Is all unstable angina the same? insights from the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT-I). The CAVEAT-Investigators

Myocardial infarction: contemporary management strategies

Myocardial infarction (MI) is a common clinical diagnosis, associated with significant morbidity and mortality, not only in the short term, but also years following the index event. A more complete understanding of the pathophysiology of MI has ushered the era of multipronged treatment approach, with a combination of goal-directed revascularization, a broad adjunctive pharmacological therapy and aggressive secondary prevention measures. The goals of this article are to review the basic pathophysiological processes, which lead up to a clinical diagnosis of MI, to highlight the essential elements of clinical presentation and to summarize the evidence for comprehensive therapy. Emphasis has been placed on the choice of primary reperfusion therapy for ST-elevation MI, on risk-stratification of patients with non-ST elevation MI, and on rationale behind the selection of anti-ischaemic and antithrombotic therapy. Finally, evidence-based approach to secondary prevention is outlined.

In stent restenosis: bane of the stent era

The long term outcome of stent implantation is affected by a process called in stent restenosis (ISR). Multiple contributory factors have been identified, but clear understanding of the overall underlying mechanism remains an enigma. ISR progresses through several different phases and involves numerous cellular and molecular constituents. Platelets and macrophages play a central role via vascular smooth muscle cell migration and proliferation in the intima to produce neointimal hyperplasia, which is pathognomic of ISR. Increased extracellular matrix formation appears to form the bulk of the neointimal hyperplasia tissue. Emerging evidence of the role of inflammatory cytokines and suppressors of cytokine signalling make this an exciting and novel field of antirestenosis research. Activation of Akt pathway triggered by mechanical stretch may also be a contributory factor to ISR formation. Prevention of ISR appears to be a multipronged attack as no therapeutic "magic bullet" exists to block all the processes in one go.

Impact of contemporary guideline compliance on risk stratification models for acute coronary syndromes in The Registry of Acute Coronary Syndromes

We compared the predictive value of the Rush score with the Thrombolysis In Myocardial Infarction (TIMI) risk score in unselected patients with an acute coronary syndrome and evaluated the effect of compliance with established guidelines on the accuracy of these models. The Registry of Acute Coronary Syndromes is a retrospective registry of 3,754 consecutive patients (38% women; mean age 67 years) who presented with acute coronary syndrome to the emergency department between April 1, 1999, and December 31, 2000, at 9 hospitals. The primary end point was death, myocardial infarction, or urgent revascularization during hospitalization. Rush classification was based on quartiles of predicted risk of cardiac complication (<2% for class I vs >15% for class IV). The TIMI score was implemented as published. Compliance with guidelines for acute coronary syndrome was assessed with a 4-point scale based on the aggregate use of aspirin, beta blockers, heparin, and glycoprotein IIb/IIIa inhibitors. Fifteen percent of patients met the primary end point. The primary end point rates for TIMI scores 0/1, 2, 3, 4, 5, and 6/7 were 11%, 14%, 13%, 11%, 14%, and 12%, respectively (p = NS). The primary end point rates for Rush classes I, II, III, and IV were 6%, 8%, 9%, and 17%, respectively (p <0.001). After controlling for compliance with established guidelines, the odds ratio of an event increased by 46% for each unit increase in Rush score (p <0.001). After adjusting for the Rush score, the odds ratio decreased by 54% for each unit increase in compliance (p <0.001). Thus, compliance with current American College of Cardiology/American Heart Association guidelines significantly improves prognosis, regardless of the risk score. The use of established risk scores may overestimate event rates in unselected populations.

Risk stratification in non-ST segment elevation acute coronary syndromes with special focus on recent guidelines

Patients with unstable angina or non-ST segment elevation (non-Q-wave) myocardial infarction are a heterogeneous group with respect to their risk of developing clinically significant adverse events such as subsequent myocardial infarction and death. Recent guidelines promote risk stratification of these patients, targeting high-risk patients for maximal antithrombotic and antiischemic therapy and low-risk patients for early discharge. We reviewed current and future modalities for risk stratification of patients and the predictive value of these methods in context with available pharmacologic agents. Unfortunately, most of the data identifying a particular pharmacologic regimen as beneficial in high-risk patients are retrospectively derived from large trials. Until prospective studies that use markers to guide therapy are available, clinicians should be familiar with the use of these risk markers and their application to the role of a given management strategy, including pharmacologic therapy.