第二军医大学学报  2019, Vol. 40 Issue (7): 749-753   PDF    
血小板参数与同种异体肾移植术后移植肾功能延迟恢复的关系
孙婷婷, 符永叶, 周正宇, 蓝欢, 贾音     
海军军医大学(第二军医大学)长海医院实验诊断科, 上海 200433
摘要: 目的 探讨同种异体肾移植患者术后移植肾功能延迟恢复(DGF)与外周血血小板参数变化的关系。方法 应用回顾性研究方法,选取2016年7月至2018年5月在海军军医大学(第二军医大学)长海医院器官移植科接受同种异体肾移植术的患者109例,根据术后是否发生DGF分为DGF组(n=41)和非DGF(non-DGF)组(n=68)。分别采集两组患者术前及术后1、3、7、14 d的外周血,检测血小板计数(PLT)、大型血小板比值(P-LCR)、平均血小板体积(MPV)、血小板分布宽度(PDW)、血小板比容(PCT),观察上述指标的动态变化并进行组间比较。采用受试者工作特征(ROC)曲线分析上述指标预测同种异体肾移植术后DGF的价值。结果 肾移植术前DGF组与non-DGF组血小板参数差异无统计学意义。肾移植术后1、3、7、14 d,DGF组PLT始终低于non-DGF组,MPV始终高于non-DGF组,且在术后7 d时差异均有统计学意义(P均 < 0.05);肾移植术后DGF组与non-DGF组PCT均呈先降低后升高趋势,术后7 d时DGF组PCT低于non-DGF组且差异有统计学意义(P < 0.05);肾移植术后DGF组与non-DGF组PDW和P-LCR均呈先升高后降低趋势,术后7 d时DGF组PDW大于non-DGF组且差异有统计学意义(P < 0.05),而P-LCR在DGF组和non-DGF组之间差异无统计学意义(P=0.184)。肾移植术后7 d PDW和PCT预测DGF的ROC曲线下面积分别为0.781和0.758,最佳截断值分别为16.75 fL和0.155%,特异度分别为92.6%和63.2%,灵敏度分别为61.0%和75.6%。结论 对接受同种异体肾移植术的患者进行血小板参数的动态监测有助于DGF的早期诊断,移植术后7 d PDW>16.75 fL、PCT < 0.155%时患者发生DGF的风险增加。
关键词: 肾移植    血小板    肾功能延迟恢复    早期诊断    
Relationship between platelet parameters and delayed graft function after renal transplantation
SUN Ting-ting, FU Yong-ye, ZHOU Zheng-yu, LAN Huan, JIA Yin     
Department of Laboratory Medicine, Changhai Hospital, Naval Medical University(Second Military Medical University), Shanghai 200433, China
Co-first authors
Abstract: Objective To explore the relationship between the changes of platelet parameters after renal transplantation and delayed graft function (DGF). Methods A retrospective analysis was conducted with 109 patients who underwent allograft renal transplantation from Jul. 2016 to May 2018 in the Department of Organ Transplantation of Changhai Hospital, Naval Medical University (Second Military Medical University). The patients were divided into DGF group (n=41) and non-DGF group (n=68). Peripheral blood samples were collected from the two groups before and at 1, 3, 7 and 14 d after operation. The platelet parameters, including platelet count (PLT), platelet-large cell ratio (P-LCR), mean platelet volume (MPV), platelet volume distribution width (PDW) and platelet hematocrit (PCT), were dynamically monitored. Receiver operating characteristic (ROC) curve was used to analyze the value of the platelet parameters for predicting DGF after renal transplantation. Results There was no significant difference in platelet parameters between the DGF group and the non-DGF group before operation. At 1, 3, 7, and 14 d after renal transplantation, PLT values in the DGF group were lower than those in the non-DGF group, MPV values were higher than those in the non-DGF group, with statistical significance found at 7 d after renal transplantation (both P < 0.05). PCT in the DGF group was decreased first and then increased after renal transplantation. At 7 d after operation, PCT in the DGF group was markedly lower than that in the non-DGF group (P < 0.05).PDW and P-LCR in the DGF group and the non-DGF group increased first and then decreased after renal transplantation. At 7 d after operation, PDW in the DGF group was markedly higher than that in the non-DGF group (P < 0.05). There was no significant difference in P-LCR between the two groups at 7 d after operation (P=0.184). At 7 d after operation, the area under ROC curve for PDW and PCT were 0.781 and 0.758, with the optimal cut-off values being 16.75 fL and 0.155%, specificity being 92.6% and 63.2%, and sensitivity being 61.0% and 75.6%, respectively. Conclusion Dynamic monitoring of platelet parameters early after renal transplantation is helpful for the early diagnosis of DGF. There is an increased risk of DGF in patients with PDW>16.75 fL and PCT < 0.155% at 7 d after operation.
Key words: kidney transplantation    blood platelets    delayed graft function    early diagnosis    

