彩色多普勒超声在腓静脉及小腿肌肉内静脉血栓诊断中的价值

目的探讨彩色多普勒超声对腓静脉及小腿肌肉内静脉血栓形成的诊断价值。方法对48例临床高度疑似腓静脉及小腿肌肉内静脉血栓形成的患者进行彩色多普勒超声及磁共振血管成像检查,检查结果进行对比研究。结果48例患者中,彩色多普勒超声发现腓静脉血栓24例,小腿肌肉内静脉血栓17例,二者均有血栓11例,磁共振血管成像发现腓静脉血栓25例,小腿肌肉内静脉血栓19例,二者均有血栓12例,彩色多普勒超声和磁共振血管成像对小腿静脉血栓的诊断无明显统计学差异（P〉0．05）。结论彩色多普勒超声是腓静脉及小腿肌肉内静脉血栓形成诊断及疗效观察的理想方法。     

老年患者经外周置入中心静脉导管术后发生上肢静脉血栓的危险因素分析

目的对老年患者经外周置入中心静脉导管(PICC)术后上肢静脉血栓发生的多因素分析。方法选择我院PICC术的650例患者,分为血栓组233例和对照组417例,对2组患者的临床资料进行回顾性单因素分析和logistic多元回归分析。结果 650例患者中,发生上肢深静脉血栓233例,血栓发生率35.8%。血栓组患者的年龄[(86.2±6.3)岁vs(78.9±9.7)岁]和体质量指数[(24.5±3.5)kg/m2 vs(23.3±3.0)kg/m2]显著高于对照组(P0.01),血栓组恶性肿瘤(44.2%vs 22.8%)、血栓史(18.0%vs 8.4%)、慢性肾功能不全(23.6%vs 6.0%)、近期手术外伤史(25.3%vs 0.7%)、年龄80岁的比例(89.3%vs 50.8%)明显高于对照组(P0.01)。logistic多元回归分析显示,年龄、慢性肾功能不全和近期手术外伤史是老年患者PICC术后上肢静脉血栓形成的独立危险因素(P=0.000)。结论老年患者PICC术后上肢静脉血栓形成的危险因素很多,有年龄、体质质量指数、恶性肿瘤、血栓病史、慢性肾功能不全、近期手术外伤史、置管手臂、PICC管尖端位置,其中年龄、慢性肾功能不全和近期手术外伤史是老年患者PICC术后上肢静脉血栓形成的独立危险因素。     

彩色多普勒超声和D-二聚体及凝血酶原时间联合检测对脑梗死患者下肢深静脉血栓的诊断价值

目的 探讨彩色多普勒超声和D-二聚体及凝血酶原时间联合检测对脑梗死患者下肢深静脉血栓(deep vein thrombosis, DVT)的诊断价值。方法 选取2020年1月至2021年6月杭州市上城区紫阳街道社区卫生服务中心收治的急性脑梗死患者80例，根据静脉造影检查为金标准确定是否形成DVT分为对照组38例和DVT组42例。2组均行彩色多普勒超声检查，采用酶联免疫吸附法检测D-二聚体、凝血酶原时间。采用ROC曲线下面积(AUC)分析各参数对DVT的诊断价值。结果 超声检查显示，肌间静脉血管管腔局部扩张，内透声不佳，可见絮状低回声，加压探头显示血管管腔改变不明显。与对照组比较，DVT组D-二聚体水平明显升高，凝血酶原时间明显缩短，差异有统计学意义[(0.88±0.33)mg/L vs(0.37±0.10)mg/L,(9.19±2.50)s vs(13.35±3.46)s,P<0.01]。彩色多普勒超声对DVT阳性预测值为97.6%,阴性预测值为78.9%;D-二聚体对DVT阳性预测值为88.1%,阴性预测值为89.5%;凝血酶原时间对DVT阳性预测值为88.1%,阴性预测值为8...     

