Minimalist immediate mechanical intervention in acute ST-segment elevation myocardial infarction: is it time to redefine targets?

One of the greatest frustrations of the interventional cardiologist is that restoring flow down an occluded epicardial artery in patients with ST segment elevation myocardial infarction (STEMI) does not equate to normalisation of downstream microvascular flow. Far from being a rare occurrence, microvascular obstruction (MVO), which can be suspected from absence of ST-segment elevation resolution, angiographic scores (TIMI grade flow <3 and myocardial blush grade <3) or, more accurately, magnetic resonance imaging (MRI), occurs in 5–50% of STEMIs (1). Of note, MVO is a strong negative prognosticator associated with a higher prevalence of arrhythmias, pericardial effusion, tamponade, early congestive heart failure, adverse left ventricular remodelling, readmissions for heart failure and mortality (1).