The transjugular intrahepatic portosystemic shunt (TIPS) was "enthusiastically embraced by the interventional and surgical communities when it first became practical," notes Dr. Robert Andrews of Dotter Interventional Institute at Oregon Health Sciences University in Portland. However, the shunt's failure to maintain patency over time requires monitoring and repeat interventions, limiting the use of TIPS compared to surgical shunts or endoscopic treatments.
Following up on animal studies showing that use of covered stents or stent-grafts could improve the patency of TIPS, Andrews and colleagues implanted their own "de novo stent-graft TIPS" in patients with symptomatic portal hypertension. The study group was limited to eight patients who were awaiting liver transplants so that histologic response to the stent-grafts could be evaluated.
Their early findings are reported this month in "Stent-Grafts for De Novo TIPS: Technique and Early Results" by Andrews RT, Saxon RR, Bloch RD, Petersen BD, Uchida BT, Rabkin JM, Loriaux MM, Keller FS, Rosch J in the Journal of Vascular and Interventional Radiology, November-December 1999, Volume 10:10; pp. 1371-1378.
The researchers used handmade stent-graft TIPS created in their labs. The stent-grafts were 10 mm in diameter and 5 to 7 cm in length, with two single-body Z stents and covered with thin-walled polytetrafluoroethylene (PTFE), specifically 4-mm Gore vascular graft material.
The new TIPS were successfully implanted to join the right hepatic and portal veins in all eight patients, with no procedural complications. Procedural time averaged 31.6 minutes compared to an average of 21.4 minutes for standard TIPS deployment by the same interventionalist.
The de novo stent-graft TIPS required no follow-up intervention in five cases where patients went for up to 574 days before transplantation. Another patient who died of unrelated complications from cholecystectomy also maintained a patent TIPS for 326 days.
Two patients developed significant stenoses at 127 and 460 days. However, the location of these stenoses, according to the authors, "suggests that a slightly longer stent-graft in both patients, with coverage of the entire hepatic vein to the inferior vena cava wall, might have resulted in their TIPS being single-step procedures as well."
Commercial stent-graft devices are under investigation by several companies, according to Dr. Andrews. "While I am aware of one device being developed specifically for TIPS, another stent-graft that could be modified for TIPS [the Hemobahn stent-graft] will likely be approved by the FDA this spring," he said.
By Tracie L. Thompson
AuntMinnie.com staff writer
December 21, 1999
Copyright © 1999 AuntMinnie.com
