Abstract 15233: Presence of Endothelial Colony-Forming Cells is Associated With Reduction of Microvascular Obstruction Limiting Infarct Size and Left Ventricular Remodelling: A Magnetic Resonance Imaging Study in Patients With Acute Myocardial Infarction
Background: Endothelial colony-forming cells (ECFCs) have proliferative and vasculogenic capacities and can be detected in patients with myocardial infarction (MI). Although high levels of ECFCs have been reported to lead to positive left ventricular (LV) remodelling after acute MI, the potential mechanism by which these cells improve LV function has never been assessed. The aim of this study was to evaluate the relationship between ECFC levels and microvascular obstruction (MVO), and the impact of this relation on infarct size and LV remodelling at 6 months as assessed by magnetic resonance imaging (MRI).
Methods: We enrolled 109 patients <75 years old, admitted with a first MI within 12 hours of onset of symptoms. Peripheral blood samples were drawn to assess number of ECFC colonies (culture cells). Measurements of infarct size by MRI were performed at day 5 and at 6 months follow-up. MVO was defined as subendocardial areas of hypoenhanced signal surrounded by hyperenhanced myocardial tissue and expressed as % total myocardium.
Results: ECFC colonies were detected in 51/109 patients (47.2% of pts) at admission (ECFCpos patients).At 5 days, MVO was more frequently observed (63% vs 33% p=0.003) and of greater magnitude (7±6% vs 3±5%, p=0.0004) in ECFCneg patients versus ECFCpos patients respectively. At 6 months, there was a significantly greater reduction in infarct size in ECFCpos patients compared with their ECFCneg counterparts (−33.7±33.2% vs −15.1±24.6%, respectively; p=0.003). This reduction in infarct size was associated with a significant improvement in LV ejection fraction and a significant reduction in LV end diastolic and systolic volumes in ECFCpos patients. Moreover, a significant positive correlation was observed among ECFCpos patients between MVO at day 5 and infarct size at 6 months follow-up (r2=0.58, p<0.0001), while the number of ECFC colonies was significantly correlated with the relative change in infarct size at 6 months MRI (r2=0.33, p<0.0001).
Conclusions: The presence of ECFC colonies is associated with a reduced degree of MVO early after MI, leading to reduced infarct size and positive LV remodelling at 6 months and can be considered as a marker of microvascular integrity in acute MI patients.
- © 2010 by American Heart Association, Inc.