Effects of intermittent cold-exposure on culprit plaque morphology in ST-segment elevation myocardial infarction patients: a retrospective study based on optical coherence tomography

Abstract Objective Present study aimed to explore the effects of intermittent cold-exposure (ICE) on culprit plaque morphology in patients with ST-segment elevation myocardial infarction (STEMI) in frigid zone. Methods Totally 848 STEMI patients with plaque rupture (N = 637) or plaque erosion (N = 211) were enrolled consecutively according to optical coherence tomography imaging. Data on the changes of outdoor air temperature corresponding to 24 solar terms were collected. Patients were divided into different groups according to 24 solar terms and the number of days with indoor central heating. Imaging data were measured and analyzed qualitatively and quantitatively. Statistical analysis was conducted to elucidate the possible association of the STEMI patients of different groups with plaque morphology of culprit vessel with alterations of ambient temperature. Results The incidence of both plaque rupture and plaque erosion presented trough in summer. The incidence of plaque rupture reached a peak value in early winter when outdoor air temperature dropped below 0 °C and declined with supply of central heating. Persistent cold exposure in early winter was positively and significantly associated with plaque rupture. The incidence of plaque erosion presented a peak in severe winter with outdoor air temperature dropping below −20°C and steady supply of central heating. ICE in severe winter was positively and significantly associated with plaque with intact intima, especially in aged male or current smoking patients. The positive correlation of cold exposure with lipid size in culprit plaque in winter weakened with central heating. Conclusion ICE resulted from switching staying in between outdoor cold environment and indoor warm temperature with central heating in severe winter changed culprit plaque morphology in STEMI. Plaque rupture decreased whereas plaque erosion increased impacted by ICE. The effect of ICE on the transformation of plaque morphology might be explained by reduced lipid deposition.