- All patients with true bifurcational coronary arteries lesion defined as (lesions in which there is more than 50% diameter stenosis in both the parent vessel and the ostium of the side branch arising from the lesion, and both are more than 2.0 mm in diameter by visual estimation) (13) undergoing intervention either urgent or elective in Assiut university Cath. lab during period from September 2017 to September 2018 will be included in this study.