Ramos Filho José, Nascimento Marcos Welber, Silva Rafael Mariano Gislon da, Camargo Thiago Negrini de, Almeida Roberto Simões de, Lima Eloá Jacinto
Universidade São Francisco, Bragança Paulista, SP, Brasil.
Arq Bras Cardiol. 2008 Sep;91(3):134-41, 148-55. doi: 10.1590/s0066-782x2008001500003.
The selection of patients with chronic coronary disease for recanalization is based on the detection of the affected myocardium that is potentially viable.
To evaluate the potentially viable ischemic myocardium through single photon emission computed tomography (SPECT) with MIBI after a maximum tolerated dose of I.V. nitroglycerin.
We prospectively investigated by SPECT with Tc-99m (MIBI), from April 2004 to November 2005, 40 patients (mean age: 62 +/- 8.9 yrs, 30 men) with coronary obstruction demonstrated angiographically; the myocardium scintigraphy was carried out at rest and after intravenous (I.V.) nitroglycerin, which was started at a dose of 1 microg/kg/min and increased every minute until the systolic blood pressure decreased by 20 mmHg. The decrease in the perfusion of the segments was classified as moderate or severe and compared after the nitroglycerin. The angiographic, hemodynamic and myocardial perfusion variables were analyzed.
We analyzed 680 myocardial segments at rest: 538 with a homogenous distribution and 142 with hypoperfusion (54 with moderate and 88 with severe decrease). After the nitroglycerin, there was an increase in the perfusion in 19 (47.5%) of 40 patients and 55 of 142 segments became viable: 33 (61.1%) with moderate and 22 (25%) with severe decrease; both presented a significant increase in the radiotracer distribution (p < 0.001, Chi-square).
One of the components with Tc-99m is Tc-99m 2-methoxy-isobutyl-isonitrile (MIBI), which, when used with an optimized dose of I.V. nitroglycerin, can increase the radiotracer uptake in areas with moderate and severe hypoperfusion. The results of the present study suggest the increase in the Tc-99m (MIBI) sensitivity by nitroglycerin for the detection of viable myocardium.
慢性冠心病患者再灌注治疗的选择基于对潜在存活的受影响心肌的检测。
通过静脉注射最大耐受剂量硝酸甘油后行单光子发射计算机断层扫描（SPECT）联合甲氧基异丁基异腈（MIBI）评估潜在存活的缺血心肌。
2004年4月至2005年11月，我们对40例经血管造影证实有冠状动脉阻塞的患者（平均年龄：62±8.9岁，30例男性）进行了99m锝（MIBI）SPECT前瞻性研究；心肌闪烁扫描在静息状态下及静脉注射硝酸甘油后进行，硝酸甘油起始剂量为1微克/千克/分钟，每分钟增加剂量直至收缩压下降20毫米汞柱。节段灌注减少分为中度或重度，并在硝酸甘油注射后进行比较。分析血管造影、血流动力学和心肌灌注变量。
我们分析了静息状态下的680个心肌节段：538个分布均匀，142个灌注减低（54个中度减低，88个重度减低）。硝酸甘油注射后，40例患者中有19例（47.5%）灌注增加，142个节段中有55个节段变为存活：33个（61.1%）中度减低节段和22个（25%）重度减低节段；两者放射性示踪剂分布均显著增加（p<0.001，卡方检验）。
99m锝的成分之一是99m锝甲氧基异丁基异腈（MIBI），当与优化剂量的静脉注射硝酸甘油联合使用时，可增加中度和重度灌注减低区域的放射性示踪剂摄取。本研究结果提示硝酸甘油可提高99m锝（MIBI）检测存活心肌的敏感性。
