Visualization of coronary blood flow using Doppler echocardiography and its clinical applications.

我们尝试使用脉冲多普勒超声心动图无创评估冠状动脉的血流量。在项目的第一年，使用3.6 MHz多普勒设备进行经胸入路。左前降支在1 ~ 2mm细血管内可见多普勒信号。血流信号表现为舒张期快速稳定的血流，其次是第二次心音。肥厚型心肌病的峰值速度为44 ~ 71 mm/sec，明显快于扩张型心肌病的25 ~ 43 cm/sec。流速也受到药物的影响，如硝酸甘油的还原作用。虽然经胸入路提供了有用的信息，但检测冠状动脉血流的灵敏度较低。第2年采用经食管超声心动图。传感器设置在胃镜的尖端，宽度为9毫米。80%的患者均可见左主干回声，80%的患者均可见冠状动脉血流多普勒信号。该方法测得舒张血流的最大流速为40+/-14 cm/秒。主动脉内球囊泵送提高了冠状动脉舒张期血流速度，表明其不仅对体循环有辅助作用，而且对冠状动脉循环也有有益作用。在去年，冠状动脉血流的评估是通过多普勒导管，其中20兆赫的微传感器连接在其尖端。对计算血流速度的方法进行了评价，结果表明FFT法优于零交叉法。冠状动脉狭窄时最大血流速度降低。我们已经评估了冠状动脉血流在各种疾病或干预使用多普勒超声心动图和揭示其在临床设置的实用性。

We attempted to assess the blood flow of the coronary artery noninvasively using pulsed Doppler echocardiography. At the first year of this project, 3.6 MHz Doppler equipment was used for transthoratic approach. As for left anterior descending artery, Doppler signal was detected inside of the thin vessel with 1 to 2 mm width. The flow signal was characteristic showing rapid and steady flow throughout diastole followed by the 2nd heart sound. The peak velocity was 44-71 mm/sec in hypertrophic cardiomyopathy, which was significantly faster than 25-43 cm/sec in dilated cardiomyopathy. The flow velocity was also influenced by drugs, such as reduction by nitroglycerin. Although the transthoratic approach provides the useful information, the sensitivity for detecting coronary flow was low. At the 2nd year, transesophageal echocardiography was used. The transducer is set at the tip of the gastrofiberscope with 9 mm width. The echo of the left main trunk was detected about 80% of the patients and the Doppler signal of the coronary blood flow was observed in all of these 80% patients. The maximum velocity of the diastolic flow detected by this method was 40+/-14 cm/sec. Intraaortic balloon pumping augmented the diastolic flow velocity of the coronary artery, indicating not only its assisting effect of systemic circulation but also benefiting effect to the coronary circulation. In the last year, Coronary flow was assessed by Doppler catheter, in which the 20 MHz microtransducer was attached to its tip. Methodology for calculating flow velocity of blood was evaluated, and it was shown that FFT method was superior to the zero- cross method. Maximum flow velocity was reduced in a narrowed coronary artery.We have assessed the coronary flow in various disease or interventions using Doppler echocardiography and revealed its usefulness in the clinical setting.