Assessment of Residual Coronary Stenoses Using 99mTc-N-NOET Vasodilator Stress Imaging to Evaluate Coronary Flow Reserve Early After Coronary Reperfusion in a Canine Model of Subendocardial Infarction

Journal of Nuclear Medicine

Mirta Ruiz¹  David K. Glover¹  George A. Beller¹  Denny D. Watson¹  Frank D. Petruzella¹  Kazuya Takehana¹ 

[1] Experimental Cardiology Laboratory, Cardiovascular Division, Department of Medicine, University of Virginia, Charlottesville, Virginia Experimental Cardiology Laboratory, Cardiovascular Division, Department of Medicine, University of Virginia, Charlottesville, Virginia Experimental Cardiology Laboratory, Cardiovascular Division, Department of Medicine, University of Virginia, Charlottesville, Virginia

关键词: coronary flow reserve;    myocardial infarction;    ^99mTcN-NOET;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Reperfusion is often incomplete after recanalization therapy because of the presence of residual coronary stenoses. Detecting mild to moderate stenoses requires assessing coronary flow reserve with vasodilator stress. 99mTc-(N-ethoxy-N-ethyl-dithiocarbamato)nitrido (N-NOET) is a viability-independent flow tracer and thus may be well suited for assessing coronary flow reserve in the acute phase of reperfusion. Methods: Twelve open-chest dogs underwent 60 min of total left anterior descending artery (LAD) occlusion followed by either full reperfusion (group 1; n = 4) or reperfusion through a residual critical stenosis (group 2; n = 8). 99mTc-N-NOET was given during peak vasodilator stress 165 min after reperfusion, and initial and 60-min delayed images were acquired. Regional blood flow was assessed with radiolabeled microspheres. Results: Infarct size was similar in both groups (9% ± 2% vs. 8% ± 2% of left ventricle). Both initial (0.61 ± 0.02 vs. 0.73 ± 0.01; P < 0.01) and 60-min (0.67 ± 0.02 vs. 0.80 ± 0.01; P < 0.01) defect count ratios (LAD/left circumflex coronary artery [LCx]) differentiated between the 2 groups, reflecting the greater diminution in coronary flow reserve in group 2 dogs (LAD/LCx flow ratios = 0.37 ± 0.04 vs. 0.57 ± 0.09; P < 0.01). Interestingly, coronary flow reserve in the reperfused zone of group 1 was diminished despite the absence of a stenosis. Thus, the difference in 99mTc-N-NOET uptake between the 2 groups was less than expected. Conclusion: In this canine myocardial infarction model with some coronary flow reserve preservation, 99mTc-N-NOET imaging can detect residual coronary stenoses. However, with more prolonged occlusion resulting in more severe endothelial or microvascular dysfunction, it may be difficult to distinguish varying degrees of vessel patency using any coronary flow reserve technique.

【 授权许可】

Unknown