Left ventricular mechanical unloading by total support of Impella during acute myocardial infarction reduced infarct size compared to no support (2.1% vs 16.3%; P<0.001) in dogs.
Does left ventricular mechanical unloading by Impella reduce infarct size and preserve LV function in dogs with myocardial infarction?
In a canine model of myocardial infarction, total mechanical unloading with Impella during the acute phase significantly reduced infarct size and preserved left ventricular function.
Absolute Event Rate: 2.1% vs 16.3%
p-value: p=<0.001
Background: Acute myocardial infarction remains a leading cause of chronic heart failure. Excessive myocardial oxygen demand relative to supply is the fundamental mechanism of myocardial infarction. We thus hypothesized that left ventricular (LV) mechanical unloading by the total support of transvascular LV assist device Impella could minimize oxygen demand, thereby reducing infarct size and preventing subsequent heart failure. Methods and Results: In 20 dogs, we ligated the left anterior descending coronary artery for 180 minutes and then reperfused. We introduced Impella from 60 minutes after the onset of ischemia to 60 minutes after reperfusion. In the partial support group, Impella supported 50% of total cardiac output. In the total support group, systemic flow totally depends on Impella flow. Four weeks after ischemia/reperfusion (I/R), we compared LV function and infarct size among 4 groups: sham (no I/R), I/R (no Impella support), partial support, and total support. Compared with I/R, total support lowered LV end-diastolic pressure (15.0±3.5 versus 4.7±1.7 mm Hg; P <0.001), increased LV end-systolic elastance (4.3±0.8 versus 13.9±5.1 mm Hg/mL; P <0.001), and decreased NT-proBNP (N-terminal pro-B-type natriuretic peptide) level (4081±1123 versus 1773±390 pg/mL; P <0.05). Furthermore, total support markedly reduced infarct size relative to I/R, whereas partial support decreased infarct size to a lesser extent (I/R, 16.3±2.6; partial support, 8.5±4.3; and total support, 2.1±1.6%; P <0.001). Conclusions: LV mechanical unloading by the total support of Impella during the acute phase of myocardial infarction reduced infarct size and prevented subsequent heart failure in dogs.
Saku et al. (2018) studied Acute myocardial infarction (n=20). Impella vs. No Impella support (I/R) was evaluated on Infarct size (%) (p=<0.001). Left ventricular mechanical unloading by total support of Impella during acute myocardial infarction reduced infarct size compared to no support (2.1% vs 16.3%; P<0.001) in dogs.