Long-term histopathologic evaluation of inferior vena cava after modified Greenfield filter implantation - Experimental study in sheep

Aim. The authors assess a modified Greenfield filter (GF) for the long-term patency, filter tilting and histopathologic alterations of the inferior vena cava (IVC).Methods. Adult sheep (n=7) underwent modified GF placement in the IVC. Cavograms were obtained every 3 months and pulmonary angiography at 12 months. Histopathologic and scanning electron microscopy (SEM) analyses were performed on the IVC explanted at 12 months.Results. Cavograms showed that all IVC were patent at the end of the study. Filter tilting occurred in 2/7 animals and extrusion of struts was not observed. Macroscopic examination at explantation showed minimal venous wall thickening. Microscopic examination showed minimal IVC fibrosis and intimal hyperplasia. SEM showed endothelium on the IVC surface at the filter implantation site and a presumed endothelial layer covering partially or totally the struts. The interface filter-IVC was covered by deposits of leucocytes and platelets. No signs of pulmonary embolism were found in all pulmonary angiograms of both groups.Conclusion. The modified filter presented good biocompatibility, stability and absence of thrombogenicity at 12 months. It presented low tendency to tilting and extrusion of struts. The long-term histopathologic alterations in vena caval wall were minimal and the appearance of the studied filters in the IVC was similar to stents placed in the arterial system.

An open-label, comparative study of the efficacy and safety of once-daily dose of enoxaparin versus unfractionated heparin in the treatment of proximal lower limb deep-vein thrombosis

Background: Treatment of deep-vein thrombosis (DVT) with a once-daily regimen of enoxaparin, rather than a continuous infusion of unfractionated heparin (UFH) is more convenient and allows for home care in some patients. This study was designed to compare the efficacy and safety of these two regimens for the treatment of patients with proximal lower limb DVT. Methods: 201 patients with proximal lower limb DVT from 13 centers in Brazil were randomized in an open manner to receive either enoxaparin [1.5 mg/kg subcutaneous (s.c.) OD] or intravenous (i.v.) UFH (adjusted to aPTT 1.5-2.5 times control) for 5-10 days. All patients also received warfarin (INR 2-3) for at least 3 months. The primary efficacy endpoint Was recurrent DVT (confirmed by venography or ultrasonography), and safety endpoints included bleeding and serious adverse events. The rate of pulmonary embolism (PE) was also collected. Hospitalization was at the physician's discretion. Results: Baseline patient characteristics were comparable between groups. The duration of hospital stay was significantly shorter with enoxaparin than with UFH (3 versus 7 days). In addition, 36% of patients receiving enoxaparin did not need to be hospitalized, whereas all of the patients receiving UFH were! hospitalized. The treatment duration was slightly longer with enoxaparin (8 versus 7 days). There was a nonsignificant trend toward a reduction in the rate of recurrent DVT with enoxaparin versus UFH, and similar safety. Conclusions: A once-daily regimen of enoxaparin 1.5 mg/kg subcutaneous is at least as effective and safe as conventional treatment with a continuous intravenous infusion of UFH. However, the once daily enoxaparin regimen is easier to administer (subcutaneous versus intravenous), does not require aPTT monitoring, and leads to both a reduced number of hospital admissions and an average 4-day-shorter hospital stay. (C) 2004 Elsevier Ltd. All rights reserved.

Arteriovenous fistula between the right internal mammary artery and the subclavian vein: percutaneous closure with detachable ballooncatheter embolization

A case of iatrogenic fistula from the right internal mammary artery to the subclavian vein following subclavian vein catheterization is reported. The patient had undergone percutaneous Intracath catheterization of the subclavian vein to treat hypovolemic shock during the surgical treatment of ectopic pregnancy. She had remained symptom-free for 7 years and then started to complain of effort dyspnea. The patient was found to have a thrill and a bruit at the subclavian region, and arteriography demonstrated a fistula between the right internal mammary artery and the subclavian vein. The fistula was successfully closed by embolization with a percutaneous detachable balloon catheter. © 1993.

