Increased thrombolysis in myocardial infarction frame count in patients with myocardial infarction and normal coronary arteriogram: a possible link between slow coronary flow and myocardial infarction.

BACKGROUND

Thrombolysis in myocardial infarction (TIMI) frame count is a simple clinical tool for assessing quantitative indexes of coronary blood flow. This technique counts the number of cineangiographic frames from initial contrast opacification of the proximal coronary artery to opacification of distal arterial landmarks. We hypothesized that patients with normal coronary artery (NCA) and myocardial infarction (MI) might have impaired coronary flow. Accordingly, we assessed the TIMI frame counts of patients with NCA and MI and compared to patients with NCA and without MI.

MATERIALS AND METHOD

This retrospective study included consecutive patients with MI and who were found to have normal coronary angiograms performed between 1999 and 2003. Fifty patients (group I) with NCA and MI were enrolled in the study. Fifty consecutive patients with NCA and without MI were also enrolled in the study as control group (group II). Mean time interval between MI and coronary angiography was 6 +/- 2 days.

RESULTS

There were statistically significant differences between groups I and II in respect to gender (11 females (22%) versus 22 females (44%), p = 0.003, respectively) and smoking status (62% (31/50) versus 38% (19/50), p = 0.02). Comparison of TIMI frame counts between two groups revealed that group I patients had significantly higher TIMI frame counts than group two patients for all three coronary arteries (LAD: 40 +/- 12 versus 23 +/- 7, Cx: 47 +/- 14 versus 27 +/- 7, RCA: 36 +/- 10 versus 26 +/- 10, respectively, p < 0.001 for all). Smokers were significantly younger when compared to non-smokers (44 +/- 5 years versus 51 +/- 9 years, p = 0.008, respectively). TIMI frame counts of smokers did not significantly differ from those of non-smokers in group I patients. There were statistically significant differences between smokers and non-smokers in group II patients regarding TIMI frame counts for all three coronary arteries (LAD: 29 +/- 7 versus 18 +/- 3, LCX: 34 +/- 10 versus 22 +/- 4, RCA: 34+ /- 13 versus 20 +/- 4, respectively, p < 0.001 for all).

CONCLUSION

We have shown that patients with MI and NCA have higher TIMI frame counts for all coronary arteries when compared to patients without MI and NCA. Absence of difference between smokers and non-smoker in the myocardial infarction group in respect to TIMI frame count, has suggested that smoking does not lead to further increase of TIMI frame counts. On the other hand, in patients without MI and with NCA, smokers have higher TIMI frame counts than non-smokers have.