Experimental evaluation of portal venous pulsatile flow synchronized with heartbeat intervals: effects of vascular clamping on portal hemodynamics

Purpose

We previously showed that blood flow in the portal vein was pulsatile and influenced by both the inferior vena cava and the arterial system in a complex manner (Nihei et al., 38:141–149, 2011). The objective of the present study is to identify determinants of blood flow and to clarify the source of pulsatile flow in the portal vein.

Methods

Three-breed terminal crossbreed mini-pigs underwent general anesthesia. Pressure and flow in the portal vein, inferior vena cava, hepatic artery, and mesenteric artery were measured simultaneously. Vascular occluders were placed in the inferior vena cava, hepatic artery, and mesenteric artery to examine the effects of clamping on portal venous flow.

Results

Clamping of the mesenteric artery altered pressure and flow waves in the portal vein to waveforms similar to those in the inferior vena cava. Waves resembling those of the inferior vena cava superimposed on portal venous flow appeared later than waves of the inferior vena cava. Clamping of the inferior vena cava promptly altered portal venous pressure and flow. Because clamping of the inferior vena cava led to a sharp rise in portal venous pressure, detailed evaluations were not feasible. Clamping of the hepatic artery had no effect on flow-wave pulsation in the portal vein.

Conclusions

In the hepatic circulation, flow-wave pulsation in the portal vein is influenced by flow in the inferior vena cava via the sinusoids and by flow in the mesenteric artery via the capillary vessels of the intestine.     

Absence of the ductus venosus: report of 10 new cases and review of the literature.

OBJECTIVE: To assess the clinical significance of the absence of the ductus venosus. DESIGN: A retrospective study with a review of the literature. METHODS: The archives of our ultrasound laboratory and the English literature were searched for cases with a prenatal diagnosis of absence of the fetal ductus venosus. RESULTS: Between 1985 and 2000, 10 fetuses were diagnosed in our center as having absence of the ductus venosus. The review of the literature revealed 23 cases. Three main patterns of abnormal venous circulation were documented: (1) umbilical vein bypassing the liver and connecting directly to the right atrium (46%); (2) umbilical vein bypassing the liver and connecting to the inferior vena cava mostly through one of the iliac veins (25%); (3) umbilical vein connecting to the portal circulation without giving rise to the ductus venosus (21%). Major anomalies, including chromosomal aberrations, were found in 8/33 (24%) cases. Hydrops developed in 11/33 (33%) cases. Twenty fetuses with isolated absence of the ductus venosus were delivered, and 5 (20%) died. The portal vein was found to be absent in half of the infants examined after birth. CONCLUSIONS: Our results and the review of literature suggest that absence of the ductus venosus is associated with a high incidence of fetal anomalies and adverse outcomes, including associated malformations, chromosomal aberrations, in utero heart failure and absence of the portal vein. Heart failure and absence of the portal vein seem particularly frequent when absence of the ductus venosus is associated with a connection of the umbilical vein to either the inferior vena cava or the right atrium.     

Prenatal diagnosis of abnormal course of umbilical vein and ductus venosus agenesis: Report of three cases

Ductus venosus connecting the portal and embryonic venous circulation into the inferior vena cava has a crucial role in fetal circulation. The absence of ductus venosus is a rare anomaly, in which the umbilical vein connection to the venous system may be extrahepatic, bypassing the liver or intrahepatic via the portal venous system. We report three cases of ductus venosus agenesis with associated anomalies. In two of them the connection was directly to the right atrium, whereas the umbilical vein drained to the left internal iliac artery in the third case. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012;     

MSCT血管造影诊断儿童门静脉畸形

目的 探讨螺旋CT血管造影(MSCTA)在儿童先天性门静脉畸形诊断中的价值.方法 对超声诊断或疑诊的7例儿童门静脉畸形患儿行MSCTA检查.对所有图像进行VR、MIP和(或)曲面重建(CPR)重建门静脉,分析门静脉畸形的影像学特征.结果 7例患儿中,4例诊断为门静脉海绵样改变,典型表现为第一肝门区见肝内门静脉周围纡曲、...     