移植肾功能延迟恢复(delayed graft function,DGF)是肾移植术后的常见并发症[1]。移植肾穿刺活组织检查是诊断DGF的金标准,但其属于有创性检查,特异度不高且并发症多,临床应用有限[2]。目前常用术后7 d血肌酐>400 μmol/L作为DGF的诊断指标[1]。但血肌酐易受体质量、年龄、性别和肌肉代谢等其他因素的影响,诊断特异度不高[3]。肾缺血再灌注损伤引起的炎症和氧化损伤是导致DGF的危险因素[4]。研究表明,血小板可以参与机体炎症反应过程[5]。因此,本研究拟通过动态监测同种异体肾移植患者术后5个临床常规检测的血小板参数——血小板计数(platelet count,PLT)、大型血小板比值(platelet-large cell ratio,P-LCR)、平均血小板体积(mean platelet volume,MPV)、血小板分布宽度(platelet volume distribution width,PDW)和血小板比容(platelet hematocrit,PCT)的动态变化,探讨血小板参数与肾移植术后发生DGF的关系。

1 资料和方法 1.1 研究对象

本研究共纳入2016年7月至2018年5月在海军军医大学(第二军医大学)长海医院器官移植科接受肾移植手术的患者109例,根据术后是否发生DGF分为DGF组(n=41)和非DGF组(non-DGF组,n=68)。DGF诊断标准:患者肾移植术后7 d内需要血液透析治疗,或者虽未经过血液透析治疗,但在术后7 d血肌酐仍>400 μmol/L [4, 6]。纳入标准:(1)供者和受者ABO血型相符;(2)群体反应性抗体(panel reactive antibody,PRA)均≤ 10%,淋巴细胞毒交叉配合试验死细胞比例≤ 10%,人类白细胞抗原(human leukocyte antigen,HLA)配型错配数为1~5个,热缺血时间3~10 min,冷缺血时间6~24 h;(3)所有受者均采用口服他克莫司(FK506)+霉酚酸酯+醋酸泼尼松的三联抗排斥药物方案。排除标准:(1)术前7 d内使用过影响血小板聚集功能药物的患者;(2)输注过全血或血液制品者;(3)术后出现各种感染或其他并发症的患者;(4)观察时间内失访;(5)亲属供肾活体肾移植受者;(6)临床资料收集不全者。本研究经海军军医大学(第二军医大学)长海医院伦理委员会审批。

1.2 血液标本采集及检测方法

用EDTA抗凝管分别采集患者术前和术后1、3、7、14 d的外周血各2 mL,1 h内在Sysmex XN-9000血液分析仪(日本希森美康公司)上使用同品牌配套进口试剂进行检测,获取PLT、P-LCR、MPV、PDW和PCT等数据。

1.3 统计学处理

采用SPSS 22.0软件进行统计学分析。符合正态分布的计量资料以x ± s表示,两组间比较采用独立样本t检验;计数资料以例数和百分数表示。采用受试者工作特征(receiver operating characteristic,ROC)曲线判断血小板参数预测DGF的效能,并计算灵敏度和特异度,选取约登指数(约登指数=灵敏度+特异度-1)最大时所对应的值为最佳截断值。检验水准(α)为0.05。

2 结果 2.1 血小板参数在肾移植术后的变化趋势

纳入研究的109例患者中男70例、女39例,年龄为15~70岁,平均年龄为(40.0 ± 12.4)岁。供者均为尸体供肾,受者均为首次接受肾移植。由表 1可见,肾移植术后DGF组和non-DGF组患者的PLT均迅速降低,至术后3 d时达到最低值,随后两组PLT均缓慢升高,在术后14 d时基本恢复到术前水平;DGF组PLT在术后14 d内始终低于对照组,其中术后7 d时两组差异有统计学意义(P<0.05)。肾移植术后DGF组和non-DGF组患者的MPV均呈先升高后降低趋势,两组分别于术后7 d和术后3 d达到最高值;DGF组MPV在术后14 d内始终高于对照组,其中术后7 d时两组差异均有统计学意义(P均<0.05)。肾移植术后DGF组和non-DGF组患者的PCT呈先降低后升高的趋势,在术后3 d时最低;术后7 d时DGF组低于non-DGF组,差异有统计学意义(P<0.05)。肾移植术后DGF组与non-DGF组PDW呈先升高后降低趋势,两组PDW均在术后7 d时达到最大,且术后7 d时DGF组PDW大于non-DGF组,差异有统计学意义(P<0.05)。肾移植术后DGF组与non-DGF组P-LCR呈先升高后降低趋势,两组P-LCR均在术后7 d时达到最大,但术后7 d时两组P-LCR差异无统计学意义(P=0.184)。

表 1 肾移植术后两组患者血小板参数的动态比较 Tab 1 Comparison of platelet parameters between 2 groups after renal transplantation

