Doppler ultrasound of the hepatic artery and vein performed daily in the first two weeks after orthotopic liver transplantation. Useful for the diagnosis of acute rejection?

Prognostic value of ultrasound in early arterial complications post liver transplant

Liver transplantation is the primary therapeutic intervention for end-stage liver disease. However, vascular complications, particularly those involving the hepatic artery, pose significant risks to patients. The clinical manifestations associated with early arterial complications following liver transplantation are often nonspecific. Without timely intervention, these complications can result in graft failure or patient mortality. Therefore, early diagnosis and the formulation of an optimal treatment plan are imperative. Ultrasound examination remains the predominant imaging modality for detecting complications post liver transplantation. This article comprehensively reviews common causes and clinical presentations of early hepatic artery complications in the post-transplantation period and delineates abnormal sonographic findings for accurate diagnosis of these conditions. Overall, ultrasound offers the advantages of convenience, safety, effectiveness, and non-invasiveness. It enables real-time, dynamic, and precise evaluation, making it the preferred diagnostic method for post-liver transplantation assessments.

Vascular complications after adult living donor liver transplantation: Evaluation with ultrasonography

Living donor liver transplantation (LDLT) has been widely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrast-enhanced ultrasound (CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional gray-scale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

Hepatic transplantation: postoperative complications

Advances in surgical techniques and immunosuppression have made orthotopic liver transplantation a first-line treatment for many patients with end-stage liver disease. The early detection and treatment of postoperative complications has contributed significantly to improved graft and patient survival with imaging playing a critical role in detection. Complications that can lead to graft failure or patient mortality include vascular abnormalities, biliary abnormalities, allograft rejection, and recurrent or post-transplant malignancy. Vascular abnormalities include stenosis and thrombosis of the hepatic artery, portal vein, and inferior vena cava, as well as hepatic artery pseudoaneurysm, arteriovenous fistula, and celiac stenosis. Biliary abnormalities include strictures, bile leak, obstruction, recurrent disease, and infection. While imaging is not used to diagnose allograft rejection, it plays an important role in identifying complications that can mimic rejection. Ultrasound is routinely performed as the initial imaging modality for the detection and follow-up of both early and delayed complications. Cholangiography and magnetic resonance cholangiopancreatography are used to characterize biliary complications and computed tomography is used to confirm abnormal findings on ultrasound or for the evaluation of postoperative collections. The purpose of this article is to describe and illustrate the imaging appearances and management of complications associated with liver transplantation.

How far can we go with positive end-expiratory pressure (PEEP) in liver transplant patients?

STUDY OBJECTIVE

To assess the effect of positive end-expiratory pressure (PEEP) up to 15 cm H(2)O on blood flow throughput of the liver and its effects on systemic hemodynamics in patients following liver transplantation.

DESIGN

Prospective, interventional study.

SETTING

Intensive care unit (ICU) of a university hospital.

PATIENTS

74 consecutive liver transplant recipients with a regular allocated cadaveric graft.

INTERVENTION

The lungs of all study patients were postoperatively mechanically ventilated with biphasic positive airway pressure. Three different PEEP levels (5, 10, and 15 cm H(2)O) were randomly set within 4 hours of admission to the ICU. Systemic hemodynamic parameters were recorded using a pulmonary artery catheter and flow velocities were measured of the hepatic artery, portal vein, and right hepatic vein using a Doppler.

MEASUREMENTS AND MAIN RESULTS

PEEP of 15 cm H(2)O induced a significant increase in central venous pressure and pulmonary capillary wedge pressure versus PEEP 5 cm H(2)O. Flow velocities of the right hepatic vein, portal vein, and hepatic artery were not influenced by PEEP. There also was no impact of increased PEEP on mean arterial pressure or cardiac index.

CONCLUSION

PEEP up to 15 cm H(2)O does not impair liver outflow or systemic hemodynamics in liver transplant patients.

Is positive end-expiratory pressure suitable for liver recipients with a rescue organ offer?

PURPOSE

Rescue organ offers may help to overcome the organ shortage. However, because of initial poor liver function, the recipient may develop a severe lung injury with the requirement for higher positive end-expiratory pressure (PEEP) levels to achieve adequate oxygenation. Positive end-expiratory pressure has been associated with perfusion impairment in the hepatosplanchnic area. We assessed the effects of increased PEEP levels on systemic hemodynamic and liver perfusion in liver transplantation (LT) patients with a rescue organ.

