Kenny A, Shapiro L M
Regional Cardiac Unit, Papworth Hospital, Papworth Everard, Cambridge, UK.
Circulation. 1994 Feb;89(2):731-9. doi: 10.1161/01.cir.89.2.731.
Intraoperative epicardial coronary Doppler ultrasound has the potential to provide anatomic and functional information. This technique has been hindered by the large size of standard transducers, but a miniature transducer is available that may fulfill the potential of coronary ultrasound.
Twenty consecutive patients who were undergoing coronary artery bypass grafting were studied and compared with 9 control patients with normal coronary arteries who were undergoing routine mitral valve surgery. A miniature 6.5-MHz transducer was used to image coronary arteries and measure coronary blood flow velocities. Seventeen proximal left anterior descending and 3 right coronary artery stenoses were studied. As defined by coronary angiography (1 to 34 days before surgery), there were 13 severe stenoses (> 70%), 4 moderate stenoses (40% to 70%), 2 minor stenoses (< 40%), and 1 subtotal occlusion. Stenoses were readily identified by ultrasound. Color flow mapping demonstrated laminar flow in normal arteries and nonlaminar flow across moderate and severe stenoses. In the control patients with unobstructed arteries, peak and mean diastolic velocities were 35 +/- 2.1 and 26 +/- 1.9 cm/s with peak and mean systolic velocities of 16 +/- 1.4 and 11 +/- 0.8 cm/s, respectively. Prestenotic flow velocities were not significantly different from normal control values, but a wide range of poststenotic flow disturbances were detected. Analysis of the 20 study patients did not reveal significant differences in poststenotic compared with prestenotic flow. A subgroup analysis of 12 patients with severe left anterior descending coronary artery stenoses was performed, and reversed poststenotic systolic flow was seen in 9. Prestenotic peak and mean systolic velocities were 16.5 +/- 1.7 and 11.9 +/- 1.1 cm/s, respectively, and were significantly altered downstream of the stenoses at -22.7 +/- 17.2 and -15.9 +/- 10.9 cm/s (P < .05 and P < .01, respectively). Reversed systolic flow was seen only distal to severe left anterior descending coronary artery stenoses and did not correlate with retrograde collateral filling as determined by preoperative coronary angiography. Moderate stenoses appeared to increase both systolic and diastolic components of poststenotic flow.
Epicardial Doppler ultrasound with a miniature transducer identifies coronary stenoses and associated blood flow disturbances. Compared with moderate lesions, severe stenoses demonstrated different poststenotic flow patterns. Intraoperative use of this technique may determine the hemodynamic significance of coronary stenoses.
术中的心外膜冠状动脉多普勒超声有潜力提供解剖和功能信息。这项技术一直受到标准换能器尺寸较大的限制，但现在有一种微型换能器，可能实现冠状动脉超声的潜力。
对连续20例接受冠状动脉搭桥术的患者进行了研究，并与9例接受常规二尖瓣手术、冠状动脉正常的对照患者进行比较。使用一个微型6.5兆赫换能器对冠状动脉进行成像并测量冠状动脉血流速度。研究了17处左前降支近端和3处右冠状动脉狭窄。根据冠状动脉造影（手术前1至34天）确定，有13处严重狭窄（>70%）、4处中度狭窄（40%至70%）、2处轻度狭窄（<40%）和1处次全闭塞。狭窄很容易通过超声识别。彩色血流图显示正常动脉内为层流，中度和重度狭窄处为非层流。在动脉通畅的对照患者中，舒张期峰值和平均速度分别为35±2.1厘米/秒和26±1.9厘米/秒，收缩期峰值和平均速度分别为16±1.4厘米/秒和11±0.8厘米/秒。狭窄前血流速度与正常对照值无显著差异，但检测到广泛的狭窄后血流紊乱。对20例研究患者的分析未发现狭窄后与狭窄前血流有显著差异。对12例左前降支冠状动脉严重狭窄患者进行了亚组分析，其中9例出现狭窄后收缩期血流逆转。狭窄前收缩期峰值和平均速度分别为16.5±1.7厘米/秒和11.9±1.1厘米/秒，在狭窄下游显著改变为-22.7±17.2厘米/秒和-15.9±10.9厘米/秒（分别为P<.05和P<.01）。仅在左前降支冠状动脉严重狭窄远端可见收缩期血流逆转，且与术前冠状动脉造影确定的逆行侧支充盈无关。中度狭窄似乎增加了狭窄后血流的收缩期和舒张期成分。
使用微型换能器的心外膜多普勒超声可识别冠状动脉狭窄及相关血流紊乱。与中度病变相比，严重狭窄表现出不同的狭窄后血流模式。术中使用该技术可能确定冠状动脉狭窄的血流动力学意义。
