Serial angiographic and endovascular documentation of peri-stent contrast stains after sirolimus-eluting stent implantation: Multiple cavity formations between entirely covered stent struts.

A 72-year-old woman with a history of treatment with a single sirolimus-eluting stent (SES) for right coronary artery stenosis 21 months previously, was hospitalized to undertake invasive coronary evaluation due to recurrence of symptoms of effort angina. At the time of 9 months of angiographic follow-up, no in-stent restenosis was detected, however, several contrast filled "dimples" were noticed outside the stent border. At this time, further increments in the numbers of dimple formation were documented, in addition to progression of stenosis at the distal non-stented portion. Intravascular ultrasound demonstrated multiple cavity formations between the stent struts, due to positive remodeling occurring at the previously relatively disease-free side of the vessel wall. Surprisingly, optical coherence tomography demonstrated all the stent struts, including those located adjacent to cavities, were exclusively covered with neointima or other tissue components, completely attaching to the vessel wall throughout the stented segment. No evident thrombus formation was detected in these cavities. Despite no exposed stent struts, a hypothetical concern remains because such cul-de-sac formations may produce local blood flow turbulence within stents, which may be potentially associated with activation of local platelet aggregation. Careful long-term follow-up may be necessary for these patients.