RESUMO
Although the widespread adoption of timely invasive reperfusion strategies over the last two decades has significantly improved the prognosis of patients with ST-segment elevation myocardial infarction (STEMI), up to half of patients after angiographically successful primary percutaneous coronary intervention (PCI) still have signs of inadequate reperfusion at the level of coronary microcirculation. This phenomenon, termed coronary microvascular dysfunction (CMD), has been associated with impaired prognosis. The aim of the present review is to describe the collected evidence on the occurrence of CMD following primary PCI, means of assessment and its association with the infarct size and clinical outcomes. Therefore, the practical role of invasive assessment of CMD in the catheterization laboratory, at the end of primary PCI, is emphasized, with an overview of available technologies including thermodilution- and Doppler-based methods, as well as recently developing functional coronary angiography. In this regard, we review the conceptual background and the prognostic value of coronary flow reserve (CFR), index of microcirculatory resistance (IMR), hyperemic microvascular resistance (HMR), pressure at zero flow (PzF) and angiography-derived IMR. Finally, the so-far investigated therapeutic strategies targeting coronary microcirculation after STEMI are revisited.
RESUMO
AIMS: Previous studies indicated that a chronic total occlusion (CTO) in a non-infarct-related artery is linked to higher mortality mainly in the acute setting in patients with ST-elevation myocardial infarction (STEMI). Our aim was to assess the temporal distribution of mortality risk associated with non-culprit CTO over years after STEMI. METHODS AND RESULTS: The study included 8679 STEMI patients treated with primary percutaneous coronary intervention (PCI). Kaplan-Meier cumulative mortality curves for non-culprit CTO vs. no CTO were compared with log-rank test, with landmarks set at 30 days and 1 year. Adjusted Cox regression models were constructed to assess the impact of non-culprit CTO on mortality over different time intervals. Tests for interaction were pre-specified between non-culprit CTO and acute heart failure and left ventricular ejection fraction. The primary outcome variable was all-cause mortality, and the median follow-up was 5 years. Non-culprit CTO was present in 11.6% of patients (n = 1010). Presence of a CTO was associated with increased early [30-day adjusted hazard ratio (HR) 1.91, 95% confidence interval (CI) 1.54-2.36; P < 0.001] and late mortality (5-year adjusted HR 1.66, 95% CI 1.42-1.95; P < 0.001). Landmark analyses revealed an annual two-fold increase in mortality in patients with vs. without a CTO after the first year of follow-up. The observed pattern of mortality increase over time was independent of acute or chronic LV impairment. CONCLUSIONS: Non-culprit CTO is independently associated with mortality over 5 years after primary PCI for STEMI, with a constant annual two-fold increase in the risk of death beyond the first year of follow-up.
