This study is undertaken to determine if intravenous Lipo-PGE1 therapy would improve coronary microvascular perfusion in patients with ischemic heart disease by CMRI.

Inclusion Criteria:

1. Patients giving written consent after being provided with sufficient explanation about participation in this clinical trial
2. Patients aged between 35-70, no limitation on gender
3. Patients with significant CAD and no need to PCI: 50%-70% luminal stenosis as determined by diagnostic coronary angiography, and left main coronary artery stenosis less than 50%; no history of revascularization procedures before
4. MPRI<2.0
5. Type 2 DM patients with glycosylated hemoglobin levels>7%
6. All patients were PGE1-naive, defined as receiving no PGE1 therapy for more than 7 days during the previous 12 months
7. Hypertension remained stable for last 3 months, patients with controlled BP level: SBP<160mmHg and DBP<95mmHg

Exclusion Criteria:

1. Patients with a history of allergic to PGE1 or a history of prior PGE1 treatment.
2. History of revascularization procedures before: PCI or CABG
3. Patients with implanted pacemaker or ICD, ventricular assist device and intra-aortic balloon counter pulsation pump
4. Patients who have experienced myocardial infarction
5. Patients with serious systolic left ventricular function failure: echocardiography EF<25%
6. Claustrophobia
7. Patients who used Insulin pumps
8. SBP<90mmHg
9. Chronic renal function failure: creatinine level >2.5mg/dl or 221umol/l
10. Patients with serious or frequent arrhythmia ,atrial fibrillation、frequent ventricular premature contraction、sick sinus syndrome, second- or third degree atrioventricular block
11. Prior non-cardiac illness with estimated life expectancy <2-yrs
12. Women who are pregnant, lactation,or maybe pregnant in the study period
13. Unable to give informed consent