Acute Coronary Syndrome: from Epidemiology to Treatment

The term "acute coronary syndrome" (ACS) was introduced a decade ago to describe a spectrum of conditions resulting in acute myocardial ischaemia.It comprises unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI) and ST-segment myocardial infarction (STEMI).ACS is often the fi rst presentation of coronary artery disease (CAD), the leading cause of mortality and morbidity in many parts of the world, including Singapore.Patients presenting with ACS frequently present fi rst to primary healthcare physicians, who then routinely refer them directly to Emergency Departments.Remarkable achievements in understanding ACS, and consequently to the diagnosis and treatment of this condition have been made over the past 10 years.The underlying cause of ACS is a sudden rupture of a preexisting atherosclerotic plaque.Unlike stable and often fl ow limiting plaques that present with typical effort angina, the plaques that rupture (coined vulnerable plaques) are often non-occlusive and hence un-detectable by conventional stress testing.Imaging by modalities such as CT angiography or routine angiography are unable to detect with any certainty those plaques prone to rupture, therefore explaining why ACS is often the fi rst presentation of patients to physicians.Once plaque rupture takes place, this is immediately followed by thrombosis around the plaque.If the thrombus is occlusive, this leads to a classic STEMI.However, if the thrombus is only partially occlusive, patients will present with symptoms of UA and/or a NSTEMI.Whatever the presentation, there is now understanding that unless the diagnosis is quickly made and fl ow restored, usually by percutaneous coronary intervention (PCI), there would be as a consequence cardiac muscle damage and loss of effective cardiac output, leading to cardiac failure.In this issue of Annals, we published 16 excellently prepared papers on ACS.It is particularly encouraging that we received papers not only from cardiologists, but also from psychiatrists and rheumatologists, as there are numeourous other medical conditions related to ACS.Likewise, apart from papers originated from Singapore, there are contributions from Hong Kong and the United Kingdom.