While anatomical grading of obstructive coronary lesions are quiet easy ,functionalc assessment is always difficult.The famous TIMI grading system had one unique problem .TIMI 1 and 2 grades are relatively easy to grade. TIMI 3 flow which corresponds to normal penetration and normal distal perfusion . This distal perfusion was entirely optical .
This was an important issue , in assessing post PCI or thromolysis patients . It was realised much later , TIMI 3 flow is stunningly heterogenous group .It was ironical , even after a successful PCI , restoration of TMI3 flow could not be relied upon as an index of successful PCI .
So , the PAMI study group included time as additional factor in grading TIMI 3 flow. PAMI 3 is essentailly same as TIMI 3 flow but with a condition , complete distal vessel filling must occur within 3 cardiac cycle . PAMI 3 can be termed as a refined version of TIMI 3 introduced in the evaluation of success of primary PCI . This helps us define or diagnose slow filling .
What are the other ways to grade TIMI 3 flow
- Myocardial blush index
- TIMI frame count ( < 25 frames )
PAMI : Primary angioplasty in myocardial infarction
TIMI : thromolysis in acute myocardial infarction