Innovations in drug-eluting stents.

Coronary artery disease affects patients worldwide and is a major cause of morbidity and mortality. Historically, the treatment approach for patients with coronary syndromes has been surgical. In the 1970s, percutaneous balloon angioplasty was introduced, leading to creation of a new field of interventional cardiology, which allowed a non-surgical minimally invasive approach to treat patients with coronary artery disease. However, the major limitations of balloon angioplasty were acute vessel closure and later restenosis. The introduction of bare metal stents and then drug-eluting stents (DES) revolutionized the practice of interventional cardiology and allowed for safe treatment of increasingly complex coronary artery lesions. Although drug-eluting coronary stents improve patient outcomes, they still have limitations. These limitations may arise from delayed endothelialization, local vessel hypersensitivity and endothelial dysfunction secondary to the drug elution, the durable polymer coating, or the stent scaffold. This comprehensive review will discuss the evolution of intracoronary stents from their introduction to current utilization of DES as well as future research on bioabsorbable stents and polymers.

Reperfusion therapy in ST-elevation myocardial infarction: guidelines, strategies, pharmacology, and stent selection.

Treatment of acute ST-elevation myocardial infarction (STEMI) has rapidly evolved with many advances made in the past decade. Percutaneous coronary intervention is the preferred strategy when available, although there remains a role for thrombolytic therapy, with prompt reperfusion as the primary goal. With regards to antithrombotic therapy, bivalirudin now has a significant role in STEMI care with improved outcomes over unfractionated heparin plus GP IIb/IIIa inhibitors. Dual antiplatelet therapy has become a mainstay of treatment with combination of aspirin and clopidogrel, as well as an expanding role of more potent novel agents, prasugrel and ticagrelor. In primary PCI in STEMI, coronary stents are now being used routinely, although short-term and long-term outcomes of drug-eluting stents (DES) versus bare metal stents (BMS) continue to be studied. Recent meta-analyses have examined the trade-off of lower rates of in-stent restenosis and need for target vessel revascularization with DES versus the potential increase in the risk of stent thrombosis and need for longer course of dual antiplatelet therapy. This review will discuss the current STEMI guidelines and strategies, recent advances in pharmacotherapy, and data on stent selection.

Cell-free and erythrocytic S-nitrosohemoglobin inhibits human platelet aggregation.

BACKGROUND: Nitric oxide (NO) and related molecules are thought to inhibit human platelet aggregation by raising levels of cGMP. METHODS AND RESULTS: Both oxidative stress (reactive oxygen species) and hemoglobin (Hb) seem to oppose NO effects. A major fraction of NO in the blood is bound to thiols of Hb, forming S-nitrosohemoglobin (SNO-Hb), which releases the NO group on deoxygenation in the microcirculation. Here we show that (1) both cell-free and intraerythrocytic SNO-Hb (SNO-RBC) inhibit platelet aggregation, (2) the oxidation state of the hemes in Hb influences the response--SNO-metHb (which is functionally similar to SNO-deoxyHb) has greater platelet inhibitory effects than SNO-oxyHb, and (3) the mechanism of platelet inhibition by SNO-Hb is cGMP independent. CONCLUSIONS: We suggest that the RBC has evolved a means to counteract platelet activation in small vessels and the proaggregatory effects of oxidative stress by forming SNO-Hb.