Parodi O, Sambuceti G, Roghi A, Testa R, Inglese E, Pirelli S, Spinelli F, Campolo L, L'Abbate A
CNR Clinical Physiology Institute, Pisa, Italy.
Circulation. 1993 Feb;87(2):330-44. doi: 10.1161/01.cir.87.2.330.
Experimental data demonstrate the persistence of a transmural vasodilator reserve in the face of depressed resting myocardial perfusion. The present study was designed to determine whether resting myocardial hypoperfusion indicates exhausted coronary reserve (CR).
Fifteen patients with stable angina, isolated left anterior descending coronary artery (LAD) stenosis, and no previous myocardial infarction were evaluated by means of 99mTc human albumin microsphere scintigraphy. Regional myocardial perfusion and CR were assessed at baseline and after LAD papaverine (10-12 mg) by means of two microsphere injections in the left ventricle and compared with five normal subjects. Two 300-second scans were obtained with a mobile gamma camera positioned in the 70 degrees left anterior oblique projection; actual microsphere distribution after papaverine was obtained by image subtraction. The two arterial input functions (basal and papaverine) were measured from the first-pass time-activity curves and validated with the reference arterial sample technique. From the comparison of circumferential profile analysis between patients and normal subjects, nine patients (group 1A) showed perfusion defects at rest (reduction of percent radioactivity below 2 SD of normal subjects) in the LAD territory, and the other six (group 1B) showed homogeneous perfusion. CR (papaverine/resting perfusion) was 3.8 +/- 0.2 and 1.51 +/- 0.27 in normal subjects and in ischemic patients, respectively (p < 0.01). Despite resting hypoperfusion, group 1A showed a papaverine-recruitable CR similar to that of group 1B (1.57 +/- 0.33 and 1.43 +/- 0.16, respectively, p = NS).
In patients with stable angina pectoris, isolated LAD stenosis, and no previous myocardial infarction, microsphere scintigraphy disclosed a high incidence of resting perfusion defects; in those patients, a residual CR was observed despite decreased resting blood flow.
实验数据表明，在静息心肌灌注降低的情况下，透壁血管扩张储备依然存在。本研究旨在确定静息心肌灌注不足是否表明冠状动脉储备（CR）已耗竭。
对15例稳定型心绞痛、孤立性左前降支冠状动脉（LAD）狭窄且既往无心肌梗死的患者，采用99mTc人白蛋白微球闪烁显像进行评估。通过在左心室内注射两次微球，在基线时以及注射LAD罂粟碱（10 - 12毫克）后评估局部心肌灌注和CR，并与5名正常受试者进行比较。使用置于左前斜70度的移动γ相机进行两次300秒扫描；通过图像相减获得罂粟碱注射后的实际微球分布。从首次通过时间 - 活性曲线测量两个动脉输入函数（基础和罂粟碱），并采用参考动脉样本技术进行验证。通过比较患者与正常受试者的圆周轮廓分析，9例患者（1A组）在LAD区域静息时出现灌注缺损（放射性百分比降低至低于正常受试者2个标准差），另外6例（1B组）显示灌注均匀。正常受试者和缺血患者的CR（罂粟碱/静息灌注）分别为3.8±0.2和1.51±0.27（p < 0.01）。尽管存在静息灌注不足，但1A组显示出与1B组相似的可被罂粟碱激发的CR（分别为1.57±0.33和1.43±0.16，p =无显著性差异）。
在患有稳定型心绞痛、孤立性LAD狭窄且既往无心肌梗死的患者中，微球闪烁显像显示静息灌注缺损的发生率很高；在这些患者中，尽管静息血流减少，但仍观察到残余的CR。
