Assessment of left ventricular segmental function after autologous bone marrow stem cells transplantation in patients with acute myocardial infarction by tissue tracking and strain imaging

BACKGROUND: Emerging evidence suggests that stem cells can be used to improve cardiac function in patients after acute myocardial infarction. In this randomized trial, we aimed to use Doppler tissue tracking and strain imaging to assess left ventricular segmental function after intracoronary transfer of autologous bone-marrow stem cells (BMCs) for 6 months' follow up. METHODS: Twenty patients with acute myocardial infarction and anterior descending coronary artery occlusion proven by angiography were [corrected] randomized into intracoronary injection of bone-marrow cell (treated, n = 9) or diluted serum (control, n = 11) groups. GE vivid 7 and Q-analyze software were used to perform echocardiogram in both groups 1 week, 3 months and 6 months after treatment. Three apical views of tissue Doppler imaging were acquired to measure peak systolic displacement (Ds) and peak systolic strain (epsilonpeak) from 12 segments of LV walls. Left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume (ESV) were obtained by Simposon's biplane method. RESULTS: (1) 3 months later, Ds and epsilonpeak over the infract-related region clearly increased in the BMCs group [Ds: (4.49 +/- 2.71) mm vs (7.56 +/- 2.95) mm, P < 0.01; epsilonpeak: (-13.40 +/- 6.00)% vs (-17.06 +/- 6.05)%, P < 0.01], but not in the control group [Ds: (4.74 +/- 2.67) mm vs (5.01 +/- 3.23) mm, P > 0.05; epsilonpeak: (-13.84 +/- 6.05)% vs (-15.04 +/- 6.75)%, P > 0.05]. At the same time, Ds over the normal region also increased, but the Ds enhancement was markedly higher in the BMCs group than that in the control group [(3.21 +/- 3.17) mm vs (0.76 +/- 1.94) mm, P < 0.01]. Parameters remained steady from the 3rd to 6th month in either group (P > 0.05). (2) LVEF in treated and control groups were almost the same at baseline (1st week after PCI) [(53.37 +/- 8.92)% vs (53.51 +/- 5.84)%, P > 0.05]. But 6 months later, LVEF in the BMCs group were clearly higher than that in the control group [(59.33 +/- 12.91)% vs (50.30 +/- 8.30)%, P < 0.05]. (3) There were no evident difference in EDV or ESV between two groups at baseline [EDV: (113.74 +/- 23.24) ml vs (129.94 +/- 32.72) ml, P > 0.05; ESV: (57.12 +/- 18.66) ml vs (62.09 +/- 17.68) ml, P > 0.05]. Three months later, EDV and ESV in the control group were markedly greater than those in the BMCs group [EDV: (154.89 +/- 46.34) ml vs (104.85 +/- 33.21) ml, P < 0.05; ESV: (82.91 +/- 35.79) ml vs (49.54 +/- 23.32) ml, P < 0.05]. But EDV and ESV did not change much from 3rd to 6th month in either group (P > 0.05). CONCLUSIONS: Emergency transplantation of autologous BMCs in patients with acute myocardial infarction helps to improve global and regional contractility and attenuate post-infarction left ventricular remodeling. Tissue tracking and strain imaging provide quick, simple and noninvasive methods for quantifying left ventricular segmental function in humans.