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Fig. 2. Shown here is a histogram displaying the percent of patients with a given CTFC (grouped by bins of 5 frames) following thrombolysis in the TIMI 4, TIMI 10A, and TIMI 10B trials. Note that very few patients have a CTFC > 100.

Corrected TIMI Frame Count

Fig. 2. Shown here is a histogram displaying the percent of patients with a given CTFC (grouped by bins of 5 frames) following thrombolysis in the TIMI 4, TIMI 10A, and TIMI 10B trials. Note that very few patients have a CTFC > 100.

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Fig. 3. Cumulative distribution function of corrected TIMI frame counts in 960 patients from the TIMI 4, 10A, and 10B studies. Any CTFC can be chosen on the X-axis as a definition of thrombolytic success. The corresponding value on the Y-axis displays the percent of patients that satisfy that definition of success. Only approx one quarter of patients have normal flow (i.e., a CTFC < 28) following thrombolysis.

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Corrected TIMI Frame Count

Fig. 3. Cumulative distribution function of corrected TIMI frame counts in 960 patients from the TIMI 4, 10A, and 10B studies. Any CTFC can be chosen on the X-axis as a definition of thrombolytic success. The corresponding value on the Y-axis displays the percent of patients that satisfy that definition of success. Only approx one quarter of patients have normal flow (i.e., a CTFC < 28) following thrombolysis.

deviation among 78 arteries with normal flow was only 3.1 frames, a coefficient of variation of approx 14% (2). We have recently studied the impact of the force of injection and shown that the CTFC following power injections performed at the 10th and 90th percentile of human injection rates differ from each other by only 2 frames (13,14).

Using the CTFC, coronary blood flow appears to be unimodally distributed as a continuous variable (2) (Figs. 2 and 3). Thus, any division of flow into normal and abnormal categories is arbitrary. Although we do not use the CTFC to determine the TFGs, in a retrospective analysis, the TIMI Angiographic Core Laboratory tended to classify flow as TIMI grade 2 flow if the CTFC was >40 (approx 1.3 s) (2). In the TIMI 4, 10A and 10B trials (7-9), the 90-min CTFC in culprit arteries is unimodally distributed with a mean CTFC of 35.6 ± 20.8 frames (n = 960) at 90 min following thrombolysis (Figs. 2 and 3). Approximately one quarter of patients achieved normal flow with a CTFC <28 frames, (i.e., within the 95% confidence interval for flow in patients without acute MI) (Fig. 3).

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