彩色多普勒超声对PICC置管术后血栓形成诊断的价值

目的研究彩色多普勒超声对外周静脉穿刺置入中心静脉导管术（PICC）后血栓诊断的意义。方法所有病人置巴德三向瓣膜式PICC管,超声检查从置管处沿静脉走行向近心端追踪,对肘正中静脉、头静脉、贵要静脉、颈内静脉、锁骨下静脉进行全程显示,以观察导管在血管内是否呈现出规整的平行线回声,位置及大体的走向,且置管部位是否能被挤压。结果156例病人血管内无血栓形成,内壁光滑,血管内血流通畅持续。26例病人都有不同程度的血栓形成,管腔局部或者全部闭塞,可见低回声,静脉增宽,局部管腔内不可以压瘪。26例有血栓的病人中,I级血栓13例,Ⅱ级血栓5例,Ⅲ级血栓8例。此外,有血栓的病人置管后至血栓出现,历经时间最短为11d,最长为35d,平均17d。结论血栓是PICC置管术后的主要并发症,彩色多普勒超声可对该并发症状进行及时监测,尽早发现血栓形成。     

3CG心电定位技术经颈内静脉行隧道式PICC置管技术在1例老年头颈部肿瘤患者中的应用

总结3CG心电定位联合超声引导经颈内静脉隧道式PICC置管在肿瘤科1例头颈部肿瘤老年患者的应用经验。笔者收治了1例双上肢及下肢重度水肿,呼吸困难,无法平卧,营养状况差的患者。患者无法在上肢或下肢行PICC置管,因此采取3CG心电定位联合超声引导经颈内静脉行隧道式PICC置管术。患者成功置入PICC导管,穿刺时间为42分钟,X线摄片显示导管到达上腔静脉,置管患者无并发症的发生。应用3CG心电定位联合超声引导从颈内静脉行隧道式PICC置管,可有效解决无法从四肢血管进行PICC置管患者的静脉治疗难题,避免了化学性静脉炎的发生,为疑难危重患者开辟了一条新的输液路径。     

80岁以上住院老人并发深静脉血栓危险因素分析

目的探讨≥80岁住院老人并发深静脉血栓的危险因素。方法回顾性分析住院的≥80岁老人105例,对36例发生深静脉血栓(研究组)与69例未发生深静脉血栓者(对照组)的营养状况(以入院当日血白蛋白值)、血D-二聚体、有无贫血、有无深静脉置管、基础疾病、近期骨折、急性肺部感染、日常生活能力(BI)等进行Logistic回归分析。结果静脉血栓发生部位以左下肢为主,5例患者发生了上肢静脉血栓和颈内静脉血栓;患有糖尿病、近期发生骨折以及患者的BI障碍和D-二聚体升高与深静脉血栓发生有显著相关性(P0.05)。结论≥80岁住院老人易发生深静脉血栓,血栓发生与患者是否患糖尿病、近期发生骨折、BI障碍及D-二聚体升高有关,上肢静脉血栓和颈内静脉血栓仍与深静脉置管有关,临床上应重视危险因素并采取防范措施,减少深静脉血栓的发生。     

临床评分和D-二聚体检查在下肢深静脉血栓中的应用

目的 评价临床Wells评分和(或)D-二聚体检查能否安全、可靠地排除或诊断下肢深静脉血栓(DVT).方法 回顾性收集两家医院疑诊DVT的住院患者,所有患者均在48 h内进行临床评价、D-二聚体检查和双侧下肢静脉加压超声检查.比较单独应用临床评分或D-二聚体检查,以及临床评分结合D-二聚体检查诊断DVT的敏感性、特异性、阳性预测值和阴性预测值.描述性资料采用频数分析,组间比较采用卡方检验,以P<0.05为差异有统计学意义.结果 共有274例患者纳入研究.以低度可能性为阴性结果,中、高度可能性为阳性结果,临床Wells评分诊断DVT的敏感性、特异性、阳性预测值和阴性预测值分别为78.4%、66.1%、52.3%和86.6%;以D-二聚体≥500μg/L为阳性结果,D-二聚体检查诊断DVT的敏感性、特异性、阳性预测值和阴性预测值分别为73.9%、66.1%、50.8%和84.2%;以低度可能性同时D-二聚体<500μg/L为阴性结果,中、高度可能性同时D-二聚体≥500μg/L为阳性结果,临床Wells评分结合D-二聚体检查诊断DVT的敏感性、特异性、阳性预测值和阴性预测值分别为88.3%、76.8%、67.1%和92.5%.结论 针对临床疑诊DVT的患者,单独应用临床Wells评分或D-二聚体检查,以诊断或排除DVT是不准确的;联合应用临床Wells评分和D-二聚体检查,才能对患者是否患有DVT作出较为准确的判断.     

