Timing of angiography in non-ST elevation myocardial infarction

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. Figure 1 Diagnostic approach to the patient with chest pain. NSTE-ACS, non-ST elevation acute coronary syndrome; NSTEMI, non-ST elevation myocardial infarction; STEMI, ST elevation acute myocardial infarction; UAP, unstable angina pectoris. In patients presenting with a suspected NSTE-ACS, the first hurdle is to confirm …