Three distinct degrees of assurance about occlusion length are defined in the Euro CTO club consensus statement. Without a doubt: The flow was verified to be TIMI grade 0 in an earlier angiography performed more than three months ago.Most likely: More than three months ago, a clinical diagnosis of acute myocardial infarction was made in the area of the blocked artery.Unknown: chronic total occlusion (CTO) with TIMI grade 0 flow and angiographic evidence of chronic occlusion; three months of stable angina symptoms have not improved. An epicardial coronary artery blockage with no antegrade flow, mature collaterals, no thrombus, no proximal cap staining, and a duration of three months or more is defined as a chronic complete occlusion (CTO) by the CTO Academic Research Consortium (CTO-ARC). The terms "intraplaque" (wire tracking inside plaque) and "extraplaque" (outside plaque but within adventitia) have been substituted for "true lumen" and "subintimal"(1) in the CTO-ARC paper. By doing away with the word "escalation" to represent both the escalation and de-escalation of wire tip-load, it creates two new categories for crossing techniques: antegrade wiring (AW) and retrograde wiring (RW).