Acute coronary syndromes

Acute chest pain remains one of the most difficult challenges for the clinician. Nowadays, chest pain and its related complaints account for up to 10% of the adult emergency admissions and around 25% of all hospital admissions.^w1 Notably, the number of patients presenting with complaints of chest pain is rising.^w2 In a typical population of patients presented for the evaluation of acute chest pain in emergency departments, about 20% will have an acute coronary syndrome (ACS).^{w3 w4} The principal pathophysiological mechanism of an ACS is one of myocardial underperfusion resulting from either atherosclerotic plaque rupture or from erosion with different degrees of superimposed thrombus.1 ,2 A minority of patients, estimated to be around 10% of those who presented with chest pain, will not have an ACS but another life threatening problem such as a pulmonary embolism or an acute aortic dissection.^w1 Most patients are discharged with the diagnosis of a non-cardiac condition. These non-cardiac conditions include musculoskeletal syndromes, gastrointestinal syndromes, and psychological disorders.

When evaluating cardiac chest pain, an ECG provides the initial classification. Patients are subdivided into those with a persistent ST segment elevation and those without a persistent ST segment elevation. The latter is called a non-ST elevation ACS (NSTE-ACS). The concentration of the biomarkers of necrosis above a certain prespecified threshold differentiates NSTE-ACS patients into those with a non-ST elevation myocardial infarction (NSTEMI) as opposed to those with unstable angina (Ofigure 1). This article focuses on the timing of invasive evaluation in those patients with a suspected NSTE-ACS.

Evaluate the probability of an ACS

In patients presenting with a suspected NSTE-ACS, the first hurdle is to confirm …