Hemodynamic changes in portal circulation after portosystemic shunts: use of duplex sonography in 43 patients

Forty-five patients with 46 surgical portosystemic shunts were examined by duplex Doppler sonography, and the results were compared with those of esophageal endoscopy, angiography, surgery, and clinical follow-up. Thirty-eight shunts were patent, and in 33 of these, the shunt was directly visualized and flow was observed with Doppler sonography. Eight shunts were obstructed. After a successful portosystemic shunt procedure, flow in the shunted splanchnic vein was directed toward the shunt and the systemic vein. We studied the intrahepatic portal venous circulation in all of the patients; we found that in the presence of patent portosystemic shunt, portal flow is hepatofugal. This reversal of blood flow occurred in all but four patients. In the end-to-side portacaval shunt, where the portal vein is ligated, blood in intrahepatic portal branches presumably reaches the shunt through perihepatic collaterals. In the presence of a thrombosed shunt, intrahepatic portal venous flow was hepatopetal. To our knowledge, this is the first noninvasive in vivo study of intrahepatic portal circulation after portosystemic shunt surgery. The duplex Doppler evaluation of portosystemic shunts appears to be reliable and should be the method of choice for shunt patency assessment in patients with recurrent signs of portal hypertension. In addition to demonstrating flow at the site of the anastomosis, the Doppler study may yield an easy and reliable sign of shunt patency: reversed flow (hepatofugal flow) in the intrahepatic portal veins probably signals a patent shunt, even if the site of the anastomosis cannot be visualized directly by sonography.     

Portal venous system after portosystemic shunts or endoscopic sclerotherapy: evaluation with Doppler sonography

We sought to determine the usefulness of duplex Doppler sonography in the assessment of blood flow and clot formation in the portal vein in 44 patients with portal hypertension and bleeding esophageal varices who had undergone either endoscopic sclerotherapy (28 cases) or portosystemic shunt procedures (16 cases). The main, left, and right portal veins (collectively referred to as intrahepatic portal veins), superior mesenteric vein, splenic vein, and shunt were assessed for flow direction, presence of thrombi, and collaterals. Patent shunts were visualized in 12 (75%) of the 16 cases. Clot was detected in 27 (69%) of 39 intrahepatic portal veins in patients with end-to-side shunts, in six (67%) of nine intrahepatic portal veins in patients with distal splenorenal shunts, and in five (5%) of 92 intrahepatic portal veins in patients who had had endoscopic sclerotherapy. Flow in the main portal vein was hepatopetal in two (15%) of 13 patients with patent shunts (one end-to-side portacaval shunt and one distal splenorenal shunt). Flow in the main portal vein was hepatopetal in 26 (93%) of 28 patients who had had endoscopic sclerotherapy. Our data suggest endoscopic sclerotherapy preserves antegrade portal flow and results in fewer portal vein clots than surgical portosystemic shunts do. Patterns of thrombosis and flow direction vary unpredictably from patient to patient. Shunt patency should not be inferred without direct visualization of the shunt.     

Budd-Chiari syndrome: the results of duplex and color Doppler imaging

This study was designed to evaluate duplex and color-flow Doppler imaging as potential noninvasive methods of diagnosing patients with Budd-Chiari syndrome and following them after surgery. Five patients with confirmed hepatic venoocclusive disease were imaged. All five underwent duplex Doppler examinations; three were also evaluated with color-flow Doppler. The hepatic vasculature was examined in all five patients; decompressive mesoatrial shunts were present and were evaluated in four of the five patients. Color-flow Doppler precisely defined intrahepatic, portal, and inferior vena caval circulatory dynamics. Correlation with angiography was excellent. In the two patients in whom hepatic vasculature was evaluated with duplex Doppler alone, the results were less impressive. Intrahepatic flow abnormalities were identified, but the sites of occlusion were not determined convincingly. Signals transmitted from the heart and the inability to visualize the hepatic veins made duplex Doppler evaluation problematic. Duplex Doppler was able to define patency and the direction of flow in the portal vein and inferior vena cava. Our results suggest that color-flow Doppler is an excellent technique for the initial evaluation of patients suspected of having Budd-Chiari syndrome. In the evaluation of decompressive mesoatrial shunts, color-flow Doppler produced dramatic images. However, both duplex and color-flow Doppler were highly accurate in determining the patency of decompressive shunts. Either duplex or color-flow Doppler may be used as the primary imaging procedure to determine shunt patency.     

