Persistence of right ventricular dysfunction and altered morphometry in asymptomatic preterm Infants through one year of age: Cardiac phenotype of prematurity

Cardiac Mechanics Evaluation in Preschool-Aged Children with Preterm Birth History: A Speckle Tracking and 4D Echocardiography Study

Background: The premature-born adult population is set to grow significantly, and prematurity has emerged as an important cardiovascular risk factor. We aimed to comprehensively assess cardiac mechanics and function in a cohort of ex-preterm preschoolers. Methods: Ex-preterm children (<30 weeks of gestation), aged 2 to 5 years, underwent transthoracic 2D, speckle-tracking, and 4D echocardiography. The findings were compared with 19 full-term children. Results: Our cohort of 38 children with prematurity history showed a normal morpho-functional echocardiographic assessment. However, compared to controls, the indexed 3D end-diastolic volumes of ventricular chambers were reduced (left ventricle 58.7 ± 11.2 vs. 67.2 ± 8.5 mL/m2; right ventricle 50.3 ± 10.4 vs. 57.7 ± 11 mL/m2; p = 0.02). Left ventricle global and longitudinal systolic function were worse in terms of fraction shortening (32.9% ± 6.8 vs. 36.5% ± 5.4; p = 0.05), ejection fraction (59.2% ± 4.3 vs. 62.3% ± 3.7; p = 0.003), and global longitudinal strain (-23.6% ± 2.4 vs. -25.5% ± 1.7; p = 0.003). Finally, we found a reduced left atrial strain (47.4% ± 9.7 vs. 54.9% ± 6.8; p = 0.004). Conclusions: Preschool-aged ex-preterm children exhibited smaller ventricles and subclinical impairment of left ventricle systolic and diastolic function compared to term children. Long-term follow-up is warranted to track the evolution of these findings.

A scoping review of echocardiographic and lung ultrasound biomarkers of bronchopulmonary dysplasia in preterm infants

Despite recent improvements in neonatal care, moderate to severe bronchopulmonary dysplasia (BPD) is still associated with high mortality and with an increased risk of developing pulmonary hypertension (PH). This scoping review provides an updated overview of echocardiographic and lung ultrasound biomarkers associated with BPD and PH, and the parameters that may prognosticate their development and severity, which could be clinically helpful to undertake preventive strategies. A literature search for published clinical studies was conducted in PubMed using MeSH terms, free-text words, and their combinations obtained through appropriate Boolean operators. It was found that the echocardiography biomarkers for BPD, and especially those assessing right ventricular function, are reflective of the high pulmonary vascular resistance and PH, indicating a strong interplay between heart and lung pathophysiology; however, early assessment (e.g., during the first 1-2 weeks of life) may not successfully predict later BPD development. Lung ultrasound indicating poor lung aeration at day 7 after birth has been reported to be highly predictive of later development of BPD at 36 weeks' postmenstrual age. Evidence of PH in BPD infants increases risk of mortality and long-term PH; hence, routine PH surveillance in all at risk preterm infants at 36 weeks, including an echocardiographic assessment, may provide useful information. Progress has been made in identifying the echocardiographic parameters on day 7 and 14 to predict later development of pulmonary hypertension. More studies on sonographic markers, and especially on echocardiographic parameters, are needed for the validation of the currently proposed parameters and the timing of assessment before recommendations can be made for the routine clinical practice.

Early diagnosis and targeted approaches to pulmonary vascular disease in bronchopulmonary dysplasia

Pulmonary hypertension has emerged as a life-threatening disease in preterm infants suffering from bronchopulmonary dysplasia (BPD). Its development is closely linked to respiratory disease, as vasculogenesis and alveologenesis are closely interconnected. Once clinically significant, BPD-associated pulmonary hypertension (BPD-PH) can be challenging to manage, due to poor reversibility and multiple comorbidities frequently associated. The pulmonary vascular disease process underlying BPD-PH is the result of multiple innate and acquired factors, and emerging evidence suggests that it progressively develops since birth and, in certain instances, may begin as early as fetal life. Therefore, early recognition and intervention are of great importance in order to improve long-term outcomes. Based on the most recent knowledge of BPD-PH pathophysiology, we review state-of-the-art screening and diagnostic imaging techniques currently available, their utility for clinicians, and their applicability and limitations in this specific population. We also discuss some biochemical markers studied in humans as a possible complement to imaging for the detection of pulmonary vascular disease at its early stages and the monitoring of its progression. In the second part, we review pharmacological agents currently available for BPD-PH treatment or under preclinical investigation, and discuss their applicability, as well as possible approaches for early-stage interventions in fetuses and neonates. IMPACT: BPD-associated PH is a complex disease involving genetic and epigenetic factors, as well as environmental exposures starting from fetal life. The value of combining multiple imaging and biochemical biomarkers is emerging, but requires larger, multicenter studies for validation and diffusion. Since "single-bullet" approaches have proven elusive so far, combined pharmacological regimen and cell-based therapies may represent important avenues for research leading to future cure and prevention.

