TIMI flow grade 4
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: TIMI 4, TIMI 4 flow, TIMI 4 flow grade, TFG 4, TFG4, hyperemia, hyperemic flow
Overview
TIMI grade 4 flow is a term developed by Dr. C. Michael Gibson, M.S., M.D. to describe hyperemic flow on a coronary arteriogram.[1] Hyperemic flow on a coronary arteriogram is defined qualitatitively as near instantaneous filling of the coronary artery with dye, and quantitatively as a corrected TIMI frame count < 14 frames. Hyperemic flow in a coronary artery may be due to either repayment of oxygen debt following ischemia due to a balloon inflation for instance, or distal embolization. If it is due to distal embolization, and if impaired myocardial perfusion is present (TIMI myocardial perfusion grade 0 or TIMI myocardial perfusion grade 1), then the mortality associated with TIMI grade 4 flow is actually higher than that of TIMI grade 3 flow.[1] In this scenario, the hyperemic flow is a surrogate or marker of endogenous adenosine release due to distal embolization, rather than being causally related to adverse outcomes.
References
- ↑ 1.0 1.1 Gibson CM, Pride YB, Buros JL, Kunadian V, Southard MC, Harrigan CJ; et al. (2008). "Relation of hyperemic epicardial flow to outcomes among patients with ST-segment elevation myocardial infarction receiving fibrinolytic therapy". Am J Cardiol. 101 (9): 1232–8. doi:10.1016/j.amjcard.2007.12.023. PMID 18435949.