LV Unloading using Impella CP Improves LA Pressure, Function, and Stiffness

The impact of pLVAD on LA function and stiffness in HF remains unclear. Hypothesis: Unloading the LV with an Impella CP improves trans-mitral pressure gradient, leading to a reduction of LA pressure and improved LA function and stiffness. HF is induced by percutaneously occluding the proximal LAD for 90 minutes in Yorkshire pigs (n=4, 40-50 Kg). Two-weeks after the MI, animals underwent LV unloading with an Impella CP for 150 minutes. LA pressure was directly measured by a trans-septal approach and LA volumes were assessed by 3-dimensional echocardiography. LA stiffness was approximated as the slope of minimal and maximal LA pressure–volume coordinates as described previously (Circ Heart Fail. 2015;8:295-303.). Two-weeks after the MI, the animals presented with impaired LVEF (69.7±10.5 to 38.6±7.0 %, P=0.03) and a dilated LV (LV end-systolic volume: 24.55±10.7 to 65.3±16.3 mL, P=0.04) without significant mitral regurgitation. LV unloading with maximal pump support (P8) resulted in an increase in total cardiac output (2.80±0.18 to 3.27±0.22 l/min, P=0.03) and reduced LV end-diastolic pressure (27.5±10.1 to 17.9±4.5 mmHg, P=0.06). These changes were accompanied by a significant reduction in mean LA pressure (17.3±2.6 to 10.8±2.1 mmHg, P=0.001). LA volumes assessed by 3-dimensional echocardiography were also reduced (LA Maximal volume: 40.3±4.6 to 29.0±2.3 ml, P=0.006, LA Minimal volume: 20.3±2.7 to 15.0±2.3 ml, P=0.002). While the total LAEF was not altered from the baseline (49.3±6.4 to 48.5±6.5%, P=0.85), passive LAEF was significantly increased (17.7±1.9 to 39.4±5.6 %, P=0.008), suggesting an improved trans-mitral suction effect. Additionally, LA stiffness assessed by pressure-volume coordinates was improved with Impella support (1.41±0.52 to 0.30±0.16 mmHg/ml, P=0.03). LV unloading using an Impella CP improves passive LA function and reduces mean LA pressure in a recent MI setting. Along with improved LA stiffness, these data implicate a beneficial impact of LV unloading on relieving HF symptoms.