Abstract 3162: Mobilization of CXCR4+ Stem Cells in Acute Myocardial Infarction is Correlated with Left Ventricular Ejection Fraction and Myocardial Perfusion Assessed by MRI in 1 year follow-up (REGENT Trial)
Stem cells are mobilized into peripheral blood early in acute myocardial infarction (AMI). In patients with low left ventricular ejection fraction (LVEF) in acute phase of AMI the mobilization of stem cells is significantly impaired, however there is no data regarding the long-term MRI follow-up. AIM of the study was to correlate the early mobilization of CD34/CXCR4 + stem cells and the number of circulating cells after 1 year in patients with AMI treated with primary PCI with LVEF, left ventricular remodeling, late enhancement and adenosine first pass myocardial perfusion after 1 year follow-up.
METHODS: 48 patients were enrolled during index AMI and 15 patients underwent control MRI scan after 12–14 months. Stem cells number was measured on admission, after 24 hours, 7 days and 1 year. MRI study was performed using 1.5 T scanner. First pass study (Turbo-FLASH, 3 slices, short axis view, 30 images per slice) was performed first in stress conditions (adenosine 140 ug/min/kg, 4 min) and after 15 min in rest conditions. Delayed contrast enhancement study was performed in 3,6,9,15 min after second contrast injection by using inversion recovery segmented 3D turbo FLASH.
RESULTS: In patients with baseline LVEF < 40% the number of mobilized stem cells on admission was significantly lower in comparison to patients with LVEF > 40% (p < 0.03). Patients with LVEF < 40% after 1 year had lower baseline CXCR4+ cell counts than patients with LVEF > 40% on follow-up visit (p< 0.03). Baseline number of CD34/CXCR4+ cells was positively correlated with LVEF after 1 year (r=0.51; p< 0.02), and negatively with parameters of LV remodeling: LVEDV (r=−0.31; p< 0.03) and LVESV (r=−0.34; p<0.04). The peak number of mobilized CD34/CXCR4+ cells early in AMI was also significantly negatively correlated with the mean delayed enhancement after 1 year (r=−0.30; p<0.03). In patients with low number of circulating CD34/CXCR4+ cells the number of segments displaying impaired adenosine first pass perfusion was significantly higher (p < 0.05) than in patients with higer number of circiulating cells.
CONCLUSION: In AMI patients the number of circulating CD34/CXCR4 cells is significantly correlated with LVEF, left ventricular remodeling and myocardial perfusion measured using MRI after 1 year follow-up.