Lesões intestinais decorrentes de isquemia e reperfusão: Fisiopatologia e modelos experimentais

The intestinal ischemia is unusual in vascular surgery emergency. Its main causes are embolisms and arterial thrombosis. In addition to severe ischemia, reperfusion of the ischemic tissues can lead to several complications that may worsen the ischemic lesion and produce a life threatening situation caused by systemic alterations. Intestinal tissue injuries due to ischemia and reperfusion have been demonstrated in clinical and experimental studies, in which pathophysiology and adequate treatment were also studied. The great variety of experimental models used and results achieved reflect the need for an intestinal ischemia and reperfusion experimental model that is simple, reproducible and consistent, in order to search for treatments that can reduce the damage caused by this situation. In this review, the main pathophysiologic aspects and the most used experimental models will be reviewed. Copyright © 2005 by Sociedade Brasileira de Angiologia e Cirurgia Vascular.

Abordagem diagnóstica dos pacientes com suspeita de trombose venosa profunda dos membros inferiores

Deep venous thrombosis is a relatively common disease, which can present pulmonary embolism as a complication in its acute phase, and later the post-thrombotic syndrome. Thus, diagnosis should be made as soon as possible, in order to prevent or minimize such complications. Several studies have shown that the symptoms and the clinical signs are inaccurate for the deep venous thrombosis diagnosis and that complementary exams are necessary. As an attempt to simplify the patients' assessment, Well et al., in 1997, developed a clinical prediction index that combines symptoms, signs and risk factors for deep venous thrombosis and managed to make a simpler approach through an association of this index with the complementary exams. Phlebography has been considered the gold standard of complementary exams. However, since it is an invasive exam and thus subject to complications, other diagnostic methods were introduced aiming at making the diagnostic approach simpler and less invasive. Doppler ultrasound, duplex scan, impedance plethysmography, computed tomography, and blood tests such as the D-dimer are some of the available methods for assessing the patient with suspicion of deep venous thrombosis. Among them, duplex scan has shown excellent accuracy and it is currently widely accepted as the first choice test for approaching the patient with deep venous thrombosis. Several authors have suggested an association of diagnostic methods to simplify and make the assessment of such patients more cost-effective, leading to the introduction of a wide range of diagnostic strategies. The different diagnostic methods used for assessing deep venous thrombosis are discussed, as well as a review of the literature on the accuracy, advantages and disadvantages of these methods. Copyright © 2005 by Sociedade Brasileira de Angiologia e Cirurgia Vascular.

Ftalato de di-(2-etilexila) (DEHP) em bolsas de PVC para soluções parenterais de grandes volumes

Large volume parenteral solutions (LVPS) are widely used as vehicles for intravenous administration of drugs and polyvinyl chloride (PVC) flexible bags are, nowadays, the plastic containers most commonly used to pack and drip-feed LVPS. An advantage of using bags is that they collapse flat and thus reduce the risk of airborne contamination and embolism caused by air in the bloodstream. They are mainly used in hospitals. This review deals with some important aspects of the PVC packaging containing the plasticizer DEHP, generally used to pack LVPS. The interaction between drug and package is discussed, with an emphasis on the migration of DEHP from the PVC bag to LVPS containing the immunosuppressant cyclosporin, and toxicological aspects are considered.

