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Commencing Volume 19, Issue 1, MedReviews has ceased the publication of this journal. Reviews in Cardiovascular Medicine will continue to be published by IMRPress, Ltd. (www.imrpress.org)

Volume 8, Supplement 3, 2007

Volume 8, Supplement 3, 2007

Table of Contents

Risk Stratifying the Acute Coronary Syndrome Patient: A Focus on Treatable Risk TEACH-PCI
Providing the optimal treatment for patients who present to the emergency room with chest pains or suspected acute coronary syndrome (ACS) remains a dilemma for many practitioners due to subjectivity, delayed diagnoses, and widely variable mechanisms with similar clinical presentations. In treating patients with chest pain but no obvious electrocardiogram changes, practitioners frequently utilize the American College of Cardiology (ACC)/American Heart Association (AHA) Guidelines. The guidelines group possible ACS patients together as unstable angina/non–ST-segment elevation myocardial infarction (NSTEMI) and recommend that treatment be based on level of risk. The challenge for practitioners is discriminating between “risk” and “treatable risk.” Evaluation of troponin levels can help identify patients with possible ACS who are at high risk of death and MI, and guide early decision making. Available data indicate that in the troponin-negative patient, routine interventions such as unfractionated heparin, glycoprotein IIb/IIIa receptor antagonists, and invasive approaches have no benefit in terms of reducing death and MI. Although the ACC/AHA Guidelines combine patients with unstable angina and NSTEMI, it is essential to evaluate troponin status in order to optimize patient outcomes and safety in the treatment of suspected ACS. [Rev Cardiovasc Med. 2007;8(suppl 3):S3-S8]
Anticoagulation for Acute Coronary Syndromes: From Heparin to Direct Thrombin Inhibitors TEACH-PCI
The anticoagulant properties of heparin were discovered in 1916, and by the 1930s researchers were evaluating its therapeutic use in clinical trials. Treatment of unstable angina with unfractionated heparin (UFH), in addition to aspirin, was introduced into clinical practice in the early 1980s. UFH was combined with aspirin to suppress thrombin propagation and fibrin formation in patients presenting with acute coronary syndromes (ACS) or patients undergoing percutaneous coronary intervention (PCI). However, UFH stimulates platelets, leading to both activation and aggregation, which may further promote clot formation. Clinical trials have demonstrated that newer agents, such as the low-molecular-weight heparins (LMWHs), are superior to UFH for medical management of unstable angina or non–ST-segment elevation myocardial infarction. Increasingly, the LMWHs have been used as the anticoagulant of choice for patients presenting with ACS. For patients undergoing PCI, LMWH provides no substantial benefit over UFH for anticoagulation; however, direct thrombin inhibitors (DTIs) have demonstrated safety and efficacy in this setting. UFH is likely to be replaced by more effective and safer antithrombin agents, such as DTIs. DTIs have antiplatelet effects, anticoagulant action, and most do not bind to plasma proteins, thereby providing a more consistent dose-response effect than UFH. The FDA has approved 4 parenteral DTIs for various indications: lepirudin, argatroban, bivalirudin, and desirudin. The antiplatelet, anticoagulant, and pharmacokinetic properties of bivalirudin support its use as the anticoagulant of choice for both lower- and higherrisk patients, including those undergoing PCI. [Rev Cardiovasc Med. 2007;8(suppl 3):S9-S17]
Implications of Bleeding and Blood Transfusion in Percutaneous Coronary Intervention TEACH-PCI
For patients undergoing percutaneous coronary intervention (PCI), bleeding complications are a major clinical concern. With advances in pharmacotherapy and devices over the past 2 decades, the risk of ischemic outcomes, such as myocardial infarction or death, has decreased. Bleeding complications have more recently become a clinical and research priority. Determining the incidence of and risk factors for bleeding is complicated by the multiple systems used to classify bleeding severity and report bleeding events. The origin of the data, clinical trials versus registries, also influences the incidence of reported bleeding events. Registry data suggest that risk of bleeding among patients undergoing PCI is higher in clinical practice than the incidence observed in clinical trials. Another clinical concern is the possible association between PCI-related bleeding complications and myocardial infarction, stroke, or death. Reduction in bleeding risk is a desirable goal that may potentially improve survival and increase comfort for patients undergoing PCI. Using strategies such as careful vascular access, alternative radial artery access, and modified antithrombotic regimen may reduce bleeding during PCI as well as improve patient outcomes. [Rev Cardiovasc Med. 2007;8(suppl 3):S18-S26]
Clopidogrel: Who, When, and How? TEACH-PCI
Clopidogrel has demonstrated improved outcomes for patients with acute coronary syndromes in several large randomized controlled trials. However, some questions exist about the use of clopidogrel in practice. Who benefits from clopidogrel? When should clopidogrel treatment be initiated? How much clopidogrel should be administered and for how long? Reviewing the results from trials completed to date that have assessed clopidogrel in patients with acute coronary syndromes may help to answer some of these questions. Clinical trial results have demonstrated a reduction in the composite endpoint of death, myocardial infarction, or stroke for patients with acute coronary syndromes who received clopidogrel plus aspirin compared with aspirin alone. For this patient population, early treatment with clopidogrel more than 6 hours before percutaneous coronary intervention (PCI) was associated with a reduction in the risk of death or recurrent ischemic events. The benefits of initiating patients on a 600-mg loading dose of clopidogrel before PCI have been demonstrated in several clinical trials. Clinical trial results and current guidelines recommend long-term treatment with clopidogrel for up to 1 year after PCI. [Rev Cardiovasc Med. 2007;8(suppl 3):S27-S34]
Coronary Intervention in Patients With Diabetes, Chronic Renal Disease, and the Elderly: Therapeutic Implications TEACH-PCI
Patients with diabetes mellitus, chronic renal disease, or advanced age who are undergoing percutaneous coronary intervention are at an increased risk of bleeding and thrombosis. This article reviews the clinical implications of these conditions and discusses the therapeutic options currently available for these patient groups. [Rev Cardiovasc Med. 2007;8(suppl 3):S35-S41]