characteristics were noted, length of stay 16 (4-66) vs 7 (2-50) days (Mann-Whitney p < 0.001); admission to ITU 13/16 vs 46/80 (Fishers chi-squared p = 0.10); length of ITU stay 3 (1-20) vs 3 (1-14) days (Mann-Whitney p = 0.41). Frequent hospital attendance, age, emergency admission, diabetes or renal failure were not commoner in those with MRSA acquisition.

CONCLUSIONS

these data indicate that 4% of patients undergoing arterial surgery are pre-existing carriers of MRSA. Length of hospital stay is the single most important determinant of MRSA acquisition.