Adam D J, Haggart P C, Ludlam C A, Bradbury A W
Vascular Surgery Unit, Royal Infirmary of Edinburgh, UK.
Eur J Vasc Endovasc Surg. 2003 Oct;26(4):412-7. doi: 10.1016/s1078-5884(03)00013-3.
von Willebrand factor (vWF) is essential for the formation of platelet aggregates at sites of vascular endothelial cell (EC) injury. Peri-operative thrombocytopenia is associated with poor outcome in ruptured abdominal aortic aneurysm (AAA) repair. This prospective study examines the relationship between vWF and platelet count (PC) in ruptured AAA repair.
plasma vWF antigen, PC and C-reactive protein (CRP) were measured pre-operatively, and immediately before and 5 min after aortic clamp release, and on post-operative days 1 and 2 in 20 patients (18 men and 2 women of median age 74, range 63-86, years) with ruptured AAA.
elevated vWF was present in 13 (65%) patients pre-operatively, and 14 of 16 (88%) survivors at 24 h post-operatively. All patients demonstrated an intra-operative fall in vWF. There was no significant difference in vWF levels between survivors and non-survivors. PC was below the normal range in 8 (40%) patients pre-operatively and all patients at 24 h. Eighteen (90%) patients demonstrated an intro-operative fall in PC. PC was significantly lower in non-survivors pre-operatively (p=0.007), immediately before (p=0.009) and 5 min (p=0.009) and 24 h (p=0.02) after clamp release. There was a significant positive correlation between vWF and PC pre-operatively (r= +0.48, p=0.033), and immediately before (r= +0.47, p=0.044) and 5 min after clamp release (r= +0.5, p=0.043). There was a significant positive correlation between peak vWF level and the greatest fall in PC (r= +0.65, p=0.006). There was a significant negative correlation between vWF and CRP and operative blood loss; and between PC and CRP, operative blood loss and aortic clamp time.
these data demonstrate that EC activation, the acute phase protein response, operative blood loss and aortic clamp time all contribute to the peri-operative fall in PC in patients with ruptured AAA. The peri-operative fall in circulating levels of vWF and PC may represent consumption secondary to macro- and microvascular thrombus formation. The resultant procoagulant state may partly explain the association between low PC and poor outcome in ruptured AAA.
血管性血友病因子（vWF）对于在血管内皮细胞（EC）损伤部位形成血小板聚集体至关重要。围手术期血小板减少与腹主动脉瘤（AAA）破裂修复术后不良预后相关。这项前瞻性研究探讨了vWF与AAA破裂修复术中血小板计数（PC）之间的关系。
对20例（18例男性和2例女性，中位年龄74岁，范围63 - 86岁）AAA破裂患者术前、主动脉夹闭松开前及松开后5分钟、术后第1天和第2天测量血浆vWF抗原、PC和C反应蛋白（CRP）。
13例（65%）患者术前vWF升高，术后24小时存活的16例患者中有14例（88%）vWF升高。所有患者术中vWF均下降。存活者与非存活者的vWF水平无显著差异。8例（40%）患者术前PC低于正常范围，所有患者术后24小时PC均低于正常范围。18例（90%）患者术中PC下降。非存活者术前（p = 0.007）、夹闭松开前（p = 0.009）、5分钟后（p = 0.009）和24小时（p = 0.02）的PC显著更低。术前（r = +0.48，p = 0.033）、夹闭松开前（r = +0.47，p = 0.044）和5分钟后（r = +0.5，p = 0.043）vWF与PC之间存在显著正相关。vWF峰值水平与PC最大降幅之间存在显著正相关（r = +0.65，p = 0.006）。vWF与CRP及手术失血量之间存在显著负相关；PC与CRP、手术失血量及主动脉夹闭时间之间也存在显著负相关。
这些数据表明，EC激活、急性期蛋白反应、手术失血量和主动脉夹闭时间均导致AAA破裂患者围手术期PC下降。围手术期vWF和PC循环水平下降可能代表了大、微血管血栓形成后的消耗。由此产生的促凝状态可能部分解释了低PC与AAA破裂不良预后之间的关联。