METHODS

Twenty-four LT recipients of a rescue organ offer were enrolled. All patients were postoperatively mechanically ventilated with biphasic positive airway pressure, and 3 different PEEP levels (0, 5, 10 mbar) were randomly set within 4 hours after admission at the intensive care unit. Systemic hemodynamic parameters were recorded using a pulmonary artery catheter; and flow velocities of the hepatic artery, portal vein, and right hepatic vein were measured using Doppler.

RESULTS

Positive end-expiratory pressure of 10 mbar did not impair the systemic hemodynamic. Flow velocities in the right hepatic vein, the portal vein, and the hepatic artery were not influenced by PEEP.

CONCLUSION

Our study demonstrates that PEEP up to 10 mbar did not impair the liver outflow in recipients with a rescue organ offer.

Non-invasive evaluation of liver cirrhosis using ultrasound

Ultrasound (US) is essential in both assessment of the potentially cirrhotic liver and surveillance of selected patients with chronic hepatitis as liver biopsy can be misleading or inaccurate in up to 25% of cases. Various techniques are already in routine use, such as grey-scale imaging, Doppler US, and contrast-enhanced US (CEUS), while newer techniques such as elastography and hepatic vein transit time (HVTT) have the potential to exclude patients without significant fibrosis or cirrhosis; however, they are operator dependent and require specific software. Grey-scale imaging may demonstrate changes, such as volume redistribution, capsule nodularity, parenchymal nodularity, and echotexture changes. The Doppler findings in the hepatic and portal veins, hepatic artery, and varices allow assessment of liver cirrhosis. However, the operator needs to be aware of limitations of these techniques. Low mechanical index CEUS plays an important role in the assessment of complications of cirrhosis, such as hepatocellular carcinoma and portal vein thrombus. Optimized US technique is crucial for accurate diagnosis of the cirrhotic liver and its complications.

Role of imaging in the management of splenic artery steal syndrome

OBJECTIVE

The purpose of this study is to discuss the etiology and role of imaging in the management of splenic artery steal syndrome (SASS) following orthotropic liver transplantation (OLT).

METHODS

Hepatic arterial thrombosis and stenosis have been the most commonly recognized arterial complications following OLT. Splenic artery steal syndrome is a recently described entity in the transplant literature and thought to be an under-recognized cause of graft ischemia. It is characterized by hepatic arterial hypoperfusion accompanied by splenic arterial and portal venous hyperperfusion and leads to various vascular and biliary graft complications. Because the clinical manifestations of SASS are so non-specific, imaging plays a key role in the diagnosis of this condition.

RESULTS

This article discusses the role of imaging in the management of this potentially reversible cause of graft ischemia.

CONCLUSIONS

Awareness of the imaging features and having a high index of suspicion are essential for the early diagnosis and prompt management of this condition.

Spectrum of normal or near-normal sonographic findings after orthotopic liver transplantation

The initial imaging immediately after orthotopic liver transplantation is generally performed with ultrasound. Although significant posttransplant complications do occur, many abnormal findings including minor vascular waveform abnormalities, anastomotic mismatches, and fluid collections can be seen in asymptomatic patients. It is important to differentiate these benign findings from more serious complications to avoid unnecessary intervention.

Damping index of Doppler hepatic vein waveform to assess the severity of portal hypertension and response to propranolol in liver cirrhosis: a prospective nonrandomized study

BACKGROUND AND AIMS

Alterations in the Doppler hepatic vein (HV) waveform are associated with cirrhosis and portal hypertension. We prospectively evaluated the correlation between the extent of abnormal Doppler HV waveforms expressed as damping index (DI) and the hepatic venous pressure gradient (HVPG) and response to propranolol in patients with cirrhosis.

MATERIAL AND METHODS

In 76 patients with cirrhosis (69 men and seven women), both DI of Doppler HV waveform and HVPG were measured, and the relationship between them was analysed. DI was calculated by the minimum velocity/maximum velocity of the HV waveform. An HVPG>12 mmHg was defined as severe portal hypertension. In a subgroup of 19 patients receiving propranolol, changes in both DI and HVPG were evaluated after propranolol administration for 3 months. One author (S. K. B.) performed all DI of Doppler HV waveform studies.

