Age-related effects of smoking on culprit lesion plaque vulnerability as assessed by grayscale and virtual histology–intravascular ultrasound

BACKGROUND: Although smoking is a risk factor for coronary atherosclerosis, the age-related impact on lesion characteristics and plaque instability remains unclear. PATIENTS AND METHODS: In ADAPT-DES, 780 patients with 916 culprit lesions were evaluated by preprocedural grayscale and virtual histology-intravascular ultrasound. RESULTS: Current smokers (smoking within 1 month) more often presented with acute coronary syndrome (67 vs. 51 vs. 51%, P<0.05) compared with former smokers (no smoking for >1 month) or nonsmokers. In patients 65 or more years of age, current smokers (vs. nonsmokers) showed larger normalized volumes of plaque and media [8.6 (7.8-9.4) vs. 7.2 (6.8-7.7) mm/mm, P=0.016] and external elastic membrane [14.4 (13.2-15.5) vs. 12.8 (12.2-13.4) mm/mm, P=0.05]. At the minimal lumen area site, despite a greater plaque burden, the larger external elastic membrane area [14.4 (13.1-15.7) vs. 12.0 (11.3-12.7) mm, P=0.003] contributed toward preserving the minimal lumen area [2.6 (2.4-2.7) vs. 2.6 (2.5-2.7) mm, P=0.91] in current smokers (vs. nonsmokers) 65 or more years of age. Moreover, current smokers (vs. nonsmokers) 65 or more years of age showed a greater normalized necrotic core volume [1.19 (0.96-1.46) vs. 0.75 (0.66-0.85) mm/mm, P=0.0007], more thin-cap fibroatheromas (61 vs. 48%, P=0.04), and plaque ruptures (38 vs. 26%, P=0.051). Conversely, in patients younger than 65 years of age, there was no significant difference in culprit lesion morphology among current, former, and nonsmokers. CONCLUSION: In patients 65 or more years (not in patients<65 years), smoking increased culprit lesion plaque instability (greater plaque with more necrotic core, thin-cap fibroatheromas, positive remodeling, and plaque ruptures).