Comparative Hemodynamic Effects of Contemporary Percutaneous Mechanical Circulatory Support Devices in a Porcine Model of Acute Myocardial Infarction
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OBJECTIVES: The aim of this study was to directly compare the hemodynamic effects of 2 contemporary percutaneous mechanical circulatory support devices in a porcine model of acute myocardial infarction. BACKGROUND: Percutaneous support devices offer the ability to unload the ischemic left ventricle, but the comparative hemodynamic effects of contemporary platforms are unclear. METHODS: Yorkshire swine (mean weight 76 ± 2 kg; n = 7) were instrumented with a left ventricular (LV) pressure-volume (PV) catheter and subjected to a 2-h coronary occlusion. Hemodynamic parameters and PV-derived indexes of LV performance were assessed 30 min after reperfusion and during LV support with Impella CP (ICP) and TandemHeart devices (in randomized order) at comparable flow rates. RESULTS: Myocardial infarction produced a rightward shift of the PV loop and increased LV end-diastolic pressure (from 9 ± 2 mm Hg to 15 ± 2 mm Hg; p = 0.04). After reperfusion, both devices maintained aortic pressure, shifted the PV loop to the left, and decreased LV end-diastolic pressure (ICP vs. TandemHeart; 11 ± 1 mm Hg vs. 7 ± 4 mm Hg; p = 0.04). However, only TandemHeart elicited significant reductions in native LV stroke volume (from 75 ± 7 ml to 39 ± 7 ml; p < 0.01), dP/dtmax (from 988 ± 77 mm Hg/s to 626 ± 42 mm Hg/s; p < 0.01), stroke work (from 0.70 ± 0.03 J to 0.26 ± 0.05 J; p < 0.01), PV area (from 0.95 ± 0.11 J to 0.47 ± 0.10 J; p < 0.01), and pre-load-recruitable stroke work slope (from 41.7 ± 2.8 J/ml to 30.6 ± 3.9 J/ml; p = 0.05). CONCLUSIONS: At comparable device flow rates, TandemHeart decreased LV pre-load, native LV stroke volume, and myocardial contractility to a greater degree than ICP. Reductions in load-independent indexes of LV performance indicate favorable effects on myocardial oxygen balance and support further study of TandemHeart in clinical scenarios requiring mechanical support in the setting of acute myocardial ischemia.
