Fenestrated stent-graft repair: which stent should be used to secure target vessel fenestrations?
OBJECTIVE
To investigate in an in vitro model the ability of different covered and uncovered stents to resist displacement/migration of a fenestrated stent-graft.


METHODS
Three different types (2 covered, 1 bare) of commonly used 7-mm balloon-expandable stainless steel stents (Jostent, Advanta V12, and Palmaz Genesis) were investigated in a testing rig consisting of 2 overlapping tubes with 2 sets of 7-mm holes representing bilateral renal artery fenestrations and ostia. The rig was attached to a tensile tester via pneumatic clamps. The stents were deployed without flaring to 7 mm through the overlapping holes. The rig was moved apart at a constant rate of 12 mm/min up to a maximum displacement of 6 mm; force versus displacement values were recorded while stent deformation was observed. Tests were repeated at least 6 times for each stent type at room temperature. The median force required to cause a 25%, 50%, or 75% reduction in cross-sectional area of the bilateral "renal artery" stents was determined.


RESULTS
The median force (interquartile range) required to cause a 50% reduction in cross-sectional area of identical bilateral "renal artery" stents securing fenestrations was 25.1 N (8.1) for a covered Jostent, 9.3 N (0.9) for a covered Advanta V12 stent, and 7.5 N (0.7) for a bare Palmaz Genesis stent. The differences were statistically significant (p<0.01) between stents at each of the 3 levels of cross-sectional area reduction.


CONCLUSIONS
There is a significant difference in the ability of different commercial "non-dedicated" stents to withstand a crushing force when deployed within endograft fenestrations, which has important implications for clinical practice.
Regional Vascular Unit, Royal Liverpool University Hospital, Liverpool, UK. scurrj@hotmail.com
James R H
JR
Scurr
Thien V
TV
How
Richard G
RG
McWilliams
Steven
S
Lane
Geoffrey L
GL
Gilling-Smith
D001011:Aorta / Q000601:surgery*; D001363:Awards and Prizes; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D019544:Equipment Failure Analysis; D005548:Foreign-Body Migration / Q000209:etiology*; D006801:Humans; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012077:Renal Artery / Q000601:surgery*; D015607:Stents; D013314:Stress, Mechanical