Bach R G, Kern M J, Donohue T J, Aguirre F V, Caracciolo E A
Department of Internal Medicine, St Louis University School of Medicine, Mo.
Circulation. 1993 Nov;88(5 Pt 2):II133-40.
Coronary artery bypass conduits derived from internal mammary arteries show relative resistance to atherosclerosis and significantly improved long-term patency compared with saphenous vein grafts. Atherothrombotic occlusion of venous conduits has previously been correlated with lower flow rates measured intraoperatively. To quantitate coronary bypass conduit flow velocity, we examined the phasic blood flow velocity patterns by intravascular Doppler spectral analysis in patients during cardiac catheterization to test the hypothesis that resting systolic and diastolic phasic blood flow velocity patterns differ significantly between arterial and venous bypass conduits.
Spectral phasic blood flow velocity was measured using an intravascular Doppler-tipped angioplasty guidewire in the proximal, mid, and distal segments of 18 internal mammary artery conduits and 11 saphenous vein grafts in 27 patients at a mean of 4 years (range, 1 to 11) postoperatively. In situ internal mammary artery conduits demonstrated a gradual longitudinal transition in the phasic flow pattern from predominantly systolic velocity proximally (diastolic/systolic peak velocity ratio, 0.6 +/- 0.2) to predominantly diastolic velocity distally (diastolic/systolic peak velocity ratio, 1.4 +/- 0.3; P < .001). Saphenous vein graft flow velocity pattern, however, showed a consistently diastolic predominance, both proximally and distally (diastolic/systolic peak ratios, 1.4 +/- 0.6 and 1.5 +/- 0.7, respectively; P = NS). Mean flow velocities, total velocity integral, and calculated maximal shear rates were significantly higher in all segments of internal mammary arteries compared with values in saphenous vein grafts.
Patterns of resting phasic blood flow, as well as mean velocity and total velocity integral, differ significantly between internal mammary artery and saphenous vein bypass conduits. These differences may have implications regarding blood-vessel wall interactions, the development of degenerative graft disease, and long-term conduit patency.
与大隐静脉移植物相比，取自乳内动脉的冠状动脉搭桥血管对动脉粥样硬化具有相对抗性，且长期通畅率显著提高。此前，静脉血管的动脉粥样硬化血栓形成性闭塞与术中测量的较低血流速度相关。为了定量冠状动脉搭桥血管的血流速度，我们在心脏导管插入术期间通过血管内多普勒频谱分析检查了患者的血流速度相位模式，以验证以下假设：动脉和静脉搭桥血管在静息收缩期和舒张期的血流速度相位模式存在显著差异。
在27例患者中，使用血管内多普勒尖端血管成形术导丝测量了18条乳内动脉血管和11条大隐静脉移植物近端、中段和远端的频谱血流速度相位，这些患者术后平均4年（范围1至11年）。原位乳内动脉血管的血流速度相位模式呈现出从近端以收缩期速度为主（舒张期/收缩期峰值速度比为0.6±0.2）到远端以舒张期速度为主（舒张期/收缩期峰值速度比为1.4±0.3；P<.001）的逐渐纵向转变。然而，大隐静脉移植物的血流速度模式在近端和远端均始终以舒张期为主（舒张期/收缩期峰值比分别为1.4±0.6和1.5±0.7；P=无显著差异）。与大隐静脉移植物相比，乳内动脉各段的平均血流速度、总速度积分和计算出的最大剪切率均显著更高。
乳内动脉和大隐静脉搭桥血管在静息血流速度相位模式以及平均速度和总速度积分方面存在显著差异。这些差异可能对血管壁相互作用、移植血管退行性病变的发展以及长期血管通畅性产生影响。
