Abstract 14581: Occlusion of Left Anterior Descending Artery Impairs Microvascular Function in the Left Circumflex and the Right Coronary Artery Area in Adult Porcine
Introduction: Occlusion of major coronary artery induces myocardial infarction (MI) leading to remodeling of the left ventricle (LV), which is reportedly caused by progressive dysfunction of the microvasculature.
Hypothesis: We herein hypothesized occlusion of the major coronary artery may induce microvascular dysfunction in the adjacent area which is perfused by the intact coronary arteries.
Methods: MI was induced by the placement of the ameroid constrictor ring around the left anterior descending artery (LAD) in adult Göttingen pigs 8 weeks before the assessment, while age-matched normal ones were used for the control (n=6 each). Regional wall motion, myocardial blood flow (MBF) and index of microvascular resistance (IMR) of the LV was studied by cardiac magnetic resonance (CMR), 13N-ammonia positron emission tomogram (PET) and fluoroscopy-guided pressure wire studies, respectively.
Results: The CMR study consistently showed akinetic anterior LV wall with an ejection fraction of 40±7% at 4 weeks and 40±8 at 8 weeks after the MI induction. Systolic regional wall motion in the adjacent area of the infraction was progressively worsened over the period, assessed by the CMR. In the PET study, MBF at hyperemia was significantly greater in the left circumflex (LCX; 1.5±0.2ml/min/g) and the right coronary (RCA; 1.3±0.3 ml/min/g) areas than that in the LAD area (1.0±0.1 ml/min/g, P <0.05) at 4 weeks, and then that in the LCX and the RCA area significantly decreased (-25±8% and -23±12%, respectively), approximating to that in the LAD at 8 weeks. Fluoroscopy showed a development of collateral arteries chiefly from the LCX to the LAD area. In the pressure wire study, IMR of the LCX (53±16) and the RCA (34±21) areas was significantly higher than those of the control (23±15, P <0.01 and 20±17, P <0.05, respectively). Moreover, CFR of the LCX area (1.1±0.3) was significantly smaller than that of the control (2.2±1.0, P <0.01), while CFR of the RCA area was not different between them. Electron microscopy study showed swelling of the endothelium and disruption of the microvasculature in the LCX and the RCA areas.
Conclusions: Anterior MI caused coronary microvascular dysfunction in the adjacent area, associated with reduction of myocardial blood flow and regional wall motion.
Author Disclosures: S. Yajima: None. S. Miyagawa: None. S. Fukushima: None. Y. Sawa: None.
- © 2016 by American Heart Association, Inc.