Risk-assessment algorithm and recommendations for venous thromboembolism prophylaxis in medical patients

The risk for venous thromboembolism (VTE) in medical patients is high, but risk assessment is rarely performed because there is not yet a good method to identify candidates for prophylaxis. Purpose: To perform a systematic review about VTE risk factors (RFs) in hospitalized medical patients and generate recommendations (RECs) for prophylaxis that can be implemented into practice. Data sources: A multidisciplinary group of experts from 12 Brazilian Medical Societies searched MEDLINE, Cochrane, and LILACS. Study selection: Two experts independently classified the evidence for each RF by its scientific quality in a standardized manner. A risk-assessment algorithm was created based on the results of the review. Data synthesis: Several VTE RFs have enough evidence to support RECs for prophylaxis in hospitalized medical patients (eg, increasing age, heart failure, and stroke). Other factors are considered adjuncts of risk (eg, varices, obesity, and infections). According to the algorithm, hospitalized medical patients ≥40 years-old with decreased mobility, and ≥1 RFs should receive chemoprophylaxis with heparin, provided they don't have contraindications. High prophylactic doses of unfractionated heparin or low-molecular-weight-heparin must be administered and maintained for 6-14 days. Conclusions: A multidisciplinary group generated evidence-based RECs and an easy-to-use algorithm to facilitate VTE prophylaxis in medical patients. © 2007 Rocha et al, publisher and licensee Dove Medical Press Ltd.

Treatment of pulmonary thromboembolism in patients with systemic blood pressure stability and right ventricular dysfunction

Pulmonary thromboembolism (PTE) ranges from incidental, clinically unimportant thromboembolism to massive embolism with sudden death. Its treatment is well established in two groups of patients: heparin for those with normal systemic blood pressure without right ventricular dysfunction (RVD) and thrombolysis for those with RVD and circulatory shock. In an intermediate group of patients with systemic blood pressure stability combined with RVD, which is usually associated with worse outcome, the treatment is controversial. There are authors who strongly suggest thrombolysis while others contraindicate this procedure and recommend anticoagulation with heparin. This is a narrative review that includes clinical trials comparing thrombolysis and heparin for the treatment of PTE patients with systemic blood pressure stability and RVD published since 1973. The results show that there are only four trials on this subject with less than 500 patients. Many PTE patients with systemic blood pressure stability and RVD might benefit from thrombolysis but, on the other hand, the risk for hemorrhagic events may be increased. Large randomized clinical trials are required to clarify this. © 2008 Bentham Science Publishers Ltd.

Highlights from the I international symposium of thrombosis and anticoagulation in internal medicine, October 23-25, 2008, Sao Paulo, Brazil

The importance of thrombosis and anticoagulation in clinical practice is rooted firmly in several fundamental constructs that can be applied both broadly and globally. Awareness and the appropriate use of anticoagulant therapy remain the keys to prevention and treatment. However, to assure maximal efficacy and safety, the clinician must, according to the available evidence, choose the right drug, at the right dose, for the right patient, under the right indication, and for the right duration of time. The first International Symposium of Thrombosis and Anticoagulation in Internal Medicine was a scientific program developed by clinicians for clinicians. The primary objective of the meeting was to educate, motivate and inspire internists, cardiologists and hematologists by convening national and international visionaries, thought-leaders and dedicated clinician-scientists in Sao Paulo, Brazil. This article is a focused summary of the symposium proceedings. © Springer Science+Business Media, LLC 2009.

Significância clínica de tromboembolismo venoso recorrente

Recurrent venous thromboembolism is a significant problem leading to increased morbidity and mortality. It has a high impact on patients' quality of life and imposes a great financial burden on society. Cumulative recurrence has been reported as 40% at 10 years, while the chance of developing postthrombotic signs and symptoms in the lower extremities almost quadruples when ipsilateral. There is also a higher chance of developing pulmonary hypertension. Important factors for recurrence are unprovoked episodes of deep vein thrombosis, malignancy and older age. The evidence for other factors is controversial. Accurate diagnosis and treatment tailored to the patients' history, thrombotic events and risk factors are necessary to optimize management and prevent recurrence.

