Lutz Büllesfeld | PubMed Health

PubMed2002

[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.

Angioplasty, Balloon, Coronary↗

PubMed2002

Initial experience with paclitaxel-coated stents.

Local delivery of immunosuppressive or antiproliferative agents using a drug-eluting stent is a new technology that is supposed to inhibit in-stent restenosis, thus providing a biological and mechanical solution. This technique is a very promising. To date, several agents have been used, including paclitaxel, QP-2, rapamycin, actinomycin D, dexamethason, tacrolimus, and everolimus. Several studies, published recently or still ongoing, have evaluated these drugs as to their release kinetics, effective dosage, safety in clinical practice, and benefit. These studies include: SCORE (paclitaxel derivative), TAXUS I-VI, ELUTES, ASPECT, DELIVER (paclitaxel), RAVEL, SIRIUS (sirolimus), ACTION (actinomycin), EVIDENT, PRESENT (tacrolimus), EMPEROR (dexamethason), and FUTURE (everolimus). Paclitaxel was one of the first stent-based antiproliferative agents under clinical investigation that provided profound inhibition of neointimal thickening depending on delivery duration and drug dosage. The randomized, multicenter SCORE trail (Quanam stent, paclitaxel-coated) enrolled 266 patients at 17 sites. At 6-month's follow-up, a drop of 83% in stent restenosis using the drug-eluting stent could be achieved (6.4% drug-eluting stent vs 36.9% control group), which was attributable to a remarkable decrease in intimal proliferation. Unfortunately, due to frequent stent thrombosis and side-branch occlusions, the reported 30-day MACE rate was 10.2%. The randomized TAXUS-I safety trial (BSC, NIRx, paclitaxel-coated) also demonstrated beneficial reduction of restenotic lesions at 6-month's follow-up (0% vs 10%) but was associated with the absence of thrombotic events presumably due to less drug dosage. The ongoing TAXUS II-VI trials are addressing additional insight regarding the efficacy of the TAXUS paclitaxel-eluting stent. ASPECT and ELUTES evaluated paclitaxel-coated stents (i.e., Cook and Supra G), including subgroups with different drug dosages. With respect to stent restenosis and neointimal proliferation, both studies demonstrated a clear dose response. The RAVEL and the SIRIUS trials evaluated sirolimus-coated stents (i.e., Cordis, Johnson & Johnson, and Bx VELOCITY stents). Results confirmed the beneficial findings regarding reduction of renarrowing using a drug-eluting stent without any major adverse effects. Although parameters such as drug toxicity, optimal drug dosage, or delayed endothelial healing still need to be evaluated, today's clinical experience indicates that drug-coated stents are extremely beneficial in the interventional treatment of coronary lesions.

Clinical Trials as Topic↗