Jeanmart H, Perrault L P, Desjardins N, Chavanon O, Carrier M, Fonger J D
Research Center and Department of Surgery, Montreal Heart Institute, Quebec, Canada.
Ann Thorac Surg. 2001 Sep;72(3):810-5; discussion 816. doi: 10.1016/s0003-4975(01)02895-8.
Harvesting of the internal mammary artery (IMA) for use in myocardial revascularization may result in spasm, which can impair early graft flow. Hydrostatic and mechanical dilatation can exert an intraluminal shear force, causing denudation of the IMA endothelium. A new long balloon dilatation technique (LB) has been developed to mechanically increase IMA diameter and flow without exerting any shear force on the endothelium.
Vascular rings of porcine IMA were divided into four groups: no manipulation (control), metal dilators (MD), short balloon (SB), or LB intraluminal dilation. In situ flows after dilation and percentage of intact endothelium after silver nitrate staining were determined. Endothelium-dependent contractions with arachidonic acid, relaxations with acetylcholine, endothelium-independent contractions with norepinephrine, and relaxation with sodium nitroprusside were recorded in organ chamber experiments.
Increases in IMA flows were similar in all dilated groups. Endothelium-independent contractions and relaxations of IMA smooth muscle were unaffected by any type of mechanical dilation. However, endothelium-dependent contractions and relaxations were significantly impaired after MD and SB but preserved after LB dilation compared with control. Silver nitrate staining showed a greater preservation of the endothelial coverage after LB dilation.
IMA dilatation with the novel arterial LB catheter increases IMA flow and preserves endothelial cell integrity, making it an effective and atraumatic method to relieve IMA spasm before use for coronary artery bypass grafting.
获取乳内动脉（IMA）用于心肌血运重建可能会导致痉挛，这会损害早期移植物血流。流体静力扩张和机械扩张可施加腔内剪切力，导致IMA内皮剥脱。已开发出一种新的长球囊扩张技术（LB），可在不对内皮施加任何剪切力的情况下机械性增加IMA直径和血流。
将猪IMA血管环分为四组：不进行操作（对照组）、金属扩张器（MD）、短球囊（SB）或LB腔内扩张。测定扩张后的原位血流以及硝酸银染色后完整内皮的百分比。在器官腔实验中记录用花生四烯酸进行的内皮依赖性收缩、用乙酰胆碱进行的舒张、用去甲肾上腺素进行的非内皮依赖性收缩以及用硝普钠进行的舒张。
所有扩张组的IMA血流增加情况相似。IMA平滑肌的非内皮依赖性收缩和舒张不受任何类型机械扩张的影响。然而，与对照组相比，MD和SB扩张后内皮依赖性收缩和舒张显著受损，但LB扩张后得以保留。硝酸银染色显示LB扩张后内皮覆盖的保留情况更好。
使用新型动脉LB导管对IMA进行扩张可增加IMA血流并保持内皮细胞完整性，使其成为在用于冠状动脉旁路移植术前缓解IMA痉挛的一种有效且无创的方法。
