Five randomized, controlled trials failed to demonstrate any benefit of a stainless-steel
stent over angioplasty alone. The nitinol stent has proven superior primary patency than
balloon angioplasty in superficial femoral artery (SFA) lesions. Several studies reported
stent fractures were associated with a higher risk of in-stent restenosis and reocclusion. In
vitro, Stefan et al. reported the 7 different SFA stents showed differences in the incidence
of high strain zones, which indicates a potential for stent fracture, as demonstrated by the
mechanical fatigue tests. They claimed differences in stent design might play a major role in
the appearance of stent strut fracture related to restenosis and reocclusion. Also, in
retrospective study, Iida et al. reported there was significant difference in stent fracture
between S.M.A.R.T. stent group and Luminexx stent group and primary patency was worse in
those associated with stent fracture than in those without stent fractures. Recent stent
design improvements focus on decreasing stent fracture rates which can negatively impact
patency rates by rearranging strut alignment.
The design of self-expandible nitinol stents might be different depending on the developed
time; The first-generation nitinol stents (e.g., LuminexxTM and SmartTM) showed a remarkably
high rate of stent strut fracture. A second generation of slotted tube nitinol stents has
been developed. These stents had a better flexibility, by reducing the number of connections
between cells or crowns, and by configurating spiral orientation of these interconnections.
Several studies reported that these nitinol stents are more fracture-resistant and more
flexible, some of them providing superior patency rate (e.g., LifeTM and EverflexTM).
However, the one of the important limitations to their studies is that those was the
non-randomized study of relative small sample size or was confined to in-vitro. Upto date,
the multicenter, randomized controlled trial for direct comparison of stent fracture and
primary patency between two different nitinol stents has not been done except one study;
SMART versus Luminexx stent. SMART and Luminexx stent have been classified into 1st
generation self-expandable nitinol stent. Complete-SE stent of Medtronic company was
different to Smart stent of Cordis company in that the configuration of interconnection of
Complete-SE stent had peak-to-peak connection and more spiral orientation of interconnection,
compared to mart stent. On the other hand, Smart stent has the peak-to-valley bridge and
in-line interconnection. Medtronics company have claimed Complete's stent crowns have been
configured to minimize crown to crown interaction, increasing the stent's flexibility without
compromising radial strength. We made the hypothesis that the design of Complete-SE stent
might be more fracture-resistant or effective for in-stent restenosis, compared with Smart
stent.
On the other hand, to date, in previous many reports, the dual antiplatelet therapy consisted
of aspirin and clopidogrel have proven to decrease the incidence of cardiovascular death,
myocardial infarction, or revascularization without an increase in major bleeding in patients
who underwent percutaneous coronary intervention regardless of stent type (bare metal stent
or drug-eluting stent). In 2011 ESC (European society of cardiology) guideline, dual
antiplatelet therapy with aspirin and a thienopyridine for at least one month is recommended
after infra-inguinal bare metal stent implantation (Class I, Level C). However, there have
been no the definite evidence or guideline for the optimal antiplatelet agents after stent
implantation one month later. There have been many studies for the efficacy of thienopyridine
in peripheral arterial disease. Also, With the potential benefit of cilostazol on vascular
function in vitro, there have several previous efforts to prove the efficacy of cilostazol in
patients undergoing endovascular therapy or stent implantation in peripheral arterial
disease. However, still specific data regarding a variety of antiplatelet regimen are
limited. Also, very few trials have effectively nor properly addressed the direct comparison
for the efficacy and safety between clopidogrel and cilostazol. This trial designed to
evaluate the efficacy and safety between aspirin plus clopidogrel versus aspirin plus
cilostazol in patients undergoing stent implantation in femoropopliteal lesions.
