An interview with Dr Sabiha Gati

In this interview Dr Sabiha Gati discusses her research on aortic root dilatation in young athletes and how the condition can be managed (“Prevalence and progression of aortic root dilatation in highly trained young athletes.” Gati S, Malhotra A, Sedgwick C et al. Heart, June 2019).

How did you conduct your study?

Aortic root enlargement is reported in young people and athletes; however, it is unclear whether these changes are due to intensive physical activity or represent a potentially serious condition that may cause sudden cardiac death. Between 2003 and 2015, we conducted an observational study collecting echocardiography data (ultrasound of the heart) on athletes aged 14-35 years old to identify individuals with an enlarged aorta which is the main vessel that leaves the heart called the aorta. We had screened 3,781 young athletes who trained for an average of 17 hours per week and compared them with 806 young sedentary volunteers who were recruited from a population screening programme offered by CRY. These individuals were subsequently followed up for approximately 7 years.

What were the main findings of this study?

Athletic individuals revealed a larger aortic diameter compared with sedentary controls. The 99th percentile value for aortic diameter in athletes was defined as the upper limit and was 40mm in males and 38mm in females. The aortic diameter measured >40mm in 5 males (0.17%); (range of 40-43mm) and >38mm in 6 females (0.4%); (range 39-41mm). None of the athletes with an enlarged aortic root diameter fulfilled the clinical features of Marfan syndrome, a condition known to cause aortic enlargement and sudden death.

The main determinants of an enlarged aorta were body surface area and the size of the main pumping chamber called the left ventricular cavity, suggesting that large athletes who trained intensively were more likely to have an enlarged aortic diameter compared with smaller athletes who trained less intensively. Whether you were of black or white ethnicity had no significant influence on the size of the aorta. Our study also showed that males and females competing in predominantly endurance sports such as running and cycling showed a trend towards a larger aortic diameter compared with athletes performing mixed sports such as football. During the follow-up period of just under 7 years, none of the athletes with an enlarged aorta showed progressive aortic enlargement compared with their first evaluation despite ongoing participation in exercise or competitive sport.

What impact does an aortic root dilatation have on an athlete?

This study provides upper limits for an aortic root diameter derived form a large cohort of young athletes. A small minority (0.3%) of athletes reveal an enlarged aortic size. Over a modest follow-up, athletes did not reveal progressive enlargement of their aorta to indicate pathology of the tissue lining the wall of the aorta. The precise mechanism for aortic root enlargement is unknown. A combination of size, sporting discipline, duration and intensity of training may be contributing factors, but blood pressure responses to exercise and genetic factors are also likely important. Athletes with an enlarged aortic root should remain under surveillance and have an annual echocardiography (ultrasound scan of their heart) whilst participating in intensive exercise or competitive sport. Progressive enlargement of the aorta >2mm over a 5 year period may be abnormal and consistent with pathology. Longer surveillance studies are required to establish the precise significance of an enlarged aortic diameter in athletes.

What can be done to treat and manage aortic root dilatation?

The majority of people with aortic enlargement simply require close monitoring with echocardiography (ultrasound scan of their heart) on a 6-12 monthly basis. Occasionally your doctor may send you for more advanced imaging test such as CT or MRI scan of the aorta for a detailed evaluation. The treatment of aortic enlargement depends on how big it is. If it’s less than 5cm or 2 inches, individuals might receive treatment with medications initially from their clinicians. The medications help lessen the chance of an enlarged aorta rupturing and causing sudden death. Your doctor may also give you advice on avoiding heavy lifting which could potentially put pressure on the aorta. If your enlarged aorta continues to grow and if you report symptoms of chest pain, jaw pain or back pain, your doctor may request you undergo surgery to replace the section of the aorta which is deformed and enlarged with a fabric tube called a graft.

Dr Gati presenting some of her research into aortic assessment in athletes at CRY’s 2016 International Medical Conference.

How has this research changed the way clinicians would treat a person with an aortic root dilation?

The current guidelines recommend that male athletes with an aortic root of 40 mm (41 mm in tall males) and female athletes with an aortic root of 36 mm (36–38 mm in tall females) should only participate in low-intensity competitive sport. Our study suggests that male athletes with an aortic diameter up to 43 mm and female athletes with an aortic diameter up to 41 mm do not show progressive aortic enlargement over 5 years despite participation in sporting disciplines of a more dynamic nature. Therefore, there is scope for being more liberal in athletes with a slightly enlarged aortic diameter in the future, although annual assessments are recommended.

This study provides a guide for clinicians on the upper limits of aortic diameters in individuals who exercise to help differentiate physiological changes from exercise versus pathology which requires close monitoring and potential future treatment/surgery.

What kind of studies should be carried out next to further the findings of this research?

In this study, we did not do genetic testing to exclude for serious cardiac conditions such as Marfan syndrome and this is something we can think about for future studies involving individuals who exercise intensively with an enlarged aorta.

Furthermore, we need to collect data over a long term such as 15-20 years to decide how much the aorta grows with exercise. We know that the aorta size is affected by age, exercise and blood pressure. In fact, the elasticity (i.e. stretchiness of the tissue lining the aorta wall) becomes stiff with age and perhaps we need to evaluate our mature/veteran athletes over the age of 40 years compare to our younger population and whether there any predictors as to which individuals may enlarge their aorta rapidly placing them at risk of sudden death and therefore, allowing the clinician to instigate treatment early.

Abbreviation: *Aortic root; LA: left atrium; LV: left ventricle; RA: right atrium; RV right ventricle.

You can read this study by going to https://bit.ly/2HNhC1D