State of treatment of coronary artery disease by drug releasing stents

BACKGROUND: Despite improved technologies restenosis remains the main drawback of catheter-based interventions in coronary artery disease. Local application of anti-proliferative drugs through drug releasing stents is a promising concept addressed to solve this problem. DRUG RELEASING STENTS: Today, given the technical capabilities for controlled drug release from coronary stents, the development of drug eluting stents has emerged as one of the main research areas in interventional cardiovascular medicine. Several different approaches for drug loading on coronary stents as well as a variety of antiproliferative and anti-inflammatory agents, such as paclitaxel, actinomycin D, sirolimus, tacrolimus, everolimus and dexamethasone are under clinical investigation. RESULTS: Since the first enthusiastic reports from first in-man observations with drug coated stents, the success of the combination of both a biological and a mechanical approach has been proved in several controlled studies with restenosis rates between 0% in the RAVEL trial (sirolimus, Cordis Bx Velocity trade mark stent), 0% in the TAXUS I trial (paclitaxel, Boston Scientific NIRx trade mark stent) and 4% in the ASPECT Study (paclitaxel, Cook V-Flex plus trade mark stent). The risk of stent thrombosis seems to depend on the dose of the antiproliferative drug - in the SCORE trial stent thrombosis occurred in 6.3% of patients with high dose of QP2 and the antiplatelet therapy, in the ASPECT subgroup with cilostazol instead of clopidogrel and high dose of paclitaxel in up to 25%, whereas in RAVEL and TAXUS I no stent thrombosis was observed. CONCLUSION: If the "one digit" restenosis rate observed in clinical trials could be confirmed in clinical practice without increase of complications, especially stent thrombosis using multiple and/or long stents, we can expect in the near future that implanting drug eluting stents in larger patient groups and lesion subsets will cause a reduction of patients with need for surgical revascularization.