Diagnosis of absent ductus venosus in a population referred for fetal echocardiography: association with a persistent portosystemic shunt requiring postnatal device occlusion.

OBJECTIVE: The purpose of this series was to assess the incidence, anatomic variants, and implications of an absent ductus venosus (ADV) in patients referred for fetal echocardiography. METHODS: We searched our fetal cardiology database for diagnoses of ADV from May 2003 to December 2006. RESULTS: During the study period, we performed 1328 fetal echocardiographic examinations in 990 fetuses. We found 6 cases of ADV (6/1000). Indications for fetal echocardiography were cardiomegaly, dilated umbilical or systemic veins, and extracardiac abnormalities. We identified 5 anatomic variants of ADV. In 2 patients, the umbilical vein connected to the systemic venous circulation by way of the portal sinus: via an abnormal venous channel from the portal sinus to the right atrium (case 1) and presumably via hepatic sinusoids to the hepatic veins (case 2). In the remaining 4 patients, the umbilical vein bypassed the portal sinus and the liver and connected to the systemic venous circulation via an abnormal venous channel: from the umbilical vein to the right atrium (case 3), from the umbilical vein to the inferior vena cava (cases 4 and 5), and from the umbilical vein to the right iliac vein (case 6). All patients survived; 2 required cardiovascular intervention. No intervention was required in 3 patients. CONCLUSIONS: An ADV should be ruled out in a fetus with unexplained cardiomegaly or dilatation of the umbilical vein, systemic veins, or portal sinus. To our knowledge, prenatal diagnosis of an ADV with an abnormal communication between the portal sinus and the right atrium has not been reported previously. The portosystemic communication persisted after birth and required device occlusion.     

Hepatosplanchnic circulatory dysfunction in acute hepatic infection: the case of dengue hemorrhagic fever

The mechanism of shock in patients with dengue hemorrhagic fever (DHF) has not yet been fully understood. In this study, we investigated the possibility of splanchnic venous pooling as a contributor for circulatory dysfunction in these patients. Ultrasonographic studies of portal vein and inferior vena cava were done in 45 patients with serologically or PCR-confirmed diagnosis of dengue virus infection. The size of portal vein and inferior vena cava, mean blood flow velocity in the right portal vein, and modified portal vein congestion index were compared between patients with dengue fever (DF, n = 20), DHF without shock (n = 14), and dengue shock syndrome (DSS, n = 11) during the toxic stage, convalescent stage, and at follow-up. The portal vein was significantly more dilated in patients with shock (DSS) than DHF without shock and than DF during the toxic and convalescent stages (P < 0.05), but not at follow-up. The change in the size of inferior vena cava followed the opposite trend (not statistically significant). Portal vein blood flow velocity was lower and congestion index was higher in shock cases (DSS) than DHF without shock and than DF at toxic and convalescent stages (P < 0.01). The differences disappeared at follow-up. Hepatosplanchnic venous pooling and/or dysfunction occur and correlate with the severity of circulatory derangement and shock in patients with DHF. The cause(s) and significance of hepatosplanchnic circulatory dysfunction in DHF and possibly other viral hepatic diseases deserve further study.     

Anatomic variation of portal venous anatomy in the porta hepatis: ultrasonographic evaluation.

The appearance of the portal vein as it crosses anterior to the inferior vena cava and enters the liver at the porta hepatis was evaluated on 100 longitudinal and 100 transverse ultrasonograms. Three major variations were noted on the parasagittal scans, while four major variations were evident on the transverse images. These variations were primarily related to the size of the left portal vein and the angle at which the left portal vein coursed away from the main portal vein. The appearance and course of the proximal right portal vein was extremely constant and may therefore be used as a landmark to detect pathologic processes in the porta hepatis. Detection of altered anatomy in this region may be especially helpful in correctly differentiating dilated intrahepatic bile ducts from normal portal veins.     

