Figure 1

Intimal hyperplasia after balloon overdilation and nicotine injection in the coronary arteries. The control group showed thin and compact coronary artery wells (A). All treatment groups showed an increase of the percentage intimal hyperplasia in the OCT images (B–H). In the volumetric analysis of OCT, percentage intimal area significantly increased in the balloon overdilation group compared to the control groups (26.38 ± 3.81% in the control group vs 36.15 ± 7.65 in the balloon overdilation groups vs 29.26 ± 3.48 in the 0.05 mg/kg nicotine injection group). The percentage intimal area significantly increased in the 0.25 mg/kg and 0.5 mg/kg nicotine injection groups compared to the 0.05 mg/kg nicotine injection group (29.26 ± 3.48 in the 0.05 mg/kg nicotine injection group vs 42.07 ± 6.75 in the 0.25 mg/kg nicotine injection group vs 44.11 ± 8.16 in the 0.5 mg/kg nicotine injection group). The percentage intima area significantly increased in the 0.25 mg/kg nicotine with balloon overdilation and 0.5 mg/kg nicotine with balloon overdilation groups compared to the 0.05 mg/kg nicotine injection with balloon overdilation group (50.6 ± 5.52 in the 0.05 mg/kg nicotine injection with balloon overdilation vs 60.86 ± 7.2 in the 0.25 mg/kg nicotine injection with balloon overdilation vs 65.36 ± 3.40 in the 0.5 mg/kg nicotine injection with balloon overdilation groups; p < 0.05) (I).