2.2 血小板参数对肾移植术后DGF的预测价值

选择DGF组和non-DGF组肾移植术后7 d差异有统计学意义的4项血小板参数(MPV、PDW、PLT和PCT)进行ROC曲线分析,结果(图 1表 2)显示PDW和PCT对DGF有中度预测效能,ROC曲线下面积(area under curve,AUC)分别为0.781和0.758,95%置信区间(confidence interval,CI)分别为0.683~0.880和0.662~0.853,最佳截断值分别为16.75 fL和0.155%。以最佳截断值为标准时二者诊断DGF的特异度分别为92.6%和63.2%,灵敏度分别为61.0%和75.6%。肾移植术后7 d PCT和PDW联合检测诊断DGF的AUC为0.805,95% CI为0.718~0.891,灵敏度为73.2%,特异度为79.4%。上述结果提示PDW和PCT对DGF有早期诊断价值,但PDW的特异度更高,PCT的灵敏度稍高于PDW,当患者术后7 d PDW>16.75 fL、PCT<0.155%时发生DGF的风险增大,且PCT和PDW联合检测的诊断效能优于单独检测。

图 1 血小板参数预测肾移植术后DGF的ROC曲线 Fig 1 ROC curve of DGF predicted by platelet parameters after renal transplantation DGF: Delayed graft function; ROC: Receiver operating characteristic; MPV: Mean platelet volume; PDW: Platelet volume distribution width; PLT: Platelet count; PCT: Platelet hematocrit

表 2 血小板参数预测肾移植术后DGF的价值比较 Tab 2 Comparison of platelet parameters in predicting DGF after renal transplantation

3 讨论

DGF是肾移植术后同种异体移植物存活的主要障碍。发生DGF的患者术后早期住院时间延长,生活质量下降,长期预后较差,包括长期同种异体移植肾功能差、排斥率高[7-9]、移植物功能丢失和患者死亡等[10]。目前还没有有效治疗DGF的方法,但早期诊断和治疗干预可能会提高移植物和患者的生存率[11]。DGF损伤的发病机制目前仍未完全清楚,可能是多因素联合作用导致。研究表明,缺血再灌注损伤可能会导致细胞损伤和死亡,并且加重氧化应激反应,氧化应激失调可在移植的器官内诱发一系列炎症反应引起细胞损伤,从而导致移植肾受损[12-15]。有研究证实,血小板的产物5-羟基二十碳四烯酸(5-hydroxyeicosatetraenoic acid,5-HETE)、12-羟基二十碳四烯酸(12-hydroxyeicosatetraenoic acid,12-HETE)和15-羟基二十碳四烯酸(15-hydroxyeicosatetraenoic acid,15-HETE)在人体内的含量与移植术后肾功能恢复情况有关[16-17]。血小板的另一产物血栓烷B2(thromboxane B2,TXB2)也可以作为肾功能恢复相关的移植前监测指标[17]。这些研究表明,肾移植术后血小板表现出不同的活化水平,是导致移植术后肾功能恢复差异的原因之一。

本研究通过观察5项临床常规检测的血小板参数(PLT、MPV、PCT、PDW和P-LCR)在肾移植术前、术后的动态变化,分析血小板与DGF的关系。结果显示,肾移植受者的PLT和PCT在移植术后降低,然后缓慢恢复至术前水平;MPV、PDW和P-LCR在肾移植术后均有所增高,后缓慢降低至正常水平。术后早期PLT和PCT降低,可能因为肾移植是有创手术,早期血小板参与创伤的止血和凝血过程,从而造成血小板的破坏增多。MPV、PDW和P-LCR增加,可能是因为移植术后尿毒症潴留产物对骨髓的抑制作用下降,骨髓造血功能逐渐恢复正常,造血干细胞可正常分化成熟,巨核系细胞正常增殖,产生较多年轻的大血小板。本研究还发现,肾移植术后发生DGF的患者,PLT始终低于未发生DGF的患者,术后7 d两组间差异有统计学意义(P<0.05);MPV始终高于未发生DGF的患者,术后7 d两组间差异有统计学意义(P<0.05);PCT在术后7 d时低于未发生DGF的患者,两组间差异有统计学意义(P<0.05)。该结果提示DGF患者在骨髓造血干细胞分化成熟过程中出现血小板活化过程,血小板破坏增多,消耗增加,进一步佐证了血小板参与移植肾炎症反应和损伤再修复过程。

本研究采用ROC曲线评估血小板参数对DGF的预测价值。结果显示,肾移植术后7 d PDW和PCT均对DGF有中等程度的诊断效能(AUC为0.7~0.9),但PDW特异度高于PCT,PCT灵敏度稍高于PDW,PCT和PDW联合检测的诊断效能优于单独检测。上述结果提示当肾移植患者术后7 d发现PDW>16.75 fL、PCT<0.155%时应警惕DGF的发生。

综上所述,同种异体肾移植患者血小板参数的动态变化与DGF的发生有一定的关系,术后7 d的PCT和PDW对预测DGF具有一定的临床价值,当术后7 d PDW>16.75 fL、PCT<0.155%时患者发生DGF的风险增大。相比病理活组织检查,血液标本易于获取,患者更易于接受,因此血小板参数有望成为肾移植术后早期预测DGF的无创性标志物。

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