胎儿脐静脉-门静脉系统正常解剖与异常分流的超声特征分析

目的探讨胎儿脐静脉-门静脉系统的正常超声图像以及异常分流的超声诊断特征。 方法回顾性选取2018年1月至2020年12月在郑州大学第三附属医院行产前超声筛查和诊断的正常胎儿85例,观察脐静脉-门静脉系统的超声图像特征。另收集产前超声诊断为脐静脉-门静脉系统异常分流的26例胎儿的资料,对其产前超声图像及合并异常进行分析。 结果正常胎儿脐静脉-门静脉系统中门静脉主干与门静脉窦连接方式分为3种：“T”形连接60例;“X”形连接11例;“H”形连接14例。脐静脉-门静脉系统异常分流的26例胎儿中,脐静脉-体静脉分流6例,其中脐静脉回流入右心房4例,回流入下腔静脉1例,肝静脉异常分流1例,6例均合并静脉导管缺失,3例合并畸形,3例合并心脏增大;静脉导管-体静脉分流4例,其中静脉导管下腔静脉入口位置下移2例,经冠状静脉窦回流入右心房1例,直接回流至肝静脉1例,2例合并心内、心外多发畸形;肝内门静脉-体静脉分流16例,Ⅰ型1例、Ⅱ型6例、Ⅲ型3例、Ⅳ型6例。其中4例合并胎儿生长受限,2例合并心脏畸形,2例合并单脐动脉。 结论正确识别正常脐静脉-门静脉系统超声图像有助于发现和诊断异常分流;各类型异常分流有不同的超声图像特征;评估肝内门静脉系统发育、心功能及各系统发育可为临床咨询和处理提供信息和依据。     

多层螺旋CT静脉血管成像价值探讨

目的探讨多层螺旋CT静脉血管造影的应用价值.方法收集不同部位CT静脉血管造影21例,颈静脉及门静脉系统血管造影由上肢静脉注入对比剂,下腔静脉及下肢造影由小隐静脉注入对比剂,行三维重建及多平面重建,结合临床资料分析血管成像技术及诊断价值.结果静脉血管CT造影表现不同于动脉CT造影,不同部位的静脉血管表现不同.21例中发现颈鼻咽癌侵犯血管1例,血管走行纡曲1例;下腔静脉瘤1例,肿瘤压迫下腔静脉1例;门静脉高压1例,疑肠系膜上静脉内血栓1例;11例下肢静脉血栓.结论不同部位的静脉影像表现存在差异,不同的重建技术对血管的显示有影响.下腔静脉造影应注意假象的存在.     

Prenatal diagnosis of abnormalities of the fetal venous system.

OBJECTIVE: To present our experience in the prenatal diagnosis of anomalies of fetal veins using high-resolution color Doppler ultrasound. DESIGN: An observational study of 16 fetuses with abnormalities of the umbilical, portal, hepatic and caval venous system being diagnosed at the Division of Prenatal Diagnosis and Therapy (Bonn, Germany) over the past 5 years. The abnormality of the venous system, the underlying embryologic disorder and the outcome of the pregnancy are presented and compared with the literature. RESULTS: In group A, eight fetuses had an abnormal course of the umbilical vein with a patent (n = 3) or absent (n = 5) ductus venosus. No portal veins and absent or abnormal hepatic veins were visualized by color Doppler sonography. Six fetuses (75%) did not have an associated malformation and have survived. Two pregnancies with fetal hydrops due to a small heart and to Turner's syndrome were terminated or ended in fetal demise. In group B, seven of eight fetuses with an abnormal caval system had a situs ambiguus or an atrial isomerism. A cardiac defect was detected in six cases (86%). These six pregnancies ended in four terminations of pregnancy and two infant deaths due to the severity of the congenital cardiac defect. One child with a normal heart and a child with an isolated abnormal course of the lower inferior vena cava are developing well. CONCLUSIONS: In a targeted fetal scan the course of the umbilical vein, ductus venosus, the portal and hepatic veins and inferior vena cava should be carefully examined using color Doppler. Any suspicious finding should be followed by a detailed assessment of the specificity of this abnormality taking into consideration the embryologic development of the fetal venous system together with the associated malformations.     