RESULTS

Abnormal HV waveforms were seen in 66 of 76 patients (86.8%). DI significantly correlated with the grade of HVPG, i.e. with higher HVPG increased DI was observed (P<0.01). By logistic regression analysis, DI>0.6 was significantly more likely to be severe portal hypertension (odds ratio: 14.19, 95% confidence interval: 4.07-49.55). Receiver-operating characteristic curve according to the value of 0.6 of DI showed a sensitivity of 75.9% and a specificity of 81.8% for the presence of severe portal hypertension. In 19 patients of the propranolol subgroup, change of DI following propranolol treatment also significantly correlated with that of HVPG (P<0.01).

CONCLUSIONS

Damping index of the HV waveform by Doppler ultrasonography might be a non-invasive supplementary tool in evaluating the severity of portal hypertension and in responding to propranolol in patients with liver cirrhosis.

Does PEEP impair the hepatic outflow in patients following liver transplantation?

OBJECTIVE

Evaluation of the impact of end-expiratory pressure (PEEP) ventilation on venous liver outflow, portal vein, and hepatic artery flows as well as systemic hemodynamics in patients following liver transplantation (LT).

DESIGN

Prospective, interventional patient study.

SETTING

University hospital intensive care unit.

PATIENTS

65 consecutive patients after LT.

INTERVENTIONS

All patients were intubated and mechanically ventilated with biphasic positive airway pressure (BIPAP). The effects of three levels of PEEP (0, 5, and 10 mbar) applied at random order on hepatic inflow and outflow were studied in the immediate postoperative period.

MEASUREMENT AND RESULTS

Central venous-, arterial pressure, and cardiac index was recorded from every patient at three different PEEP levels (0, 5, and 10 mbar). Simultaneously, flow velocities in the hepatic-, portal vein, and hepatic artery were determined by Doppler ultrasound. PEEP of 10 mbar significantly increased central venous pressure in comparison with zero PEEP. Mean arterial pressure and cardiac index was not influenced. Hepatic inflow and outflow of the transplanted livers were not impaired by any of the used PEEP levels.

CONCLUSIONS

BIPAP ventilation with PEEP levels up to 10 mbar does not affect systemic hemodynamics. Furthermore, neither venous outflow nor portal venous or hepatic artery inflow of the liver are impaired at PEEP levels up to 10 mbar immediately following liver transplantation. Although these results suggest that PEEP ventilation up to 10 mbar does not affect liver hemodynamics, further studies are needed to determine whether these findings could be confirmed for a longer ventilation period with PEEP.

Doppler ultrasonographic findings on hepatic arterial vasospasm early after liver transplantation

OBJECTIVE

Hepatic arterial vasospasm has not been well recognized clinically as a post-liver transplant vascular complication because of the lack of sufficient data and diagnostic standards. The goal of this study was to provide new evidence and a diagnostic model for the clinical appreciation of hepatic arterial vasospasm and evaluate the role of ultrasonography in the diagnostic process.

METHODS

Nine post-orthotopic liver transplant cases were retrospectively reviewed. Multiple clinical measurements were analyzed. Routine Doppler ultrasonography was performed within 24 hours, and additional ultrasonographic examinations were conducted as indicated. Each of the 9 patients was given a single 10 mg dose of nifedipine sublingually and monitored by ultrasonography when vasospasm was suspected on the basis of the Doppler ultrasonographic results.

RESULTS

Doppler ultrasonography showed high-resistance hepatic arterial flow with absence of antegrade flow and even reversal of flow during diastole both extrahepatically and intrahepatically in all cases. Ten to 45 minutes after administration of the vasodilator, antegrade diastolic flow was observed along the course of the main hepatic artery and its intrahepatic branches with the resistive indices decreasing on average from 1.0 to 0.76. In addition, the peak systolic velocities increased from 57 cm/s before nifedipine administration to 77 cm/s after administration.

CONCLUSIONS

High-resistance hepatic arterial flow (resistive index = 1) early after liver transplantation is indicative of hepatic arterial vasospasm if it responds to vasodilators. Doppler ultrasonography is a useful tool for the diagnosis of this vascular complication.