两种方法对预防老年患者下肢静脉血栓形成的比较

目的观察气压治疗预防老年内科患者深静脉血栓(DVT)的形成的临床疗效。方法将85例wells评分达到高度可能的老年患者(年龄60岁)分成两组,治疗组采用间隙充气加压泵(ntermittent pneumatic compression,IPC)预防,对照组采用低剂量的低分子肝素预防。通过比较两组间患者D-二聚体、纤维蛋白原、抗凝血酶Ⅲ(AT-Ⅲ)指标数值的差异以及下肢血管彩色多普勒超声检查深静脉血栓检出率。结果气压预防组与对照组D-二聚体值、纤维蛋白原、抗凝血酶Ⅲ(AT-Ⅲ)指标数值差异无统计学意义气压预防。气压预防组与对照组下肢血管彩色多普勒超声检查深静脉血栓检出率差异无统计学意义。结论 IPC能够预防老年内科患者静脉血栓(DVT),临床预防效果与低分子肝素相当。     

两种方法对预防老年患者下肢静脉血栓形成的比较简

目的 观察气压治疗预防老年内科患者深静脉血栓（DVT）的形成的临床疗效.方法将85例wells 评分达到高度可能的老年患者（年龄〉60岁）分成两组,治疗组采用间隙充气加压泵（ntermittent pneumatic compression,IPC）预防,对照组采用低剂量的低分子肝素预防.通过比较两组间患者D-二聚体、纤维蛋白原、抗凝血酶Ⅲ（AT-Ⅲ）指标数值的差异以及下肢血管彩色多普勒超声检查深静脉血栓检出率.结果 气压预防组与对照组 D-二聚体值、纤维蛋白原、抗凝血酶Ⅲ（AT-Ⅲ）指标数值差异无统计学意义气压预防.气压预防组与对照组下肢血管彩色多普勒超声检查深静脉血栓检出率差异无统计学意义.结论 IPC能够预防老年内科患者静脉血栓（DVT）,临床预防效果与低分子肝素相当.     

膜性肾病伴发静脉血栓栓塞症的超声诊断及相关因素分析

目的:回顾性分析膜性肾病(MN)患者伴发静脉血栓栓塞症(VTE)的超声特点及临床意义。方法:经肾活检确诊MN患者104例,应用彩色多普勒超声观察肾静脉、下腔静脉、髂静脉、下肢静脉及肺动脉、右心腔内部结构,了解是否存在异常回声及肺动脉高压。结果:104例患者中,发现肺栓塞14例,肾静脉血栓5例,下腔静脉血栓2例,髂静脉血栓4例,下肢静脉血栓4例。血栓组与无血栓组比较,血清白蛋白、肌酐、D-二聚体及纤维蛋白原,差异具有统计学意义(P0.05),24h尿蛋白定量及凝血酶原时间,两组差异无统计学意义(P0.05)。结论:彩色多普勒超声可作为MN患者筛查静脉血栓的首选影像学检查方法,为患者疗效评估提供了简便、无创、无辐射的检测方法。     

老年患者下肢深静脉血栓的超声诊断价值

目的探讨灰阶及彩色多普勒超声在老年患者下肢深静脉血栓诊断中的应用价值。方法对65例经临床确诊的老年下肢深静脉血栓形成患者进行灰阶超声和彩色多普勒超声检查,按照发病时间将血栓分型,观察血栓形成的部位、大小、回声、栓塞程度、彩色血流充盈情况等。结果 65例患者72条患肢中,左下肢血栓41条共计105个部位,右下肢血栓31条共计79个部位。急性期血栓共40例(45条),亚急性期血栓26例(27条),其中1例患者右侧胭静脉急性血栓,合并左侧股总静脉亚急性血栓。急性期血栓呈低回声,病变静脉管径明显增宽,探头加压血管不能压瘪,彩色多普勒显示阻塞处血流充盈缺损;亚急性血栓可呈强回声、等回声、偏低回声或不均质回声,管径粗细不均,管壁增厚粗糙、回声增强,彩色多普勒显示血栓处彩色血流充盈缺损。结论灰阶及彩色多普勒超声对老年患者下肢深静脉血栓的阻塞部位、程度及局部血流情况可做出及时诊断,为临床选择治疗方案提供依据。     

