Importance of the TIMI frame count: implications for future trials

Mark A Appleby,C Gibson Michael,Michael Chen,Andrew D Michaels

doi:10.1186/cvm-1-1-031

Abstract

Although the TIMI (Thrombolysis In Myocardial Infarction) flow grade classification scheme is widely used to assess angiographic outcomes, it is limited by poor reproducibility and its categoric nature. The corrected TIMI frame count (CTFC) is a simple, more objective continuous variable index of coronary blood flow that can be broadly and inexpensively applied. This measure of the time for dye to traverse a coronary artery is both accurate (highly correlated with Doppler velocity measurements) and precise (reproducible). The method has been prospectively validated as providing independent risk stratification above and beyond the conventional TIMI flow grades. It has been shown to be a predictor of restenosis, and has been of value in elucidating the underlying pathophysiology of acute myocardial infarction. In view of the above and its ease of use, we anticipate that CTFC will become a widely used method to evaluate coronary blood flow.

Highlights

The TIMI (Thrombolysis in Myocardial Infarction) flow grade is a widely used method for the assessment of coronary artery flow in acute coronary syndromes
A correction factor is required to compensate for the longer length of the left anterior descending artery (LAD) compared with the circumflex and right coronary arteries
Distance along coronary arteries measured using angioplasty guidewires may be combined with TIMI frame count measurements to give absolute velocity and flow assessments that are sensitive to small changes in perfusion [10]

Summary

Introduction

Introduction The TIMI (Thrombolysis in Myocardial Infarction) flow grade is a widely used method for the assessment of coronary artery flow in acute coronary syndromes. TIMI flow grade assessment is limited by interobserver variability (core laboratories agree 71% of the time) [3] and by the need for a more objective quantification of the different degrees of complete perfusion in a coronary artery. In order to overcome these problems, the TIMI frame count was developed as a more quantitative index of coronary artery flow [4].

Results

Conclusion