A novel echocardiographic parameter considering left ventricular afterload during V-A ECMO support.

BACKGROUND: Left ventricular stroke work index (LVSWI) and cardiac power index (CPI) account for the haemodynamic load of the left ventricle and are promising prognostic values in cardiogenic shock. However, accurately and non-invasively measuring these parameters during veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is challenging and potentially biased by the extracorporeal circulation. This study aimed to investigate, in an ovine model of cardiogenic shock, whether Pressure-Strain Product (PSP), a novel speckle-tracking echocardiography parameter, (1) can correlate with pressure-volume catheter-based LVSWI and CPI, and (2) can be load-independent during the flow modification of V-A ECMO. METHODS: Nine Dorset-cross ewes (51 ± 4 kg) were included. After cardiogenic shock was induced, full support V-A ECMO (X L/min based on 60 mL/kg/min) commenced. At seven time points during 24-h observation, echocardiographic parameters as well as pressure-volume catheter-based LVSWI and CPI were simultaneously measured with X and following X-1 L/min of ECMO flow. PSP was calculated by multiplying global circumferential strain or global radial strain, and mean arterial pressure, for PSPcirc or PSPrad, respectively. RESULTS: PSPcirc showed a stronger correlation with LVSWI (correlation coefficient, CC = .360, p < .001) and CPI (CC = .283, p < .001) than other echocardiographic parameters. The predictability of PSPcirc for pressure-volume catheter-based LVSWI (AUC .82) and CPI (AUC .80) was also higher than other echocardiographic parameters. No statistically significant differences were identified between the two ECMO flow variations in PSPcirc (p = .558). CONCLUSIONS: A novel echocardiographic parameter, PSP, may non-invasively predict pressure-volume catheter-based LVSWI and CPI in a load-independent manner in a cardiogenic shock supported by V-A ECMO.

A comprehensive evaluation of hemodynamic energy production and circuit loss using four different ECMO arterial cannulae.

OBJECTIVE: Pulsatile-flow veno-arterial extracorporeal membrane oxygenation (V-A ECMO) has shown encouraging results for microcirculation resuscitation and left ventricle unloading in patients with refractory cardiogenic shock. We aimed to comprehensively assess different V-A ECMO parameters and their contribution to hemodynamic energy production and transfer through the device circuit. METHODS: We used the i-cor® ECMO circuit, which composed of Deltastream DP3 diagonal pump and i-cor® console (Xenios AG), the Hilite 7000 membrane oxygenator (Xenios AG), venous and arterial tubing and a 1 L soft venous pseudo-patient reservoir. Four different arterial cannulae (Biomedicus 15 and 17 Fr, Maquet 15 and 17 Fr) were used. For each cannula, 192 different pulsatile modes were investigated by adjusting flow rate, systole/diastole ratio, pulsatile amplitudes and frequency, yielding 784 unique conditions. A dSpace data acquisition system was used to collect flow and pressure data. RESULTS: Increasing flow rates and pulsatile amplitudes were associated with significantly higher hemodynamic energy production (both p < 0.001), while no significant associations were seen while adjusting systole-to-diastole ratio (p = 0.73) or pulsing frequency (p = 0.99). Arterial cannula represents the highest resistance to hemodynamic energy transfer with 32%-59% of total hemodynamic energy generated being lost within, depending on pulsatile flow settings used. CONCLUSIONS: Herein, we presented the first study to compare hemodynamic energy production with all pulsatile ECLS pump settings and their combinations and widely used yet previously unexamined four different arterial ECMO cannula. Only increased flow rate and amplitude increase hemodynamic energy production as single factors, whilst other factors are relevant when combined.