Maturational patterns of left ventricular rotational mechanics in pre-term infants through 1 year of age

Abstract

Background: Pre-mature birth impacts left ventricular development, predisposing this population to long-term cardiovascular risk. The aims of this study were to investigate maturational changes in rotational properties from the neonatal period through 1 year of age and to discern the impact of cardiopulmonary complications of pre-maturity on these measures. Methods: Pre-term infants (<29 weeks at birth, n = 117) were prospectively enrolled and followed to 1-year corrected age. Left ventricular basal and apical rotation, twist, and torsion were measured by two-dimensional speckle-tracking echocardiography and analysed at 32 and 36 weeks post-menstrual age and 1-year corrected age. A mixed random effects model with repeated measures analysis was used to compare rotational mechanics over time. Torsion was compared in infants with and without complications of cardiopulmonary diseases of pre-maturity, specifically bronchopulmonary dysplasia, pulmonary hypertension, and patent ductus arteriosus. Results: Torsion decreased from 32 weeks post-menstrual age to 1-year corrected age in all pre-term infants (p < 0.001). The decline from 32 to 36 weeks post-menstrual age was more pronounced in infants with cardiopulmonary complications, but was similar to healthy pre-term infants from 36 weeks post-menstrual age to 1-year corrected age. The decline was due to directional and magnitude changes in apical rotation over time (p < 0.05). Conclusion: This study tracks maturational patterns of rotational mechanics in pre-term infants and reveals torsion declines from the neonatal period through 1 year. Cardiopulmonary diseases of pre-maturity may negatively impact rotational mechanics during the neonatal period, but the myocardium recovers by 1-year corrected age.

Left Ventricle Phenotyping Utilizing Tissue Doppler Imaging in Premature Infants with Varying Severity of Bronchopulmonary Dysplasia

“…BPD status was determined based on a modified version of the National Institute of Child Health and Human Development (NICHD) consensus definition [22] by utilizing the described respiratory support and/or oxygen requirement at 36 weeks postmenstrual age (PMA) [23]. Late PH was defined based on echocardiographic evidence of PH at 36 weeks PMA as having two or more of the broadbased criteria described by Mourani et al [24] (and utilized in other studies [17,18,25]): estimated RV systolic pressure of more than 40 mmHg, a ratio of RV systolic pressure to systemic systolic blood pressure > 0.5, any cardiac shunt with bidirectional or right to left flow, RV hypertrophy or dilatation, or ventricular septal wall flattening. For this study, we defined Group I as infants with no or mild BPD; Group II as infants with moderate to severe BPD, and Group III as BPD of any grade complicated by late PH, labeled BPD-PH.…”

“…Transthoracic echocardiograms were performed at three time points over the first year of age in the preterm infant: 32 and 36 weeks PMA, and one year CA. The timings of the echocardiograms were selected to avoid the early postnatal period of clinical and cardiopulmonary instability and early mortality associated with extreme preterm birth [17]. We performed echocardiograms in term controls at one year of age.…”

“…Our group has previously demonstrated that BPD-PH adversely impacts contraction patterns in the circumferential-longitudinal plane (rotational mechanics) [17] with the preservation of LV longitudinal deformation (strain), [18] but there has not been any study to discern the presence of LV dysfunction using TDI derived PSM in preterm infants. We hypothesize that preterm infants with the BPD-PH phenotype have PSM as a marker of ventricular dysfunction and dyssynchrony over the first year of age.…”

Comparison of left ventricular rotational mechanics between term and extremely premature infants over the first week of age

“…A recent study of 117 infants born prematurely at <29 weeks gestation with longitudinal follow-up documented decreasing torsion from 32 weeks corrected age to 1 year corrected age in all preterm infants (p<0.001). 17 This decline in torsion was due to alterations in the direction and magnitude of apical rotation with age. Although twist was required in early premature life, these findings suggest it is not as critical as the infant ages and that their myocardium is capable of recovery.…”

“…Adequate myocardial performance in the absence of twist over time can be achieved. 17 In such a circumstance the lack of twist demonstrated in the developing ex-premature heart with age is akin to the state of a healthy infant born at term.…”