Clinical Research

	A 4.5 year follow-up of stenting multiple severe obstructions of SVC, IVC, and their branches. Altogether, seven multi-body GRZ stents were used.

Clinical research is an extension of the device research done at the Institute laboratory. Research areas include: TIPS; effectiveness of GRZ self-expandable stents in treatment of obstructions of the venous system, tracheobronchial tree and esophagus; use of stent grafts in treatment of aneurysms and fistulas; and, more recently, on embolization of uterine fibroids. The neurointerventional group has concentrated on treatment of carotid artery obstructions, management of acute stroke, and arteriovenous fistulas and malformations.

In exploring TIPS, the Institute staff has been working closely with liver transplant and hepatology teams. Based on experience with treatment, and close follow-up of almost 400 treated patients, TIPS benefits and limitations have been well defined. The Institute’s experimental clinical study showed that use of the PTFE stent graft has significant potential to prevent shunt obstruction, a major limitation of TIPS. These stent grafts were effective not only in treatment of shunt obstructions, but were equally effective when used for the primary TIPS procedure.

	One year follow up of a patient with direct transjugular portocaval shunt

Evaluation of GRZ stents has found them to be very effective in offering long-term treatment of benign stenoses in the venous system and tracheobronchial tree. Covered GRZ stents offered excellent palliation of tumorous obstructions in the esophagus. Use of stent grafts was found to be very effective in the treatment of large thoracic and iliac aneurysms and abdominal pseudoaneurysms and eliminated the need for major surgeries. Covered stents proved to be also effective in the treatment of iatrogenic biliary fistulas that developed after surgical procedures.

Uterine fibroid embolization introduced at the Institute in 1998 offers an effective treatment of large, symptomatic uterine fibroids. It is a benign procedure and is usually done on an outpatient basis. As an alternative to surgical hysterectomy, many women have requested it. The Institute staff has treated over 50 patients with this technique. Outcomes have been excellent, with volume reductions of 40-60 percent, and symptoms either resolved or significantly improved in 80 percent.

In the treatment of carotid artery stenoses, the Institute’s neurointerventional group found percutaneous transluminal angioplasty very effective, but recently preferred stenting of stenoses, to decrease the rate of restenoses.

	Successful stenting of proximal internal carotid artery stenosis. A) Before, B) after stenting.

The stent placement has been used effectively not only for treatment of stenoses of the internal carotid artery, but occasionally for intracranial stenoses. More than 100 patients with obstructive carotid and intracranial disease were treated with stent placement. The neurointerventional team will be participating in a multi-institutional Carotid Revascularization Endoarterectomy vs. Stent Trial (CREST).

Acute stroke treatment with catheter-directed, local intra-arterial thrombolysis, was done in cooperation with the Oregon Stroke Treatment Center at OHSU and was part of a multi-institutional study with the Institute as one of the research sites. After CT scan exclusion of intracranial bleeding, and new brain infarct and angiographic documentation of the intracranial arterial occlusion site, a microcatheter was guided inside a clot and a thrombolytic agent was infused. Restoration of perfusion of the occluded vessel and excellent clinical results were achieved in more than 180 treated patients.