Clinical evidence on polymer-based sirolimus and paclitaxel eluting stents

Percutaneous coronary interventions with the use of stents have become the mainstay treatment of patients with various clinical manifestations of coronary artery disease. Despite their remarkable success, restenosis has remained the major drawback and its prevention has absorbed intensive experimental and clinical research work. After the failure of multiple efforts with systemic use of various drugs, local application of antiproliferative and anti-inflammatory agents released by specially designed coated stents led to considerable suppression of neointima and opened new prospects in the prevention of restenosis. An increasing body of evidence is showing the advantages provided by drug-eluting stents (DES) in almost all subsets of patients with coronary artery disease with a drastic decrease in the need for reintervention. To date, the most commonly used and the only US Food and Drug Administration (FDA) approved DES are a sirolimus-eluting stent (Cypher) and a paclitaxel-eluting stent (Taxus), both of which are polymer-based DES and will constitute the focus of this review. Recent data demonstrate that DES are not equal in their safety and efficacy. A less optimistic aspect of DES technology are the reiterated concerns about a more prolonged risk of stent thrombosis. Although all agree on the need of a longer duration of dual antiplatelet therapy in patients treated with DES, its optimal length is still to be defined. Because polymers used for stent coating are often seen at the origin of the compromised long-term safety of DES, new technologies able to avoid permanent polymers may offer a valuable alternative.