Acute Liver Rejection: Accuracy and Predictive Values of Doppler US Measurements—Initial Experience

PURPOSE

To prospectively evaluate accuracy and predictive values of Doppler ultrasonographic (US) measurement of portal blood velocity (PBV) and splenic pulsatility index (SPI) in diagnosis of clinically relevant acute rejection in patients with clinicobiochemical hepatic dysfunction after orthotopic liver transplantation (OLT).

MATERIALS AND METHODS

Study was approved by the institutional review board, and protocol conformed to ethical guidelines of Declaration of Helsinki. Patient informed consent was obtained. In 27 patients with OLT (23 men, four women; mean age, 48 years; range, 27-64 years), PBV and SPI were measured at Doppler US within 48 hours before or after liver biopsy for clinically suspected acute rejection. Biopsy specimens were assigned scores according to Banff method, and rejection activity index (RAI) was calculated. RAI score of 4 or greater was considered clinically relevant acute rejection. Doppler US parameters were analyzed as absolute values and as percentage point changes with respect to values obtained at last examination before rejection was suspected. Information from two Doppler US parameters was combined; Doppler US composite index was calculated. Statistical tests were conducted to assess accuracy, sensitivity, specificity, and predictive values of Doppler US parameters in diagnosis of graft rejection.

RESULTS

Clinically relevant acute rejection was diagnosed in nine patients. Median time from OLT until histologic diagnosis of acute rejection was 8 days (range, 5-20 days). Rejection was associated with a marked reduction in mean PBV (-43% +/- 5 [standard error of the mean]) and a slight increase in SPI (+12% +/- 16). The calculated Doppler US composite index was strictly related to severity of rejection (P < .001). When applied retrospectively, this index had good accuracy (88%) for prediction of rejection (specificity, 89%; sensitivity, 86%; negative predictive value, 94%).

CONCLUSION

During the first weeks after OLT, a marked decrease in PBV associated with increased SPI supports suspicion of clinically relevant acute rejection.

Significance of and contributing factors for a high resistive index on Doppler sonography of the hepatic artery immediately after surgery: prognostic implications for liver transplant recipients

OBJECTIVE

The goal of our study was to investigate the contributing factors, clinical repercussions, and implications for prognosis of high-resistance flow at the hepatic artery detected on Doppler sonography during the period immediately after orthotopic liver transplantation.

MATERIALS AND METHODS

We retrospectively studied the transplanted livers of 90 patients who had been examined on Doppler sonography within the first 3 days after grafting. Seventeen variables from organ donors, transplant recipients, graft characteristics, and surgical procedures were investigated. Early clinical evolution was also analyzed. Follow-up was performed for 5 years.

RESULTS

Forty-one (45.6%) of the 90 patients showed a high resistive index at the hepatic artery during the first 72 hr after transplantation. Two factors showed a statistically significant effect on the occurrence of a high resistive index at the hepatic artery immediately after transplantation: an older liver donor (p = 0.008) and extended preservation time (p = 0.005). No relation with early graft function was detected. The incidence of bile duct complications, retransplantation, or death was not higher at follow-up in patients with high-resistance flow than in those with normal flow.

CONCLUSION

High-resistance flow at the hepatic artery detected on Doppler sonography during the period immediately after transplantation is a frequent finding and is related to older donor age and prolonged period of ischemia. This finding has neither significant clinical repercussions nor prognosis implications for early and long-term follow-up.

Orthotopic liver transplants in children: change in hepatic venous Doppler wave pattern as an indicator of acute rejection

PURPOSE

To determine whether a change in hepatic venous flow pattern can be seen during hepatic graft rejection and if it is reversible with treatment.

MATERIALS AND METHODS

Thirty-nine children received 42 liver allografts during a 10-year span. Doppler ultrasonographic (US) recordings of hepatic venous wave patterns were reviewed. Nine children (ten grafts) with continuously monophasic flow were not included in the study. Changes from triphasic to monophasic flow were recorded and correlated with clinical findings in all 30 patients and biopsy findings in 25. Biopsy results were compared with US data recorded within 24 hours of biopsy. Standard statistical tests were conducted to assess value of Doppler US in diagnosis of graft rejection. Significance was assessed with chi(2) statistics.

