This study is an exploratory clinical study to observe the improvement of heart function before and after the treatment by human umbilical cord mesenchymal stem cells, and the purpose is to evaluate the safety and effectiveness of human umbilical cord mesenchymal stem cells in the treatment of heart failure. The study is a randomized parallel controlled study. Patients receive a review of which main content includes symptom improvement, cardiac function improvement, and adverse events.

This study is an exploratory clinical study to observe the improvement of heart function before and after the treatment by human umbilical cord mesenchymal stem cells, and the purpose is to evaluate the safety and effectiveness of human umbilical cord mesenchymal stem cells in the treatment of heart failure. The study is a randomized parallel controlled study. The research process is as follows: 1. Twenty eligible patients with ischemic heart disease were recruited, fully informed, and signed a consent form, and randomly divided into CABG group (n=10) or CABG + stem cell treatment group (n=10); 2. CABG was performed under general anesthesia in both groups. In the cell therapy group, 1×10^7 human umbilical cord Mesenchymal Stem Cells were injected to the edge of the myocardial infarction area at 20 points at the same time in CABG; 3. Use vasoactive drugs and antibiotics to prevent infection one week after surgery. After the operation, before discharge, 1 month, 3 months, 6 months, 12 months after discharge, and once a year thereafter, until the death of the patient. Patients receive a review of which main content includes symptom improvement, cardiac function improvement, and adverse events.

Inclusion Criteria:

• The patients with coronary heart disease, the effect of drug treatment is not good, and the clinical manifestations of left ventricular insufficiency occur, EF<40%;
• Coronary angiography confirmed that there is a chronic occlusive disease of the coronary artery, which is manifested as severe stenosis of single or multiple coronary vessels (≥75%), or even complete occlusion;
• After the doctor explained the treatment process and possible toxic and side effects, he was willing to treat and agreed to cooperate in the observation of the efficacy. But patients can withdraw from clinical trials and long-term follow-up observation at any time and unconditionally;
• The patient has no mental illness and language dysfunction and can fully understand the treatment method.

Exclusion Criteria:

• Does not meet the above selection criteria;
• Unable to sign the informed consent form, unable to comply with the agreed timetable of this study;
• There are reasons to suspect that the patient was forced to join the trial;
• Acute left ventricular insufficiency, cardiogenic shock;
• The patient has any infectious diseases (including bacterial and viral infections);
• Others who are clinically considered unsuitable for this treatment.