Diagnostic imaging in deep vein thrombosis of the limbs

The clinically suspected deep vein thrombosis (DVT) should always be confirmed by instrumental procedures. In fact, about 70% of patients with clinically suspected DVT are shown to be negative on instrumental investigations. Phlebography is still the gold standard in the diagnosis of peripheral DVT. Main phlebographic findings are: persistent filling defect; abrupt interruption of contrast in a vein; lack of opacification in all or some deep veins; flow diversion with opacification of collateral branches. At present, peripheral phlebography is performed when the other noninvasive exams (Color Doppler US and Duplex Doppler) are doubtful, technically limited or when thrombosis of innominate veins or superior vena cava, is suspected. Real-time US enables direct visualization of the limb proximal veins. The venous wall, the venous valves, the thrombus and its development, the anatomic variants, the perivenous structures which may impact on the normal physiology of venous return, are depicted. However, the distal veins of the leg and arm and deep veins (the iliac veins, the superficial femoral vein in the adductor canal) are not accurately visualized. The US findings in DVT include: the presence of echoes within the vascular lumen; the veins in axial scans are not compressible. Pulsed Doppler and duplex Doppler combine the morphologic and functional study. Injury caused by DVT at the valvular level (postphlebitic syndrome) is visualized. Primary deep vein thrombosis caused by valvular disorders (valvular aplasia) is identified. Inadequate superficial and perforating veins to be treated with surgery are mapped. Color Doppler US depicts directly superficial and deep limb veins combining the morphologic with the functional assessment represented by the visualization of the map of flow velocity and direction. Recently, a new diagnostic procedure, the color Doppler Energy (CDE) or Power Doppler has been introduced. Together with mean flow velocity and spectral variance, the signal energy or power is also analyzed. The CDE is independent of the US incidence angle, it does not shows the flow direction, detects particularly slow flows, early canalization of thrombi and non occlusive thrombosis. Color Doppler diagnosis of thrombosis is prompt because an area with absence of color is visualized. Collateral vessels and flow direction within them, is well depicted. Beside the site and extension of thrombosis, color Doppler US is able to directly visualize the distal end of the thrombus, which when floating is at high risk for embolism. CT allows an adequate study of the iliocaval axis and is useful if phlebography or color Doppler US are not diagnostic. Iliocaval thrombosis represents a not infrequent finding during abdominal CT. The thrombus appears as a hypodense mass encircled by the hyperdense rim of contrast medium.     

Unusual approach of a pacemaker electrode in a patient with a silent superior vena cava syndrome

A man with a history of bilateral pectoral pocket infection and subsequent pacemaker implantation with a screw-in epicardial lead was referred because of increasing lead impedance. Venography revealed bilateral total occlusion of the subclavian and innominate veins with extensive collateral formation in this asymptomatic patient. Both internal jugular veins were also totally occluded. Because repeated pacemaker implantation using epicardial leads resulted in increasing lead impedance of the ventricular lead within 1 year after implant, an alternative approach was found using the superior caval vein with minimal invasive thoracotomy for single lead VDD pacing.     

Therapy of venous stenosis using wall stents

OBJECTIVE: To evaluate the patency of Wallstents implanted for the treatment of venous stenoses in patients with benign or malignant disease. PATIENTS AND METHODS: 22 Wallstents (20 central venous; two peripheral) were implanted during a period of two years in 12 patients (nine men, three women; mean age 57.8 [26-76] years) with malignant venous stenoses (n = 9) or stenosed dialysis shunts (n = 3). Stent diameter ranged from 8-16 mm, length from 32-91 mm. Introduction of the stents were by percutaneous transfemoral catheterisation, in six patients with simultaneous wire placement from a cubital to the femoral vein. The superior vena cava was the involved vessel in six patients (in two each also the subclavian or brachiocephalic veins), in three only the subclavian vein, twice only the inferior vena cava and once the cephalic vein. RESULTS: The patency of the stents was checked after 4.7 +/- 3.6 (1-14) months, in seven patients clinically, by digital subtraction phlebography in three, by computed tomography in two. In nine patients there was no evidence of obstruction to flow or flow was normal. Stent occlusion had occurred in three patients, 4, 9 and 14 months after placement. There were no complications. Five patients died after a mean period of 4.8 +/- 3.6 (1-6.5) months from the underlying disease, without symptoms of obstruction to flow. CONCLUSION: Stent placement should be considered early, as it is a well-tolerated and effective palliative procedure for central venous stenoses associated with malignant disease or stenosis of dialysis shunts.     

