Abstract 14298: Primary Left Ventricular Unloading Enhances Collateral Blood Flow and Reduces Infarct Size: A Preclinical Proof of Concept Study

• Published in: Circulation (New York, N.Y.) N.Y.), 2018-11, Vol.138 (Suppl_1 Suppl 1), p.A14298-A14298
• Main Authors: Annamalai, Shiva, Briceno, Natalia, Reyelt, Lara, Qiao, Xiaoying, Swain, Lija, Pedicini, Robert, Jorde, Lena, Yesodharan, Gemini, Beale, Corinna, Perara, Divaka, Kapur, Navin K
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539

IntroductionThe Collateral Flow Index (CFI) measures microcirculatory flow in myocardium subtended by an occluded coronary artery. The impact of left ventricular (LV) load on the CFI is unknown. The Impella pump reduces LV load, while veno-arterial extracorporeal membrane oxygenation (VA-ECMO) increases LV load. We hypothesized that LV unloading reduces myocardial infarct size, in part, by increasing the CFI in acute myocardial infarction (AMI).MethodsThe left anterior descending artery (LAD) was occluded via angioplasty for 90 min in adult Yorkshire swine (n=4-6/group). After 90 min of ischemia, the LAD was reperfused for 180 min in the primary reperfusion (PR) group. In the primary unloading (PU) and primary loading (PL) groups, an Impella CP or VA-ECMO was activated and the LAD left occluded for an additional 30 min, followed by 180 min of reperfusion. Using a pressure wire, the CFI was calculated during LAD occlusion as (Pw - RA)/(Pa - RA), where Pa, RA, Pw are aortic, right atrial and coronary wedge pressure. Myocardial infarct size was quantified using TTC.ResultsAfter 90 min of LAD occlusion, there was no difference in CFI among the groups. After 30 minutes of PU, the CFI increased compared to pre-activation (+0.07 ± 0.03, p = 0.03) and compared to PR (-0.008 ± 0.02, p = 0.003) or PL (-0.02 ± 0.03, p = 0.001; Figure A). PU reduced LV stroke work (LVSW) at 120 min compared to pre-activation (-26%, p=0.03) and compared to PR (-24%, p=0.03) and PL (-25%, p=0.03). Among all groups, the change in CFI between 90 and 120 min correlated inversely with the change in LVSW (r = 0.43, p = 0.01; Figure B). PU reduced infarct size relative to the area at risk (35% ± 6%) compared to PR (51% ± 14%, p = 0.04) and PL (66% ± 13%, p = 0.0009; Figure C). The change in CFI correlated inversely with infarct size (r = 0.42, p = 0.02).ConclusionsPrimary Unloading increases microcirculatory flow to ischemic myocardium and reduces infarct size. Compared to Impella unloading, VA-ECMO failed to increase the CFI and increased myocardial infarct size.