CD34 and angina pectoris: A prospective, randomized, double-blinded phase I clinical trial recruiting 38 patients with severe diffuse coronary artery disease refractory to medication and unsuitable for coronary intervention, who were subjected to intra-coronary CD34+ cell infusion after subcutaneous granulocyte colony-stimulating factor (G-CSF) administration twice a day for four days, showed highly significant improvements in left ventricular ejection fraction and increases in neovascularization, as well as the alleviation of angina and heart failure symptoms [49].