CT and MRI in detection of intrahepatic portosystemic shunts in patients with liver cirrhosis

OBJECTIVE: Our goal was to determine the prevalence and anatomic location of intrahepatic portosystemic shunts (IPSs) in patients with hepatic cirrhosis as shown by CT and MRI. MATERIALS AND METHODS: We retrospectively reviewed CT and MR scans of 33 cirrhotic patients who had IPSs. In addition, two series of 100 consecutive CT or MR were reviewed to determine the prevalence of IPSs and the percentage of intrahepatic and extrahepatic paraumbilical veins. RESULTS: Intrahepatic portosystemic shunts were divided into three groups according to the intrahepatic course: paraumbilical shunt between the left portal vein and the paraumbilical vein anterior to the liver (n = 29); inferior vena caval shunt between the posterior branch of the right portal vein and the inferior vena cava (n = 2); and miscellaneous (n = 2). Shunts of the paraumbilical type ran through the medial (n = 23), lateral (n = 3), or both medial and lateral (n = 3) segments of the left lobe of the liver. Twenty-five patients had one shunt, and four had more than one. Six cases were also associated with extrahepatic paraumbilical veins. CONCLUSION: Intrahepatic portosystemic shunts, especially the paraumbilical type, were not infrequently visualized in patients with hepatic cirrhosis.     

Hot spots on liver scans associated with superior or inferior vena caval obstruction

Although hot spots on hepatic scintigrams have been reported in association with superior and inferior vena caval obstruction, these studies were not clinically correlated, and are hampered by the poor resolution of earlier scintillation cameras. In this report, a modern scintillation camera was used to study the formation of hot spots associated with superior and inferior vena caval obstruction. Moreover, radionuclide cavography was performed in 70 patients with superior vena caval (SVC) obstruction and in 95 patients with inferior vena caval (IVC) obstruction. As a result, 13 cases of hot spots in the liver were observed. In cases of SVC obstruction, hot spots were seen in the quadrate lobe, the medial segment, and the bare area of the liver. In IVC obstruction, a hot spot was seen in the quadrate lobe in all cases. In rare instances, in cases of both SVC and IVC obstruction, a hot spot was seen in the wide area. For these hot spots to develop, it appears necessary to have systemic-portal venous blood flow through the internal thoracic vein and the paraumbilical vein.     

Hepatic emboli following inferior vena caval ligation. Brief report

Radionuclide venography performed by foot vein injection of 99mTc MAA and 99mTc DTPA in a 34-year-old man approximately one year after inferior vena caval ligation demonstrated an unusual collateral pathway between the veins of the lower extremities and the portal vein, and also evidence for multiple hepatic emboli. This is a newly recognized sequela of inferior vena caval ligation.     

Studies on the inferior phrenic vein of rats: the probability of its being a collateral route of blood from the lower portion of the body to the heart

The principal aim of this study was to elucidate key features of the inferior phrenic vein (IPV) of adult rats to determine whether the IPV has the potential to function as a collateral return route conveying blood from the lower portion of the body to the heart, bypassing the subhepatic vein segment of the inferior caval vein. In rats, the IPVs on both sides were found to reveal a symmetric appearance. They were both composite vessels, being made up of two fellow subvessels, the sternocostal and the lumbocostal veins, which in turn anastomosed in tandem in their periphery with each other, formed a collateral route bridging the interval between the suprarenal and the hepatic vein segments of the inferior caval vein. In rat embryos of E17.5, the sternocostal and lumbocostal veins of the IPV were observed to have been well developed, forming tandem anastomoses more clearly than in adults, thus connecting the subcardinal vein to the hepatic vein segment of the inferior caval vein. This fact substantiates our supposition that the rat's IPV originally has the potential to act as a collateral returning route which allows blood to bypass the subhepatic vein segment of the inferior caval vein.     

