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Our Procedures - Expert Presentations
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In the field of interventional cardiology restenosis after stent implantation is a substantial medical problem, occurring
in 20-35% of the patients within 6 months from implant. In patients with diabetes, this percentage increases on average to
40%.
In-stent restenosis is the consequence of an excessive scar formation (similar to that occuring on the skin when a
cheloid forms). In fact, restenosis occurs when the scar formation, which is the response to the initial vessel wall
injury induced by stent implantation, goes beyond the normal vessel wall healing. In detail, this excessive scar formation
is due to an increased proliferation of the smooth muscle cells of the vessel wall, which pass through the stent struts,
invading the vessel lumen.
Sirolimus, a naturally occurring macrocyclic antibiotic, is a potent immunosuppressive agent inducing late G1 cell
cycle arrest (cytostatic agent). The drug, approved in Italy and used clinically for the prevention of rejection after
renal transplantation, is incorporated on the stent surface binded to a polimer.
The quantity of Sirolimus delivered in the bloodstream, thus its potential systemic effect after stent implantation, is
mimimum (dose 100 times lower) compared with the doses used in the clinical setting, as chronic treatment for the
prevention of rejection after renal transplantation. Therefere, there are not the contraindications related to the usage
of systemic dosages of the drug.
The Sirolimus-eluting stent accomplishes two tasks: 1) scaffolds the vessel lumen and 2) slowly elutes in the 2-3 weeks
after implantation the drug which reduces restenosis by its antiproliferative effect.
Thanks to this new stent, an increasing number of patients will avoid Coronary Artery Bypass Graft (CABG) surgery, an
invasive open-chest surgical intervention performed with cardiac arrest and extracorporeal
circulation.
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