| Objective: Coronary flow reserve (CFR) has been reported to have important clinical implications for the evaluation and treatment of coronary artery diseases. The aim of this study was to measure CFR using TIMI frame count (TFC) method and to evaluate its reliability.Methods: We studied three groups of patients: group A consisted of 67 arteries of 50 patients with chest pain and normal angiograms (23 male, 27 female, age 57 10); group B consisted of 72 culprit arteries of 62 patients with angina pectoris (45 male, 17 female, age 59 9); group C consisted of 53 infarct related coronary arteries (IRAs) of 53 patients with acute myocardial infarction (AMI) (45 male, 8 female, age 57 9). We measured the number of cineframes required for contrast from the ostium of coronary artery to first reach the standardized distal landmark with a frame counter (baseline TFC, B-TFC) as recording an angiogram in a suitable projection [the right anterior oblique projection with caudal angulation for the left anterior descending coronary artery (LAD) and the left circumflex coronary artery (LCx), the left anterior oblique projection for the right coronary artery (RCA)]. A repeat angiogram in the same projection was recorded 15 seconds after an intracoronary bolus of adenosine 5'-triphosphate (ATP) (the left coronary artery 50ug, the right coronary artery 20jig), then the number of cineframes was measured (hyperemic TFC, H-TFC). The LAD frame counts were corrected by dividing by 1.7 to derive the corrected TFC (CTFC). The CFR using this method was defined as the baseline CTFC (B-CTFC) divided by the hyperemic CTFC (H-CTFC). 35 culprit arteries of 62 patients with angina pectoris and 48 IRAs of 53 patients with AMI were performed percutaneous coronary intervention (PCI) (all with intracoronary stenting). The same measurements were repeated after the procedure.Results: B-CTFC was not different between group A and group B (25 8 versus 25 10, P>0.05), and it was higher in group C than in group A and group B (P<0.01) before PCI. This index was not changed in both group B and group C (P>0.05) after PCI. The H-CTFC in group B and group C was higher than that in group A (15 7 and 26 14 versus 10 4, P<0.01), and it was higher in group C than that in group B (P<0.01) beforePCI. The H-CTFC in group B was improved to the level of that in group A (P>0.05) after PCI. In group C, this index was improved after PCI (26 14 versus 18 8, P<0.01), although it was still higher than that in group A and B(P<0.01). The CFR in group A was significantly higher than that in group B and group C (2.64 + 0.94 versus 1.79 + 0.51 and 1.47 + 0.28, P<0.01) before PCI. After PCI, the CFR in group B was improved significantly (2.59 + 0.98 versus 1.84 + 0.54, P<0.01) and was close to that in group A (P>.05). The improvement was also observed in group C (1.88 + 0.08 versus 1.47 + 0.04, P<0.01), but its CFR did not recover to the normal level. Before PCI, there was a negative correlation between the CFR and percent diameter stenosis (%DS) in group B (r=-0.553, P<0.001), but the correlation between the CFR and % DS was not existed in group C (r=-0.142,P=0.311).Conclusion: As a surrogate method for measuring coronary flow velocity, TIMI frame count can be used to assess coronary flow reserve effectively in different coronary artery diseases. |
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