Saphenofemoral arteriovenous fistula as hemodialysis access

Background: An upper limb arteriovenous (AV) fistula is the access of choice for haemodialysis (HD). There have been few reports of saphenofemoral AV fistulas (SFAVF) over the last 10-20 years because of previous suggestions of poor patencies and needling difficulties. Here, we describe our clinical experience with SFAVF.Methods: SFAVFs were evaluated using the following variables: immediate results, early and late complications, intraoperative and postoperative complications (up to day 30), efficiency of the fistula after the onset of needling and complications associated to its use.Results: Fifty-six SFAVF fistulas were created in 48 patients. Eight patients had two fistulas: 8 patent (16%), 10 transplanted (20%), 12 deaths (24%), 1 low flow (2%) and 20 thrombosis (39%) (first two months of preparation). One patient had severe hypotension during surgery, which caused thrombosis of the fistula, which was successfully thrombectomised, four thrombosed fistulae were successfully thrombectomised and revised on the first postoperative day. After 59 months of follow-up, primary patency was 44%.Conclusion: SFAVF is an adequate alternative for patients without the possibility for other access in the upper limbs, allowing efficient dialysis with good long-term patency with a low complication rate.

Heparin, heparin plus ASA and dipyridamole, and arteriovenous fistula as adjuvant methods to prevent rethrombosis after venous thrombectomy. Experimental study in rabbits

Venous rethrombosis following thrombectomy is a common event. The aim of the present study was to verify the action of heparin, heparin plus acetyl salicylic acid (ASA) and dipyridamole, and of an arteriovenous fistula (AVF) in the prevention of this complication. Thrombosis was induced in 48 male rabbits by the injection of thrombin in a segment of the left jugular vein, in which the blood flow was arrested for 10 minutes. After 48 hours, the animals were randomly allocated into one of 4 groups of treatment: (1) control, (2) subcutaneous heparin (600 S.I. Units/kg - 8/8 hours), (3) heparin, in the same dose, plus ASA (10 mg/kg/once a day), and dipyridamole (0.5 mg/kg thrice a day), (4) an AVF was surgically constructed between the left carotid after and the left maxillar vein. After 30 minutes, thrombectomy was performed. The venous blood flow, the hematocrit, activated partial thromboplastin time and thrombin time tests were performed before, right after the thrombectomy and 48 hours after thrombectomy. Venography was performed after thrombectomy and at the end of the experiment. The animals were killed 48 hours after thrombectomy and the veins were examined macroscopically. Venous rethrombosis was significantly prevented only in the AVF group (9/12), when compared to control group (0/12), heparin group (1/12) and heparin plus antiaggregating agents group (2/12). These results validate further clinical and experimental investigations with the use of AVF to prevent rethrombosis after venous thrombectomy, when a reduction of venous flow is present.

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.

Tratamento da síndrome do roubo devido a fístula arteriovenosa para hemodiálise em membro inferior por meio da técnica de ligadura arterial e revascularização distal (técnica de DRIL)

RESUMO A fístula arteriovenosa com bom fluxo sangüíneo é de fundamental importância para os pacientes portadores de insuficiência renal crônica em tratamento hemodialítico. Uma das complicações da fístula arteriovenosa é a síndrome do roubo, mas esta é de ocorrência incomum, e o seu tratamento está diretamente indicado quando há sintomas manifestos. Vários métodos foram propostos para sua correção nos membros superiores, sendo considerada a revascularização distal com ligadura arterial o procedimento de escolha. Neste relato de caso inédito, descreve-se o tratamento da síndrome do roubo de uma fístula arteriovenosa realizada em membro inferior, tratada com sucesso por meio da mesma técnica indicada para os membros superiores.

Myocardial dysfunction with increased ventricular compliance in volume overload hypertrophy

The aim this study was to evaluate systolic and diastolic function in volume overload induced myocardial hypertrophy in rats.Volume overload myocardial hypertrophy was induced in thirteen male Wistar rats by creating infrarenal arteriovenous fistula (AVF). The results were compared with a SHAM operated group (n = 11). Eight weeks after surgery, tail-cuff blood pressure was recorded, then rats were sacrificed for isolated heart studies using Langendorffs preparation.AVF rats presented increased left and right ventricular weights, compared to controls. The increased normalized ventricular volume (V0/LVW, 0.141 +/- 0.035 mL/g vs. 0.267 +/- 0.071 mL/g, P < 0.001) in the AVF group indicated chamber dilation. Myocardial hydroxyproline concentration remained unchanged. There was a significant decrease in +dP/dt (3318 +/- 352 mm Hg s(-1) vs. 2769 +/- 399 mm Hg s(-1); P=0,002), end-systolic pressure-volume relation (246 +/- 56 mm Hg mL(-1) vs. 114 +/- 63 mm Hg mL(-1);, P < 0,001), and -dP/dt (1746 +/- 240 min Hg s(-1) vs. 1361 +/- 217 mm Hg s(-1), P < 0.001) in the AVF group, which presented increased ventricular compliance (Delta V-25: SHAM=0.172 +/- 0.05 mL vs. AVF=0.321 +/- 0.072 mL, P < 0.001) with preserved myocardial passive stiffness (Strain(25): SHAM=13.5 +/- 3.0% vs. AVF=12.3 +/- 1.9%, P > 0.05).We conclude that volume-overload induced hypertrophy causes myocardial systolic and diastolic dysfunction with increased ventricular compliance. These haemodynamic features help to explain the long-term compensatory phase of chronic volume overload before transition to overt congestive heart failure. (c) 2006 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.

