Transplantation of Bone Marrow-Derived Stem Cells Improves Myocardial Diastolic Function: Strain Rate Imaging in a Model of Hibernating Myocardium

Background: The aim of this study was to evaluate the cardioprotective effects of bone marrow-derived stem cells on myocardial compliance in a chronic ischemia model regarding strain rate (SR) parameters during dobutamine stress echocardiography (DSE). Methods: Ameroid constrictors were placed around the circumflex arteries of 23 domestic pigs to induce chronic vessel occlusions. Fifteen pigs received transendocardially bone marrow derived stem cells, and 8 received placebo injections (a 0.9% solution of NaCl) into the ischemic region. At week 6, the animals were evaluated regarding myocardial fibrosis, neovascularization, apoptosis, and diastolic function during DSE. Results: Stem cell-injected hearts showed significantly less fibrosis, higher ejection fractions, significant neovascularization, and less ventricular dilatation than controls (P < .05). Strain rate imaging revealed improved diastolic function, with higher early diastolic SR values and lower E/Ea ratios compared with controls (P < .05). Early diastolic SR during DSE identifies viable myocardium (extent of fibrosis, r = 0.86, P = .0001). Conclusion: The endocardial injection of stem cells improves diastolic function in chronic ischemic myocardium and helps attenuate postinfarction remodeling. (J Am Soc Echocardiogr 2009; 22: 1180-9.)