Zafrir Nili, Arditi Alexander, Ben-Gal Tuvia, Solodky Alejandro, Hassid Yosef, Sulkes Jaqueline, Battler Alexander
Nuclear Cardiology Unit, Department of Cardiology, Rabin Medical Center, Beilinson Campus, Petah Tiqva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Clin Cardiol. 2003 Nov;26(11):530-5. doi: 10.1002/clc.4960261111.
The two most useful methods for myocardial viability assessment are perfusion imaging and dobutamine echocardiography.
The present study investigated the additive value of a new method, dobutamine technetium 99m (99mTc)-sestamibi-gated single-photon emission computed tomography (SPECT), which combines these two modalities, to the prediction of wall motion improvement after revascularization.
Fifty-five consecutive patients with ischemic cardiomyopathy, who were referred for viability evaluation, underwent resting and dobutamine (dose, 5-10 microkg/kg/min) gated SPECT with 99mTc-sestamibi. Of these patients, 36 underwent coronary artery bypass graft (CABG) within 1 month of the study and 32 had repeat resting gated SPECT within 1 year. Global and regional wall motion, wall thickness, and perfusion were simultaneously analyzed at rest and after dobutamine using the 20-segment model; the sestamibi uptake and wall motion response to dobutamine of each segment were rated quantitatively. Based on these findings, the segments were categorized as normal, viable, or nonviable. The predictive values for wall motion improvement were assessed by perfusion, using cutoffs of 50 and 60% of sestamibi uptake, and thereafter by the addition of dobutamine response in the segments that were rated nonviable.
Of the 1,080 myocardial segments studied, 906 (84%) had abnormal wall motion and were analyzed for viability. Concordance between perfusion and wall motion response to dobutamine was 60% with the 50% cutoff of sestamibi uptake, and increased to 65% with the 60% sestamibi cutoff (p < 0.04). The respective predictive values of wall motion improvement using the 50 and 60% cutoff points were as follows: sensitivity 93 and 70%, respectively, (p < 0.01); specificity 59 and 86% (p < 0.001), respectively; accuracy 77% for both. The addition of the wall motion response to dobutamine to the assessment of the nonviable segments by perfusion (60% cutoff) increased the sensitivity from 70 to 85% (p = 0.001) and the negative predictive value from 70 to 81% (p = 0.009); the positive predictive value remained high (86 vs. 82%). No additive value of wall motion response to dobutamine was demonstrated for nonviable segments by perfusion with a 50% cutoff.
Dobutamine sestamibi-gated SPECT is a feasible method for the analysis of myocardial perfusion, function, and contractile reserve of individual myocardial segments in patients with ischemic cardiomyopathy. Viability assessment based on a threshold of 60% uptake of sestamibi, with the addition of the wall motion response to dobutamine in the nonviable segments, seems to yield better predictive values for wall motion improvement after CABG.
评估心肌存活性最有用的两种方法是灌注成像和多巴酚丁胺超声心动图。
本研究探讨了一种新方法——多巴酚丁胺锝99m（99mTc）-甲氧基异丁基异腈门控单光子发射计算机断层扫描（SPECT），该方法结合了这两种模式，对血运重建后室壁运动改善的预测价值。
55例因存活性评估而转诊的缺血性心肌病患者接受了静息和多巴酚丁胺（剂量为5 - 10微克/千克/分钟）门控99mTc-甲氧基异丁基异腈SPECT检查。这些患者中，36例在研究的1个月内接受了冠状动脉旁路移植术（CABG），32例在1年内进行了重复静息门控SPECT检查。使用20节段模型在静息和多巴酚丁胺注射后同时分析整体和局部室壁运动、室壁厚度及灌注情况；对每个节段的甲氧基异丁基异腈摄取及对多巴酚丁胺的室壁运动反应进行定量评分。基于这些结果，将节段分为正常、存活或无存活能力。通过灌注评估室壁运动改善的预测价值，使用甲氧基异丁基异腈摄取量的50%和60%作为截断值，然后在评定为无存活能力的节段中加入多巴酚丁胺反应进行评估。
在研究的1080个心肌节段中，906个（84%）室壁运动异常并进行了存活性分析。甲氧基异丁基异腈摄取量截断值为50%时，灌注与多巴酚丁胺室壁运动反应的一致性为60%，甲氧基异丁基异腈截断值为60%时一致性增至65%（p < 0.04）。使用50%和60%截断点时室壁运动改善的各自预测价值如下：敏感性分别为93%和70%（p < 0.01）；特异性分别为59%和86%（p < 0.001）；准确性均为77%。在对无存活能力节段进行灌注评估（截断值为60%）时加入多巴酚丁胺室壁运动反应，敏感性从70%提高到85%（p = 0.001），阴性预测值从70%提高到81%（p = 0.009）；阳性预测值仍较高（86%对82%）。对于截断值为50%的灌注无存活能力节段，未显示多巴酚丁胺室壁运动反应的附加价值。
多巴酚丁胺甲氧基异丁基异腈门控SPECT是分析缺血性心肌病患者个体心肌节段心肌灌注、功能和收缩储备的可行方法。基于甲氧基异丁基异腈摄取量60%阈值的存活性评估，在无存活能力节段中加入多巴酚丁胺室壁运动反应后，似乎对CABG后室壁运动改善具有更好的预测价值。