Right Atrial Strain in Preterm Infants With a History of Bronchopulmonary Dysplasia

BACKGROUND

Few studies have utilized right atrial (RA) strain to evaluate right ventricular (RV) diastolic dysfunction in preterm infants with bronchopulmonary dysplasia (BPD). We aimed to evaluate the associations of RA strain with BPD severity and respiratory outcomes in preterm infants with BPD.

METHODS

We retrospectively studied 153 infants with BPD born before 32 weeks of gestational age at CHA Bundang Medical Center. Peak longitudinal right atrial strain (PLRAS) was obtained using velocity vector imaging and compared among infants across BPD severity. Conventional echocardiographic parameters and clinical characteristics were also evaluated.

RESULTS

In infants with severe BPD, mean gestational age (27.4 ± 2.1 weeks) and mean birth weight (971.3 ± 305.8 g) were significantly smaller than in those with mild BPD (30.0 ± 0.9 weeks, 1,237.3 ± 132.2 g) and moderate BPD (29.6 ± 1.3 weeks, 1,203.2 ± 214.4 g). PLRAS was significantly lower in infants with severe BPD (26.3 ± 10.1%) than in those in the moderate BPD group (32.4 ± 10.9%) or mild BPD group (31.9 ± 8.3%). Tricuspid E/e′ and maximum RA volume index were similar across BPD severity. A decrease in PLRAS was significantly correlated with increased duration of mechanical ventilation duration; however, tricuspid E/e′ and maximum RA volume index were not.

CONCLUSIONS

Evaluating PLRAS with other parameters in infants with BPD might detect RV diastolic dysfunction. Longer follow-up and larger study populations may elucidate the association between PLRAS and respiratory outcomes in infants with BPD.

Cardiovascular impact and sequelae of bronchopulmonary dysplasia

The development, growth, and function of the cardiac, pulmonary, and vascular systems are closely intertwined during both fetal and postnatal life. In utero, placental, environmental, and genetic insults may contribute to abnormal pulmonary alveolarization and vascularization that increase susceptibility to the development of bronchopulmonary dysplasia (BPD) in preterm infants. However, the shared milieu of stressors may also contribute to abnormal cardiac or vascular development in the fetus and neonate, leading to the potential for cardiovascular dysfunction. Further, cardiac or pulmonary maladaptation can potentiate dysfunction in the other organ, amplify the risk for BPD in the neonate, and increase the trajectory for overall neonatal morbidity. Beyond infancy, there is an increased risk for systemic and pulmonary vascular disease including hypertension, as well as potential cardiac dysfunction, particularly within the right ventricle. This review will focus on the cardiovascular antecedents of BPD in the fetus, cardiovascular consequences of preterm birth in the neonate including associations with BPD, and cardiovascular impact of prematurity and BPD throughout the lifespan.

Echocardiographic Monitoring of Cardiac Parameters to Predict Bronchial Dysplasia in Very Premature Infants

Echocardiography was used to measure the cardiac parameters in high-risk premature infants prone to bronchopulmonary dysplasia (BPD). These measurements were used to determine the correlation between the parameters and BPD and whether they could be used to predict the parameters associated with cardiac health of BPD in very premature infants at a very early stage. Seventy-four very premature infants (gestational age < 32 weeks) were recruited in this retrospective, single-center, observational studies. All infants were examined using echocardiography within a week after birth, and the cardiac chamber parameters were recorded. Of these, 14 infants with BPD were reexamined at 4 weeks after birth. Statistical analysis and comparison of the data of these 14 infants indicated that 1-week after birth, the inner diameters of PA/AS/AO/LA/ROVT/LVPW/LV were significantly smaller (P < 0.05), and that of AS/AO/LA/LV were highly significantly smaller (P < 0.001) in the BPD group compared with the non-BPD group. Comparing the cardiac parameters between 1 and 4 weeks after birth in infants with BPD showed a significant difference in the diameter of PA/AS/AO/ROVT/IVS/LVPW/LV, suggesting that the ventricular cavity developed more efficiently during growth.

