Persistent Scleroderma-like Microvascular Remodeling Associated with Chronic Passive Smoking: A Three-Year AI-Assisted Capillaroscopic Study

Objective To determine whether chronic passive smoke exposure may be associated with persistent structural microvascular alterations detectable by quantitative nailfold videocapillaroscopy. Methods A longitudinal observational analysis was conducted in a nonsmoking adult with sustained domestic secondhand smoke exposure. Nailfold videocapillaroscopy was performed at two time points separated by three years under standardized conditions. Images were analyzed using artificial intelligence–assisted quantitative software (CAPI-Detect) to measure capillary density, apical diameter, proportion of enlarged and giant capillaries, and microhemorrhages per millimeter. Results Quantitative analysis demonstrated persistent structural abnormalities, including 64.1% enlarged capillaries, 16.7% giant capillaries (mean apical diameter 59.1 µm), and 4.13 microhemorrhages/mm, with preserved capillary density (7.32/mm). Findings remained stable over three years. Comprehensive immunologic and systemic evaluation remained negative throughout follow-up. Conclusions Chronic passive smoke exposure was temporally associated with persistent structural microvascular alterations detectable by longitudinal quantitative capillaroscopy. These findings suggest that sustained endothelial stress may contribute to stable architectural remodeling in susceptible individuals and highlight the utility of AI-assisted microvascular phenotyping.