Balacumaraswami Lognathen, Abu-Omar Yasir, Selvanayagam Joseph, Pigott David, Taggart David P
Department of Cardiothoracic Surgery, John Radcliffe Hospital, Headington, Oxford, United Kingdom.
J Thorac Cardiovasc Surg. 2008 Mar;135(3):533-9. doi: 10.1016/j.jtcvs.2007.10.027.
Despite profound differences in the neurohumoral milieu in patients undergoing on-pump and off-pump coronary artery bypass grafting, it is uncertain how this affects graft blood flow.
We prospectively recorded intraoperative transit-time flow measurements (MediStim BF 2004; MediStim AS, Oslo, Norway) in all internal thoracic artery, radial artery, and long saphenous vein conduits in patients undergoing off-pump and on-pump bypass grafting by a single surgeon. We calculated a flow/pressure ratio as a ratio of mean graft flow to mean arterial pressure for all the conduits just before chest closure.
Transit-time flow measurements were recorded in 266 grafts (203 off-pump; 63 on-pump) in 100 patients (80 off-pump; 20 on-pump). Overall, mean graft flow (milliliters per minute) was higher for all grafts in the on-pump group despite a significantly lower mean arterial pressure compared with the off-pump group (P < .05). Consequently the flow/pressure ratio was greater for all grafts in the on-pump group (internal thoracic artery 0.55 vs 0.35, radial artery 0.61 vs 0.36, long saphenous vein 0.77 vs 0.55). Overall mean graft flow was significantly greater in the long saphenous vein than in the internal thoracic artery (P < .001) and radial artery (P = .001), but there was no significant difference in mean graft flow in internal thoracic artery or radial artery grafts within each group.
In comparison with the off-pump group, the overall mean graft flow and flow/pressure ratio were significantly higher and mean arterial pressure significantly lower for all grafts in the on-pump group. These findings are probably a result of vasodilatation resulting from cardiopulmonary bypass and reactive hyperemia resulting from a period of ischemia. There was no difference in the mean graft flow and flow/pressure ratio of arterial grafts, which were significantly less than for long saphenous vein grafts. In patients with unstable angina and/or hemodynamic instability, in whom rapid and maximum restoration of myocardial perfusion is a priority, potentially lower graft flow in arterial grafts and off-pump surgery should be considered.
尽管接受体外循环和非体外循环冠状动脉搭桥术的患者在神经体液环境方面存在显著差异，但尚不清楚这如何影响移植血管的血流。
我们前瞻性地记录了由同一位外科医生进行非体外循环和体外循环搭桥术的患者所有胸廓内动脉、桡动脉和大隐静脉移植血管的术中渡越时间血流测量值（MediStim BF 2004；MediStim AS，挪威奥斯陆）。我们计算了关胸前夕所有移植血管的血流/压力比，即平均移植血管血流与平均动脉压之比。
在100例患者（80例非体外循环；20例体外循环）中对266根移植血管（203根非体外循环；63根体外循环）进行了渡越时间血流测量。总体而言，尽管体外循环组的平均动脉压显著低于非体外循环组（P <.05），但其所有移植血管的平均血流（毫升/分钟）更高。因此，体外循环组所有移植血管的血流/压力比更大（胸廓内动脉为0.55对0.35，桡动脉为0.61对0.36，大隐静脉为0.77对0.55）。大隐静脉的总体平均移植血管血流显著高于胸廓内动脉（P <.001）和桡动脉（P =.001），但每组胸廓内动脉或桡动脉移植血管的平均移植血管血流无显著差异。
与非体外循环组相比，体外循环组所有移植血管的总体平均移植血管血流和血流/压力比显著更高，而平均动脉压显著更低。这些发现可能是体外循环导致血管扩张以及一段时间缺血后反应性充血的结果。动脉移植血管的平均移植血管血流和血流/压力比无差异，且显著低于大隐静脉移植血管。对于不稳定型心绞痛和/或血流动力学不稳定的患者，快速和最大程度恢复心肌灌注是首要任务，应考虑动脉移植血管和非体外循环手术中潜在较低的移植血管血流。
