The Coronary Microcirculation in STEMI: The Next Frontier?

This editorial refers to ‘How does coronary stent implantation impact on the status of the microcirculation during primary percutaneous coronary intervention in patients with ST elevation myocardial infarction?’, by G.L. De Maria et al ., doi:10.1093/eurheartj/ehv353. There have been significant reductions in the mortality associated with ST elevation myocardial infarction (STEMI) over the last several decades. On the background of declining coronary heart disease mortality in the USA and Western Europe, the use of prompt reperfusion strategies and adjunctive pharmacotherapy, mortality in STEMI patients has continued to improve. The 30-day mortality from four French registries over 15 years decreased from 11.3 to 4.4% between 1995 and 2010.1 Data from the American College of Cardiology National Cardiovascular Data Registry (ACC-NCDR) reveal a risk-adjusted in-hospital mortality of 5.5% among STEMI patients in 2009.2 A large registry of STEMI patients in Sweden demonstrated a reduction in 30-day and 1-year mortality from 15.0 to 8.6% ( P < 0.001) and 21.0 to 13.3% ( P < 0.001), respectively.3 The reperfusion era was ushered in during the 1980s with mortality reductions obtained using thrombolytic therapy.4 This was followed by the use of mechanical reperfusion with percutaneous coronary intervention (PCI). Subsequent meta-analyses of randomized trials comparing thrombolytic therapy and PCI documented PCI as the preferred strategy leading to reductions in mortality, stroke and re-infarction. In longer-term (>1 year) follow-up, PCI for STEMI patients was found to lower mortality and re-infarction rates.5 This has led to PCI as the preferred strategy in patients presenting with STEMI and is endorsed by guidelines internationally.6 Despite prompt restoration of epicardial coronary flow, however, normalization of flow at the myocardial or microcirculatory level …