预先腹内控制下腔静脉防治肝切除术中肝静脉及下腔静脉损伤大出血

作者对7例半肝以上肝切除术及2例ⅦⅧ肝段切除应用止血带在腹腔内围绕肝下肾上及膈下肝上之下腔静脉,同时用橡皮管控制肝门血管,而暂不阻断,以预防术中可能发生的肝静脉或/和下腔静脉损伤大出血,其中2例还同时控制膈下腹腔动脉以上的腹主动脉。9例中7例无意外,2例术中发生肝中静脉损伤大出血,经止血带迅速控制,修补裂口,抢救成功。本文对肝叶切除术中误伤肝静脉或/和下腔静脉的原因和预防处理方法进行了讨论,认为在病变接近或累及第二肝门或下腔静脉的肝叶肝段切除,以及在半肝或三叶切除术中常规控制下腔静脉和肝门是一个简而有效的防治肝静脉或/和下腔静脉损伤大出血的好方法。     

Two ductus venosus: a previously unreported anomaly

In early fetal life, the ductus venosus (DV) connects the umbilical vein, carrying nutrient-rich and oxygenated blood from the placenta to the inferior vena cava (IVC). We present the first ever case of a fetus with two ductus venosus. The fetus presented with a four-vessel cord and a dilated bowel at 31 weeks of gestation. Ultrasonography showed a persistent right umbilical vein. Echocardiographic investigation revealed normal cardiac anatomy with no major malformations. Two DVs with slightly different Doppler patterns were visualized anastomosing with the IVC. The baby was born uneventfully at 39 weeks of gestation with stable hemodynamics. Assuming every supernumerary umbilical vein should be connected to a DV for balanced circulation, a fetus with supernumerary umbilical veins lacking a corresponding number of DV connections is likely to be predisposed to complications such as hydrops fetalis and poor perinatal outcomes. The possibility of one or more umbilical veins lacking a DV connection warrants significant attention and regular monitoring from feto-maternal specialists, given the severity of the associated morbidity and mortality.     

3.0T MR门静脉和下腔静脉血管成像对腹部肿瘤血管侵犯的评价

[目的]探讨阴道镜检查在宫颈病变诊断中的临床价值.[方法]2007年6月至2009年6月诊治275例宫颈病变患者,对其宫颈阴道镜及镜下活检结果进行分析.[结果]经病理确诊为慢性宫颈炎221例,宫颈上皮内瘤变（CIN） 39例 （CIN Ⅰ10例、CINⅡ16例、CIN Ⅲ13例）,宫颈癌15例.阴道镜检查对CIN的灵敏度为69%,特异度为94%,阳性预测值为64.3%,阴性预测值为94.8%,阳性似然比为10.89,阴性似然比为0.33,诊断符合率为90.18%.阴道镜检查对宫颈癌的灵敏度为67%,特异度为98%,阳性预测值为71.4%,阴性预测值为98.1%,阳性似然比为43.33,阴性似然比为0.34,诊断符合率为96.73%.[结论]阴道镜检查对宫颈癌尤其是癌前病变的早期诊断有重要的临床价值.     

多层螺旋CT血管成像评价肝移植受者移植前后血管结构

背景:多层螺旋CT具有先进的扫描技术和强大的图像后处理功能,其亚秒级的扫描速度及各向同性的成像功能,在血管成像上有很多优势.目的:探讨多层螺旋CT血管成像技术对肝移植受者移植前后血管结构评价的应用价值.设计、时间及地点:回顾性分析,以肝移植受者肝脏血管为观察对象,自身对照观察,于2003-10/2006-12在中山大学附属第五医院放射科完成.对象:选择拟行原位肝移植患者27例,年龄31～67岁,男17例,女10例.方法:轴位螺旋扫描范围为膈顶上方2 cm至双肾下极以下.电压120 kV,动脉期准直0.75 mm,平扫、门脉期、肝静脉期准直1.5 cm;使用非离子型对比剂优维显,注射速度为3 mL/s,三期增强扫描延迟时间分别为20～25 s,50～55 s,75～80 s.重建增强的薄层图像序列,动脉期层厚1 mm,间隔0.7 mm;门脉期、肝静脉期层厚2 mm,间隔1 mm.将图像序列传入后处理工作站,以MIP、VR等方式显示腹腔干系、门脉系、肝静脉及下腔静脉血管的三维结构.主要观察指标:肝移植前后患者血管三维结构.结果:移植前所有患者腹腔干系均得到良好显示,21例肝动脉走形正常,6例患者肝动脉变异,其中门静脉海绵样变2例,门脉多发血栓1例,因不适宜手术此3例未进行肝移植.24例患者第二肝门及下腔静脉肝内段血管结构显示清楚,肝右静脉单独汇入下腔静脉、肝左静脉和肝中静脉先汇合后再注入下腔静脉18例,肝有静脉、肝中静脉及肝左静脉分别单独汇入下腔静脉6例,下腔静脉肝后段狭窄2例.17例肝移植后CT血管成像发现肝动脉吻合口部狭窄2例,门脉高压侧支迂曲缓解10例,另7例患者因检查费用问题选择B超检查.结论:多层螺旋CT血管成像能够清晰显示肝移植患者移植前后血管结构,对适宜手术的病例筛选、指导手术方案及移植后血管结构的评价具有重要意义.     

