Page 119 - Coronary hemodynamics in acute myocardial infarction - Matthijs Bax
P. 119

Recovery of microvascular dysfunction following STEMI
Introduction
In 30 to 40% of ST-elevation myocardial infarction (STEMI) patients, myocardial tissue perfusion remains compromised, despite restoration of epicardial patency after primary percutaneous coronary intervention (PPCI)1. Microvascular dysfunction, due to reperfusion injury, endothelial dysfunction, neurohumoral activation or intramyocardial haemorrhage, has been described as a possible cause for this phenomenon2-4. This is, in turn, proposed as the pathophysiological mechanism in the development of adverse left ventricular (LV) remodeling and overt heart failure1,5,6.
Microvascular function can be measured invasively with coronary flow reserve
(CFR) and hyperaemic microvascular resistance index (HMRI). CFR estimates
the vasodilatory capacity of the coronary microvascular bed7. Insights into
the temporal evolution of microvascular dysfunction and its implications on
long-term left ventricular function (LVF) are currently lacking. The primary
objective of this study was to assess whether microvascular dysfunction in the infarct-related artery (IRA), as assessed by CFR within one week after PPCI, was associated with LVF at two years as assessed by cardiac magnetic resonance 7 (CMR) imaging. This was compared to the prognostic value of HMRI. Secondary
objectives were to assess whether an improvement in microvascular function was associated with LVF improvement.
Methods
Study population and procedures
For the current study, we included a subpopulation of the HEBE trial, designed to assess the effect of bone marrow mononuclear cell therapy on cardiac improvement in STEMI patients8-10. This substudy included patients who underwent paired intracoronary flow measurements in the Academic Medical Center and the VU University Medical Center, Amsterdam (n=64). Patients who experienced a reinfarction during follow-up (n=2) were excluded. The study was conducted in accordance with the Declaration of Helsinki and the study protocol was approved by the institutional review boards of both centers.
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