Left Ventricular Unloading Using an Impella CP Improves Coronary Flow and Infarct Zone Perfusion in Ischemic Heart Failure

Abstract

BackgroundDelivering therapeutic materials, like stem cells or gene vectors, to the myocardium is difficult in the setting of ischemic heart failure because of decreased coronary flow and impaired microvascular perfusion (MP). The aim of this study was to determine if mechanical left ventricular (LV) unloading with the Impella increases coronary flow and MP in a subacute myocardial infarction.Methods and ResultsAnterior transmural myocardial infarction (infarct size, 26.0±3.4%) was induced in Yorkshire pigs. At 2 weeks after myocardial infarction, 6 animals underwent mechanical LV unloading by Impella, whereas 4 animals underwent pharmacological LV unloading using sodium nitroprusside for 2 hours. LV unloading with Impella significantly reduced end‐diastolic volume (−16±11mL, P=0.02) and end‐diastolic pressure (EDP; −32±23 mm Hg, P=0.03), resulting in a significant decrease in LV end‐diastolic wall stress (EDWS) (infarct: 71.6±14.7 to 43.3±10.8 kdynes/cm2 [P=0.02]; remote: 66.6±20.9 to 40.6±13.3 kdynes/cm2 [P=0.02]). Coronary flow increased immediately and remained elevated after 2 hours in Impella‐treated pigs. Compared with the baseline, MP measured by fluorescent microspheres significantly increased within the infarct zone (109±81%, P=0.003), but not in the remote zone. Although sodium nitroprusside effectively reduced LV‐EDWS, 2 (50%) of sodium nitroprusside–treated pigs developed profound systemic hypotension. A significant correlation was observed between the infarct MP and EDWS (r 2=0.43, P=0.03), suggesting an important role of EDWS in regulating MP during LV unloading in the infarcted myocardium.Conclusions LV unloading using an Impella decreased EDWS and increased infarct MP without hemodynamic decompensation. Mechanical LV unloading is a novel and efficient approach to increase infarct MP in patients with subacute myocardial infarction.

Novel Porcine Model of Coronary Dissection Reveals the Impact of Impella on Dissected Coronary Arterial Hemodynamics

“…Specifically, the Impella heart pump (Abiomed, Danvers, MA) is a catheter-based transaortic LV microaxial assist device that has been gaining in popularity and utilization ( 5 ). Owing to its position across the aortic valve, the Impella augments cardiac output and mean arterial pressure while simultaneously decreasing the workload of the heart ( 6 ) and increasing coronary blood flow into the infarct zone of the LV after myocardial infarction ( 7 ). Although this pleiotropic ability of the Impella device to stabilize hemodynamics and attenuate ischemic burden makes it a therapeutic candidate for CAD patients, no study has investigated the impact of Impella in a setting of dissected coronary artery.…”

Large Animal Models of Heart Failure

“…For example, TandemHeart was implanted during LCx occlusion (30 min) and effectively unloaded the LV while maintaining systemic pressure, which was evident via decreased stroke volume, end-diastolic volume, and EDP ( 151 ). Impella devices have also been investigated in swine ( 152 , 156 , 157 , 158 , 159 , 160 , 161 ) and ovine ( 162 , 163 ) models of adult and pediatric HF. Using their recently described combination I/R−coronary microembolization protocol in Yorkshire swine, Watanabe et al.…”

“…Using their recently described combination I/R−coronary microembolization protocol in Yorkshire swine, Watanabe et al. ( 159 ) examined mechanical LV unloading 2 weeks post-MI using the Impella CP. After 2 h of circulatory support, Impella decreased LV end-diastolic volume and EDP, maintained peripheral vascular pressure, and increased coronary vascular perfusion in the infarct area.…”

Left ventricular unloading in ST‐elevation myocardial infarction without cardiogenic shock

“…Additional potential benefits of primary LV unloading at the time of AMI such as improvement in microvascular perfusion were also reported in other studies. 31…”