Non-ST segment elevation (NSTE) acute coronary syndromes (ACS) account for the majority of coronary care unit admissions. Registry data from the UK reveal that six months after such an admission there is a 12.2% rate of death or non-fatal myocardial infarction (MI), and a 30% rate of death, MI, refractory angina or readmission to hospital for unstable angina. 1 The pathophysiology of these syndromes is increasingly understood and is associated with improved targeting of medical therapy. 2,3 Risk stratification is the foundation of the current strategy for early coronary angiography and revascularisation (either percutaneous or surgical) in patients with ACS, with the aim of detecting those known to be at higher risk of further events, including death, MI or readmission with further unstable symptoms. Markers of high risk have been discussed in an earlier article in this section. In brief, the invasive cardiologist expects to be offered three categories of patients with NSTE ACS who should be referred for inpatient angiography and revascularisation because of their risk of further early events: 1 Patients with ongoing pain or ECG changes. 2 Patients with elevated troponin (Tn) levels (for example, (TnT) >0.05 ng/ml). 3 Patients with ST depression on admission ECG. What is the evidence that offering angiography and then revascularisation to patients in one of these high risk clinical categories provides them with a better outcome? Several trials can be used to address this question. From the viewpoint of modern interventional cardiology, they may be divided into two groups: historical and contemporary. The relevance of the historical trials is dubious because they are so far away from modern clinical practice in terms of intervention (stents and drug-coated stents) and adjunctive pharmacological therapy (clopidogrel, glycoprotein (GP) IIb/IIIa inhibitors, statins, angiotensinconverting enzyme inhibitors). Even the contemporary studies provide only some indication of the potential benefit of the newer therapies available.