Evaluating percutaneous support for cardiogenic shock: data shock and sticker shock

Abstract

Cardiogenic shock, a state of systemic hypoperfusion resulting from cardiovascular dysfunction, is the leading cause of death in patients with ST-elevation myocardial infarction (STEMI).1 In spite of tremendous advances in cardiovascular care over the past two decades, mortality rates for patients with cardiogenic shock remain quite high, with some estimates as high as 50%.2 Given the underlying pathophysiology of cardiogenic shock, most commonly attributed to left ventricular failure resulting from STEMI, prompt institution of mechanical circulatory support seems intuitively important. The intra-aortic balloon pump (IABP) counterpulsation device was first introduced in the 1960s and has gained widespread acceptance as the device of choice for most patients with cardiogenic shock. Registry data suggest that cardiogenic shock is one of the most common conditions for which IABPs are used, accounting for 20% of all insertions.3 In fact, the ESC and ACC/AHA guidelines on STEMI strongly endorse the placement of an IABP in patients with cardiogenic shock refractory to pharmacological therapy.4,5 However, the evidence base from which these recommendations emanate is limited. There are no large randomized controlled trials which have rigorously evaluated the impact of IABPs in cardiogenic shock. Observational data from the Should We Emergently Revascularize Occluded Coronary Arteries in Shock (SHOCK) trial registry as well as the National Registry of Myocardial Infarction (NRMI)-2 suggest that patients treated with an IABP in addition to thrombolytics had lower in-hospital mortality than those receiving thrombolytics alone.6,7 Notably, patients undergoing primary percutaneous coronary intervention (PCI) in NRMI-2 did not benefit from IABP placement. A recent systematic review of >10 000 patients with cardiogenic shock in the setting of acute myocardial infarction (AMI) published in the European Heart Journal presented similar findings and concluded by challenging contemporary clinical guidelines.8 One of the theoretical shortcomings of … *Corresponding author. Tel: +1 857 203 6840/6841, Fax: +1 857 203 5550, Email: dlbhattmd{at}alum.mit.edu