D-二聚体在急性肺栓塞快速临床诊断中的价值

目的探讨血浆D-二聚体、下肢深静脉血栓在急性肺栓塞(acute pulmonary embolism,APE)快速临床诊断中的价值。方法回顾性分析疑诊为APE的178例患者的计算机(X线)断层摄影扫描肺血管造影或右心导管选择性肺动脉造影的临床资料、血浆D-二聚体浓度及下肢深静脉彩色多普勒检查结果。结果 APE患者血浆D-二聚体浓度阳性者59例(96.72%,59/61),非APE患者阳性32例(27.4%,32/117),两者比较差异有统计学意义(P0.05)。APE患者经彩色多普勒超声检查发现下肢深静脉血栓形成(deep venous thrombosis,DVT)50例(82.0%,50/61),非APE患者DVT 6例(5.0%,6/117),两组比较差异有统计学意义(P0.05)。48例(78.7%,48/61)APE患者血浆D-二聚体浓度阳性合并DVT,两项指标同为阳性时诊断APE的特异性99.1%,阳性预测值98.0%。血浆D-二聚体浓度阳性诊断APE的敏感性96.7%,特异性72.6%,阳性似然比3.54,阴性似然比0.04,阳性预测值64.8%,阴性预测值97.7%。结论血浆D-二聚体、下肢深静脉彩色多普勒检查值得作为常规方法为快速诊断及治疗APE提供依据。     

急性股骨干骨折患者深静脉血栓的诊断及治疗

目的探讨诊断治疗急性股骨干骨折患者深静脉血栓（DVT）的方法。方法回顾性分析因急性股骨干骨折来我院住院治疗的148例患者的临床资料,患者入院后监测D-二聚体。对于可疑DVT患者,均首选下肢彩色多普勒超声,必要时行静脉造影以明确诊断。全部患者均接受物理治疗和预防性抗凝治疗。结果共诊断27例DVT,其中中心型或混合型18例,周围型9例。入院时患者总体的D-二聚体值均升高。经预防性抗凝之后,非DVT的患者的D-二聚体值呈逐渐下降趋势;而DVT患者在监测的第3天和第5天D-二聚体仍维持在高水平状态。周围型DVT患者术后抗凝2周,中心型或混合型DVT患者骨科手术前放置了临时腔静脉滤器,术后继续抗凝到半年,在整个研究期间和随访期间,均未有肺栓塞（PE）报告。结论骨折患者D-二聚体监测的特异性较差,应该根据其动态变化,结合患者的症状体征综合考虑DVT可能。     

心脏永久起搏器置入术后上肢深静脉血栓的发生率及治疗经验

目的总结心脏永久性起搏器置入后上肢深静脉血栓的发生情况及治疗经验。方法302例心脏永久起搏器置入术后或行起搏器更换手术的患者,采用彩色血流和频谱多普勒超声方法,部分患者行患侧上肢静脉造影检查,探查患者上肢深静脉血栓形成情况,门诊随访至术后6～12个月。结果上肢深静脉血栓组和无血栓组在年龄、性别、病史,植入电极导线数量,抗血小板/抗凝治疗情况等临床资料无差异。随访中发生上肢深静脉血栓形成,静脉狭窄、闭塞45例,发生率14.9%,无患者发生血栓脱落栓塞事件,其中有症状的患者14例,占31.1%,均有不同程度患侧上肢肿胀、疼痛、肤色变深,有的患者活动明显受限,出现时间于术后3天～1年,检查提示为新鲜血栓,经尿激酶溶栓、低分子肝素、华法林抗凝治疗以及抗血小板治疗后,患者症状均明显改善,治疗3个月后超声显示血栓消失。无症状者31例,占68.9%,28例(90.3%)为陈旧性血栓,侧枝循环丰富;余3例为新鲜血栓。结论心脏永久起搏器术后上肢深静脉血栓形成是常见并发症之一,术后应密切观察,定期随访。对上肢深静脉血栓形成患者,给予华法林维持治疗3个月是必须和有效的。     

Low accuracy of color Doppler ultrasound in the detection of proximal leg vein thrombosis in asymptomatic high-risk patients. The RD Heparin Arthroplasty Group.

