Background and aim The model of arterial-ventricular coupling (AVC) describes the interaction of the left ventricle (ELV) with the arterial system (EA) by the AVC-ratio (AVC = EA/ELV). Aim was to apply the model to preterm haemodynamics and to analyse time courses of AVC, EA and ELV in sick preterms with either pulmonary hypertension (PH-group) or haemodynamically significant patent ductus arteriosus (hPDA-group) and in stable preterms with uncomplicated postpartal course (control-group).
Methods Study period was from 10/2009 to 12/2012. Patient recruitment criteria were as follows: anti-PH treatment due to (supra-) systemic pulmonary pressure on echocardiography (PH-group); presence of PDA with an enddiastolic maximal velocity in the left pulmonary artery (LPAdia) ≥ 0,2 m/s and negative history of PH (hPDA-group); neither anti-PH treatment nor catecholamines, PDA with an LPAdia < 0,2 m/s and a ratio of the left atrium/aorta < 1,4 (control-group). AVC was calculated from blood pressure and M-mode measurements. Selected time points were set from days 1–3, 4–7 and 8–30 respectively.
Results Twentyone preterms were recruited to the PH-group, 19 to the hPDA-group and 63 to the control-group. AVC was lower in the PH- and hPDA-group than in the control-group (p = 0,05). ELV was higher in the PH-group (p = 0,007) and both EA and ELV were lower in the hPDA-group (EA: p = 0,0002; ELV: p = 0,02).
Conclusion The AVC-ratio was lower in sick preterms. Higher ELV in PH results from interventricular interdependence with decreased LV-filling. Lower ELV and EA in PDA result from LV-volume-overload and systemic steal-effect. Applying the AVC-model may facilitate explaining preterm haemodynamics.