Coronary atherosclerosis in athletes: recent insights and clinical considerations

Abstract

Evidence from international cohort studies has shown increased coronary atheroscle-rosis in male athletes vs controls, 1 whereas data for female athletes are scarce and contradictory but likely not different from controls. 1 A larger lifelong exercise volume and greater proportion of very vigorous intensity exercise training were identified as independent predictors of the prevalence and progression of coronary artery calcification scores (CACS) in males. 2-4 Early studies hypothesised that accelerated calcification may represent plaque stabilisation as less harmful plaque phenotypes (ie, more calcified and less mixed plaques) were found in athletes vs controls. 3 4 However, this concept was challenged by the Master@Heart study as lifelong male endurance athletes had a similar plaque morphology compared with non-athletes. 5 These collective findings raise questions whether athletes should be worried about the development of coronary atherosclerosis and its clinical sequelae. THE GOOD NEWS Athletes have a better life expectancy compared with the general population with risk reductions for all-cause and cardiovascular mortality of ~30%-40%. Moreover, individuals with a higher cardiorespiratory fitness have a lower cardiovascular event rate for any given CACS compared with individuals with lower fitness. 6 This may be partially attributable to a less harmful plaque composition. For example, in a UK cohort of 106 male master athletes (55±9 years old) without cardiovascular risk factors compared with 54 non-athletic controls, athletes had more calcified and less mixed plaque morphology, 3 which are known to be less rupture prone. 7 These findings were reinforced by the Dutch Measuring Athletes' Risk of Cardiovascular Events (MARC) study, consisting of 318 recreational male athletes (aged ≥45 years), as fewer mixed and more often only calci-fied plaques were found among the most active vs least active athletes. 4 Although the Belgian Master@Heart study showed no difference in plaque composition between 191 lifelong athletes (56 (51-61) years old) and 176 non-athletic controls, this may relate to the inclusion criteria. Controls were allowed to perform up to 3 hours of exercise per week and those with cardiovascular risk factors were excluded. The Master@Heart control group, therefore, constitutes a group of extremely healthy individuals, evidenced by their very low age-specific CAC percen-tile scores (0 (0-62)%), benign plaque composition (67% calcified plaque) and high fitness level (122 (108-138)% of predicted VO 2peak). In fact, plaque characteristics of the Master@Heart controls were comparable with the master athletes of the UK cohort 3 and the most active group of the MARC study, 4 suggesting that all participants of the Master@Heart study had predominantly favourable plaque morphology.