Left ventricular diastolic function influences right ventricular - Pulmonary vascular coupling in premature infants.

<bold>Introduction: </bold>Reduced left ventricular (LV) diastolic function can exert significant load to the right ventricle (RV) that can affect RV-pulmonary vasculature (PV) coupling. RV-PV can be assessed with the RV length-force relationship (tricuspid annular plane systolic excursion [TAPSE] to pulmonary artery acceleration time [PAAT] ratio). We aimed to determine the association between LV diastolic function measured using tissue Doppler imaging (TDI) and TAPSE/PAAT.<bold>Methods: </bold>A study of premature infants <29 weeks gestation. TAPSE/PAAT, LV e' and a' waves were measured on Day 1 following birth. Correlation between diastolic indices and TAPSE/PAAT was performed. The independent effect of LV diastolic function and TAPSE/PAAT was assessed using linear regression.<bold>Results: </bold>One hundred and sixty-two infants with a mean ± SD gestation & birthweight of 26.6 ± 1.5 weeks & 938 ± 241 g. There was a significant positive correlation between LV e' (r = 0.44, p < 0.01)/LV a' (r = 0.44, p < 0.01) and TAPSE/PAAT. This relationship remained significant when adjusting for important confounders (all p < 0.01). Infants with LV a' values in the lowest quartile had lower TAPSE values (4.2 ± 1.2 vs. 5.1 ± 1.1 mm, p < 0.01) without a difference in PAAT (41 ± 8 vs. 41 ± 10 ms, p = 0.97).<bold>Conclusions: </bold>We observed a direct correlation between LV diastolic function and RV-PV coupling in the first day of age, highlighting the importance ventricular interdependence in premature infants. TAPSE/PAAT, as the index of the RV-PV interaction may be further explored for its potential to assess RV reserve under stress with preterm infants in health and disease. [ABSTRACT FROM AUTHOR]