Surgical removal of a foreshortened right innominate vein Wallstent causing venous outflow obstruction

Objectives: Stenting of central venous stenosis to preserve upper extremity hemodialysis access is well-described, though upper extremity complications secondary to these stents are less frequently discussed. Methods: We present the case of a 43-year-old male with a right brachiocephalic fistula who developed symptoms of venous hypertension following placement of a Wallstent for central venous stenosis. Workup demonstrated venous outflow obstruction secondary to stent foreshortening into the right subclavian vein. Results: The Wallstent was removed in a piecemeal fashion using an open surgical technique and a HeRO graft was placed for dedicated fistula outflow with complete relief of the patient’s symptoms. Conclusion: In situations where a stent has migrated and endovascular removal is not possible, individual Wallstent fibers can be removed through a limited venotomy.

A critical review of surgical strategies to minimise venous stenosis in arteriovenous grafts

It is inevitable that complications arising from surgical procedures are ascribed to surgical technique, and this applies to venous stenosis (VS) in arteriovenous grafts. However, despite a wide range of cellular studies, computer modelling, observational series and clinical trials, there remains uncertainty on whether surgical technique contributes to VS. This article reviews evidence from basic science, fluid dynamics and clinical data to try and rationalise the main surgical options to modify the occurrence of venous stenosis. There is sufficient data from diverse sources to make recommendations on clinical practice (size of target vein, shape of anastomosis, angle of approach, distance from venous needling, trauma to the target vein) whilst at the same time this emphasises the need to carefully report the practical aspects of surgical technique in future clinical trials.

Endovascular retrieval of two migrated stents from pulmonary artery by means of balloon catheter

Long-term central venous catheters can be associated with central venous stenosis in up to 50% of cases. Central venous stenosis can be managed with central venous stenting which was demonstrated to restore patency and improve suboptimal results after percutaneous transluminal angioplasty. Dislodgment of venous stents into the right side of the heart or the pulmonary artery during stent deployment is one of the most feared complications of this procedure. Percutaneous removal of these migrated stents is the preferred alternative for the more invasive operative intervention, which may be very hazardous in these patients. We report an unusual case of a 52-year-old man on hemodialysis who underwent endovascular stenting to treat a tight stenosis of the right brachiocephalic vein and superior vena cava and suffered from stent migration to the left pulmonary artery, requiring removal by interventional radiologist.

Percutaneous Transluminal Angioplasty in Chronic Total Subclavian Venous Stenosis Using Coronary Guidewire: A Case Report

Arteriovenous fistula is the best permanent vascular access for hemodialysis (HD). However, in our country, HD catheter in jugular or subclavian vein is more commonly found because our patients prefer to hold HD until the complications are unbearable. The catheter increases risk of venous stenosis on site and in surrounding vessels, resulting in access loss. Percutaneous transluminal angioplasty (PTA), combined with stent deployment, can be utilized as main treatment for such stenosis in subclavian vein. This method dated back to two decades ago with high success rate. Nevertheless, reports or studies of angioplasty in total occlusion are scarce, mainly because of lower success rate and the need of smaller penetrating wire. We describe our experience in performing PTA and stent deployment using coronary wire to penetrate total occlusion in subclavian venous stenosis after vein cannulation. We hope that we can give an alternative technique to avoid surgery in such cases.

Transient bacteremia promotes catheter-related central venous thrombosis through neutrophil extracellular traps

Formation of intravenous catheter-related thrombosis leads to central venous stenosis in patients requiring renal replacement therapy or chemotherapy infusion, yet the triggering or mechanisms remain unclear, especially in patients without symptoms of infection. In this study, we found that neutrophil extracellular traps (NETs) could be detected in the fibrin sheaths from dialysis patients without clinical manifestations of infection. Confocal microscopy revealed bacteria imbedded in NETs in the fibrin sheaths. Thirty-nine of 50 (78%) fibrin sheath specimens contained bacteria detectable by 16S ribosomal RNA genome typing with a predominance of Staphylococcus aureus (69%). In rat models, transient bacteremia of S. aureus induced NETs in enlarged fibrin sheaths, and treatment with DNase I alone significantly reduced both NET and fibrin sheath formation surrounding the catheter. Therefore, transient bacteremia could be a silent trigger that induces NET-related immunothrombosis enhancing catheter-related central venous stenosis.

Screening and surveillance of venous stenosis in AVG: Is it time to rethink our assumptions?

Guidelines make no firm recommendations about surveillance of arteriovenous grafts as several randomised trials (RCT) have not shown a clear benefit in patency. However a more thorough review of these RCT based on epidemiological principles reveals significant limitations. In particular a key weakness of these older studies is the interventions performed for venous stenosis detected that was largely angioplasty. However, the observational data of modern stent-grafts shows a clear benefit over angioplasty, and thus seems to suggest that a modern well considered RCT is now mandated.