Malformação arteriovenosa uterina após doença trofoblástica gestacional

OBJETIVO: investigar a presença e resultados de malformações vasculares uterinas (MAVU) após doença trofoblástica gestacional (DTG). MÉTODOS: estudo retrospectivo com inclusão de casos diagnosticados entre 1987 e 2004; 2764 pacientes após DTG foram acompanhadas anualmente com ultra-sonografia transvaginal e Doppler colorido no Centro de Neoplasia Trofoblástica Gestacional da Santa Casa da Misericórdia (Rio de Janeiro, RJ, Brasil). Sete pacientes tiveram diagnóstico final de MAVU baseado em análise ultra-sonográfica - índice de pulsatilidade (IP), índice de resistência (IR) e velocidade sistólica máxima (VSM) - e achados de imagens de ressonância nuclear magnética (RNM). Dosagens negativas de beta-hCG foram decisivas para estabelecer o diagnóstico diferencial com DTG recidivante. RESULTADOS: a incidência de MAVU após DTG foi 0,2% (7/2764). Achados ultra-sonográficos de MAVU: IP médio de 0,44±0,058 (extremos: 0,38-0,52); IR médio de 0,36±0,072 (extremos: 0,29-0,50); VSM média de 64,6±23,99 cm/s (extremos: 37-96). A imagem de RNM revelou útero aumentado, miométrio heterogêneo, espaços vasculares tortuosos e vasos parametriais com ectasia. A apresentação clínica mais comum foi hemorragia transvaginal, presente em 52,7% (4/7) dos casos. Tratamento farmacológico com 150 mg de acetato de medroxiprogesterona foi empregado para controlar a hemorragia, após a estabilização hemodinâmica. Permanecem as pacientes em seguimento, assintomáticas até hoje. Duas pacientes engravidaram com MAVU, com gestações e partos exitosos. CONCLUSÃO: presente sangramento transvaginal em pacientes com beta-hCG negativo e história de DTG, deve-se considerar a possibilidade de MAVU e solicitar avaliação ultra-sonográfica com dopplervelocimetria. O tratamento conservador é a melhor opção na maioria dos casos de MAVU pós-DTG.

Internal carotid artery pseudoaneurysm after tonsillectomy treated by endovascular approach - A case report

Surgery on the head and neck region may be complicated by vascular trauma, caused by direct injury on the vascular wall. Lesions of the arteries are more dangerous than the venous one. The traumatic lesion may cause laceration of the artery wall, spasm, dissection, arteriovenous fistula, occlusion or pseudoaneurysm.We present a case of a child with a giant ICA pseudoaneurysm after tonsillectomy, manifested by pulsing mass and respiratory distress, which was treated by endovascular approach, occluding the lesion and the proximal artery with Histoacryl. We reinforce that the endovascular approach is the better way to treat most of the traumatic vascular lesions.

Is coronary sinus blood oxygen tension behavior determined by myocardial oxygen tension variation during cardiac reperfusion?

The relationship between coronary sinus blood oxygen tension (CSPO 2) and myocardial oxygen tension (MPO 2) variations during cardiac ischemia and reperfusion was studied in anesthetized open-chest dogs. Oxygen tension was measured by a polarographic method. Ischemia resulted in a slightly decreased CSPO 2 and a more pronounced reduction of MPO 2. After reperfusion the CSPO 2 rose rapidly and transiently before it returned gradually to the control level. By contrast, during the recovery period, the MPO 2 increased slowly, with recovery occurring long after the peak of CSPO 2. These data suggest that during the reperfusion phase, the CSPO 2 variation is probably due to opening of the myocardial arteriovenous shunts instead of an increase of flow through the myocardial capillary bed.

Fístula arteriovenosa pulmonar maciça. Causa rara, potencialmente curável de hipóxia neonatal.

