Claeys M J, Blockx P P, Rademakers F E, Vrints C J, Snoeck J P
Department of Cardiology, Antwerp University Hospital, Edegem, Belgium.
Eur J Nucl Med. 1997 Sep;24(9):1121-7. doi: 10.1007/BF01254243.
This study investigated the value of technetium-99m sestamibi scintigraphy in identifying patients at risk for post-infarct ischaemia (=jeopardized myocardium), especially within the reperfused infarct region. In 51 patients with a recent (<1 month) myocardial infarction, adenosine 99mTc-sestamibi single-photon emission tomography (SPET) and dobutamine stress echocardiography (DSE) were performed and correlated with the presence of significant coronary artery stenosis [% diameter stenosis (DS) >50%] on quantitative coronary angiography. Regional perfusion activity was analysed semi-quantitatively (score 0-4) on a 13-segment left ventricular model. DSE was used for the estimation of the infarct size (low-dose DSE) and for concomitant evaluation of ischaemia (high-dose DSE). A reversible perfusion defect within the infarct region was observed in 20 of the 37 patients with a significant infarct-related lesion (sensitivity of 54%) and only in one patient without a significant infarct-related lesion (specificity of 93%). Further analysis revealed that the scintigraphic assessment of jeopardized myocardium was fairly good in patients with a moderate (DS 51%-64%) infarct-related stenosis but was inadequate in patients with a severe (DS>/=65%) infarct-related stenosis (sensitivity of 80% vs 36%, P<0.01), while the echocardiographic detection of ischaemia was not influenced by stenosis severity (sensitivity of 73% in both subgroups). This scintigraphic underestimation of jeopardized myocardium was mainly related to a severely impaired myocardial perfusion under baseline conditions, as was evidenced by a significantly more severe rest perfusion score in the infarct region in patients with a severe stenosis as compared to those with a moderate stenosis (average score: 1.5+/-0.7 vs 2.1+/-0.6, P<0.01), while infarct size on echocardiography was similar for both subgroups. It may be concluded that early after an acute myocardial infarction, adenosine 99mTc-sestamibi SPET may underestimate reperfused but still jeopardized myocardium, particularly in patients with a severe infarct-related stenosis. In these patients the evaluation of the ischaemic burden on rest-stress scintigraphy is hampered by the presence of a severely impaired myocardial perfusion in resting conditions.
本研究调查了锝-99m 甲氧基异丁基异腈心肌灌注显像在识别心肌梗死后缺血（即濒危心肌）风险患者中的价值，尤其是在再灌注梗死区域内。对 51 例近期（<1 个月）发生心肌梗死的患者进行了腺苷负荷 99mTc-甲氧基异丁基异腈单光子发射断层扫描（SPET）和多巴酚丁胺负荷超声心动图（DSE）检查，并与定量冠状动脉造影显示的显著冠状动脉狭窄[直径狭窄率（DS）>50%]情况进行关联分析。在 13 节段左心室模型上对局部灌注活性进行半定量分析（评分 0 - 4）。DSE 用于评估梗死面积（低剂量 DSE）以及同时评估缺血情况（高剂量 DSE）。在 37 例有显著梗死相关病变的患者中，20 例在梗死区域观察到可逆性灌注缺损（敏感性为 54%），而在无显著梗死相关病变的患者中仅 1 例出现（特异性为 93%）。进一步分析显示，对于梗死相关狭窄程度为中度（DS 51% - 64%）的患者，濒危心肌的闪烁显像评估效果较好，但对于梗死相关狭窄程度为重度（DS≥65%）的患者则评估不足（敏感性分别为 80%和 36%，P<0.01），而超声心动图检测缺血情况不受狭窄严重程度影响（两个亚组的敏感性均为 73%）。这种闪烁显像对濒危心肌的低估主要与基线条件下严重受损的心肌灌注有关，重度狭窄患者梗死区域的静息灌注评分显著高于中度狭窄患者（平均评分：1.5±0.7 对 2.1±0.6，P<0.01），而两个亚组超声心动图显示的梗死面积相似。可以得出结论，急性心肌梗死后早期，腺苷负荷 99mTc-甲氧基异丁基异腈 SPET可能会低估再灌注但仍处于濒危状态的心肌，尤其是在梗死相关狭窄严重的患者中。在这些患者中，静息-负荷闪烁显像对缺血负荷的评估因静息状态下严重受损的心肌灌注而受到阻碍。