Use of magnetic resonance in patients with portal hypertension before and after diversion intervention. Initial experience in 15 cases

Fifteen patients with portal hypertension were examined by magnetic resonance imaging (MRI) using spin-echo sequences. Sagittal and transaxial images were obtained in all cases. Ten subjects have been evaluated after portosystemic shunt operations (6 portocaval and 4 splenorenal shunts); 5 patients were studied by MRI before shunt placements. Angiographic correlation was obtained in 15 cases. In each of the preoperative examinations, MRI accurately depicted inferior vena cava, portal vein and splenic vein. Shunt patency was documented in 10/10 postoperative studies: portacaval shunts patency was better determined in the transaxial plane while splenorenal shunts were better demonstrated in the sagittal plane. Thus, MRI seems to be an accurate and noninvasive method for detecting portosystemic shunt patency without the use of intravenous contrast media and without patient exposure to radiation.     

Surgical portosystemic shunts in children: assessment with duplex Doppler US. Work in progress

The patency of 12 surgical portosystemic shunts in 11 children with portal hypertension was assessed with duplex Doppler ultrasonography. Results were compared with surgical, angiographic, and clinical findings. Seven of nine patent shunts were directly seen, and flow in them was assessed. One proximal splenorenal and one mesentericocaval shunt were not directly seen because of intestinal meteorism. The obstructed shunts were not seen, and no flow could be detected at their site. The presence and direction of flow in the splanchnic venous system were determined in all children, obviating the need for further angiographic studies.     

Mesoatrial shunt for the treatment of Budd-Chiari syndrome: radiologic evaluation in eight patients

The construction of a mesoatrial shunt for portal decompression is one of the surgical procedures used for the treatment of Budd-Chiari syndrome. The results of the imaging procedures performed in eight patients treated in this fashion were retrospectively analyzed. All of the patients had angiography; seven had MR imaging and two had Doppler sonography. The demonstration of shunt patency, stenosis, or occlusion by MR and Doppler sonography was confirmed by angiography in all cases. We conclude that MR imaging may serve as an accurate screening method to assess shunt patency and to determine which patients require angiography to obtain hemodynamic data. Doppler sonography may also be a useful screening method, but additional data must be obtained to assess its role in evaluation of shunt patency.     

Mesoatrial shunts for Budd-Chiari syndrome and inferior vena cava thrombosis: angiographic and hemodynamic evaluations

When inferior vena caval obstruction complicates the Budd-Chiari syndrome, conventional portosystemic shunts are not possible. The mesoatrial shunt has been devised to enable portal and sinusoidal decompression in these patients. Findings in 12 patients with Budd-Chiari syndrome and inferior vena caval obstruction in whom a mesoatrial shunt was performed are reported. Preoperative inferior vena cavography with pressure measurements is essential to determine the appropriate shunt procedure. Postoperatively, shunt patency is assessed with superior mesenteric arterial portography. Where possible, transvenous catheterization of the shunt is performed to confirm patency and assess hemodynamic function.     

Color Doppler-US guidance in transjugular placement of intrahepatic portosystemic shunts.

Percutaneous placement of portosystemic shunts requires access to the portal system from a transjugular approach. Color Doppler sonography was used to direct the transjugular puncture in intrahepatic portosystemic shunt procedures in four patients. In each case, the technique allowed quick, safe transjugular puncture of the portal vein and close real-time monitoring of the procedure.     

Duplex ultrasound in the evaluation of portacaval shunts

The results of ultrasound imaging combined with Doppler studies of blood flow are presented in two patients with surgical portacaval shunts performed for portal hypertension. Duplex scanning proved a quick and noninvasive method of confirming the patency of the anastomoses. The demonstration of appropriate Doppler flow signals across the shunt is the most convincing ultrasound evidence of patency. Portacaval shunts are more amenable to study by ultrasound than more peripheral shunts because the liver can be used as an acoustic window.     

Portal-systemic myelopathy after transjugular intrahepatic portosystemic shunt creation: report of four cases.

The authors attempted to describe the clinical manifestations of portal-systemic myelopathy (PSM) after transjugular intrahepatic portosystemic shunt (TIPS) creation. PSM was developed in four of 212 (1.89%) patients who underwent TIPS procedures in our hospital. Three men and one woman, ranging in age from 41 to 56 years, with a history of posthepatitis cirrhosis and recurrent bleeding from gastroesophageal varices had intrahepatic shunts created with 10-mm-diameter Wallstents. Shunt patency was confirmed by color Doppler ultrasonography (US) in each patient after TIPS creation. Progressive spastic paraparesis involving the lower extremities occurred between 5 weeks and 5 months after TIPS creation in the four patients. Neurologic examination showed evidence of spasticity in all cases, with ankle clonus, extensor plantar responses, and lower extremity hyperreflexia. All sensory modalities remained intact. Cytologic examination of cerebrospinal fluid from each patient was normal. There was no evidence of spinal cord compression on the imaging studies. PSM is a rare syndrome that includes spastic paraparesis with intact sensation. Initially noted in patients who have undergone surgical placement of a portacaval shunt, it also may occur after TIPS creation.     

Budd-Chiari syndrome: detection with color Doppler sonography.

The value of color Doppler sonography in evaluating newly diagnosed Budd-Chiari syndrome in five patients was studied. Hepatic venous findings included absence of vessels (one patient), flow reversal (two patients), narrowing (four patients), and tortuosity (three patients). Detected collaterals included hepatic venous to hepatic venous (four patients), hepatic venous to subcapsular systemic venous (two patients), and portosystemic (three patients). Hepatic venous spectral Doppler waveforms were flat and essentially aphasic in four patients, indicative of distal hepatic venous compression. The inferior vena cava was markedly compressed in two patients and slightly compressed in one. Color Doppler sonography allowed more reliable and confident identification of irregular, compressed, or otherwise abnormal hepatic veins than did conventional sonography. Color Doppler sonography also showed collateral vessels that were undetected with conventional sonography or other imaging techniques. Our results suggest that color Doppler sonography may be a valuable tool in the initial diagnosis and evaluation of suspected Budd-Chiari syndrome.     

Congenital intrahepatic portosystemic venous shunt: sonographic and magnetic resonance imaging

We report an intraheptic portosystemic venous shunt (IPVS) detected by ultrasound in an asymptomatic newborn. The lesion, which was further documented using color Doppler ultrasound and magnetic resonance imaging (MRI), had almost totally disappeared 6 months later without any treatment. Intraheptic portosystemic venous shunts (IPVS) are uncommon and their etiology is controversial. Some cases of IPVS have been reported in the literature, most of them in adult patients with portal hypertension and cirrhosis of the liver [1–3]. However, only scattered reports describe IPVS in the absence of liver pathology [4–8]. A revision of the proposed etiologies of IPVS is made and the usefulness of gray-scale and color Doppler sonography and MRI in diagnosing IPVS is discussed.     

Chronic portosystemic encephalopathy: embolization of portosystemic shunts

Operative ligation of portosystemic shunts is effective in controlling chronic portosystemic encephalopathy (CPSE) but is associated with significant mortality. Review of the records of five patients with CPSE treated with radiologic occlusion procedures showed that these are suitable alternatives to surgery. Three patients had alcoholic cirrhosis, one had hepatic fibrosis from schistosomiasis, and one had post-necrotic cirrhosis. All had CPSE with progressive, severe cerebral impairment refractory to clinical treatment. Four patients had a spontaneous splenorenal shunt, and one had a surgically created mesocaval shunt (MCS). Partial splenic embolization was performed in two patients, direct shunt embolization was performed via percutaneous transhepatic portography in two other patients, and an MCS embolization was performed in one patient through the inferior vena cava. In four patients embolization controlled the CPSE. In the remaining patient it could not be evaluated because of his premature death from intraabdominal bleeding, a late complication of the procedure. Interventional radiologic procedures are effective in the control of CPSE in selected patients.     

Postoperative assessment of splenorenal shunts with MRI: preliminary investigation

Magnetic resonance imaging (MRI) was performed on nine patients with hepatic cirrhosis and portal hypertension after selective distal splenorenal shunt for decompression of bleeding esophageal varices. MRI demonstrated the splenorenal anastomosis and patency of the shunt, splenic vein, and left renal vein in each case. Imaging in the transverse plane provided optimal visualization of the shunts. The authors conclude that MRI is a safe, noninvasive technique for the postoperative evaluation of selective distal splenorenal shunts.     

Duplex and color Doppler flow sonography of occlusion and near occlusion of the carotid artery.

PURPOSETo determine whether color Doppler flow imaging with the use of slow-flow sensitivity improves sensitivity and specificity in the differentiation of occlusion and near occlusion of the internal carotid artery.METHODSColor Doppler and duplex sonography were performed in symptomatic patients who had angiographically confirmed occlusion and/or near occlusion of the internal carotid artery. The study consisted of two phases: in the first, we assessed the usefulness of color Doppler flow imaging by retrospectively reviewing the records of 35 patients with 36 angiographically confirmed occlusions or near occlusions of the internal carotid artery who were examined with color Doppler flow imaging at our institution during a period of 4 years; in the second phase, we incorporated color Doppler sonography into the routine scanning protocols of 39 patients with 41 occluded or nearly occluded internal carotid arteries seen over a period of 2 1/2 years.RESULTSOverall, color Doppler imaging correctly showed all 34 of the near occlusions (sensitivity, 100%) and 36 of the 43 occlusions (specificity, 84%). Seven patients with angiographically confirmed occlusion had sonographic findings that suggested near occlusion. In the first phase, eight near occlusions were misinterpreted as occlusions with conventional duplex sonography, but were correctly shown with color Doppler flow imaging. In the second phase, sensitivity increased from 50% to 100% (18 or 18) because of better detection of the nearly occluded lumen. This was at the expense of a decrease in specificity (from 100% to 78%). owing to identification of apparent flow in the internal carotid artery on color Doppler flow images in five of 23 occlusions.CONCLUSIONBecause of its ability to depict slow flow, color Doppler imaging with slow-flow sensitivity is superior to conventional duplex sonography for the noninvasive discrimination of occlusion from near occlusion of the internal carotid artery.     

Cranial arteriovenous malformations in neonates: color Doppler imaging with angiographic correlation

Five neonates with cranial arteriovenous malformations were studied with color Doppler sonography. Excellent correlation was found between sonography and subsequent angiography. In three patients with vein of Galen aneurysms, sonography showed a cystic structure with rapid or swirling flow. Careful adjustment of the color Doppler system was required to demonstrate flow in another patient with a dural arteriovenous malformation. An arteriovenous fistula in a fifth patient appeared as an area of increased flow. Arterial feeders and major draining veins were visualized in all five patients. Color Doppler imaging also was used to assess the effect of embolic or operative therapy in three of the patients. We conclude that color Doppler sonography is able reliably to characterize flow patterns in neonatal cranial arteriovenous malformations. Color Doppler imaging also is helpful in assessing flow after embolic or surgical therapy.     

