Myocardial blush grade (MBG) is validated measurement of myocardial perfusion . The MBG is used to assess the washout of myocardial blush during angiography. Grade 0 is defined as the failure of the contrast to enter the microvasculature. In grade 1 cases, contrast enters slowly, but fails to exit the microvasculature. Grade 2 defines delayed entry and exit from the microvasculature. Finally, grade 3 indicates normal entry and exit from the microvasculature .