Dataset Information

Left Ventricular Unloading Increases the Coronary Collateral Flow Index Before Reperfusion and Reduces Infarct Size in a Swine Model of Acute Myocardial Infarction.

ABSTRACT: Background Unloading the left ventricle and delaying reperfusion reduces infarct size in preclinical models of acute myocardial infarction. We hypothesized that a potential explanation for this effect is that left ventricular (LV) unloading before reperfusion increases collateral blood flow to ischemic myocardium. Methods and Results Acute myocardial infarction was induced by balloon occlusion of the left anterior descending artery for 120 minutes in adult swine, followed by reperfusion for 180 minutes. After 90 minutes of occlusion, animals were assigned to 30 minutes of continued occlusion (n=6) or to 30 minutes of support with either an Impella CP (n=4) or venoarterial extracorporeal membrane oxygenation (n=5) with persistent occlusion. The primary end point was measures of microcirculatory blood flow including the collateral flow index (CFI) during left anterior descending artery occlusion as (P_w-RA)/(P_a-RA), where P_a, P_w, and RA are aortic, coronary wedge, and right atrial pressure, respectively. Infarct size was quantified using triphenyltetrazolium chloride. Compared with continued occlusion, Impella, not venoarterial extracorporeal membrane oxygenation, reduced infarct size relative to the area at risk. Before reperfusion, Impella reduced LV stroke work by 25% and increased the CFI by 75%, but venoarterial extracorporeal membrane oxygenation did not. Among all groups, the change in CFI between 90 and 120 minutes correlated inversely with the change in LV stroke work (r²=0.44, P=0.01) and infarct size (r²=0.41, P=0.02). Conclusions We report for the first time that 30 minutes of LV unloading during coronary occlusion increases the CFI, which correlates inversely with LV stroke work and infarct size. Venoarterial extracorporeal membrane oxygenation failed to increase the CFI and did not reduce infarct size.

SUBMITTER: Briceno N

PROVIDER: S-EPMC6915258 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Left Ventricular Unloading Increases the Coronary Collateral Flow Index Before Reperfusion and Reduces Infarct Size in a Swine Model of Acute Myocardial Infarction.

Briceno Natalia N Annamalai Shiva K SK Reyelt Lara L Crowley Paige P Qiao Xiaoying X Swain Lija L Pedicini Robert R Foroutanjazi Sina S Jorde Lena L Yesodharan Gemini G Perera Divaka D Kapur Navin K NK

Journal of the American Heart Association 20191108 22

Background Unloading the left ventricle and delaying reperfusion reduces infarct size in preclinical models of acute myocardial infarction. We hypothesized that a potential explanation for this effect is that left ventricular (LV) unloading before reperfusion increases collateral blood flow to ischemic myocardium. Methods and Results Acute myocardial infarction was induced by balloon occlusion of the left anterior descending artery for 120 minutes in adult swine, followed by reperfusion for 180 ...[more]

PMID: 31698989

Similar Datasets

Project description:BACKGROUND:Heart failure after an acute myocardial infarction (AMI) is a major cause of morbidity and mortality worldwide. We recently reported that activation of a transvalvular axial-flow pump in the left ventricle and delaying myocardial reperfusion, known as primary unloading, limits infarct size after AMI. The mechanisms underlying the cardioprotective benefit of primary unloading and whether the acute decrease in infarct size results in a durable reduction in LV scar and improves cardiac function remain unknown. OBJECTIVES:This study tested the importance of LV unloading before reperfusion, explored cardioprotective mechanisms, and determined the late-term impact of primary unloading on myocardial function. METHODS:Adult male swine were subjected to primary reperfusion or primary unloading after 90 min of percutaneous left anterior descending artery occlusion. RESULTS:Compared with primary reperfusion, 30 min of LV unloading was necessary and sufficient before reperfusion to limit infarct size 28 days after AMI. Compared with primary reperfusion, primary unloading increased expression of genes associated with cellular respiration and mitochondrial integrity within the infarct zone. Primary unloading for 30 min further reduced activity levels of proteases known to degrade the cardioprotective cytokine, stromal-derived factor (SDF)-1?, thereby increasing SDF-1? signaling via reperfusion injury salvage kinases, which limits apoptosis within the infarct zone. Inhibiting SDF-1? activity attenuated the cardioprotective effect of primary unloading. Twenty-eight days after AMI, primary unloading reduced LV scar size, improved cardiac function, and limited expression of biomarkers associated with heart failure and maladaptive remodeling. CONCLUSIONS:The authors report for the first time that first mechanically reducing LV work before coronary reperfusion with a transvalvular pump is necessary and sufficient to reduce infarct size and to activate a cardioprotective program that includes enhanced SDF-1? activity. Primary unloading further improved LV scar size and cardiac function 28 days after AMI.

Dataset Information

Left Ventricular Unloading Increases the Coronary Collateral Flow Index Before Reperfusion and Reduces Infarct Size in a Swine Model of Acute Myocardial Infarction.

Publications

Left Ventricular Unloading Increases the Coronary Collateral Flow Index Before Reperfusion and Reduces Infarct Size in a Swine Model of Acute Myocardial Infarction.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets