Duplex sonography of hepatic artery thrombosis after liver transplantation

When hepatic artery thrombosis occurs after liver transplantation, another transplantation is required to ensure the patient's survival. Because of the importance of establishing this diagnosis, we reviewed the results of duplex sonography in 37 angiographically or surgically proved cases of hepatic artery thrombosis after liver transplantation. There were 20 children and 17 adults. Ten of the 20 children had angiographically documented hepatopetal arterial collaterals. Such collaterals were not seen in the adult patients. This subset of patients was evaluated separately to determine if intrahepatic arterial blood flow reestablished by collaterals after hepatic artery thrombosis was a cause of false-negative Doppler studies. Thirty-four (92%) of the 37 cases of hepatic artery thrombosis were correctly identified by Doppler. A Doppler pulse was not identified in any of the children with arterial collaterals. We conclude that duplex sonography is sensitive in detecting hepatic artery thrombosis after liver transplantation. Furthermore, the presence of blood flow in hepatopetal arterial collaterals does not cause false-negative examinations.     

False-negative duplex Doppler studies in children with hepatic artery thrombosis after liver transplantation

Recent reports describe formation of collateral vessels in children who have hepatic artery thrombosis after liver transplantation. This led us to reevaluate the role of duplex Doppler imaging in this population. Among 135 pediatric liver transplant patients, 20 had arteriography for suspected hepatic artery thrombosis. Duplex and/or color Doppler imaging was performed in 13 of these children. The Doppler examination failed to show hepatic artery signals in five patients. Arteriography showed hepatic artery thrombosis in all five. In three of these, subsequent Doppler examinations showed reappearance of arterial Doppler signals. Arteriography confirmed the interval development of collaterals. Hepatic artery signals were found on the Doppler examinations of the remaining eight patients. Four had normal arteriograms, but the remaining four had hepatic artery thrombosis with collateral formation. Patients with hepatic artery thrombosis and collateral circulation tended to have increased diastolic flow (decreased resistive index). In addition, early scans clearly identified patients with complete thrombosis before collateral formation. On the basis of our preliminary experience, a child with a liver transplant and a clinical history strongly suggestive of hepatic artery compromise should have arteriography despite an apparently normal Doppler examination.     

Common hepatic artery aneurysm: diagnosis with duplex sonography and color Doppler.

Hepatic artery aneurysms are uncommon lesions, often with a nonspecific clinical presentation and difficult to diagnose before rupture. The authors report a case which was correctly diagnosed with non-invasive procedures (duplex sonography and color Doppler).     

Color duplex sonography in severe transplant renal artery stenosis: a comparison of end-to-end and end-to-side arterial anastomoses

ObjectiveThe aim of this study was to investigate differences in Doppler parameters between severe transplant renal artery stenosis (TRAS, arterial lumen reduction >80%) with end-to-end (EE) arterial anastomosis and that with end-to-side (ES) arterial anastomosis.MethodsWe retrospectively reviewed color duplex sonography (CDUS) and digital subtraction angiography (DSA) images in 38 patients with severe TRAS (19 cases with EE and 19 cases with ES) between January 1, 2000, and December 31, 2006. Doppler parameters were analyzed, including peak systolic velocity (PSV) in the iliac artery, PSV at the arterial anastomosis, PSV in the transplant renal artery, PSV ratio of the stenotic artery/artery proximal to the stenosis, and acceleration time (AT) in the artery distal to the stenosis (in the intrarenal artery). All 38 cases with severe TRAS were initially diagnosed with CDUS and confirmed by DSA.ResultsThere were significant differences in PSV in the stenotic artery (P<.01), PSV in the iliac artery (P<.001), and PSV ratios of stenotic artery/artery proximal to the stenosis (P<.001) between arterial anastomosis of EE and that of ES. There was no statistically significant difference in AT in the intrarenal artery between the two types of anastomosis (P>.05).ConclusionSignificantly different PSVs in the stenotic artery, the iliac artery, and the PSV ratio between EE and ES arterial anastomoses should be considered in the interpretation of CDUS when screening for severe TRAS. Different criteria of CDUS need to be established depending on the type of arterial anastomosis in order to improve the accuracy in diagnosing severe TRAS.     

Acute allograft rejection in liver transplant recipients: lack of correlation with loss of hepatic artery diastolic flow

Eighty hepatic artery Doppler ultrasound (US) examinations performed in 49 patients after liver transplantation were retrospectively analyzed to determine if loss of diastolic flow correlated with pathologic evidence of acute allograft rejection. All 80 Doppler examinations were performed within 7 days of hepatic needle biopsy. Forty-three Doppler waveforms from 27 patients showed normal diastolic flow. Seventeen Doppler studies in 17 patients showed complete absence of diastolic flow. Review of biopsy results for each group showed no significant difference in the proportion of acute allograft rejection present (42% for the normal group and 46% for the group lacking diastolic flow). The data from 53 US and biopsy examinations performed 2 days apart in 37 patients confirmed the lack of correlation between absent hepatic artery diastolic blood flow and rejection. The authors conclude that the loss of hepatic artery diastolic flow has no apparent clinical application for the diagnosis of acute hepatic allograft rejection.     

Stent placement in four patients with hepatic artery stenosis or thrombosis after liver transplantation

Hepatic artery stenosis and thrombosis represent dangerous complications of liver transplantation because the associated mortality and morbidity rates are high. In the past, repeat transplantation was considered the first-choice therapy; however, new surgical and interventional revascularization techniques have been suggested recently. Although extensive experience has been acquired with percutaneous transluminal angioplasty (PTA) and fibrinolysis techniques, only sporadic cases of stent placement in the hepatic artery of a transplanted liver have been reported, and no long-term results of this technique are available. In this study, seven stents (five Wallstents and two Palmaz stents) were positioned in four patients (two with stenoses and two with thromboses). Stent placement was performed in three cases after PTA and fibrinolysis, whereas primary stent placement was performed in the fourth. In all cases, technical success was achieved. During 18-25 months of follow-up, all stents proved patent and no patient required another transplantation. Although experience is still limited, the authors' experience indicates that placement of a stent in the hepatic artery in cases of stenosis or thrombosis yields good medium-term success, improving the results obtained by fibrinolysis and PTA and consequently enabling the graft to survive and avoiding the need for repeat transplantation.     

Infected bilomas and hepatic artery thrombosis in infant recipients of liver transplants. Interventional radiology and medical therapy as an alternative to retransplantation

Fifteen children less than 12 kg in weight underwent transplantation of the liver for biliary atresia; eight survived. Five of the eight survivors had thrombosis of the hepatic artery without portal vein thrombosis. Three of the five patients with hepatic artery thrombosis developed infected bilomas, which were drained percutaneously under ultrasonographic (US) or computed tomographic (CT) guidance. Concurrent therapy with antibiotics and hyperoxygenation resulted in resolution of these intrahepatic collections. Although it had been thought that thrombosis of the hepatic artery most often results in necrosis of the graft and requires retransplantation, the five patients in this study survived without retransplantation. Diagnosis of hepatic artery thrombosis was achieved with the use of Doppler US in four cases, CT in four cases, and angiography in two cases. Duplex Doppler US is the preferred imaging modality.     

Early detection of saphenous vein arterial bypass graft stenosis by color-assisted duplex sonography: a prospective study

We propose a simple and rapid technique for the postoperative surveillance of developing stenosis in lower extremity saphenous vein arterial bypass grafts that uses color-assisted duplex sonography. Color Doppler flow images are used to identify points of altered flow dynamics. These points are subsequently analyzed by duplex sonography, with doubling of the peak systolic velocity at the point of suspected stenosis considered the diagnostic threshold for significant stenosis. A segment-by-segment comparison made with arteriography in 14 patients (15 grafts, 92 segments) showed this approach to be 95% sensitive (18/19) and 100% specific (73/73) for the detection and localization of focal graft stenoses that involve greater than 50% narrowing of the lumen diameter. We conclude that color-assisted duplex sonography can accurately detect the presence of saphenous vein arterial bypass graft stenoses.     

