Fuetterer Maximilian, Traechtler Julia, Busch Julia, Peereboom Sophie Marie, Dounas Andreas, Manka Robert, Weisskopf Miriam, Cesarovic Nikola, Stoeck Christian Torben, Kozerke Sebastian
Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
Department of Cardiology, University Heart Center, University Hospital Zurich, Zurich, Switzerland.
JACC Cardiovasc Imaging. 2022 Dec;15(12):2051-2064. doi: 10.1016/j.jcmg.2022.08.017. Epub 2022 Nov 16.
Prolonged ischemia and myocardial infarction are followed by a series of dynamic processes that determine the fate of the affected myocardium toward recovery or necrosis. Metabolic adaptions are considered to play a vital role in the recovery of salvageable myocardium in the context of stunned and hibernating myocardium.
The potential of hyperpolarized pyruvate cardiac magnetic resonance (CMR) alongside functional and parametric CMR as a tool to study the complex metabolic-structural interplay in a longitudinal study of chronic myocardial infarction in an experimental pig model is investigated.
Metabolic imaging using hyperpolarized [1-C] pyruvate and proton-based CMR including cine, T/T relaxometry, dynamic contrast-enhanced, and late gadolinium enhanced imaging were performed on clinical 3.0-T and 1.5-T MR systems before infarction and at 6 days and 5 and 9 weeks postinfarction in a longitudinal study design. Chronic myocardial infarction in pigs was induced using catheter-based occlusion and compared with healthy controls.
Metabolic image data revealed temporarily elevated lactate-to-bicarbonate ratios at day 6 in the infarcted relative to remote myocardium. The temporal changes of lactate-to-bicarbonate ratios were found to correlate with changes in T and impaired local contractility. Assessment of pyruvate dehydrogenase flux via the hyperpolarized [C] bicarbonate signal revealed recovery of aerobic cellular respiration in the hibernating myocardium, which correlated with recovery of local radial strain.
This study demonstrates the potential of hyperpolarized CMR to longitudinally detect metabolic changes after cardiac infarction over days to weeks. Viable myocardium in the area at risk was identified based on restored pyruvate dehydrogenase flux.
长时间缺血和心肌梗死后会伴随一系列动态过程，这些过程决定了受影响心肌恢复或坏死的命运。在心肌顿抑和冬眠心肌的情况下，代谢适应被认为在可挽救心肌的恢复中起着至关重要的作用。
研究超极化丙酮酸心脏磁共振成像（CMR）与功能和参数化CMR作为一种工具，在实验猪模型慢性心肌梗死纵向研究中研究复杂代谢 - 结构相互作用的潜力。
在纵向研究设计中，在临床3.0-T和1.5-T MR系统上，于梗死前、梗死6天、5周和9周时，使用超极化[1-C]丙酮酸进行代谢成像，并进行基于质子的CMR检查，包括电影成像、T/T弛豫测量、动态对比增强和延迟钆增强成像。采用导管闭塞法诱导猪慢性心肌梗死，并与健康对照进行比较。
代谢图像数据显示，梗死心肌在第6天时乳酸与碳酸氢盐的比值相对于远隔心肌暂时升高。发现乳酸与碳酸氢盐比值的时间变化与T的变化和局部收缩功能受损相关。通过超极化[C]碳酸氢盐信号评估丙酮酸脱氢酶通量，发现冬眠心肌中有氧细胞呼吸恢复，这与局部径向应变的恢复相关。
本研究证明了超极化CMR在纵向检测心肌梗死后数天至数周代谢变化方面的潜力。基于恢复的丙酮酸脱氢酶通量识别出危险区域的存活心肌。