静脉导管缺如并脐静脉异常连接产前超声心动图表现

目的 观察静脉导管缺如(ADV)并脐静脉肝内、肝外异常连接的产前超声心动图表现。方法 回顾性分析14胎ADV胎儿的超声心动图表现,观察心脏大小、功能变化,并随访临床预后。结果 ADV的检出率为0.12%(14/11 205),14胎中,5胎脐静脉与门静脉左支、1胎与门静脉右支相连;8胎脐静脉未与门静脉相连,而与肝外静脉系统相连,5胎直接连接于右心房,1胎直接连接于下腔静脉,1胎连接于肝右静脉,1胎连接于冠状静脉窦引流入右心房。结论 产前超声心动图能够明确诊断静脉导管缺如,且可以观察脐静脉肝内、肝外异常连接途径和管道内径。     

超声造影、术中超声在肝移植术后血管并发症中的应用

目的探讨超声造影、术中超声在肝移植术后血管并发症中的诊断价值。方法对CDFI检查疑有肝动脉、门静脉及下腔静脉狭窄或血栓形成的9例患者进行超声造影检查,对疑有门静脉血栓的3例患者进行术中超声检查;检查结果与数字减影血管造影(DSA)进行对照分析。结果超声造影提示门静脉血栓形成3例,并经术中超声检查证实肝动脉血栓形成3例,下腔静脉狭窄1例,均经DSA证实。另2例超声造影提示肝动脉未见明显异常的患者中,1例DSA诊断为肝动脉狭窄,1例肝动脉无明显异常;超声造影诊断符合(7/9)。结论超声造影可确诊门静脉、肝动脉血栓,但对准确诊断肝动脉狭窄仍有一定困难。     

下腔静脉离断产前超声诊断

目的 探讨胎儿下腔静脉离断产前超声声像图特征和有效诊断切面,以提高其产前超声诊断准确率.方法 回顾性分析我院2006年1月至2010年5月诊断的10例下腔静脉离断胎儿(其中7例经引产后尸体解剖证实)产前超声声像图,与正常超声声像图对比,总结其产前超声声像图特征及有效切面.结果 10例下腔静脉离断胎儿,9例合并严重心内结构畸形,7例合并心外结构畸形(其中5例合并内脏反位).本组10例下腔静脉离断胎儿产前超声声像图均表现为四腔心切面异常(奇静脉扩张)、上腹部横切面异常(正常下腔静脉不能显示)、胸腹部斜冠状切面异常[离断的下腔静脉异位连接于奇(半奇)静脉并穿过膈肌连于腔静脉]及右心房纵切面异常(肝上段下腔静脉入右心房,肾上段肝段间的下腔静脉缺失并离断).结论 下腔静脉离断常合并心内、外结构畸形.下腔静脉离断胎儿在四腔心切面、上腹部横切面、胸腹部斜冠状切面及右心房纵切面上均有特征性超声声像图表现.识别下腔静脉离断特征性超声声像图表现可明显提高其产前超声检出率和诊断准确率.     