Early postoperative hepatic sonography as a predictor of vascular and biliary complications in adult orthotopic liver transplant patients

OBJECTIVE: Our objective was to quantitatively assess the value of early posttransplantation hepatic artery resistive indexes in predicting vascular and nonvascular complications in adult orthotopic liver transplant (OLT) patients. MATERIALS AND METHODS: Between 1999 and 2001, 110 consecutive adults received grafts. Doppler sonographic graft evaluations measured main, right, and left resistive indexes within 24 to 48 hr after surgery (normal resistive index cutoff, 0.6). Clinical, operative, procedural, and radiologic reports were reviewed for vascular and biliary complications. Frequency, Student's t test, logistic, and regression statistical analyses were performed. RESULTS: even patients (6.4%) had vascular complications, including two (1.8%) hepatic artery and two (1.8%) hepatic vein stenoses, one (0.9%) hepatic vein thrombosis, two (1.8%) portal vein thromboses, and one (0.9%) thrombosis and two (1.8%) stenoses of the inferior vena cava (IVC). In 19 patients (17.3%), biliary complications included anastomotic strictures and leaks 1 week to 18 months after transplantation. In 11 patients (10%), sonographically large hematomas required surgical evacuation. In grafts with vascular complications or large hematomas, the mean early posttransplant main, right, and left indexes were significantly lower (< or = 0.6) than without these complications (p < 0.01). In grafts with and without biliary complications, mean early posttransplant main, right, and left indexes did not differ significantly. CONCLUSION: In adult OLT patients, low early posttransplant hepatic artery resistive indexes were sensitive (100%) and specific (80%) predictors for vascular complications (e.g., hepatic artery, portal vein, hepatic vein, and IVC) but not for biliary complications. All patients with indexes less than 0.6 within 24-48 hr after surgery should be monitored closely for vascular complications.     

Modulation of liver tumor blood flow with hepatic arterial epinephrine: a SPECT study

Changes in the relative arterial flow to hepatic tumors and adjacent normal liver, in response to varied doses of hepatic arterial epinephrine, were studied with single photon emission computed tomography. In 18 patients with known hepatic tumors, hepatic artery perfusion scans were obtained with the concurrent infusion of technetium-99m-labeled macroaggregated albumin and escalating doses of epinephrine (0-10 micrograms/min). Regions of interest were drawn around tumor and adjacent normal liver in three planes, and the average tumor-to-liver ratio (T:L) was calculated. In all 18 patients, there was a measurable baseline T:L perfusion advantage (range, 1.7-18.7; mean, 4.8). In 12 of 18 patients, this ratio increased with epinephrine (range, 1.1-53.6 times the baseline value; mean, 7.1). In six patients, no improvement in T:L could be demonstrated. In 14 patients the lung shunt index, a measurement of arteriovenous shunting, increased with escalating doses of epinephrine. This pilot study suggests that the infusion of epinephrine may improve the therapeutic index of certain regional therapies such as bolus drug infusions, hepatic arterial embolization, and radioactive microsphere therapy.     

Unusual biliary scan appearance in a child with a transplanted liver with hepatic arterial thrombosis: a case report

A 5-year-old girl with biliary atresia and a subsequent Kasai procedure is described. She had clinical symptoms suggestive of rejection after a recent orthotopic liver transplant A hepatobiliary scan showed partial hepatic infarction and a biloma in the infarcted area.     

Pulsatile portal vein flow: a sign of tricuspid regurgitation on duplex Doppler sonography

Sonography and duplex Doppler frequently fail to identify a cause for right upper quadrant pain, liver dysfunction, or ascites. The aim of our study was to describe and analyze the pulsatile portal venous waveform in which minimum velocity dropped to or below zero on duplex Doppler sonography and to investigate its possible association with tricuspid regurgitation, one of the causes of liver dysfunction. We correlated the findings in 15 patients in whom this duplex Doppler waveform was seen with the findings on Doppler echocardiography (n = 14) or ultrafast CT (n = 1). All patients had biochemical liver abnormalities or sudden onset of ascites, rapid weight gain, increased abdominal girth, and hepatomegaly. They were referred for sonography to rule out liver metastases, biliary disease, portal vein thrombosis, or Budd-Chiari syndrome. All examinations were done with a 3-MHz phased-array sector transducer with duplex Doppler capability. Seventeen volunteers with no known liver or heart disease served as a control group. We correlated maximum and minimum flow velocities on the portal venous Doppler waveform with the portal vein diameters of the study and control groups. Thirteen patients were later proved to have tricuspid regurgitation, one patient had an aortic-right atrial fistula owing to rupture of an aneurysm of the sinus of Valsalva, and one patient was proved to be normal. In none of the 17 control subjects was this pulsatile portal venous waveform seen. Our study shows that detection of a pulsatile portal venous waveform on duplex Doppler sonography in patients with liver dysfunction should raise the possibility of tricuspid regurgitation.     

