Department of Surgery, Division of Cardiovascular Surgery, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
J Thorac Cardiovasc Surg. 2010 Aug;140(2):400-7. doi: 10.1016/j.jtcvs.2009.11.063. Epub 2010 May 27.
We have demonstrated that therapeutic augmentation of systemic blood pressure during spinal cord ischemia plays an important role in minimizing spinal cord injury in both experimental and clinical aortic surgery. However, there remain concerns that excessively high blood pressure during spinal cord reperfusion may aggravate the reperfusion injury. The purpose of this study is to investigate the effect of high blood pressure during spinal cord reperfusion on postoperative neurologic outcomes after aortic surgery in rabbits.
Experiments were performed using a rabbit spinal cord ischemia-reperfusion model in 2 randomly divided groups: (1) In the HR group, the mean blood pressure was maintained at a high level (121 +/- 1.3 mm Hg) during reperfusion with intravenously administered phenylephrine; and (2) in the CR group, the mean blood pressure was not medically controlled (75 +/- 9.1 mm Hg) during reperfusion. Neurologic and histologic assessments and evaluation of early reperfusion injury were performed.
In the HR group, slow and incomplete recovery of transcranial motor-evoked potentials (P = .02) and low neurologic scores (P < .005) were observed during spinal cord reperfusion compared with the CR group. At 48 hours of reperfusion, there were significantly fewer viable neuron cells, more apoptosis, and more perivascular edema with gray matter vacuolation in the HR group (P < .001 for each). At 3 hours, myeloperoxidase activity (P = .0021), vascular permeability (P = .0012), and superoxide generation (P < .0001) were significantly increased in the HR group.
Excessively high blood pressure in the early phase of spinal cord reperfusion increased reperfusion injury in the spinal cord, leading to exacerbation of early-onset paraplegia. Avoidance of spinal cord reperfusion with high blood pressure may be one management strategy in thoracoabdominal aortic surgery.
我们已经证明，脊髓缺血期间全身血压的治疗性增强在减少实验和临床主动脉手术中的脊髓损伤方面发挥了重要作用。然而，人们仍然担心脊髓再灌注期间过高的血压可能会加重再灌注损伤。本研究旨在探讨脊髓再灌注期间高血压对兔主动脉手术后神经功能恢复的影响。
在 2 个随机分组的实验中使用兔脊髓缺血再灌注模型：（1）在 HR 组中，通过静脉注射苯肾上腺素维持再灌注期间的平均血压处于较高水平（121 ± 1.3mmHg）；（2）在 CR 组中，再灌注期间不进行医学控制（75 ± 9.1mmHg）。进行神经和组织学评估以及早期再灌注损伤评估。
在 HR 组中，与 CR 组相比，在脊髓再灌注期间，经颅运动诱发电位的恢复缓慢且不完全（P=0.02），神经评分较低（P＜0.005）。在再灌注 48 小时时，HR 组的存活神经元细胞数量明显减少，凋亡增加，血管周围水肿伴有灰质空泡化（P＜0.001 ）。在 3 小时时，HR 组的髓过氧化物酶活性（P=0.0021）、血管通透性（P=0.0012）和超氧化物生成（P＜0.0001）显著增加。
脊髓再灌注早期过高的血压增加了脊髓的再灌注损伤，导致早发性截瘫加重。避免脊髓再灌注时血压过高可能是胸主动脉瘤手术的一种治疗策略。
