Impella preserves haemodynamics with adequate stressed blood volume and normal pulmonary vascular resistance in a goat model of ventricular fibrillation

Figures

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  Figure 1. Protocol 1. We confirmed whether the haemodynamic effects of Impella during VF were consistent with the circulatory equilibrium theory in models of bleeding (A) and acute pulmonary microembolization (B) in protocol 1. SBV, stressed blood volume; VF, ventricular fibrillation; PVR, pulmonary vascular resistance. Protocol 2. We evaluated the impact of Impella support on central and peripheral perfusion during VF using protocol 2.

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  Figure 2. Time series of haemodynamics during VF with Impella support. We observed the haemodynamics during VF with Impella support (P4) under both haemorrhagic (A) and stepwise pulmonary hypertension conditions (B). We conducted stepwise blood withdrawal of 100 mL every 60 s in protocol 1A and injected 2.0 g of glass microspheres (90 µm in diameter) into the pulmonary artery every 60 s in protocol 1B. As indicated by the arrow, the SBV gradually decreased with blood withdrawal, and the PVR significantly increased after the last injection. SBV, stressed blood volume; AP, arterial pressure; LVP, left ventricular pressure; RAP, right atrial pressure; LAP, left atrial pressure; PAP, pulmonary artery pressure; PAF, pulmonary artery flow; PVR, pulmonary vascular resistance.

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  Figure 3. Time series of haemodynamics during VF with several support levels of Impella. Representative waveforms of pressure and flow changes during VF at three Impella support levels (P0, P4, and P8). A stepwise increase in Impella support levels from P0 to P8 increased AP, PAF, CAF, and CoF while reducing RAP, LAP, and LVP. ECG, electrocardiogram; AP, arterial pressure; RAP, right atrial pressure; LAP, left atrial pressure; LVP, left ventricular pressure; PAP, pulmonary artery pressure; PAF, pulmonary artery flow; CAF, carotid artery flow; CoF, coronary artery flow.

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  Figure 4. Echocardiogram and fluoroscopic view during VF with Impella support. We attached the echo probe directly to the LV and assessed the echocardiogram of one goat. An increase in the Impella support level reduced the LV chamber size. We also confirmed the Impella position using fluoroscopy. LV, left ventricle; RV, right ventricle.

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  Figure 5. The impact of Impella on systemic, pulmonary, and atrial pressures during VF. Each bar shows the mean value together with individual data (n = 6). Differences between the four conditions were examined using repeated-measures one-way analysis of variance with Greenhouse–Geisser correction, followed by Tukey’s test for all pairwise comparisons. VF, ventricular fibrillation; AP, arterial pressure; RAP, right atrial pressure; LAP, left atrial pressure; PAP, pulmonary artery pressure; CPP, coronary perfusion pressure.

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  Figure 6. The impact of Impella on systemic, carotid, and coronary flows during VF. Each bar shows the mean value together with individual data (n = 6). Differences between the four conditions were examined using repeated-measures one-way analysis of variance with Greenhouse–Geisser correction, followed by Tukey’s test for all pairwise comparisons. VF, ventricular fibrillation; PAF, pulmonary artery flow; CAF, carotid artery flow; CoF, coronary artery flow.

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  Figure 7. Schema of circulatory equilibrium during VF with Impella support. The intersection of the Impella flow rate and the venous return curve determines the haemodynamic operating point. The reduction in SBV shifts the venous return curve downward in parallel and moves the operating point to the left (A). An increase in the PVR decreased the slope of the venous return curve and moved the operating point to the left (B). SBV, stressed blood volume; PVR, pulmonary vascular resistance.