Challenges in Interpreting Deformation Values by Two-Dimensional Speckle-Tracking Echocardiography in Preterm and Term Infants

Early prediction of spontaneous Patent Ductus Arteriosus (PDA) closure and PDA-associated outcomes: a prospective cohort investigation

BACKGROUND

Patent ductus arteriosus (PDA), the most commonly diagnosed cardiovascular condition in preterm infants, is associated with increased mortality and harmful long-term outcomes (chronic lung disease, neurodevelopmental delay). Although pharmacologic and/or interventional treatments to close PDA likely benefit some infants, widespread routine treatment of all preterm infants with PDA may not improve outcomes. Most PDAs close spontaneously by 44-weeks postmenstrual age; treatment is increasingly controversial, varying markedly between institutions and providers. Because treatment detriments may outweigh benefits, especially in infants destined for early, spontaneous PDA closure, the relevant unanswered clinical question is not whether to treat all preterm infants with PDA, but whom to treat (and when). Clinicians cannot currently predict in the first month which infants are at highest risk for persistent PDA, nor which combination of clinical risk factors, echocardiographic measurements, and biomarkers best predict PDA-associated harm.

METHODS

Prospective cohort of untreated infants with PDA (n=450) will be used to predict spontaneous ductal closure timing. Clinical measures, serum (brain natriuretic peptide, N-terminal pro-brain natriuretic peptide) and urine (neutrophil gelatinase-associated lipocalin, heart-type fatty acid-binding protein) biomarkers, and echocardiographic variables collected during each of first 4 postnatal weeks will be analyzed to identify those associated with long-term impairment. Myocardial deformation imaging and tissue Doppler imaging, innovative echocardiographic techniques, will facilitate quantitative evaluation of myocardial performance. Aim1 will estimate probability of spontaneous PDA closure and predict timing of ductal closure using echocardiographic, biomarker, and clinical predictors. Aim2 will specify which echocardiographic predictors and biomarkers are associated with mortality and respiratory illness severity at 36-weeks postmenstrual age. Aim3 will identify which echocardiographic predictors and biomarkers are associated with 22 to 26-month neurodevelopmental delay. Models will be validated in a separate cohort of infants (n=225) enrolled subsequent to primary study cohort.

DISCUSSION

The current study will make significant contributions to scientific knowledge and effective PDA management. Study results will reduce unnecessary and harmful overtreatment of infants with a high probability of early spontaneous PDA closure and facilitate development of outcomes-focused trials to examine effectiveness of PDA closure in "high-risk" infants most likely to receive benefit.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03782610. Registered 20 December 2018.

Maturational Patterns of Systolic Ventricular Deformation Mechanics by Two-Dimensional Speckle-Tracking Echocardiography in Preterm Infants over the First Year of Age

BACKGROUND

The aim of this study was to determine the maturational changes in systolic ventricular strain mechanics by two-dimensional speckle-tracking echocardiography in extremely preterm neonates from birth to 1 year of age and discern the impact of common cardiopulmonary abnormalities on the deformation measures.

METHODS

In a prospective multicenter study of 239 extremely preterm infants (<29 weeks gestation at birth), left ventricular (LV) global longitudinal strain (GLS) and global longitudinal systolic strain rate (GLSRs), interventricular septal wall (IVS) GLS and GLSRs, right ventricular (RV) free wall longitudinal strain and strain rate, and segmental longitudinal strain in the RV free wall, LV free wall, and IVS were serially measured on days 1, 2, and 5 to 7, at 32 and 36 weeks postmenstrual age, and at 1 year corrected age (CA). Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately.

RESULTS

In uncomplicated preterm infants (n = 103 [48%]), LV GLS and GLSRs remained unchanged from days 5 to 7 to 1 year CA (P = .60 and P = .59). RV free wall longitudinal strain, RV free wall longitudinal strain rate, and IVS GLS and GLSRs significantly increased over the same time period (P < .01 for all measures). A significant base-to-apex (highest to lowest) segmental longitudinal strain gradient (P < .01) was seen in the RV free wall and a reverse apex-to-base gradient (P < .01) in the LV free wall. In infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n = 119 [51%]), RV free wall longitudinal strain and IVS GLS were significantly lower (P < .01), LV GLS and GLSRs were similar (P = .56), and IVS segmental longitudinal strain persisted as an RV-dominant base-to-apex gradient from 32 weeks postmenstrual age to 1 year CA.

CONCLUSIONS

This study tracks the maturational patterns of global and regional deformation by two-dimensional speckle-tracking echocardiography in extremely preterm infants from birth to 1 year CA. The maturational patterns are ventricular specific. Bronchopulmonary dysplasia and pulmonary hypertension leave a negative impact on RV and IVS strain, while LV strain remains stable.