ORIGINAL ARTICLE
Corrected TIMI frame count and count velocity
frame
M.G. Stoel, C.C. de Cock, H.J. Spruijt, F. Zijlstra, C.A. Visser
Background. Little is known about the differences between the corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and the 'frame count velocity' (FCV), an estimate of blood flow velocity derived from the TFC and the length of the related vessel, in each of the three epicardial coronary arteries. Methods. After angioplasty of 119 coronary vessels, 50 left anterior descending (LAD), 27 left circumflex (LCX) and 42 right coronary arteries (RCA), the CTFC was compared with the FCV assessed by measuring the length of the coronary arteries with an intracoronary guidewire. Results. The three vessels show a significant difference in mean length (the LAD was 14.5±1.6 cm, LCX 12.8±1.9 cm and RCA 11.3±1.4 cm, p50% were excluded, it is not likely this had a major influence on the measured flow velocities. Another limitation is that the injection of the dye was not synchronised to the cardiac cycle. This has been shown to influence the TFC.s The measurements were done at varyinm times after angioplasty, and postischaemic hyperaemia could have influenced the TFC and FCV. However, these influences were probably the same for all three arteries. Finally, in this study there was no comparison with coronary flow velocity measured with an intracoronary Doppler wire. The pressure wave generated by the contrast injection and the viscosity of the contrast medium could have influenced the flow velocity measurements.
Conclusion Because the TFC, used as an index for coronary flow velocity, is dependent on the length of the related vessel, it was corrected for the longer length of the LAD to calculate the CTFC. However, the present study shows that correction can be done more precisely by normalising the TFC to the significantly different mean length of each of the three coronary vessels. In this way the 'frame count velocity' can be calculated without having to use an intracoronary guidewire. Therefore, the frame count velocity is a fast, simple and, compared with the CTFC, more accurate angiographic method to estimate coronary blood flow velocity. U Ref nces 1 2 3
4
5
Gibson CM, Cannon CP, Daley WL, et al. TIMI frame count: a quantitative method of assessing coronary artery flow. Circulation 1996;93:879-88. Gibson CM, Dodge JTJ, Goel M, et al. Angioplasty guidewire velocity: a new simple method to calculate absolute coronary blood velocity and flow. AmJ Cardiol 1997;80:1536-9. Dodge JTJ, Brown BG, Bolson EL, et al. Intrathoracic spatial location of specified coronary segments on the normal human heart. Applications in quantitative arteriography, assessment of regional risk and contraction, and anatomic display. Circulation 1988;78:1167-80. Heller LI, Silver KH, Vlllegas BJ, et al. Blood flow velocity in the right coronary artery: assessment before and after angioplasty. J Am CoU Cardiol 1994;24:1012-7. Abaci A, Oguzhan A, Eryol NK, et al. Effect of potential confounding factors on the thrombolysis in myocardial infarction (TIMI) trial frame count and its reproducibility. Circulation 1999;100:2219-23.
Nethcrlands Heart Journal, Volumc 11, Number 3, March 2003
Corrected TIMI frame count and count velocity
frame
M.G. Stoel, C.C. de Cock, H.J. Spruijt, F. Zijlstra, C.A. Visser
Background. Little is known about the differences between the corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and the 'frame count velocity' (FCV), an estimate of blood flow velocity derived from the TFC and the length of the related vessel, in each of the three epicardial coronary arteries. Methods. After angioplasty of 119 coronary vessels, 50 left anterior descending (LAD), 27 left circumflex (LCX) and 42 right coronary arteries (RCA), the CTFC was compared with the FCV assessed by measuring the length of the coronary arteries with an intracoronary guidewire. Results. The three vessels show a significant difference in mean length (the LAD was 14.5±1.6 cm, LCX 12.8±1.9 cm and RCA 11.3±1.4 cm, p50% were excluded, it is not likely this had a major influence on the measured flow velocities. Another limitation is that the injection of the dye was not synchronised to the cardiac cycle. This has been shown to influence the TFC.s The measurements were done at varyinm times after angioplasty, and postischaemic hyperaemia could have influenced the TFC and FCV. However, these influences were probably the same for all three arteries. Finally, in this study there was no comparison with coronary flow velocity measured with an intracoronary Doppler wire. The pressure wave generated by the contrast injection and the viscosity of the contrast medium could have influenced the flow velocity measurements.
Conclusion Because the TFC, used as an index for coronary flow velocity, is dependent on the length of the related vessel, it was corrected for the longer length of the LAD to calculate the CTFC. However, the present study shows that correction can be done more precisely by normalising the TFC to the significantly different mean length of each of the three coronary vessels. In this way the 'frame count velocity' can be calculated without having to use an intracoronary guidewire. Therefore, the frame count velocity is a fast, simple and, compared with the CTFC, more accurate angiographic method to estimate coronary blood flow velocity. U Ref nces 1 2 3
4
5
Gibson CM, Cannon CP, Daley WL, et al. TIMI frame count: a quantitative method of assessing coronary artery flow. Circulation 1996;93:879-88. Gibson CM, Dodge JTJ, Goel M, et al. Angioplasty guidewire velocity: a new simple method to calculate absolute coronary blood velocity and flow. AmJ Cardiol 1997;80:1536-9. Dodge JTJ, Brown BG, Bolson EL, et al. Intrathoracic spatial location of specified coronary segments on the normal human heart. Applications in quantitative arteriography, assessment of regional risk and contraction, and anatomic display. Circulation 1988;78:1167-80. Heller LI, Silver KH, Vlllegas BJ, et al. Blood flow velocity in the right coronary artery: assessment before and after angioplasty. J Am CoU Cardiol 1994;24:1012-7. Abaci A, Oguzhan A, Eryol NK, et al. Effect of potential confounding factors on the thrombolysis in myocardial infarction (TIMI) trial frame count and its reproducibility. Circulation 1999;100:2219-23.
Nethcrlands Heart Journal, Volumc 11, Number 3, March 2003