OBJECTIVE: To evaluate the ability of color Doppler ultrasound to detect proximal deep venous thrombosis (DVT) in asymptomatic high-risk patients who subsequently underwent contrast venography. DESIGN: Prospective cohort study using blinded observers, with contrast venography as the comparison standard. SETTING: Seven medical centers (university and community hospitals) participating in a clinical trial of low-molecular-weight heparin for prevention of DVT. PATIENTS: A total of 385 consecutive patients undergoing elective unilateral hip or knee replacement. MEASUREMENTS: Ten days after surgery or before hospital discharge (whichever occurred first), patients had bilateral color Doppler ultrasound examinations of the proximal veins of the lower extremities. Subsequently, a contrast venogram of the operated leg was obtained. RESULTS: Color Doppler ultrasound studies and venograms were both evaluable in 319 of the 385 patients. Deep venous thrombosis was identified by contrast venography in 80 patients (prevalence, 25%; 95% CI, 20% to 30%) and involved the proximal veins in 21 patients (prevalence, 7%; CI, 4% to 10%). For proximal DVT, color Doppler ultrasound showed poor sensitivity (38%; CI, 18% to 62%), moderately good specificity (92%; CI, 89% to 95%), and a poor positive predictive value for this population (26%). CONCLUSION: Color Doppler ultrasound examinations are insensitive to proximal DVT in asymptomatic high-risk patients and should not be substituted for venography for identifying proximal DVT in such patients.     

Usefulness of a semiquantitative D-dimer test for the exclusion of deep venous thrombosis in outpatients

PURPOSE: The D-dimer test is used commonly in diagnostic strategies to reduce the need for ultrasonography in patients suspected of having deep venous thrombosis. We studied several clinical and laboratory variables that might limit the accuracy of a semiquantitative D-dimer test. SUBJECTS AND METHODS: In this retrospective cohort study, 704 outpatients suspected of having deep venous thrombosis underwent a semiquantitative D-dimer test and ultrasonography. The performance of the D-dimer test was calculated in patients using anticoagulants (n =61), patients with previous thrombosis (n =127), and patients with malignancy (n =47), including 39 patients with more than one of these characteristics. The 508 remaining patients were considered to be the reference group. RESULTS: A total of 254 patients (36%) had evidence of deep venous thrombosis. The D-dimer test had a sensitivity of 99% (174/176; 95% confidence interval [CI]: 96% to 100%) and a negative predictive value of 98% (98/100; 95% CI: 93% to 100%) in the reference group. The sensitivity of the D-dimer test in patients using oral anticoagulants was 75% (6/8; 95% CI: 35% to 97%; P =0.01 compared with the reference group). Test sensitivity was 96% (51/53; 95% CI: 87% to 100%) in patients with previous thrombosis, and 100% (29/29; 95% CI: 88% to 100%) in patients with cancer. However, 553 (79%) of all patients, including 43 of the cancer patients (91%), had an abnormal D-dimer test. CONCLUSION: The semiquantitative D-dimer test in this study has a high sensitivity and negative predictive value in the exclusion of deep venous thrombosis, except perhaps among patients using oral anticoagulants. D-dimer tests in patients with cancer and in patients over 70 years old may not be worthwhile, because the tests are usually positive.     

Upper body peripherally inserted central catheter in pediatric single ventricle patients

BACKGROUND There is risk of stenosis and thrombosis of the superior vena cava after upper extremity central catheter replacement. This complication is more serious among patients with single ventricle physiology, as it might preclude them from undergoing further life-sustaining palliative surgery.AIM To describe complications associated with the use of upper extremity percutaneous intravenous central catheters(PICCs) in children with single ventricle physiology.METHODS A single institution retrospective review of univentricular patients who underwent superior cavopulmonary anastomoses as their stage 2 palliation procedure from January 2014 until December 2018 and had upper body PICCs placed at any point prior to this procedure. Clinical data including ultrasonography, cardiac catheterization, echocardiogram reports and patient notes were used to determine the presence of thrombus or stenosis of the upper extremity and cervical vessels. Data regarding the presence and duration of upper extremity PICCs and upper extremity central venous catheter(CVC), and use of anticoagulation were recorded.RESULTS Seventy-six patients underwent superior cavopulmonary anastomoses, of which 56(73%) had an upper extremity PICC at some point prior to this procedure. Median duration of PICC usage was 24 d(25%, 75%: 12, 39). Seventeen patients(30%) with PICCs also had internal jugular or subclavian central venous catheters(CVCs) in place at some point prior to their superior cavopulmonary anastomoses, median duration 10 d(25%, 75%: 8, 14). Thrombus was detected in association with 2 of the 56 PICCs(4%) and 3 of the 17 CVCs(18%). All five patients were placed on therapeutic dose of low molecular weight heparin at the time of thrombus detection and subsequent cardiac catheterization demonstrated resolution in three of the five patients. No patients developed clinically significant venous stenosis.CONCLUSION Use of upper extremity PICCs in patients with single ventricle physiology prior to super cavopulmonary anastomosis is associated with a low rate of catheterassociated thrombosis.     

