Intravascular endoprostheses. Effect of surface geometry on restenosis and side branch patency.

To investigate the effects of gaps between the wire pitches of a shape memory Nitinol alloy intravascular endoprosthesis (IVEP), 42 stents with and without gaps were implanted transluminally into the infrarenal abdominal aortae of 11 normal and 10 atherosclerotic rabbits. Digital subtraction angiography was done every 4 weeks to examine the restenosis rate and major side branch patency. Restenosis rates within IVEPs with gaps were significantly lower than in stents without gaps in both normal and atherosclerotic rabbits. The side branch patency rate was significantly higher with IVEPs having gaps. These results suggest that the placement of gaps between wire pitches reduced the restenosis rate within IVEPs, and prevented the obstruction of major side branches.