The case of a six-day-old neonate admitted in an emergency situation because of dyspnea and increasing cyanosis is reported. Despite abnormal opacification on the chest X-ray and left ventricular overload on the electrocardiogram and echocardiogram, features compatible with the disease, the diagnosis of massive pulmonary arteriovenous fistula affecting the whole left superior lobe, was made possible only after necroscopic examination.

Abordagem initial do paciente com mielopatia aguda não compressiva

Acute myelopathy are characterized by spinal cord dysfunction, developing sensitive, motor and autonomic signs and symptons. Since they are relatively rare, there are some difficulties to early diagnosis and to the beginning of the treatment. So, literature was reviewed to describe the main aetiologies of acute non compressive myelopathy: 1) demyelinating diseases; 2) systemic disease; 3) parainfectious; 4) delayed radiation myelopathy; 5) vascular myelopathy; 6) idiopatic and 7) vitamin B12 deficiency. Besides, we suggest an algorithm to initial approach of these patients and further aethiologic investigation. © Copyright Morelra Jr. Editora.

Successful prevention of tunneled central catheter infection by antibiotic lock therapy using cefazolin and gentamicin

Catheter-related bacteremia (CRB) is one of the various complications related to hemodialysis (HD). As a result of this high rate of infection, the antibiotic lock technique (ALT) has been recommended to prevent CRB. However, adverse effects of ALT such as increased emergence of strains resistant to antibiotics and increased mechanical dysfunction catheter were poorly evaluated. We prospectively evaluated the efficacy of catheter-restricted filling using an antibiotic lock solution in preventing CRB. A total of 233 HD patients requiring 325 new tunneled catheters while waiting for placement and maturation of an arteriovenous fistula or graft were enrolled in this study. Patients with a tunneled catheter were assigned to receive either an antibiotic-heparin lock solution (antibiotic group: cefazolin 10 mg/ml, gentamicin 5 mg/ml, heparin 1,000 U/ml) or a heparin lock solution (no-antibiotic group: heparin 1,000 U/ml) as a catheter lock solution during the interdialytic period. The present study aimed to assess the efficacy of ALT using cefazolin and gentamicin in reducing CRB in patients undergoing HD with tunneled central catheter and to identify its adverse effects. CRB developed in 32.4 % of patients in the no-antibiotic group and in 13.1 % of patients in the antibiotic group. CRB rates per 1,000 catheter-days were 0.57 in the antibiotic group versus 1.74 in the no-antibiotic group (p < 0.0001). Kaplan-Meier analysis also showed that mean CRB-free catheter survival was significantly higher in the antibiotic group than in the no-antibiotic group (log-rank statistic 17.62, p < 0.0001). There was statistically significant difference between the two groups in causative organisms of CRB, with predominance of negative culture in both groups, but this prevalence was higher in ALT group (57.9 vs 90.1 %, p < 0.0001), and the two groups also were different in prevalence of gram-positive bacteria as causing organisms (ALT group 21.05 vs = 0 % in control group, p < 0.0001). There was no statistically significant difference between the two groups in drug-resistant germs. There were statistically significant differences between the two groups in the catheter removal causes, with higher rate of infectious cause in control group (12.32 vs 2.22 %, p < 0.0001) and mechanical cause in ALT group (28.26 vs 37.78 %, p < 0.0001). The results suggest that ALT may be a beneficial means of reducing the CRB rate in HD patients with tunneled catheter, without association between ALT and emergence of strains resistant. However, mechanical complications were more prevalent in antibiotic group. Further studies are required to determine the optimal drug regimen, concentrations for ALT, and its adverse effects. © 2012 Springer Science+Business Media Dordrecht.

Síntese e caracterização de partículas esféricas de poli(álcool vinílico) e poli(acetato vinílico) para utilização em embolização

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise da perda volêmica em pacientes submetidos a expansão rápida de maxila assistida cirurgicamente

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Recanalization after acute deep vein thrombosis

O processo de recanalização das veias dos membros inferiores, após um episódio de trombose venosa profunda aguda em pacientes anticoagulados com heparina e inibidores da vitamina K, faz parte da evolução natural da remodelagem do trombo venoso. Esse complexo processo de remodelagem envolve a adesão do trombo à parede da veia, à resposta inflamatória da parede do vaso, levando à organização e subsequente contração do trombo, à neovascularização e à lise espontânea de áreas no interior do trombo. A presença de fluxo arterial espontâneo em veias com trombose recanalizada tem sido descrita como secundária à neovascularização e se caracteriza pelo desenvolvimento de fluxo com padrão de fístulas arteriovenosas, identificadas por meio de mapeamento dúplex colorido. Nesta revisão, são discutidos alguns aspectos controversos da história natural da trombose venosa profunda, para uma melhor compreensão da sua evolução e do seu impacto sobre a doença venosa.