Embryogenetic malformations of the inferior vena cava, and their manifestations in adults

Five male patients with congenital anomalies of the inferior vena cava aged 20 to 43 were examined. The diagnosis and the level of aplasia were established on the basis of complex instrumental examination (duplex scanning of inferior extremity veins, pelvic veins, and retroperitoneal veins; computed and magnetic resonance tomography of the abdominal cavity; pelvic phlebography; retrograde cavagraphy). Together with inferior vena cava anomalies, other malformations such as pulmonary arterial stenosis or duplication of renal collector system were diagnosed in two patients. In three or 60% of the patients the disease had first manifested by the clinical picture of peripheral thrombosis (shin and femoral edema); fever, chill and subsequent edema of both legs had been first manifestations in two patients. Aplasia of the infrarenal segment of the inferior vena cava was revealed in two patients; in other two patients aplasia of the infrarenal, renal, and partly suprarenal segments of this magistral vessel was found; in one patient the whole vein was aplastic except a small part of the suprarenal segment, where the hepatic veins and the right suprapolar renal vein flew into. To establish an early diagnosis of a congenital inferior vena cava anomaly, the protocol of examination of patients with venous diseases should include ultrasound mapping of the suprarenal and infrarenal segments of the vena cava; in cases of agenesia it should include computed and magnetic resonance tomography and retrograde cavagraphy.     

A new method for the measurement of intrahepatic shunts

After transhepatic portal pressure determination, 96 patients were assessed for the presence of intrahepatic shunts by injection of microspheres (25 +/- 5 micron diameter) into the portal vein using RISA-131I as an indicator of dilution. Multiple portal vein injections in each patient allowed blood sampling from the hepatic vein (site 1) and from two inferior vena cava sampling sites (site 2, at the junction of the hepatic vein orifice with the inferior vena cava, and site 3, 2 to 3 cm closer to or within the right atrium). Intrahepatic shunting was calculated from each site: hepatic vein in 57 patients and inferior vena cava, site 2 in 43 patients and site 3 in 77 patients. At least one valid IHS calculation was available in 92 of the patients. Intrahepatic shunting calculated from sequential portal vein injections with sampling from the hepatic vein was highly correlated (r = 0.98, p less than 0.0001, slope = 1.0), with a mean difference of 1.9% +/- 1.9%. There was no significant difference by t test comparison of the mean IHS calculated from sites 1, 2, and 3. The IHShv was correlated with the IHSivc (site 2) (r = 0.79, p less than 0.0001, slope = 1.0) and IHSivc (site 3) (r = 0.82, p less than 0.0001, slope = 2.1). Occasional marked discrepancies were noted between IHS calculated from site 1 or site 2 compared with site 3, and the site 3 calculation was always greater. A shunt index in all patients included shunts calculated from the hepatic vein in 57 patients plus shunt calculation from the inferior vena cava in the remaining patients (site 2 in 26 patients and site 3 in nine). A control group with minimal chronic liver disease (10 patients) had a portal pressure (greater than IVC) of 4.1 +/- 1.4 mm Hg and shunt index of 0.5% +/- 0.6%. The 82 patients with portal hypertension or chronic liver disease had a higher portal pressure, 13.8 +/- 4.6 mm Hg, and a significantly greater shunt index, 13.7% +/- 24.5% (p less than 0.0001) compared with controls. The frequency distribution of IHS in patients with chronic liver disease demonstrated less than 2% IHS in 49% of patients and less than 5% IHS in 63%. The validity of our methods and the implications of the infrequent demonstration of a large IHS are discussed.     

Pulmonary artery catheter placement with two-dimensional echocardiographic guidance: a technique applicable in critically ill neonates

In nine critically ill neonates with persistent fetal circulation, femoral venous catheters were inserted at the bedside to initiate treatment and provide venous access. After femoral vein puncture or cutdown, a 5-F sheath was placed in the inferior vena cava through the femoral vein. With use of two-dimensional echocardiographic guidance, a 5-F balloon angiographic catheter was advanced through the inferior vena cava into the right atrium and subsequently manipulated through the tricuspid valve and into the main pulmonary artery. No major complications were attributable to the procedure. When performed by a pediatric cardiologist, this technique is as safe as umbilical catheter placement.