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Thrombolysis in Myocardial Infarction frame count in saphenous vein grafts
E N Al-Mousa1, J T Dodge, M Rizzo
1Department of Medicine, the Brigham and Women's Hospital, Harvard Medical School, Boston, Mass, USA.
Insights
The Thrombolysis in Myocardial Infarction frame count method, a continuous measure of coronary blood flow, has been successfully extended to assess saphenous vein grafts, providing normal reference values for improved graft assessment.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Medical Imaging
Background:
- The Thrombolysis in Myocardial Infarction (TIMI) flow grade system, while common, has limitations in assessing coronary blood flow.
- A novel continuous measure, the TIMI frame count (TFC), was previously developed for native coronary arteries.
- This study aimed to adapt and validate the TFC method for coronary artery bypass grafts.
Purpose of the Study:
- To extend the Thrombolysis in Myocardial Infarction frame count (TFC) methodology to evaluate blood flow in coronary artery bypass grafts (CABGs).
- To establish normal reference values for TFC in saphenous vein grafts (SVGs).
Main Methods:
- Retrospective analysis of cinefilms from patients post-coronary artery bypass grafting.
- Exclusion of patients with recent myocardial infarction and grafts with stenosis.
- Measurement of cineframes for dye transit from graft ostium to anastomosis (TFCg) and to a distal coronary landmark (TFC).
Main Results:
- For 93 vein grafts, the mean TFCg was 19.2 ± 5.7 frames.
- For 67 grafts, the mean TFC was 33.9 ± 8.0 frames.
- Upper limits for normal flow were determined as 31 frames for TFCg and 50 frames for TFC.
Conclusions:
- The Thrombolysis in Myocardial Infarction frame counting technique is applicable to normal saphenous vein grafts.
- Normal reference values for TFC in SVGs are now established, aiding in clinical assessment.
Background:
Although the Thrombolysis in Myocardial Infarction flow grade system is a widely used index of coronary blood flow, it has important limitations. We recently described a new continuous measure of blood flow in native coronary arteries, the Thrombolysis in Myocardial Infarction frame count (TFC), and sought to extend this method to coronary artery bypass grafts.
Methods:
We retrospectively analyzed cinefilms of patients' status after coronary artery bypass grafting, excluding patients with recent myocardial infarction and grafts with stenoses in the graft or native vessel. We counted the cineframes required for dye to travel from the ostium of the graft to the graft anastomotic site (TFCg) and to a standardized distal coronary landmark (TFC).
Results:
For all vein grafts combined, TFCg was 19.2+/-5.7 frames (mean+/-SD, n = 93) and the TFC was 33.9+/-8.0 frames (n = 67). The upper limits for "normal" flow, calculated from the 95% confidence intervals, were 31 frames for TFCg and 50 frames for TFC.
Conclusions:
The Thrombolysis in Myocardial Infarction frame counting method has now been extended to normal saphenous vein grafts, and normal reference values are provided.