RESULTS

Of 113 Doppler US recordings in 30 children, 74 showed an episode of change in flow from triphasic to monophasic in 27 patients; biopsy correlation existed for 39 episodes. Thirty-five episodes were due to acute graft rejection (true-positive results). Thirty-nine episodes were due to a variety of pathologic causes (determined with biopsy results for 12 and by clinical means for 27) (false-positive results). Thirty-six assessments were true-negative (US and biopsy results negative for rejection); three were false-negative. When US results were evaluated against clinical and biopsy data, analysis revealed that change to monophasic flow predicted rejection with sensitivity of 92% (35 of 38) and specificity of 48% (36 of 75). Negative predictive value of evidence of persistent triphasic flow was 92% (36 of 39). In the subgroup of US findings with biopsy correlation, specificity increased from 48% (36 of 75) to 75% (36 of 48). It was zero (0 of 27) for the group with clinical correlation only.

CONCLUSION

Change of hepatic venous flow pattern from triphasic to monophasic is sensitive but nonspecific for detection of graft rejection. Evidence of persistent triphasic flow helps eliminate the possibility of graft rejection with a high negative predictive value.

Pediatric Liver Transplantation

Pediatric liver transplantation is a fast-growing and challenging field. Healthcare providers must stay informed of advancements in the management of liver transplant candidates and recipients. The goal of this paper is to provide nurses who care for pediatric liver transplant candidates and recipients with a review of the basic medical management of these patients, from the preoperative evaluation to postoperative care.

Comparison of the SonoSite and Acuson 128/XP10 ultrasound machines in the 'bed-side' assessment of the post liver transplant patient

Hepatic artery thrombosis after liver transplant is associated with biliary sepsis and irretrievable loss of the graft. Early identification of hepatic artery thrombosis, using a 'high-specification' ultrasound machine incorporating spectral Doppler, is crucial to patient management in the postoperative period with portable ultrasound as the first line of investigation for evaluation of the hepatic artery. We evaluated the efficacy of the SonoSite portable ultrasound machine, which uses power Doppler only, in the evaluation of the post transplant hepatic artery. An Acuson 128/XP10 ultrasound machine was used as the comparison 'reference-standard' with identification of the hepatic artery by both colour and spectral Doppler trace. The SonoSite accurately identified the hepatic artery in 88.4% of patients with power Doppler. The SonoSite was easier to transport and manage at the bedside leading to considerable time saving. In 11.6% of patients a repeat ultrasound using the 'reference-standard' machine would be necessary.

Duplex Doppler ultrasound of the hepatic artery in patients with acute alcoholic hepatitis

BACKGROUND

Acute alcoholic hepatitis (AAH) is a clinical diagnosis associated with increased hepatic artery diameter and flow. Duplex Doppler ultrasound (DDU) has been shown to accurately measure arterial flow in both liver and kidney transplant patients. The authors conducted a blinded, controlled study to evaluate the accuracy of measuring hepatic artery parameters with DDU in diagnosing AAH.

STUDY

Duplex Doppler ultrasound was performed by an investigator, blinded to group makeup, on 22 consecutive hospital inpatients with the clinical diagnosis of AAH. The diagnosis of AAH was based on specific criteria, including the following: recent alcohol abuse, hyperbilirubinemia, prolonged prothrombin time, leukocytosis, hepatomegaly, hepatic bruit, and marked redistribution of isotope on 99mTc-sulfur colloid liver-spleen scan. Controls were 12 cirrhotic patients without AAH and 17 healthy volunteers. Duplex Doppler ultrasound measurements were obtained most consistently from the proximal right hepatic artery. Measured parameters included the following: peak systolic velocity (PSV); resistive index = (PSV - end diastolic velocity [EDV])/PSV; pulsatility index = (PSV - EDV)/mean velocity; and hepatic artery diameter.

