We described a case of a 74-year-old man who suffered from acute coronary syndrome 7 years after coronary artery bypass grafting. The patient underwent angioplasty of the obtuse marginal branch of the left coronary artery from venous graft access, which did not result in relief of ailments. Only angioplasty of the narrowed subclavian artery caused an improvement in the patient’s condition. The clinical significance of narrowing within the subclavian artery in patients after the procedure of implanting the left subclavian artery into the coronary artery system was discussed.