Speckle tracking derived strain in infants with severe perinatal asphyxia: a comparative case control study.
BACKGROUND
Speckle tracking echocardiography is increasingly being used to assess cardiac function in neonates. The objective was to compare speckle tracking strain indices between asphyxiated infants and healthy controls and to ascertain correlations between strain and 2D Doppler derived indices and cardiac troponin (biochemical marker of myocardial injury).


METHODS
Clinical and echocardiographic data from severely asphyxiated infants undergoing therapeutic hypothermia was evaluated retrospectively. This was compared with prospective data from healthy infants. Correlations between variables were assessed using Pearson's coefficient of correlation.


RESULTS
Twenty four infants with severe perinatal asphyxia were admitted during the study period of which 3 were not cooled and were excluded. The gestational age and birth weights of cases and controls were comparable. The mean left ventricular global longitudinal strain (GLS) from apical 4 chamber view was noted to be significantly impaired in the asphyxiated infants (- 11.01% ± 2.48 vs - 21.45% ± 2.74, p <0.001). Cardiac output was significantly lower in the asphyxiated infants (97 ± 26 vs 230 ± 60 ml/kg/min). In asphyxiated infants, GLS correlated positively with cardiac output (r2 = 0.86, p< 0.001) and negatively with serum troponin levels (r2 = 0.64, p< 0.001). GLS was less impaired in infants on inotropes compared to those not on inotropic support, -12.55% (1.9) vs -10.2% (1.3), p= 0.018. Infants who died had a lower global strain value compared to survivors, - 9.7% (1.6) vs - 12.8% (2.6), p = 0.02.


CONCLUSIONS
2D Speckle derived strain was impaired in asphyxiated infants. Significant correlations between GLS and cardiac output and troponin were noted.
Monash Newborn, Monash Medical Centre, Melbourne, VIC 3168, Australia. arvind.sehgal@monash.edu.
Arvind
A
Sehgal
Flora
F
Wong
Samuel
S
Menahem
D001238:Asphyxia Neonatorum / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015415:Biomarkers / Q000097:blood; D002302:Cardiac Output; D016022:Case-Control Studies; D019245:Compressive Strength; D004452:Echocardiography / Q000379:methods*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013718:Tensile Strength; D014336:Troponin / Q000097:blood*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*
D015415:Biomarkers; D014336:Troponin