Over the last decade Thrombolysis in
Myocardial Infarction (TIMI) flow grades have been the gold standard for the assessment of efficacy of
infarct-artery reperfusion. However, with the introduction of core angiographic laboratories, the reproducibility of TIMI flow grades has been questioned. The corrected TIMI frame count (
CTFC) has been developed as a more reproducible method of quantifying
infarct artery blood flow after
myocardial infarction (MI). We have utilised the
CTFC in two studies to examine
infarct-artery blood flow. In the
Hirulog in Early Reperfusion and Occlusion (HERO 1) study, the
CTFC was measured at 90-120 minutes after administration of
aspirin,
streptokinase and either
Hirulog or
heparin. Only 27% of patients had a normal
CTFC (< or = 27) in the
infarct-related artery. Patients with a prolonged
CTFC (> 27) had more abnormal left ventricular function (LVF) as measured by the mean chord score in the 'area at risk' (-2.51 vs -2.06, p = 0.02), on left ventriculography. In a second study,
infarct-artery flow was examined four weeks and one year after MI. At four weeks, only 43% of patients with patient
infarct-related arteries had a 'normal'
CTFC of < or = 27. A prolonged
CTFC at four weeks was a univariate predictor of increased reocclusion at one year (p = 0.001). CTFCs are frequently abnormal in patent
infarct-related arteries, and predict reocclusion. Whether frame counting is a better predictor of late clinical outcomes than the TIMI flow grade needs to be prospectively examined in large clinical trials.