Exclusion of first-episode deep-vein thrombosis after-hours using D-dimer.

The objective of this study was to test the safety of withholding anticoagulant treatment and additional call-back diagnostic testing with ultrasound in patients who have a negative D-dimer at presentation. Patients with signs and symptoms of deep-vein thrombosis who presented to the emergency department after regular hours and on weekends underwent D-dimer testing using the STA-Liatest D-di. In patients with negative D-dimer results, heparin therapy was withheld, and no further diagnostic testing for deep-vein thrombosis was done as part of the initial evaluation. Patients with positive D-dimer results underwent compression ultrasonography. The primary outcome measure was a diagnosis of new symptomatic venous thromboembolism confirmed by diagnostic testing during the 3-month follow-up period. Of the 260 eligible patients, 81 (31%) had a negative D-dimer and 179 (69%) had a positive D-dimer. No patient with a negative D-dimer at presentation had confirmed venous thromboembolism at 3-month follow-up. Three patients died: one by intracranial hemorrhage secondary to cerebrovascular accident; and two deaths of indeterminate cause almost 3 months after entry. The automated assay for D-dimer, the STA-Liatest D-di, seems to provide a simple method with high clinical utility for excluding acute first-episode deep-vein thrombosis in symptomatic patients who present to the emergency room after regular hours.     

Color Doppler ultrasonography in patients with subacute thyroiditis.

We studied the utility of color Doppler ultrasonography in patients with subacute thyroiditis. Eighteen patients with subacute thyroiditis (SAT) with painful goiter and thyrotoxicosis underwent color Doppler ultrasonography during the acute and recovery stages of the disease. Thyroid vascularization in these patients was compared with that of 15 untreated patients with Graves' disease and 17 control subjects. During the acute stage of subacute thyroiditis, color Doppler ultrasonography showed low echogenicity without increased tissue vascularity in the affected swollen thyroid. In the recovery stage, color Doppler ultrasonography showed isoechogenicity with slightly increased vascularization. Vascularization became normal at 1 year follow-up time. In contrast, marked by increased vascularization was observed in patients with untreated Graves' disease. Color Doppler ultrasonography showed clear differences between SAT and Graves' disease patients. Vascularity was significantly correlated with serum free thyroxine (FT4) and thyrotropin (TSH) concentrations in the recovery stage (3 months after the initial ultrasonography). Color Doppler ultrasonography accurately visualized lesions without increased vascularity in the acute stage of SAT and lesions of slightly increased vascularity in the recovery stage. Color Doppler ultrasonography may be a useful, noninvasive, and rapid method for differentiating SAT from Graves' disease and for evaluating and monitoring the location and activity of lesions in SAT.     

Technical dilemma in living-donor or split-liver transplant

In partial liver transplantation for adults criteria for the extent of reconstruction of middle hepatic vein tributaries have not been clarified. After hepatic venous and portal anastomoses in living-donor liver transplantation using left liver graft without middle hepatic vein, color Doppler ultrasonography was applied to check venous and portal blood flow. Color Doppler ultrasonography demonstrated absent hepatic venous flow and reversed portal venous flow in the congested area of the left paramedian sector which had been drained by the divided branch of the middle hepatic vein. The area was darkly discolored before arterial reperfusion and under clamping of the artery. Reconstruction of the venous branch was added after arterial anastomosis. Color Doppler ultrasonography revealed restored normal venous outflow and portal inflow after venous reconstruction. Postoperative course of the recipient was uneventful with rapid recovery of liver function. We propose that middle hepatic vein tributaries should be reconstructed if color Doppler ultrasonography demonstrates absent venous flow and reversed portal flow, and if the liver volume excluding the discolored area under occlusion of the hepatic artery is estimated to be insufficient for postoperative metabolic demand.