Cardio stress test reveals impaired LV function in young adults born preterm

A new study showed for the first time that young adults who were born preterm as infants had significantly impaired left ventricular systolic response to physical exercise. This finding might help explain why these individuals have an increased risk of early heart failure, researchers noted in a recent article in Journal of the American College of Cardiology.

About 10% of young adults worldwide were born preterm, so “there is an increasing need for further research into whether lifestyle and clinical interventions can beneficially modify cardiac morphology and function in this growing population of individuals,” wrote study director Adam J. Lewandowski, DPhil, and colleagues at the University of Oxford, Oxford, UK.

Prematurity itself is a risk factor

Previous research identified preterm birth as a novel risk factor for incident heart failure in childhood and adolescence.

For this investigation—part of the Young Adult Cardiovascular Health sTudy (YACHT)—researchers tested the cardiovascular response to exercise in 47 young adults (ages 18 to 40 years) who were born preterm in comparison to 54 term-born control subjects.

All participants completed a peak cardiopulmonary exercise test on a seated stationary cycle ergometer. Results of the test showed that preterm-born individuals had greater left ventricular mass and, at rest, had lower peak systolic longitudinal strain and similar ejection fraction as term-born controls.

“However, by 60% exercise intensity, ejection fraction was 6.7% lower in preterm subjects and further declined to 7.3% below the term-born group at 80% exercise intensity,” Dr. Lewandowski and coauthors reported.

Submaximal cardiac output reserve was also lower in preterm-born subjects, with a 56% decrease compared with controls at 40% of peak exercise capacity. The researchers noted that left ventricular length and degree of prematurity were highly predictive of an adverse systolic response in preterm-born individuals.

“It is consequential that the systolic deficits we observed manifested under moderate intensity physical exercise and were clearly evident in this cohort of healthy, normotensive, preterm-born young adults, which indicated that … prematurity alone confers this systolic impairment and diminished myocardial functional reserve,” Dr. Lewandowski and coauthors wrote.

“Most notably, the novel finding of impaired exercise response offered insights that might help explain the recently verified relationship between preterm birth and increased risk of early heart failure,” they predicted.

More studies needed

In a related editorial, Anna-Karin Edstedt Bonamy, MD, PhD, and Hanna Carr, BSc, of the Karolinska Institute, Stockholm, Sweden, asserted that this type of study is essential to providing preventive measures to such patients at risk of cardiovascular disease (CVD).

“To better learn how we can start CVD prevention in the perinatal period, we need more studies that are powered to disentangle if and how different perinatal exposures are related to later cardiovascular phenotypes,” they wrote.