Influence of cardiovascular risk factors on levels of matrix metalloproteinases 2 and 9 in human abdominal aortic aneurysms.

OBJECTIVE: To evaluate the influence of cardiovascular risk factors on levels of matrix metalloproteinases (MMP) 2 and 9 in human abdominal aortic aneurysms (AAA). METHODS: Aortic samples were collected from patients who underwent AAA repair (n = 89). Patients were stratified according to the maximum transverse aorta diameter: small diameter (<55 mm), moderate diameter (55-69.9 mm) and large diameter (≥70 mm). Aortic walls were studied using real-time PCR and immunohistochemistry. MMP-2, MMP-9, α-actin, CD45, and CD68 transcript levels were determined relative to ß-actin. Quantitative data were expressed as median (IQ-range). RESULTS: No differences were found in MMP-2 expression between the patient groups, which was mainly associated with vascular smooth muscle cells (VSMC); however, MMP-9 displayed the maximum level in the moderate-diameter group, associated with infiltrating macrophages. Current smoking (CS) and renal insufficiency (RI) significantly increased local levels of MMP-2 (CS 349.5 [219.5-414.1] vs. no-CS 184.4 [100.0-320.5]; p < .008; RI 286.8 [189.6-410.8] vs. no-RI 177.3 [99.3-326.9]; p = .047). Nevertheless, after stepwise linear regression analysis only CS remained as an independent variable predicting local levels of MMP-2 (p = .002). No risk factors influenced local levels of MMP-9. CONCLUSIONS: The results show that local levels of MMP-2, an important factor for AAA development, were increased in current smoking AAA patients. MMP-2 was mainly associated with VSMC. It is suggested that MMP-2 could contribute significantly to the increased AAA growth rate observed in current smoking patients. These findings support inclusion of smokers in screening for aneurysmal disease, and emphasize the need for more aggressive monitoring of aneurysmal disease outside the surgical range in patients who smoke at the time of diagnosis and in those who continue to smoke during follow-up.

A computational fluid dynamics study on hemodynamics for different locations of the distal anastomosis of a bypass nearby a collateral vessel in the femoropopliteal area.

Revascularization of the femoropopliteal sector is often performed by the placement of a bypass. In this paper, we have studied the effects of hemodynamics on patency of the bypass for different positions of the distal anastomosis close to a collateral artery. Computational fluid dynamics (CFD) are used for this study. The cardiac cycle-averaged wall shear stress (WSS) and oscillation index (OSI) have been analyzed. Low WSS and high OSI may increase the risk of intimal hyperplasia (IH), which may reduce bypass patency. From the CFD simulations, spots of low WSS and high OSI are found within and near the entrance of the collateral artery, near the suture line, at the floor, toe, and heel. We regarded flow ratios of 20:80 and of 35:65. It is found that for the high flow ratio anastomosis located proximal to the collateral artery is clearly more advantageous. However for the low flow ratio anastomosis located distal to the collateral artery seems to be slightly more advantageous, the results are less conclusive. One of the studied flow geometries has been validated by in vitro experiments using a time resolved particle image velocimetry technique. Velocity fields from these experiments are in good agreement with the CFD results.

Healthcare quality indicators of peripheral artery disease based on systematic reviews.

OBJECTIVES: Peripheral artery disease (PAD) is a major health problem whose clinical management includes multiple options regarding risk factor control, diagnosis, and medical and surgical treatment. The aim was to generate indicators based on systematic reviews to evaluate the quality of healthcare provided in PAD. METHODS: Electronic searches were run for systematic reviews in The Cochrane Library (Issue 6, 2011), MEDLINE, EMBASE, and other databases (up to June 2011). Conclusive systematic reviews of high methodological quality were selected to formulate clinical recommendations. Indicators were derived from clinical recommendations with moderate to very high strength of evidence as assessed by the GRADE system. RESULTS: From 1,804 reviews initially identified, 29 conclusive and high-quality systematic reviews were selected and nine clinical recommendations were formulated with a moderate to very high strength of recommendation. Six indicators were finally generated: four on pharmacological interventions, antiplatelet agents, naftidrofuryl, cilostazol, and statins; and two lifestyle interventions, exercise and tobacco cessation. No indicators were derived for diagnostic tests or surgical techniques. Most indicators targeted patients with intermittent claudication. CONCLUSIONS: These quality indicators will help clinicians to assess the appropriateness of healthcare provided in PAD. The development of evidence-based indicators in PAD is limited by the lack of methodological quality of the research in this disease, the inconclusiveness of the evidence on diagnostic and surgical techniques, and the dynamic nature of the vascular diseases field.

[Mobile carotid plaque]. / Placa móvil carotídea.

INTRODUCTION: In the literature only seven cases have been published describing a mobile carotid plaque, and lack of precise description makes it difficult to differentiate these lesions from mobile thrombotic lesions. The natural history of these lesions is not known and their treatment is controversial, although there is a tendency to choose the type of treatment to be given according to the embologenic potential of the lesion. CLINICAL CASES: We report two cases with mobile carotid plaques. In both cases diagnosis was made on ultrasound Doppler. The first patient had neurological symptoms and a mobile plaque associated with stenosis of over 70%. Surgical treatment was indicated. The second patient had no neurological symptoms. On ultrasound Doppler studies there was a fragment of mobile plaque in the common carotid artery, in the region of the carotid sinus with stenosis of 30 50%. Distal to this zone, in the bulb of the internal carotid artery there was stenosis of >70%. In this case medical treatment was given in view of deterioration in the patient s general state. Both patients improved. CONCLUSIONS: Including our second case, three patients with mobile carotid plaques (neurologically asymptomatic) have now been reported to have made good progress with medical treatment. Until there is more data regarding the natural history of these lesions, they should not be considered to be in themselves sufficient reason for carrying out carotid endarterectomy. The possibility of indicating surgical treatment depends on the degree of carotid stenosis.

[Indications for carotid endarterectomy without arteriography. A validation study using eco-Doppler]. / Indicaciones de endarterectomía carotídea sin arteriografía. Estudio de validación mediante eco-Doppler.

INTRODUCTION: The possibility of diagnosing carotid stenosis and carrying out surgery without arteriography has increased with the use of different diagnostic methods. The eco-Doppler has been shown to be a useful method, although it requires previous individualised validation. OBJECTIVE: We aim to validate our Vascular Diagnostic Laboratory in the diagnosis of stenosis of the carotid bifurcation using eco-Doppler as compared with angiography, and the therapeutic indication thus obtained. PATIENTS AND METHODS: We made a prospective study for one year of 62 consecutive patients diagnosed on eco-Doppler as having carotid stenosis of over 70% and subsequent carotid arteriography. The treatment indicated is given, without waiting for the result of the angiography, on clinical evaluation, computerized tomography or cranial magnetic resonance and eco-Doppler, and subsequently on angiography. The degree of correlation of both methods, both for the therapeutic indication and for the degree of stenosis was determined. RESULTS: In five cases there was discrepancy and the therapeutic indication was different. Three of these were related to the diagnosis of carotid occlusion and in the other two cases there were bilateral lesions of over 50% on eco-Doppler, which were classified as minor on angiographic study. In the group with stenosis of over 70% with < 50% contralateral stenosis, eco-Doppler showed sensitivity and specificity of 100%, with a kappa correlation index = 1. CONCLUSION: It is possible to indicate carotid endarterectomy in patients with unilateral stenosis greater than 70% and contralateral stenosis < 50%, based on the eco-Doppler studies done in our Vascular Diagnostic Laboratory.