Arteriographic demonstration of collateral arterial supply to the liver after hepatic artery ligation.

Eight patients were studied arteriographically after hepatic artery ligation (done to control bleeding in 6). Sources of arterial flow to the liver after ligation were (a) replaced or accessory hepatic artery; (b) interlobar collaterals in the liver; (c) right inferior phrenic artery; (d) through the gastroduodenal artery from arterial branches in the pancreas, duodenum, and omentum; (e) fine collateral branches of the gastroduodenal artery as they pass into the porta hepatis; and (f) recanalization of the ligated hepatic artery. Collateral vessels, seen as early as four hours after ligation, increase in size and number during the following six months.     

11例肝移植术后肝动脉血栓形成的观察与护理

肝动脉血栓(Hepatic artery thrombosis,HAT)形成是肝移植术后最常见的血管并发症,也是导致术后移植物功能丧失和患者死亡的主要原因之一[1],发生率为3%~9%。HAT一旦发生,绝大多数情况下终将导致移植肝脏功能丧失,被迫接受再次肝移植。2002年4月~2006年6月,我院694例同种异体原     

An evaluation of internal carotid artery and cerebral blood flow volume using color duplex sonography in patients with vertebral artery hypoplasia

INTRODUCTION: Vertebral artery hypoplasia (VAH) may be defined as VA flow volume below approximately 30-40 mL/min using color duplex sonography. The aim of this study was to evaluate the effect of VAH on internal carotid artery (ICA) flow volume and cerebral blood flow (CBF) volume. MATERIAL AND METHODS: In this study, 17 patients with VAH and 20 control subjects with normal VA flow volume were enrolled. The patients and control subjects were 50-75 years aged. The ICA and VA flow volumes were determined by using color duplex sonography. The ICA and CBF volumes of patients with VAH were compared with control group flow volumes. RESULTS: There was no statistically significant difference in flow volumes of right, left and sum of both ICA between VAH and control group. However, CBF volume was lower in patient with VAH than control group. CONCLUSIONS: Evaluation of CBF using color duplex sonography is noninvasive and easily applicable to all patients and provides valuable diagnostic data. To the best of our knowledge, this is the first study demonstrating lower CBFV and normal ICA flow volume in patients with VAH.     

Transcranial duplex sonography of middle cerebral artery stenosis: a comparison of colour-coding techniques – frequency- or power-based Doppler and contrast enhancement

Abstract The main limitation of transcranial colour-coded duplex sonography (TCCD) is the inadequate acoustic window, which prevents transtemporal identification of the basal cerebral arteries in up to 30 % of cases, especially in the elderly. TCCD with different colour-coding techniques, including frequency-based colour-flow (CFD) or power (PD) Doppler sonography, used alone or in combination with contrast media, were used in 23 patients with middle cerebral artery (MCA) stenosis. In 10 patients a contrast medium (400 mg/ml SHU 508 A) was administered because of inadequate colour-coded visualisation with TCCD. The data were compared with angiographic methods. Digital subtraction angiography (DSA) revealed 2 low-grade, 11 middle-grade and 10 high-grade stenoses in the M1 segment. With TCCD, we found a 7.7 % higher blood flow velocity (systolic peak velocity) than with transcranial duplex sonography without colour-coding because of visual angle correction and a 20 % higher systolic peak velocity using contrast enhancement. CFD did not differ from PD in identification of low- and middle-grade MCA stenoses, but PD alone revealed two more cases of high-grade stenosis than CFD. The contrast medium increased diagnostic confidence in 8 of 10 cases. Only 2 of 23 MCA stenoses (9 %) could not be shown using TCCD. Received: 27 May 1997 Accepted: 5 January 1998