By Andrea Rubboli
Triple therapy of aspirin, clopidogrel and oral anticoagulation with vitamin K antagonists (VKA) is the most effective antithrombotic treatment after percutaneous coronary intervention with stent implantation (PCI-S) to prevent both stent thrombosis and thromboembolism related to the clinical condition for which VKAs are indicated. Available data, however, suggest that triple therapy is associated with a relevant incidence of major bleeding, which may occur up to three to five times more frequently than with dual antiplatelet treatment. Moreover, an increasing incidence of major haemorrhages has been reported as triple therapy prolongs: whereas an average 6% of major bleeding has been observed at one month, as much as about 10% has been reported at six and 12 months or more (Figure 1). Since major haemorrhagic complications after an acute coronary syndrome unfavourably impact on prognosis, meticulous care needs to be paid in preventing such events. This is especially true after percutaneous coronary intervention with stent implantation, when (even minor) bleeding may lead to premature discontinuation of aspirin and/or clopidogrel, which in turn exposes patients to a potentially catastrophic event as stent thrombosis. Of note, prophylactic administration of proton pump inhibitors in the attempt to reduce the risk of gastrointestinal bleeding appears not applicable as a routine, because of the several recent reports suggesting a negative interaction between these agents and clopidogrel.
Therefore, in patients on chronic VKAs undergoing percutaneous coronary intervention the implantation of bare metal, rather than drug-eluting, stents is currently recommended in the light of the short (one month) need for clopidogrel (and accordingly, triple) therapy. Certainly, such strategy may prove much less than optimal in situations where the occurrence of restenosis is higher (i.e., long lesions and/or small vessels, diabetic patients, etc.) or troublesome (i.e., last remain vessel). The availability of drug-eluting stents which allow a shorter duration of clopidogrel treatment therefore, is more than welcome. Optima (CID Vascular, Saluggia, Italy) is a polymer-free, Carbofilm coated stent eluting Tacrolimus from abluminal reservoirs, which has been widely tested in patients with either stable or unstable coronary artery disease showing an excellent safety and efficacy profile. Of note, post-hoc analyses of the clinical studies carried out with Optima showed the efficacy of a clopidogrel duration as short as two months, which had been carried out in about 30 to 50% of patients. The subsequent Multicenter registry with Antiplatelet Treatment two-sIX months (MATRIX), in which more than 500 patients were prospectively enrolled, confirmed the safety and efficacy of a two-month only dual antiplatelet treatment regime (Figure 2). This device, which is now being tested in another prospective, multicentre registry named Ongoing WARfarin and coronary STENTing (WAR-STENT)-Optima, where patients on chronic VKAs undergoing PCI-S are enrolled, may prove the drug-eluting stent of choice in this increasingly large and fragile patient subset.
Andrea Rubboli, Cardiac Catheterization Laboratory, Division of Cardiology, Ospedale Maggiore, Bologna, Italy