Microvascular Integrity and the Time Course of Myocardial Sodium Accumulation After Acute Infarction
作者:
Carlos Rochitte,
Raymond Kim,
Hanns Hillenbrand,
Enn-ling Chen,
João Lima,
期刊:
Circulation Research: Journal of the American Heart Association
(OVID Available online 2000)
卷期:
Volume 87,
issue 8
页码: 648-655
ISSN:0009-7330
年代: 2000
出版商: OVID
关键词: magnetic resonance imaging;sodium;myocardial infarction;microcirculation;reperfusion
数据来源: OVID
摘要:
Loss of membrane permeability caused by ischemia leads to cellular sodium accumulation and myocardial edema. This phenomenon has important implications to left ventricular structure and function in the first hours after myocardial infarction. We hypothesized that during this period of time, after prolonged coronary occlusion and complete reflow, the rate of myocardial sodium accumulation is governed by microvascular integrity. We used 3-dimensional23Na MRI to monitor myocardial sodium content changes over time in an in vivo closed-chest canine model (n=13) of myocardial infarction and reperfusion. Infarcts with microvascular obstruction (MO) defined by both radioactive microspheres and contrast-enhanced1H MRI showed a slower rate of sodium accumulation as well as lower blood flow at 20 minutes and 6 hours after reperfusion. Conversely, the absence of MO was associated with faster rates of sodium accumulation and greater blood flow restoration. In addition, infarct size by23Na MRI correlated best with infarct size by triphenyltetrazolium chloride and contrast-enhanced1H MRI at 9 hours after reperfusion. We conclude that in reperfused myocardial infarction, sodium accumulation is dependent on microvascular integrity and is slower in regions of MO compared with those with patent microvasculature. Finally,23Na MRI can be a useful tool for monitoring in vivo myocardial sodium content in acute myocardial infarction.
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