Association between physical activity and sedentary behaviour on carotid atherosclerotic plaques: an epidemiological and histological study in 90 asymptomatic patients.

OBJECTIVE: Carotid atherosclerotic plaques are a source of emboli for stroke. 'Unstable' carotid atherosclerotic plaques may have intraplaque haemorrhages, neovessels, prevalent macrophages, excessive calcium deposits, a large lipid core and a thin fibrous cap. Regular physical activity (PA) may lower the risk of plaques becoming unstable. We evaluated the association of both PA and sedentary behaviour (SB) with carotid plaque histopathology.

METHODS: 90 asymptomatic patients who were undergoing carotid endarterectomy for carotid artery narrowing identified on ultrasound reported their PA and SB by questionnaires. We calculated PA intensity in MET (metabolic equivalent of task)-min/week. For analysis, the population was divided into tertiles according to PA (T1PA: the less PA patients; T2PA: the intermediate PA patients; T3PA: the most physically active patients) (T1PA<T2PA<T3PA) and SB (T1SB: the less sedentary behaviour patients; T2SB: the intermediate sedentary behaviour patients; T3SB: the most sedentary behaviour patients) (T1SB<T2SB<T3SB). PA was categorised as one of four PA intensities (600, 900, 1600 and 3000 MET-min/week). We obtained the carotid artery plaque at surgery and performed histological analysis of intraplaque haemorrhages (present/absent), neovessels, macrophages, lipid core, calcium deposits and the fibrous cap.

RESULTS: Intraplaque haemorrhage was less frequent in the most physically active tertile (T3PA, 48%) versus T1PA (74%) and in the least sedentary tertile T1SB (50%) versus T3SB (71%). The intraplaque haemorrhage was less frequent in those who exercised more than 900 MET-min/week (59% vs 47% for >900 and <900 MET-min/week, respectively). All the other features that associate with plaque instability (eg, neovessels, macrophages, etc) did not differ by level of PA or SB.

CONCLUSION: In this cross-sectional study of asymptomatic patients who underwent endarterectomy (i) higher reported PA, (ii) intensity of PA and (iii) lower reported SB were associated with lower prevalence of intraplaque haemorrhage. This could be a mechanism whereby PA protects against cerebrovascular disease (stroke) and death.