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Intravascular ultrasound assessment of postprocedural incomplete stent apposition.

BACKGROUND
There has been no detailed intravascular ultrasound (IVUS) analysis to evaluate the degree to which stent underexpansion or reference vessel/stent size mismatch contributes to the occurrence of post-procedural incomplete stent apposition (post-ISA).


METHODS
We evaluated 238 lesions treated with everolimus-eluting stents (n = 110) or paclitaxel-eluting stents (n = 128). Reference lumen/stent area ratio was defined as the ratio of lumen area adjacent to the stent edge in the reference segment to stent area at the stent edge or at stent body ISA site.


RESULTS
Post-ISA was observed in 36 of the 238 cases (15%) at the proximal stent edge, 15 of the 238 cases (6%) at the distal stent edge and 14 of the 238 cases (6%) at stent body. Reference lumen/stent area ratio was significantly greater in the ISA group compared with non-ISA in proximal edge (127 ± 20 vs. 99 ± 10%; P<.001), and greater reference lumen/stent area ratio (118 ± 18 vs. 94 ± 11%; P<.001) and higher presence of calcification (60 vs. 29%; P<0.001) were observed in distal edge ISA group compared with non-ISA. At the stent body, presence of calcification was more frequently observed in the ISA compared with the non-ISA group (86 vs. 42%; P=.002).


CONCLUSIONS
Post-ISA at the stent edge was significantly associated with vessel/stent mismatch rather than stent underexpansion. IVUS-guided appropriate stent or balloon sizing might be useful to prevent post-ISA and optimize initial stent deployment.