Sildenafil administration improves right ventricular function on 4D flow MRI in young adults born premature

Extreme preterm birth conveys an elevated risk of heart failure by young adulthood. Smaller biventricular chamber size, diastolic dysfunction, and pulmonary hypertension may contribute to reduced ventricular-vascular coupling. However, how hemodynamic manipulations may affect right ventricular (RV) function and coupling remains unknown. As a pilot study, 4D flow MRI was used to assess the effect of afterload reduction and heart rate reduction on cardiac hemodynamics and function. Young adults born premature were administered sildenafil (a pulmonary vasodilator) and metoprolol (a β blocker) on separate days, and MRI with 4D flow completed before and after each drug administration. Endpoints include cardiac index (CI), direct flow fractions, and ventricular kinetic energy including E/A wave kinetic energy ratio. Sildenafil resulted in a median CI increase of 0.24 L/min/m2 (P = 0.02), mediated through both an increase in heart rate (HR) and stroke volume. Although RV ejection fraction improved only modestly, there was a significant increase (4% of end diastolic volume) in RV direct flow fraction (P = 0.04), consistent with hemodynamic improvement. Metoprolol administration resulted in a 5-beats/min median decrease in HR (P = 0.01), a 0.37 L/min/m2 median decrease in CI (P = 0.04), and a reduction in time-averaged kinetic energy (KE) in both ventricles (P < 0.01), despite increased RV diastolic E/A KE ratio (P = 0.04). Despite reduced right atrial workload, metoprolol significantly depressed overall cardiac systolic function. Sildenafil, however, increased CI and improved RV function, as quantified by the direct flow fraction. The preterm heart appears dependent on HR but sensitive to RV afterload manipulations.NEW & NOTEWORTHY We assessed the effect of right ventricular afterload reduction with sildenafil and heart rate reduction with metoprolol on cardiac hemodynamics and function in young adults born premature using 4D flow MRI. Metoprolol depressed cardiac function, whereas sildenafil improved cardiac function including right ventricular direct flow fraction by 4D flow, consistent with hemodynamic improvement. This suggests that the preterm heart is dependent on heart rate and sensitive to right ventricular afterload changes.

Association of Bronchopulmonary Dysplasia and Right Ventricular Systolic Function in Young Adults Born Preterm

BACKGROUND

Adults born preterm are at a higher risk of cardiopulmonary disease and premature death. Preterm birth is associated with abnormalities in right ventricular (RV) structure and function, but the impact of bronchopulmonary dysplasia (BPD), a common complication of extremely preterm birth, on these parameters remains unknown.

RESEARCH QUESTION

Are preterm birth and BPD associated with alterations in RV structure and function in early adulthood?

STUDY DESIGN AND METHODS

Echocardiographic and spirometry data were obtained from the Health of Adults Born Preterm Investigation (HAPI). RV structure and performance were evaluated by using echocardiography, and respiratory function was assessed by using spirometry.

RESULTS

The study comprised 86 young adults born preterm before 30 weeks of gestation, including 28 with moderate to severe BPD, and 85 adults of the same age born full term. Individuals were assessed at a mean age of 23 years. RV systolic function was altered in the preterm group, with lower tricuspid annular plane systolic excursion and lower RV s' and RV outflow tract velocity time integral values, especially in those born preterm with BPD. Nine (36%) participants born preterm with BPD, six (13%) participants born preterm without BPD, and six (8%) participants born full term had a tricuspid annular plane systolic excursion value < 16 mm, a marker of RV systolic dysfunction (P value for the comparison between preterm no BPD and BPD, .032). No difference was found in RV diastolic function or estimates of pulmonary artery pressure between groups. Although respiratory function was altered in those born preterm, and more so in the case of BPD, no association was observed between spirometry indices of respiratory function and RV systolic function.

INTERPRETATION

Preterm birth is associated in adulthood with alterations in RV systolic function, which are more pronounced in the case of BPD.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT03261609; URL: www.clinicaltrials.gov.