Iskandrian A S, Heo J, Askenase A, Segal B L, Auerbach N
Philadelphia Heart Institute, Presbyterian-University of Pennsylvania Hospital.
Am Heart J. 1988 Feb;115(2):432-43. doi: 10.1016/0002-8703(88)90492-9.
Dipyridamole cardiac imaging is a useful alternative technique to exercise stress testing in the evaluation of patients with ischemic heart disease. Intravenous dipyridamole is still in the investigational phase, while oral dipyridamole is widely available. The hemodynamic effects of dipyridamole include an increase in coronary blood flow (due to coronary vasodilation) which is in excess of the increase in myocardial oxygen consumption and cardiac output. The disparity in the increase in coronary blood flow relative to the cardiac output results in an increase in myocardial thallium activity and an increase in the myocardial/background activity ratio. The quality of the thallium images is better or similar to that of exercise thallium images. The optimal dose of intravenous dipyridamole is 0.56 mg/kg, and of the oral dose it is 300 to 400 mg, although higher doses may be necessary in some patients. Analysis of the thallium images has been to a large extent based on visual inspection of the planar images. Delayed images are helpful to establish the nature of the perfusion abnormalities (transient or fixed). The process of redistribution is based on disparate rates of washout from the normal and abnormal zones. The sensitivity and specificity of dipyridamole thallium imaging, whether intravenous or oral, have been shown in a number of studies to be quite adequate and comparable to that achieved during exercise thallium imaging. Dipyridamole two-dimensional echocardiography has also been used in the detection of coronary artery disease; transient (new or worsening of preexisting) wall motion abnormalities have been found to be a specific marker of coronary artery disease. Transmural as well as regional coronary steal phenomena have been postulated as the mechanism for dipyridamole-induced regional wall motion abnormalities. Compared to exercise two-dimensional echocardiography, dipyridamole echocardiography provides high-quality studies and in higher proportions of patients. The results of dipyridamole thallium imaging have also been extremely important in identifying high-risk patients after acute myocardial infarction or patients with peripheral vascular disease undergoing elective vascular surgery; the presence of a dipyridamole-induced perfusion abnormality identifies patients at high risk for future cardiac events. Thus, dipyridamole cardiac imaging is helpful in the diagnosis of coronary artery disease and in risk stratification.
双嘧达莫心脏成像在评估缺血性心脏病患者时是一种有用的替代运动负荷试验的技术。静脉注射双嘧达莫仍处于研究阶段，而口服双嘧达莫广泛可得。双嘧达莫的血流动力学效应包括冠状动脉血流量增加（由于冠状动脉扩张），其增加幅度超过心肌氧耗量和心输出量的增加幅度。冠状动脉血流量增加与心输出量增加之间的差异导致心肌铊活性增加以及心肌/本底活性比值增加。铊图像的质量优于或类似于运动铊图像。静脉注射双嘧达莫的最佳剂量为0.56mg/kg，口服剂量为300至400mg，不过在某些患者中可能需要更高剂量。铊图像分析在很大程度上基于平面图像的视觉检查。延迟图像有助于确定灌注异常的性质（短暂性或固定性）。再分布过程基于正常和异常区域洗脱速率的差异。多项研究表明，无论是静脉注射还是口服双嘧达莫铊成像，其敏感性和特异性都相当充足，与运动铊成像相当。双嘧达莫二维超声心动图也已用于检测冠状动脉疾病；短暂性（新出现或原有情况加重）室壁运动异常已被发现是冠状动脉疾病的特异性标志物。透壁以及区域性冠状动脉窃血现象被认为是双嘧达莫诱发区域性室壁运动异常的机制。与运动二维超声心动图相比，双嘧达莫超声心动图能为更高比例的患者提供高质量的检查。双嘧达莫铊成像结果在识别急性心肌梗死后的高危患者或接受择期血管手术的外周血管疾病患者方面也极其重要；双嘧达莫诱发的灌注异常的存在可识别出未来发生心脏事件的高危患者。因此，双嘧达莫心脏成像有助于冠状动脉疾病的诊断和风险分层。
