Background Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence.Methods ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362.

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Acid-base homeostasis maintains systemic arterial pH within a narrow range. Whereas the normal range of pH for clinical laboratories is 7.35-7.45, in vivo pH is maintained within a much narrower range. In clinical and experimental settings, blood pH can vary in response to respiratory or renal impairment. This altered pH promotes changes in vascular smooth muscle tone with impact on circulation and blood pressure control. Changes in pH can be divided into those occurring in the extracellular space (pH o ) and those occurring within the intracellular space (pH i ), although, extracellular and intracellular compartments influence each other. Consistent with the multiple events involved in the changes in tone produced by altered pH o , including type of vascular bed, several factors and mechanisms, in addition to hydrogen ion concentration, have been suggested to be involved. The scientific literature has many reports concerning acid-base balance and endothelium function, but these concepts are not clear about acid-base disorders and their relations with the three known mechanisms of endothelium-dependent vascular reactivity: nitric oxide (NO/cGMP-dependent), prostacyclin (PGI 2 /cAMP-dependent) and hyperpolarization. During the last decades, many studies have been published and have given rise to confronting data on acid-base disorder and endothelial function. Therefore, the main proposal of this review is to provide a critical analysis of the state of art and incentivate researchers to develop more studies about these issues.

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Thromboangiitis obliterans (TAO) is a segmental inflammatory occlusive disorder that affects small- and medium-sized arteries, and arm and leg veins of young smokers. Several different diagnostic criteria have been offered for the diagnosis of TAO. Clinically, it manifests as migratory thrombophlebitis or signs of arterial insufficiency in the extremities. It is characterized by highly cellular and inflammatory occlusive thrombi, primarily of the distal extremities. Thromboses are often occlusive and sometimes display moderate, nonspecific inflammatory infiltrate, consisting mostly of polymorphonuclear leukocytes, mononuclear cells and rare multinuclear giant cells. The immune system appears to play a critical role in the etiology of TAO. However, knowledge about immunological aspects involved in the progression of vascular tissue inflammation, and consequently, the evolution of this disease, is still limited. There are several studies that suggest the involvement of genetic factors and results have shown increasing levels of antiendothelial cell antibodies in patients with active disease. Vasodilation is impaired in patients with TAO. TAO disorder may actually be an autoimmune disorder, probably initiated by an unknown antigen in the vascular endothelium, possibly a component of nicotine. There are various therapies available for treatment of TAO, but the major and indispensable measure is smoking cessation. Except for discontinuation of tobacco use, no forms of therapy are definitive. Sympathectomy, cilostazol and prostaglandin analogues (prostacyclin or prostaglandin E) have been used in specific conditions. Recently, therapeutic angiogenesis with autologous transplantation of bone marrow mononuclear cells has been studied in patients with critical limb ischemia.

PURPOSE:To investigate the protective effects of ischemic pre and postconditioning, as well as the association of both methods, in skeletal muscle injury produced by ischemia and reperfusion in rats. METHODS:An experimental study was designed using 40 Wistar rats divided in four groups (n=10): Control -rats submitted to ischemia for 240 minutes (min) and reperfusion for 60 min; Ischemic preconditioning (Pre) -animals submitted to three cycles of clamping and releasing the aorta for five min before being submitted to the ischemia/reperfusion procedure; Ischemic postconditioning (Post) -rats submitted to three cycles of clamping and releasing the aorta for one min after the 240-minute ischemic phase; Ischemic pre and postconditioning (Pre-post) -animals submitted to the same procedures of Pre and Post groups. Skeletal muscle injury was evaluated by measuring serum levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine phosphokinase (CPK); and muscular levels of malondialdehyde (MDA) and glycogen. RESULTS:AST levels were significantly higher in Pre and Pre-post groups (P<.01). There were no differences in LDH and CPK levels. Muscular MDA levels were similar. Glycogen levels were significantly higher in Pre and Pre-post groups (P<.01). CONCLUSIONS:Both preconditioning and its association with postconditioning had a protective effect by avoiding glycogen depletion in skeletal muscle in rats submitted to ischemia and reperfusion. Association of pre and postconditioning did not show advantage compared to preconditioning alone. Postconditioning alone did not show protective effect.

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