183 Interv. Cardiol. (2014) 6(2), 183–198 ISSN 1755-5310 Non-ST-elevation myocardial infarction (NSTEMI) has become the most common presentation of acute myocardial infarction. Its treatment is challenging and often less straightforward compared with ST-elevation myocardial infarction (STEMI). First, clinicians must decide whether an initial invasive or an initial conservative treatment is appropriate for their NSTEMI patient. If an invasive strategy is chosen, subsequent decisions on the optimal timing of coronary angiography and possible intervention have to be made. Both aggressive and conservative strategies have their own potential risks and benefits. Aggressive strategies may result in more procedural complications, which is especially unwanted in patients otherwise at low risk of events. By contrast, conservative strategies may be harmful in high- risk patients who benefit most from early reperfusion therapy. We aim to discuss the evidence base of this decision process where risk stratification is of paramount importance with the goal of obtaining the optimal outcome for the individual patient. Keywords:฀ acute฀coronary฀syndrome฀•฀angiography฀•฀coronary฀artery฀bypass฀grafting฀delay฀ •฀coronary฀artery฀disease฀•฀myocardial฀infarction฀•฀percutaneous฀coronary฀intervention฀•฀risk฀ stratifcation฀•฀strategy฀•฀timing With an estimated incidence of 150–200 per 100,000 in the USA, non-ST-elevation myocardial infarction (NSTEMI) repre- sents the most common presentation of acute myocardial infarction [1,2] . Its usual cause is atherosclerotic plaque rupture or erosion and formation of a nonocclusive thrombus in a coronary artery, although other conditions that cause a supply/ demand imbalance to the myocardium may also cause NSTEMI (e.g., coronary spasm or dissection or severe anemia) [3,4] . With the introduction of troponin assays the last decade has seen an increase in the incidence of NSTEMI, while the incidence of ST- elevation myocardial infarction (STEMI) has simultaneously decreased [1,2] . That the improved sensitivity to diagnose NSTEMI does not necessarily result in additional identification of low-risk NSTEMI patients is reflected in a contemporary Swedish study. In this nationwide analysis no improvement in 1-year survival of NSTEMI patients was seen between 1990 and 2010, while STEMI patients did show improved survival [5] . In an analysis from the Global Registry of Acute Coronary Events (GRACE), 6-month outcome in NSTEMI patients did show a modest improvement between 1999 and 2005, but this was only after adjustment for the worsening baseline risk profile that was seen over time in NSTEMI patients but not in STEMI patients [6] . Thus, diagnosis, risk stratification and treatment of NSTEMI continues to be a major challenge in the upcoming decade and is often less straight- forward than in STEMI. We aim to give an overview of the role and timing of coro- nary intervention as well as the importance of risk stratification in selecting an appro- priate treatment strategy in patients with NSTEMI. Karim D Mahmoud 1,2 & David R Holmes Jr* ,1 1 Division฀of฀Cardiovascular฀Diseases,฀ Mayo฀Clinic,฀200฀First฀Street฀SW,฀ Rochester,฀MN฀55905,฀USA 2 Department฀of฀Cardiology,฀Thorax฀ Center,฀University฀of฀Groningen,฀ University฀Medical฀Center฀Groningen,฀ Groningen,฀The฀Netherlands *Author฀for฀correspondence:฀ Tel.:฀+1฀507฀255฀2504 Fax:฀+1฀507฀255฀2550 holmes.david@mayo.edu part of Interventional Cardiology Review 10.2217/ICA.14.7 © 2014 Future Medicine Ltd Role and timing of coronary intervention in non-ST-elevation myocardial infarction For reprint orders, please contact: reprints@futuremedicine.com