TIMI Thrombus Grade
An angiographically evident thrombus can be classified as follows for the purpose of quantitative evaluation in clinical trials and day to day practice if needed [1]:
- Grade 0: no angiographic evidence of thrombus
- Grade 1 (possible thrombus present): reduced contrast density, haziness, irregular lesion contour, or a smooth convex meniscus at the site of total occlusion suggestive but not diagnostic of thrombus
- Grade 2 (small thrombus): definite thrombus, with greatest dimensions up to 1/2 the vessel diameter
- Grade 3 (moderate thrombus): definite thrombus but with greatest linear dimension >1/2 but <2 vessel diameters
- Grade 4 (large-sized thrombus): definite thrombus, with the largest linear dimension >2 vessel diameters
- Grade 5: total occlusion
Angiographic evidence of thrombus for study purpose is taken as the presence of thrombus grades 2 to 5.
Abbreviation: TIMI: Thrombolysis In Myocardial Infarction (From the landmark TIMI trial [2])
References
- C M Gibson, J A de Lemos, S A Murphy, S J Marble, C H McCabe, C P Cannon, E M Antman, E Braunwald, TIMI Study Group. Combination therapy with abciximab reduces angiographically evident thrombus in acute myocardial infarction: a TIMI 14 substudy. Circulation. 2001;103:2550-4.
- TIMI Study Group. The Thrombolysis in Myocardial Infarction (TIMI) trial. Phase I findings. N Engl J Med. 1985 Apr 4;312(14):932-6.