Aortic dilation in masters endurance athletes: prevalence and associations with cardiac physiology and training load

Abstract Background Aortic dilation (AoD) is rare in young endurance athletes, but emerging evidence suggests older, master’s athletes may have an increased prevalence of AoD1. Whether AoD in master’s athletes represents adaptive athletic cardiovascular remodelling or maladaptive response to lifelong extreme exercise remains unclear. Purpose To determine the prevalence of aortic dilation in master’s endurance athletes, and assess its relationship with physiologic markers of cardiac remodelling and training load. Methods This analysis evaluated master’s endurance athletes (aged ≥50 years) without heritable aortopathy who underwent transthoracic echocardiography including assessment of ascending aortic diameter. AoD was defined as per ESC guidelines2 as an ascending aortic diameter ≥40mm for males and ≥36mm for females. Historical and current training load was assessed from a standardised questionnaire. Cardiac remodelling was quantified using cardiac magnetic resonance. Peak oxygen uptake (VO2peak) and exercise systolic blood pressure (SBP) were assessed from a maximal cardiopulmonary exercise test. To explore the potential physiologic implications of AoD, circumferential aortic wall stress (AWS) was calculated at rest and peak exercise in accordance with the La Place law as aortic diameter x SBP ÷ aortic wall thickness (with wall thickness values imputed from age- and sex-specific data 3). Groups were compared using ANCOVA with adjustment for age and sex. Results We evaluated 143 master’s athletes (Age: 63±8 years, 17% female), with 35 athletes (24%) meeting AoD criteria, and a similar prevalence in male and female athletes (24% vs 25%, P=0.99). Athletes with AoD were older (68±6 yrs vs 62±7 yrs, P0.001). Athletes with AoD had more profound left-ventricular (LV) remodelling (Fig 1A) and higher VO2peak (Fig 1B). AoD was not explained by differences in peak SBP (Fig 1C), nor current or cumulative training load or sporting type (Fig 1D). AWS was systematically higher at rest and peak exercise in athletes with AoD Fig 2), such that peak exercise AWS was 15% higher in athletes with AoD. However, peak values (range: 160-384kPa) were well below the expected maximal tensile stess an aneurysmal aortic wall can tolerate before failure (800-1200kPa) reported previously using finite element analysis4. Conclusions Aortic dilation is not uncommon in master’s endurance athletes. Our observations suggest AoD in master’s athletes may in part be a compensatory vascular adaptation from lifelong exercise training, in order to accommodate greater exercise cardiac output. Furthermore, AWS may be a useful framework for considering the risk of progression or dissection with continued exercise, but requires further validation.Figure 1A-DFor image description, please refer to the figure legend and surrounding text. For image description, please refer to the figure legend and surrounding text.