In clinical trials, the treatment effect of an intervention is usually measured as the impact on a prespecified end point. All-cause mortality is an ultimate end point and often regarded as the “gold standard” for cardiovascular trials. However, since major therapeutic breakthroughs like acute revascularisation with percutaneous coronary intervention, use of antithrombotic agents, β blockers, ACE inhibitors and statins have improved prognosis after acute myocardial infarction (AMI), large-scale studies are necessary to demonstrate improved survival by a new treatment. Another option is to use an intermediate end point like quality of life or functional capacity, which may be more closely linked to disease progression. From a patient perspective, improvement of such intermediate end points may be more important than the sole prolongation of life.1

An alternative to an ultimate or intermediate end point is to use a surrogate end point. The FDA defines a surrogate end point as a laboratory measurement or physical sign which is used in therapeutic trials as a substitute for a clinically meaningful end point that is a direct measure of how a patient feels, functions or survives and is expected to predict the effect of the treatment. Changes of the …