RESULTS

The mean hepatic artery diameter was significantly larger in patients with AAH (3.55 +/- 0.72 mm) than in patients with cirrhosis (2.75 +/- 0.69 mm; p = 0.003) and healthy controls (2.68 +/- 0.69 mm; p = 0.001). The mean PSV was significantly higher in patients with AAH (187 +/- 52 cm/s) compared with cirrhotic (67 +/- 51 cm/s) and healthy (66 +/- 51 cm/s) controls (p = 0.0001). The mean resistive index was lower in AAH patients (0.60 +/- 0.11) compared with cirrhotic (0.69 +/- 0.10; p value was not significant) and healthy controls (0.72 +/- 0.11; p = 0.004). The mean pulsatility index was lower in AAH patients (1.04 +/- 0.47) compared with cirrhotic (1.36 +/- 0.45; p value was not significant) and healthy controls (1.53 +/- 0.45; p = 0.01).

CONCLUSIONS

In the appropriate clinical setting, an elevated hepatic artery diameter or PSV measurement is suggestive of AAH. Duplex Doppler ultrasound offers a noninvasive test to assist in the diagnosis of AAH.

Radiology in liver transplantation

Imaging studies are becoming essential in the management of orthotopic liver transplantation (LT). They have a very important role in the preoperative evaluation and selection of suitable candidates. At the same time, they are essential in the early detection of postoperative complications, the recognition of which allows the prompt institution of appropriate therapeutic measures. Timely recognition of complications improves the success of LT; furthermore, some complications can be treated with interventional radiologic procedures, avoiding additional surgery. This article reviews the current application of diagnostic and interventional imaging in liver transplantation, both for cadaveric and living donor transplants.

Analysis of portal venous waveform after living-related liver transplantation with pulsed Doppler ultrasound

We evaluate the portal venous waveform (PVW) with pulsed Doppler ultrasound (US) after living-related liver transplantation (LRLT) and correlate it with subsequent abnormalities. In the first 2 wk after LRLT, pulsed Doppler US demonstrated three types of PV waveform (PVW) in 33 recipients: non-phasic PVW in 19 patients, pulsatile in 10, and turbulent in 4. In the pulsatile PVW group, arterio-portal (A-P) shunt was confirmed in three grafts by either arteriograhy or computed tomography during hepatic arteriography. A severe stenosis in the grafted vein was confirmed in one case by both US and venography. The pulsatile PVW in the remaining six cases spontaneously disappeared and turned to the non-phasic PVW without treatment. The graft volume/liver standard volume (GV/SV) ratio was significantly smaller in the pulsatile PV waveform group than in the non-phasic PVW group (p<0.01). In the turbulent PVW group, aneurysmal-like dilatation of the portal vein at the umbilical portion was formed in 3 of the 4 patients. The pulsatile waveform in the PV is frequently observed with pulsed Doppler after LRLT, especially in patients that received small grafts. We should keep in mind that they often disappear without any treatment, although some examples of pulsatile waveforms represent vascular complications.

Association between duplex Doppler sonographic flow pattern in right hepatic vein and various liver diseases

PURPOSE

The aim of this study was to evaluate the association between the Doppler sonographic waveforms in the right hepatic vein and various liver diseases.

METHODS

We performed Doppler sonography of the right hepatic vein in 225 individuals (189 patients with liver disease and 36 control subjects). Patients were categorized on the basis of their histologic diagnosis: cirrhosis (n = 122), fibrosis (n = 23), fatty liver disease (n = 11), metastatic liver disease (n = 8), and noncirrhotic liver disease with neither fatty infiltration nor metastases (n = 25). The waveforms of the hepatic veins were categorized as type 1, triphasic; type 2, biphasic; or type 3, flat.

RESULTS

Type 1 waveforms were found in 100% of the control subjects and in patients with each of the various liver diseases, including 40% of those with cirrhosis. Type 2 waveforms were not found in control subjects or in patients with either fatty infiltration or metastatic liver disease. Type 2 waveforms were, however, found in 16% of patients with cirrhosis, 13% of patients with fibrosis, and 4% of patients with other noncirrhotic liver diseases. Type 3 waveforms were found in 43% of patients with liver cirrhosis, 13% of patients with liver fibrosis, 27% of patients with fatty liver disease, and 50% of patients with metastatic liver disease. In contrast, type 3 waveforms were not found in any control subjects or in patients with other noncirrhotic liver diseases without fatty liver or metastases.

CONCLUSIONS

Type 3 waveforms in the right hepatic vein are suggestive of liver cirrhosis, although they may also occur in patients with fibrosis, fatty liver disease, or metastatic liver disease.

