Paradoxical embolism following thromboaspiration of an arteriovenous fistula thrombosis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Paradoxical embolism is an increasingly reported cause of arterial embolism. Several embolic sources have been described, but thrombosis of an arteriovenous fistula as a paradoxical emboligenic source has not, to the best of our knowledge, been reported.</p> <p>Case presentation</p> <p>A 50-year-old Caucasian woman received a renal graft for primary hyperoxaluria. After transplantation, she was maintained on daily hemodialysis. Thrombosis of her arteriovenous fistula occurred two weeks post-transplantation and was treated by thromboaspiration, which was partially successful. During a hemodialysis session immediately following thromboaspiration, she developed a coma with tetraplegia requiring intensive cardiorespiratory resuscitation. Brain magnetic resonance imaging revealed various hyperdense areas in the vertebrobasilar territory resulting from bilateral occlusion of posterior cerebral arteries. Transesophageal echocardiographic examination showed a patent foramen ovale, while pulse echography of the arteriovenous fistula revealed the persistence of extensive clots that were probably the embolic source. A paradoxical embolus through a patent foramen ovale was suggested because of the proximity of the neurological event to the thrombectomy procedure.</p> <p>Conclusions</p> <p>The risk of paradoxical embolism in a hemodialyzed patient with a patent foramen ovale deserves consideration and requires careful evaluation in situations of arteriovenous fistula thrombosis.</p

Prevention of catheter lumen occlusion with rT-PA versus heparin (Pre-CLOT): study protocol of a randomized trial [ISRCTN35253449]

BACKGROUND: Many patients with end-stage renal disease use a central venous catheter for hemodialysis access. A large majority of these catheters malfunction within one year of insertion, with up to two-thirds due to thrombosis. The optimal solution for locking the catheter between hemodialysis sessions, to decrease the risk of thrombosis and catheter malfunction, is unknown. The Prevention of Catheter Lumen Occlusion with rt-PA versus Heparin (PreCLOT) study will determine if use of weekly rt-PA, compared to regular heparin, as a catheter locking solution, will decrease the risk of catheter malfunction. METHODS/DESIGN: The study population will consist of patients requiring chronic hemodialysis thrice weekly who are dialyzed with a newly inserted permanent dual-lumen central venous catheter. Patients randomized to the treatment arm will receive rt-PA 1 mg per lumen once per week, with heparin 5,000 units per ml as a catheter locking solution for the remaining two sessions. Patients randomized to the control arm will receive heparin 5,000 units per ml as a catheter locking solution after each dialysis session. The study treatment period will be six months, with 340 patients to be recruited from 14 sites across Canada. The primary outcome will be catheter malfunction, based on mean blood flow parameters while on hemodialysis, with a secondary outcome of catheter-related bacteremia. A cost-effectiveness analysis will be undertaken to assess the cost of maintaining a catheter using rt-PA as a locking solution, compared to the use of heparin. DISCUSSION: Results from this study will determine if use of weekly rt-PA, compared to heparin, will decrease catheter malfunction, as well as assess the cost-effectiveness of these locking solutions

Hemodialysis vascular access options in pediatrics: considerations for patients and practitioners

Recent data indicate that the incidence of end-stage renal disease (ESRD) in pediatric patients (age 0–19 years) has increased over the past two decades. Similarly, the prevalence of ESRD has increased threefold over the same period. Hemodialysis (HD) continues to be the most frequently utilized modality for renal replacement therapy in incident pediatric ESRD patients. The number of children on HD exceeded the sum total of those on peritoneal dialysis and those undergoing pre-emptive renal transplantation. Choosing the best vascular access option for pediatric HD patients remains challenging. Despite a national initiative for fistula first in the adult hemodialysis population, the pediatric nephrology community in the United States of America utilizes central venous catheters as the primary dialysis access for most patients. Vascular access management requires proper advance planning to assure that the best permanent access is placed, seamless communication involving a multidisciplinary team of nephrologists, nurses, surgeons, and interventional radiologists, and ongoing monitoring to ensure a long life of use. It is imperative that practitioners have a long-term vision to decrease morbidity in this unique patient population. This article reviews the various types of pediatric vascular accesses used worldwide and the benefits and disadvantages of these various forms of access

Avaliação da perviedade precoce das fístulas arteriovenosas para hemodiálise Evaluation of early patency of the arteriovenous fistulas for hemodialysis

CONTEXTO: A insuficiência renal crônica é uma doença de alta prevalência e morbidade, o que determina queda da qualidade de vida. Pacientes em hemodiálise necessitam de um acesso vascular que permita a conexão da circulação do paciente ao circuito externo de hemodiálise. Dentre os acessos disponíveis, as fístulas arteriovenosas (FAV) são as que mais se aproximam do acesso ideal. OBJETIVO: Avaliar a perviedade precoce das FAV, identificando os fatores relacionados ao insucesso destas. MÉTODOS: Foram acompanhados todos os pacientes submetidos à confecção das FAV no Hospital do Servidor Público Municipal de São Paulo, no período de agosto de 2008 a janeiro de 2009, avaliando-se a perviedade destas no 1º, 10º e 30º pós-operatório. Foram realizadas 31 FAV no período, apresentando-se média de idade de 63,06 anos, sendo 18 pacientes do sexo masculino e 13 do feminino. RESULTADOS: Vinte e seis FAV foram distais, todas radiocefálicas; quatro foram proximais, das quais duas braquiocefálicas e duas braquiobasílicas superficializadas; uma FAV confeccionada com alça de politetrafluoretileno (PTFE) fêmoro-femoral esquerda. A taxa de perviedade no primeiro mês foi de 71% dos casos. O uso de cateteres venosos centrais apresentou-se como fator de risco para oclusão da FAV (p=0,01). As FAV continuam sendo o acesso vascular para hemodiálise mais aceito e mais seguro. A indicação precoce para confecção das FAV é de fundamental importância, evitando-se, assim, o uso de cateteres e suas complicações. CONCLUSÕES: A perviedade precoce encontrada neste estudo é semelhante à da literatura, e o uso prévio de cateteres é o fator de risco mais significativo para oclusão precoce desta.<br>BACKGROUND: Chronic renal failure is a disease of high prevalence and high morbidity, which impairs the patients' quality of life. Patients on hemodialysis need a vascular access for connection with the hemodialysis equipment. Arteriovenous fistulas (AVF) are the best option for this purpose. OBJECTIVE: To evaluate the early patency of AVFs and to identify the causes of their failure. METHODS: All patients AVF underwent operations for dialysis from August, 2008 to January, 2009. The AVF patency was evaluated on the 1st, 10th and 30th postoperative days. Thirty-one operations for AVF were performed in our hospital in the period; 18 patients were males and the mean age was 63.03 years. RESULTS: Twenty-six AVF were distal, all radial-cephalic; four were proximal, out of which two were brachiocephalic and two were brachiobasilic; one AVF was a femoral-femoral loop PTFE graft. The patency rate in the first month was of 71%. The use of central venous catheters was a risk factor for AVF occlusion (p=0.01). AVF remains the most accepted and safe vascular access. Early performance of the AVF is very important to avoid the complications resulting from long-term use of central venous catheters. CONCLUSIONS: Data regarding early patency found in this study were similar to those found in literature, and the use of central venous catheters before performing AVF is an important risk factor for occlusion