Abstract
Cardiogenic shock is a complex clinical entity associated with very high mortality and intensive resource utilization. Despite the widespread use of timely reperfusion and appropriate pharmacotherapy, the survival rate remains at around 50%. Recently, percutaneous axial flow pumps have been integrated into the therapeutic spectrum of cardiogenic shock management. However, most of the literature supporting their use stems from observational studies. To date, attempts to perform randomized controlled trials with percutaneous axial flow pumps have failed. This underlines the challenge of performing a well-conducted randomized controlled trial that provides the highest level of evidence. Such a trial is warranted, because percutaneous axial flow pumps are costly, and are associated with serious complications. The major pitfalls of previous studies were lack of standardized cardiogenic shock definitions according to clinical severity, inappropriate patient and device selection, lack of standardized trial endpoints and high rates of crossovers; these issues must be carefully considered and evaluated. In light of recent trial failures, we aim to summarize the challenges associated with performing randomized controlled trials of percutaneous axial flow pumps in patients experiencing acute myocardial infarction complicated by cardiogenic shock, and to suggest potential means of overcoming them.