Vena caval filter to prevent pulmonary embolism: experimental study. Work in progress

A new inferior vena caval filter was tested in an experimental series of 23 dogs and in an in vitro study. The filter consists of a pliable basket and anchoring legs made of stainless steel. It can be inserted percutaneously in an antegrade or retrograde fashion through a 10-F Teflon catheter and can be retrieved with a snare or forceps. The filter is self-orienting in the inferior vena cava, becomes securely the inferior vena cava, becomes securely fixed to the wall, and has exhibited no tendency to migrate. It is highly effective in capturing small and large emboli. There was no significant elevation in upstream hydrostatic pressure following entrapment of emboli. Spontaneous thrombus formation within the basket was observed in two of six dogs who had short-term follow-up. In dogs who had long-term follow-up, the filter remained patent. Microscopically, the filter caused sclerosis of the intima where the wire was in contact with the vessel wall. Breakage of an anchor leg and separation at the fusion between anchor and basket were seen in the study. They were eliminated by improvement of the prototype, which is now ready for clinical application.     

MR imaging in patients with metallic implants

A total of 305 magnetic resonance (MR) examinations were performed in 236 patients with metallic implants. Most examinations were performed at 0.3 T. The metallic implants included central nervous system shunting devices, tantalum mesh, surgical wire, skin staples, surgical clips, metallic orthopedic devices, and a few miscellaneous metallic objects. Patients with cardiac pacemakers, electrical implants, prosthetic cardiac valves, and aneurysm clips were excluded from MR examinations. The images were reviewed for evidence of metallic artifact. The conspicuity of artifact was related to the composition, mass, orientation, and position of the metallic object in the body. In most instances, the metallic artifact did not interfere with the interpretation of the image. The patients' records were also reviewed for adverse effects noted by each patient during the MR examination. Only two patients reported discomfort that could possibly have been related to their metallic implants, but in both cases it seemed unlikely that the symptoms were actually related to the imaging process. There were no apparent short-term adverse effects demonstrated in these patients.     

Bleeding esophageal varices and portal vein thrombosis after pancreatic mixed-cell autotransplantation

A patient with chronic pancreatitis caused by congenital pancreatic duct atresia underwent total pancreatectomy and mixed-cell pancreatic autotransplantation by portal vein embolization. Two years later she developed massive upper gastrointestinal bleeding from gastroesophageal varices and required a mesocaval H graft. The cause of the portal hypertension was portal vein thrombosis caused by portal vein infusion of pancreatic homogenate, and it represents a serious complication of the procedure. Although this is the second report of portal hypertension that required portasystemic shunting after islet cell autotransplantation, it is the first reported case of the development of bleeding esophageal varices caused by portal vein thrombosis after pancreatic islet cell transplantation.