Current interventional cardiology reports最新文献

Transmyocardial laser revascularization (TMLR) is increasingly used for improving myocardial perfusion in patients with diffuse coronary artery disease and refractory ischemia. The efficacy of TMLR, however, is in doubt because no definite increase in blood flow or longevity has been demonstrated. Although histologic results after TMLR show some neocapillary formation, the relative amount of angiogenesis is similar to what occurs naturally after myocardial infarction. Hence, it is suspected that these few capillaries would be sufficient to maintain a viable myocardium. Alternatively, the creation of collateral vessel "arteriogenesis" rather than capillary formation alone may improve the clinical outcome. Comprehensive experimental studies seem to indicate the feasibility of producing new collaterals. This method of vascularization is dependent upon specific cytokines or enzymes that induce proliferation of native arterial endothelial cells and smooth muscle cells. It is critical that we develop a better understanding of which factors regulate arteriogenesis, and concentrate on methods to document its existence in the clinical and experimental setting.

Therapeutic angiogenesis is a novel technique that may provide a treatment strategy for ischemic heart diseasepatients who are not candidates for standard revascularization procedures. It works by promoting the growth of blood vessels provide new venues for blood flow. Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are the most widely studied angiogenic agents. They have been shown to induce functionally significant angiogenesis in various animal models of chronic myocardial ischemia using various delivery strategies. Preclinical and clinical studies using these growth factors are reviewed with an emphasis on the different delivery strategies,including intracoronary and intravenous delivery; left atrial injections; intrapericardial administration; local intravascular and perivascular delivery; and intramyocardial delivery using single bolus delivery, repeated administration, gene therapy, and sustained delivery. Although intracoronary and intravenous delivery may be preferred for their ease of use and their applicability to a large patient population, systemic recirculation and lack of sustained tissue exposure to these therapeutic agents may limit the usefulness of this approach. Intrapericardial and intramyocardial administration, sustained local delivery, and second-generation gene therapy vectors may allow a safer and more sustained administration and may be preferable for clinical use. However, only well-designed randomized, double-blind placebo-controlled trials using outcome measures tailored to myocardial angiogenesis will determine the feasibility and effectiveness of this treatment modality.

The recognition of the critical importance of platelets in acute coronary syndromes and interventional procedure outcomes has resulted in a growing armementarium of antiplatelet therapies. These medications offer the ability to achieve complete inhibition, which may be accompanied by hemorrhagic risks. Measurement of platelet function may improve dosing of these medications by optimization of clinical benefit and limitation of bleeding risks. A number of current assays can be used to assess platelet function.

This article reviews recent advances in antiplatelet therapies, compares the antiplatelet/antithrombotic efficacy of various antiplatelet strategies to that of platelet glycoprotein (GP) IIb/IIIa receptor antagonists, and discusses issues in the development of long-term anti-GP IIb/IIIa therapy, and the potential adjunct strategies with GP IIb/IIIa antagonists.

Although the equipment, techniques, and adjunctive pharmacologic agents used during coronary angioplasty have evolved dramatically over the past 20 years, unfractionated heparin remains a standard component of the procedure. This article reviews recent data and current concepts regarding the use, importance, and proper dosing of heparin during percutaneous coronary intervention, especially when concomitant platelet glycoprotein IIb/IIIa receptor antagonist therapy is used.