Differentiated therapy with prostaglandin E1 (alprostadil) after orthotopic liver transplantation: the usefulness of procalcitonin (PCT) and hepatic artery resistive index (RI) for the evaluation of early graft function and clinical course

Increasing demand for donor organs has led to new pharmacological concepts for reducing ischemia-reperfusion injury (I/R) of the graft after liver transplantation to prevent primary non-functioning of the organ. Prostaglandins have proved to be cytoprotective in several experimental models of ischemia and transplantation. The prophylactic administration after orthotopic liver transplantation is still a subject of controversial discussion. The aim of our study was the evaluation of the post-transplant hepatic artery resistive index (RI) measured by color Doppler imaging, in combination with postoperative elevation of transaminases, as parameters indicating the need for a differentiated systemic therapy with prostaglandin E1 (PGE1) (alprostadil). In addition, the value of serum procalcitonin (PCT) as a postoperative parameter for the extent of I/R is investigated. In the case of post-transplant elevated hepatic artery RI (RI > 0.75), the administration of PGE1 led to a significant reduction of transaminases (p < 0.05) and a decline of the RI. In addition, postoperative PCT levels could be reduced significantly by PGE1 application. These results suggest that determination of RI is feasible for indicating a need for therapy with PGE1. Its targeted application reduces hepatocellular damage due to I/R after liver transplantation.

Doppler waveform of hepatic veins in healthy children

OBJECTIVE

This study intends to document the presence or absence of triphasic waveforms in hepatic veins in healthy children. Does absence of triphasic hepatic vein flow indicate hepatic abnormality?

SUBJECTS AND METHODS

One hundred children without a known hepatic or intrathoracic abnormality underwent Doppler sonography of their hepatic veins. Fifty girls and 50 boys were divided into five age groups.

RESULTS

Forty-two children had triphasic flow in all three hepatic veins. Veins approaching an angle of 90 degrees with the inferior vena cava could not be assessed or had the least flow modulations despite angle correction. Neonates had the highest percentage of monophasic flow (seven of 21) in all three hepatic veins and none had triphasic flow in all three veins.

CONCLUSION

Not all healthy children have a triphasic flow pattern in all hepatic veins. Before suspecting hepatic abnormality with abnormal parenchymal compliance (cirrhosis, graft rejection) by virtue of lack of triphasic hepatic vein flow, a normal variant of the flow should be considered. Only the change of a previously documented triphasic flow to monophasic flow in a given vein should be assessed as a sign of possible abnormality.

The value of Doppler ultrasound in cirrhosis and portal hypertension

BACKGROUND

Cirrhosis and portal hypertension affect the flow profile of the liver vasculature. In these conditions Doppler ultrasound can provide important information on the hemodynamics of the portal venous system, the hepatic artery and the hepatic veins.

METHODS

The value of Doppler ultrasound in the assessment of the patient with cirrhosis and portal hypertension was determined by reviewing the literature.

RESULTS

Portal venous blood flow becomes reversed with advanced portal hypertension. Reversed flow is also demonstrated in patients with veno-occlusive disease and portosystemic shunts. Despite general agreement that portal flow velocity is decreased in cirrhotic patients, the absolute values of portal flow velocity in both healthy subjects and cirrhotic patients vary considerably. Errors in Doppler measurements, observer variability and collateral pathways contribute to these variations. Furthermore, portal blood flow is influenced by numerous factors such as changes in the body position, phase of respiration, timing of meals, exercise and cardiac output. Finally, portal flow may be unaltered due to a combination of high inflow from the splanchnic organs and increased resistance within the liver. High resistive index of the hepatic artery is seen in patients with end-stage liver disease, particularly in children with severe cirrhosis secondary to biliary atresia. However, hepatic artery flow remains normal in most patients. Abnormal hepatic vein flow profiles are seen in patients with cirrhosis, but dampening or flattening of the flow profile has a multifactorial origin (Budd-Chiari, metastases, ascites) and can be observed in healthy subjects.

CONCLUSIONS

Although many factors may affect the accuracy of volume flow and velocity measurements and the flow profile of the liver vasculature may change in different situations, Doppler ultrasound is useful in the assessment of the patient with cirrhosis and portal hypertension.