Device Research

Device Research in the Institute’s research laboratory has been focused mainly on developing and testing new tools and techniques for interventional radiology. In the early nineties, a great effort was placed into developing the Gianturco-Rösch self-expandable stent for its use in treatment of tracheobronchial and esophageal obstructions. After the Institute’s successful experimental testing, they became available commercially through Cook Inc. of Bloomington, Indiana. Cook Inc. also accepted the Institute’s improvement of the transjugular liver biopsy needle and the new biopsy needle gun set has become the standard needle for this procedure.

	Direct transjugular portocaval shunt done under intravenous ultrasound and flouroscopic control.

In the mid-nineties, the Institute’s research team concentrated on the development of covered stents and stent grafts for arterial, venous and nonvascular use and TIPS. In the arterial system, a twin tube endograft showed great promise for exclusion of abdominal aortic aneurysms. In TIPS, after exploring and identifying causes of shunt obstructions in TIPS, significant improvement of primary shunt patency was found using a polytetrafluoroethylene (PTFE) graft, supported by a Z-stent and a Wallstent. Other synthetic polymers such as silicone, Dacron or polyurethane-coated Dacron fared poorly in the Institute’s experiments. Therefore, only the PTFE stent grafts were tested in our clinical studies. Currently small intestinal submucosa covered stents are being developed.

Two new promising techniques for treatment of portal hypertension were also developed and tested. The first technique – direct intrahepatic portocaval shunt (DIPS), in which the portal vein is punctured directly from the inferior vena cava under intravenous ultrasound control, may be an alternative for conventional TIPS in the future. The second technique – percutaneous retroperitoneal splenorenal shunt – also has promising potential, but further studies have to be done.

Another study recently completed was the determination of the safety of intravascular thrombin for pseudo aneurysm occlusion. The Institute’s research results indicated that only minimal thrombin doses can be used without risks of severe complication.

Other studies in the mid-nineties led to the development of a transjugular kidney biopsy needle. This needle has a side-cutting opening and a blunt-tipped stylet that improves the efficiency and safety of kidney biopsies. Dr. Stan Cope’s research at the Institute in 1996 led to the development of the technique of percutaneous transabdominal thoracic duct catheterization.

The research laboratory staff has been also working with Dr. Michael Conlin, a urologist from the V.A. Medical Center, in developing devices for the urinary tract. The Institute’s neurointerventional group has been working with Dr. Kenton Gregory from the Oregon Medical Laser Center on laser thrombolysis in the carotid arteries. Dr. Gregory and his team have also done promising research in the Institute’s laboratories on several topics, including laser prevention and treatment of arterial intimal hyperplasia and use of a new collagen biomaterial – elastin stent cover – for prevention of arterial stenoses complicating coronary stenting.