LAUSR

The hybrid algorithm to chronic total occlusion (CTO) percutaneous coronary intervention (PCI) ( Figure 1 ) was published in 2012 and provided a systematic, angiographybased, approach to crossing coronary CTOs in 4 steps: (I) dual coronary angiography, which is essential to determine the characteristics of the lesion, especially occlusion length and the presence of collaterals appropriate for the retrograde approach; (II) systematic review of 4 lesions characteristics (proximal cap, lesion length, quality of distal vessel, and presence of interventional collaterals); (III) initial crossing strategy selection based on the aforementioned 4 parameters; and (IV) early change if the initially selected crossing strategy fails to achieve crossing within a reasonable period of time (1).