Update on the Medical Management of Acute Coronary Syndrome

Worldwide Statistics Each year: > 4 million patients are admitted with unstable angina and acute MI > 4 million patients are admitted with unstable angina and acute MI > 900,000 patients undergo PTCA with or without stent > 900,000 patients undergo PTCA with or without stent

Myocardial Ischemia Spectrum of presentation Spectrum of presentation –silent ischemia –exertion-induced angina –unstable angina –acute myocardial infarction

Cumulative 6-month mortality from ischemic heart disease Months after hospital admission Deaths / 100 pts / month Acute MI Unstable angina Stable angina Duke Cardiovascular Database N = 21,761; Diagnosis on adm to hosp

Ischemic Heart Disease evaluation Based on the patient’s –history / physical exam –electrocardiogram Patients are categorized into 3 groups –non-cardiac chest pain –unstable angina –myocardial infarction

Acute Coronary Syndrome Ischemic Discomfort Unstable Symptoms No ST-segment elevation ST-segment elevation Unstable Non-QQ-Wave angina AMI AMI ECG Acute Reperfusion History Physical Exam

Acute Coronary Syndrome The spectrum of clinical conditions ranging from: –unstable angina –non-Q wave MI –Q-wave MI characterized by the common pathophysiology of a disrupted atheroslerotic plaque

Unstable Angina Anti-coagulant Therapy Heparin –recommendation is based on documented efficacy in many trials of moderate size –meta-analyses (1,2) of six trials showed a 33% risk reduction in MI and death, but with a two fold increase in major bleeding –titrate PTT to 2x the upper limits of normal 1. Circulation 1994;89: JAMA 1996;276:

Unstable Angina Anti-coagulant Therapy Low-molecular-weight heparin advantages over heparin: –better bio-availability –higher ratio (3:1) of anti-Xa to anti-IIa activity –longer anti-Xa activity, avoid rebound –induces less platelet activation –ease of use (subcutaneous - qd or bid) –no need for monitoring