Persistently Elevated Right Ventricular Index of Myocardial Performance in Preterm Infants with Incipient Bronchopulmonary Dysplasia

OBJECTIVES: Elevated pulmonary vascular resistance occurs during the first days after birth in all newborn infants and persists in infants at risk for bronchopulmonary dysplasia (BPD). It is difficult to measure in a non-invasive fashion. We assessed the usefulness of the right ventricular index of myocardial performance (RIMP) to estimate pulmonary vascular resistance in very low birth weight infants. STUDY DESIGN: Prospective echocardiography on day of life (DOL) 2, 7, 14, and 28 in 121 preterm infants (median [quartiles] gestational age 28 [26]-[29] weeks, birth weight 998 [743-1225] g) of whom 36 developed BPD (oxygen supplementation at 36 postmenstrual weeks). RESULTS: RIMP derived by conventional pulsed Doppler technique was unrelated to heart rate or mean blood pressure. RIMP on DOL 2 was similar in infants who subsequently did (0.39 [0.33-0.55]) and did not develop BPD (0.39 [0.28-0.51], p = 0.467). RIMP declined steadily in non-BPD infants but not in BPD infants (DOL 7: 0.31[0.22-0.39] vs. 0.35[0.29-0.48], p = 0.014; DOL 14: 0.23[0.17-0.30] vs. 0.35[0.25-0.43], p<0.001; DOL 28: 0.21[0.15-0.28] vs. 0.31 [0.21-0.35], p = 0.015). CONCLUSIONS: In preterm infants, a decline in RIMP after birth was not observed in those with incipient BPD. The pattern of RIMP measured in preterm infants is commensurate with that of pulmonary vascular resistance

Development of left ventricular longitudinal speckle tracking echocardiography in very low birth weight infants with and without bronchopulmonary dysplasia during the neonatal period.

OBJECTIVES: In preterm infants, postnatal myocardial adaptation may be complicated by bronchopulmonary dysplasia (BPD). We aimed to describe the development of left ventricular function by serial 2D, Doppler, and speckle tracking echocardiography (2D-STE) in infants with and without BPD during the neonatal period and compare these to anthropometric and conventional hemodynamic parameters. STUDY DESIGN: Prospective echocardiography on day of life (DOL) 1, 7, 14, and 28 in 119 preterm infants 10%) were seen for the apical segment. While anthropometric parameters show rapid development during the first 4 weeks of life, the speckle tracking parameters did not differ statistically significantly during the neonatal period. Infants with and without BPD differed significantly (p<0.001) in the development of anthropometric parameters, conventional hemodynamic parameters except for heart rate, and 2D-STE parameters: global longitudinal systolic strain rate (GLSSR) and longitudinal systolic strain for the mid left wall (LSSR). The largest differences were seen at DOL 1 and 7 in GLSSR (p<0.001) and in LSSR (p<0.01). CONCLUSIONS: Reproducible 2D-STE measurements are possible in preterm infants <1500 g. Cardiac deformation reveals early (DOL 1 and 7) ventricular changes (GLSSR and LSSR) in very low birth weight infants who develop BPD

Decrease in RIMP during the neonatal period in infants who did or did not develop BPD (median and quartile values presented).

<p>Decrease in RIMP during the neonatal period in infants who did or did not develop BPD (median and quartile values presented).</p

Patient characteristics (presented as median values with quartiles (in brackets) or N (%)).

<p>Statistically significant p-values are printed in bold.</p

Doppler methodology.

<p>Measurement of the myocardial performance index by pulsed Doppler in the right ventricle capturing inflow and outflow. The “a” interval is the time from tricuspidal closing to opening, and the “b” interval is the ejection time in milliseconds.</p

Flow diagram of the study population.

<p>Flow diagram of the study population.</p

Correlation of RIMP with clinical and hemodynamic parameters at the 4 time points of measurement (Spearman rank order correlation coefficients and p values).

<p>Statistically significant p values are printed in bold.</p

Development of body weight (top) and body length (bottom) in VLBW infants with and without BPD during the first four weeks of life.

<p>Presented are median with interquartile range; statistical significant differences between the patient groups are marked: *** - p<0.001.</p

Development of systolic blood pressure (top) and left ventricular cardiac output (bottom) in VLBW infants with and without BPD during the first four weeks of life (the mode of presentation is the same as that in Figure 2).

<p>* - p<0.05; ** - p<0.01; *** - p<0.001</p

Comparison of intra- and inter-observer variability of the speckle tracking parameters by the coefficient of variation and intraclass-correlation coefficient.

<p>Presented are median and interquartile range; statistical significance after Bonferroni correction for p<0.0036.</p>1)<p>Comparison of the coefficient of variation between intra-and inter-observer variability.</p><p>Comparison of intra- and inter-observer variability of the speckle tracking parameters by the coefficient of variation and intraclass-correlation coefficient.</p