Coronary angiography has been used as the gold standard to determine whether reperfusion has been successful. TIMI (thrombolysis in myocardial infarction) grades have been developed for this purpose1and have been shown to provide prognostic information. It has, however, been known for a quarter of a century that reflow in the infarct related artery does not necessarily imply tissue perfusion.2 It is also known, that regions within the myocardium that show poor tissue perfusion after reflow (no reflow or low reflow) have histological evidence of tissue necrosis.2 That myocardial contrast echocardiography (MCE) can define regions of no reflow was demonstrated nearly 15 years ago in a dog model.3

As is unfortunately often the case, the medical community either ignored or was unaware of these experimental data. Not surprisingly, therefore, the first report of MCE documenting no reflow in patients who underwent reperfusion for acute myocardial infarction (AMI) published about five years ago4 was hailed as new knowledge. A number of clinical studies since then has confirmed these findings.5-7 Approximately a quarter to a third of patients with TIMI grade 3 flow on coronary angiography have poor tissue perfusion, which is associated with poor recovery in regional function and a worse prognosis.8 The paper by Czitromet al in this issue9 adds to this body of knowledge.

MCE uses microbubbles that remain in the intravascular space. Because 90% of the myocardial microvasculature consists of capillaries,10 the spatial distribution of these bubbles in the myocardium provides an assessment of regional capillary integrity. Areas with necrosis are associated with capillary damage2 and impaired microvascular function.11 A non-invasive assessment of capillary structure and microvascular function, therefore, provides a simple means of assessing tissue perfusion and integrity. The ultimate test for the success of …