Ultrasonography and Doppler Duplex compared with angiography in follow-up of mesocaval shunt patency

Thirty-four patients with portal hypertension of various etiologies were operated upon with an interposition mesocaval Goretex graft. During a period of 6 years 84 angiographic and ultrasonographic (US) examinations (53 B-mode, and 31 Doppler Duplex) were performed, with few exceptions within 3 days. Angiography served as the 'gold standard'. Shunt patency was correctly interpreted as normal in B-mode US in 38 examinations. Shunt occlusion, definite or probable, was seen in 12 B-mode examinations, where angiography demonstrated occlusion in 6 and patency in the remaining 6 shunts. Shunt occlusion was not observed sonographically in one examination. US was technically inadequate on two occasions. Doppler Duplex showed shunt patency in all 31 examinations, which was correct according to angiography. Both B-mode US, in 6 out of 6 examinations, and Doppler Duplex, in 7 out of 9 examinations failed to reveal shunt stenosis. Five patients with abundant venous collaterals (in one case with aberrant vascular anatomy) were not possible to evaluate even after the introduction of Doppler Duplex, which otherwise facilitated the evaluation. We suggest that US including Doppler should be the primary modality for follow-up in patients with interposition mesocaval Goretex grafts.     

Value of Doppler sonography in revealing transjugular intrahepatic portosystemic shunt malfunction: a 5-year experience in 216 patients

OBJECTIVE: The purpose of the study was to evaluate the long-term clinical efficacy of Doppler sonography in revealing failure of transjugular intrahepatic portosystemic shunts (TIPS). SUBJECTS AND METHODS: During a 5-year period, 1192 Doppler examinations were performed in 216 patients with TIPS. No regular follow-up shunt venography was performed. Doppler examinations were retrospectively compared with the results of shunt revisions. Sonograms with negative findings were compared with the patients' clinical status so that the number of false-negative sonographic findings leading to an episode of shunt failure (recurrence of gastrointestinal bleeding or ascites) could be ascertained. Sonographic parameters assessed included diameter, velocity, flow volume, and congestion index of the portal vein; and shunt velocities. RESULTS: Doppler sonography revealed shunt occlusion in 25 of 26 angiographically proven cases (sensitivity, 96%). The combination of velocity criteria (peak intrashunt velocity > or =250 cm/sec, maximum velocity in the portal third of the shunt < or =50 cm/sec, or maximum portal vein velocity less than or equal to two thirds of the baseline value) revealed shunt stenosis in 103 of 110 cases (sensitivity, 94%). Doppler sonography missed a significant shunt stenosis that led to an episode of gastrointestinal bleeding or ascites recurrence in only seven cases. The congestion index of the portal vein showed significant differences between patent and malfunctioning shunts (p < 0.001). CONCLUSION: Doppler sonography is an effective primary imaging method for long-term follow-up of patients with TIPS.     

Intrahepatic portosystemic venous shunt: diagnosis by colour/power Doppler imaging and three-dimensional ultrasound

Intrahepatic portosystemic venous shunt, considered to be a rare disease, can lead to hepatic encephalopathy. With recent advances in diagnostic imaging techniques, the number of reports of intrahepatic portosystemic venous shunts identified incidentally in patients without symptoms are increasing. We report an intrahepatic portosystemic venous shunt that was diagnosed incidentally by real-time ultrasound and colour Doppler imaging, including the use of three-dimensional ultrasound using minimum intensity projections and power Doppler.     

Doppler US. Part II. Clinical applications

Duplex and color Doppler ultrasound (US) are noninvasive techniques capable of providing much information about the condition of blood vessels and flow within them throughout the body. Doppler US provides more than noninvasive angiography. Besides assessment of blood vessel patency and direction of flow, analysis of the flow velocity waveform allows quantitation of arterial stenoses and evaluation of both physiologic and pathologic changes in impedance. In certain situations, Doppler US can aid in tissue characterization and estimation of absolute flow volume. Color Doppler flow imaging may both expedite and clarify the duplex Doppler examination. In addition, color Doppler imaging can demonstrate flow orientation and improve the identification of turbulence and soft plaque. Color and duplex Doppler US are complementary, with color Doppler techniques providing spatial orientation and pulse Doppler techniques providing the time-velocity spectrum for quantitation.