Deep venous thrombosis prophylaxis in oral and maxillofacial surgery: a Brazilian survey

Background : Deep venous thrombosis (DVP) is a frequent disease. Prophylaxis is the best means to reduce its incidence, for lowering morbidity and mortality rates and treatment costs caused by its complications. Objective : To evaluate the knowledge and use of any kind of DVT prophylaxis by Brazilian Oral and Maxillofacial surgeons. Materials and Methods : A questionnaire was sent to all Oral and Maxillofacial surgeons associated to the Brazilian College of Oral and Maxillofacial Surgeons that have a valid e-mail address. The data retrieved was evaluated and tabulated. Results : Of the 1100 questionnaires sent, only 4% were retrieved. The 42 retrieved were included in the study. Twenty six of the surgeons do not use any kind of deep venous thrombosis (DVT) prophylaxis, 11 use mechanical means as elastic compressive stockings or pneumatic compressive devices for prophylaxis, and 5 uses low-molecular weight heparins (LMWH) as the choice for prophylaxis. Conclusion : The data collected, despite the low rate of participation (4%) by the surgeons, shows that this subject still does not receive proper attention. Whereas other medical specialties make routine use of prophylactic means maybe the maxillofacial surgeons lack concern on that matter.

Systematic review of randomized controlled trials of new anticoagulants for venous thromboembolism prophylaxis in major orthopedic surgeries, compared with enoxaparin

Background: In the past 10 years, new anticoagulants (NACs) have been studied for venous thromboembolism (VTE) prophylaxis. Objective: To evaluate the risk/benefit profile of NACs versus enoxaparin for VTE prophylaxis in major orthopedic surgery. Methods: A systematic review of double-blind randomized phase III studies was performed. The search strategy was run from 2000 to 2011 in the main medical electronic databases in any language. Independent extraction of articles was performed by 2 authors using predefined data fields, including study quality indicators. Results: Fifteen published clinical trials evaluating fondaparinux, rivaroxaban, dabigatran, and apixaban were included. Primary efficacy (any deep vein thrombosis [DVT], nonfatal pulmonary embolism, or all-cause mortality) favored fondaparinux (relative risk [RR] 0.50; 95% CI, 0.39, 0.63) and rivaroxaban (RR, 0.50; 95% CI, 0.34, 0.73) over enoxaparin, although significant heterogeneity was observed in both series. The primary efficacy of dabigatran at 220 mg, apixaban, and bemiparin were similar, with RRs of 1.02 (95% CI, 0.86, 1.20), 0.63 (95% CI, 0.39, 1.01), and 0.87 (95% CI, 0.65, 1.17), respectively. The primary efficacy of dabigatran at 150 mg (RR, 1.20; 95% CI, 1.03, 1.41), was inferior to enoxaparin. The incidence of proximal DVT favored apixaban (RR, 0.45; 95% CI, 0.27, 0.75) only. Rivaroxaban (RR, 0.45; 95% CI, 0.27, 0,77) and apixaban (RR, 0.38; 95% CI, 0.16, 0.90) produced significantly lower frequencies of symptomatic DVT. The incidence of major VTE favored rivaroxaban (RR, 0.44; 95% CI, 0.25, 0.81), only. Bleeding risk was similar for all NACs, except fondaparinux (RR, 1.27; 95% CI, 1.04, 1.55), which exhibited a significantly higher any-bleeding risk compared with enoxaparin, and apixaban (RR, 0.88; 95% CI, 0.79, 0.99), which was associated with a reduced risk of any bleeding. Alanine amino transferase was significantly lower with 220 mg of dabigatran, (RR, 0.67; 95% CI, 0.79, 0.99) than with enoxaparin. Conclusions: NACs can be considered alternatives to conventional thromboprophylaxis regimens in patients undergoing elective major orthopedic surgery, depending on clinical characteristics and cost-effectiveness. The knowledge of some differences concerning efficacy or safety profile, pointed out in this systematic review, along with the respective limitations, may be useful in clinical practice. © 2013 Elsevier Inc. All rights reserved.