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Published on: June 11, 2020
Myocardial function including estimates of myocardial work in young adults born very preterm or with extremely low
Britt Engan1,2, Tom R Omdal3, Gottfried Greve4,3
1Department of Clinical Science, University of Bergen, Bergen, Norway. breng4295@uib.no.
Insights
Young adults born very preterm or with extremely low birthweight show impaired left ventricular global longitudinal strain, suggesting a higher lifetime risk for heart failure. Myocardial work and diastolic function remained comparable to controls.
Area of Science:
- Cardiology
- Neonatology
- Public Health
Background:
- Preterm birth and extremely low birthweight (PB/ELBW) are linked to increased risks of heart failure and cardiovascular disease in adulthood.
- Previous studies on myocardial function in PB/ELBW individuals have yielded inconsistent results.
- Echocardiographic strain analysis and myocardial work estimates offer sensitive methods for detecting early cardiac dysfunction.
Purpose of the Study:
- To assess left ventricular (LV) myocardial function, including myocardial work, in young adults born PB/ELBW.
- To compare cardiac function in PB/ELBW individuals with age- and sex-matched term-born controls.
Main Methods:
- Echocardiography was performed on 63 PB/ELBW individuals and 64 controls.
- Left ventricular ejection fraction (EF) and global longitudinal strain (GLS) were measured.
- Myocardial work was estimated using LV pressure-strain loops; diastolic function and left atrial strain were also evaluated.
Main Results:
- PB/ELBW individuals had normal LV systolic function overall, but 22% exhibited borderline impaired GLS.
- Mean LV GLS was significantly impaired in PB/ELBW (-19.4%) compared to controls (-20.6%).
- Lower birthweight correlated with more impaired GLS; EF, diastolic function, and myocardial work measures were similar between groups.
Conclusions:
- Young adults born PB/ELBW demonstrate impaired LV GLS despite largely normal systolic function.
- Reduced birthweight is associated with greater GLS impairment, potentially indicating an elevated lifetime risk of heart failure.
- Diastolic function and myocardial work were not significantly different between PB/ELBW individuals and controls.
Background:
Preterm birth and low birthweight have been associated with increased risk of heart failure and cardiovascular disease in young adulthood. However, results from clinical studies of myocardial function are not consistent. Echocardiographic strain analyses allow detection of early stages of cardiac dysfunction, and non-invasive estimates of myocardial work can provide additional information on cardiac function. We aimed to evaluate left ventricular (LV) myocardial function including measures of myocardial work in young adults born very preterm (gestational age < 29 weeks) or with extremely low birthweight (< 1000 g) (PB/ELBW), compared with term-born age- and sex matched controls.
Methods:
63 PB/ELBW and 64 controls born in Norway in the periods 1982-1985, 1991-1992, and 1999-2000 were examined with echocardiography. LV ejection fraction (EF) and LV global longitudinal strain (GLS) were measured. Myocardial work was estimated from LV pressure-strain loops after determination of GLS and construction of a LV pressure curve. Diastolic function was evaluated by determination of the presence or absence of elevated LV filling pressure, including measures of left atrial longitudinal strain.
Results:
The PB/ELBW with mean birthweight 945 (standard deviation (SD) 217) grams, mean gestational age 27 (SD 2) weeks, and mean age 27 (SD 6) years had LV systolic function mainly within normal range. Only 6% had EF < 50% or impaired GLS >-16%, but 22% had borderline impaired GLS between - 16% and - 18%. Mean GLS in PB/ELBW (-19.4% (95% confidence interval (CI) -20.0, -18.9)) was impaired compared to controls (-20.6% (95% CI -21.1, -20.1)), p = 0.003. Lower birthweight was associated to more impaired GLS (Pearson correlation coefficient - 0.2). Means of EF, measures of diastolic function including left atrial reservoir strain, global constructive and wasted work, global work index and global work efficiency was similar in PB/ELBW and controls.
Conclusion:
The young adults born very preterm or with extremely low birthweight had impaired LV-GLS compared to controls, although systolic function mainly within normal range. Lower birthweight was associated with more impaired LV-GLS. These findings could indicate an elevated lifetime risk of developing heart failure in preterm born individuals. Measures of diastolic function and myocardial work were similar compared to controls.
