New Portal Venoplasty with a self-expandablemetallic stent and a graft

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12671178
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: General surgery
• Research Institution: The Jikei University School of Medicine
• Principal Investigator: NAKABAYASHI Yukio The Jikei Univ. School of Medicine, Dept of Surgery, Lecture, 医学部, 助手 (70217818)
• Project Period (FY): 2000 – 2001
• Keywords: Portal vein / Revascularization / Stent

Research Abstract

We have examined the new Portal Venoplasty; a sel-fexpandable metal lic stent makes a graft attach to the portal vein with its expandin.g force and keeps the vascular lumen open wide, seeking after the possibility of new portal revascularization without vascular anastomosis. Regarding the stent-grafting being done with arterial aneurysm, endoleak causedby highblood pressure has been a big problem recently. However, we expect the much smaller blood leakage due to its lower pressure with portal vein, so we foresee that vascular occlusion is avoided because the self-expanding force of stent prevents the graft occlusion and stenosis caused by the increase of abdominal pressure. As the objectives of this study, we were supposed to the following points. 1. Establishment of procedure, confirming safety 2. Check of blood flow, graft patency 3. Pathologic diagnosis of the wall structure where the graft was implaUted, especially the sealed place of the graft and the portal vein
Concerning how We should do the Portal Venoplasty, after the removal of the portal vein, we fixed temporally the cut edge of lateral porta hepatis,graft and the cut edge of portal vein on the side of bowel with three points. Then, we insert the self-expandable stent from the mesenteric vein through an introducer and proceed it to the cut edge of the removed portal vein of mesenterial side, follpwed by sticking out the stent from the lumen side. Next, through the endoluminl of graft release the stent at the cut edge of lateral ports hepatis, we seal it to the lumen of portal vein. We adopted the above-mentioned procedure for the revascularization of the portal vein.
We did follow-up concentrating on the establishment of the procedure. As a result, the retention of the graft lumen was good but we had endoleak problem caused, by the bad fixation of portal side due to the rough circumferential area. This is because a gap exits between the graft and the stent by the flexion in the fixed area with the variable abdominal pressure. This happens in the case Of the positional gap shown between the released stent and the graft. We failed to establish the stable procedure because of endoleak, examining the appropriate positional relationship between the graft and the stent.