Alveolar echinococcosis of the liver: sequelae of chronic inferior vena cava obstructions in the hepatic segment

BACKGROUND: The clinical pattern and long-term course of chronic inferior vena cava (IVC) obstructions are variable and depend on the underlying cause, the segment involved, and the extension of secondary thrombosis. Pertinent data on IVC obstructions in well-defined series of patients are lacking. We report the sequelae of chronic IVC obstructions in the hepatic segment in 11 consecutive patients derived from a cohort of 104 patients with alveolar echinococcosis of the liver. METHODS: Based on the results of computed tomography scans, 11 patients (7 men, 4 women; mean age, 53.4 years) with IVC obstructions were selected from an ongoing prospective long-term chemotherapy trial comprising 104 patients with alveolar echinococcosis studied at yearly intervals according to a protocol. Obstruction of the IVC in the 11 patients existed for a mean duration of 8.6 years. In these patients, magnetic resonance imaging was performed to assess the morphologic features and extension of the IVC obstruction, as well as the collateral venous pathways. Patency and valvular function of the femoropopliteal veins were analyzed by color-coded duplex ultrasonography. RESULTS: Total occlusions of the IVC were evident in 8 patients (73%) and subtotal stenoses in 3 patients (27%). Only 4 patients (36%) exhibited signs and symptoms of chronic venous insufficiency of the lower extremities; 2 (18%) of the 4 had a history of swelling in the lower extremity. Seven patients (64%) had no lower extremity symptoms. One patient had a history of pulmonary embolism. Abdominal collateral veins were documented in 5 patients (45%) by using magnetic resonance imaging; however, they were clinically evident in only 3 patients (27%). In the 8 patients with IVC occlusion, thrombosis ended at the confluence of the hepatic veins. Obstruction of the IVC was limited to the hepatic segment in 2 patients (18%) and extended to the distal IVC or the iliofemoral veins in 6 patients (54%). Chronic venous insufficiency was present only if the femoropopliteal veins had been involved in the thrombotic process, showing residual venous obstruction, valvular incompetence, or both. Bilateral renal vein thrombosis with moderate proteinuria was observed in 2 patients (18%). The main collateral drainage was achieved through the ascending lumbar, azygos, and hemiazygos veins. CONCLUSIONS: In patients with alveolar echinococcosis, obstruction of the IVC in the hepatic segment often develops asymptomatically and rarely leads to the impairment of renal function. The collateral circulation fully compensates for obstruction of the IVC. Thrombotic involvement and valvular incompetence of the femoropopliteal veins seems to determine the development of chronic venous insufficiency of the lower extremities.     

Calcified thrombus in the inferior vena cava in infants and children

Calcified thrombi in the prerenal (suprarenal) segment of the inferior vena have a characteristic radiographic appearance that permits accurate "plain film" diagnosis. Most have been fortuitously discovered in infants and young children. None of the affected individuals has had clinical evidence of venous obstruction. Vena caval obstruction is usually incomplete. Uncalcified clot caudal to the calcified thrombus caused complete obstruction of the inferior vena cava and renal veins in one of our patients, a healthy infant; since collateral flow was adequate surgery was not advised. We believe that aggressive diagnostic and therapeutic measures are unnecessary in the management of infants and children with calcified thrombi in the inferior vena cava.     

Microvascular transplantation in the salvage of lower extremity trauma in the elderly

In the cadaver of an 86 year old man the inferior segment of the azygos vein could not be found. Furthermore, a normally developed hemiazygos vein drained the right and left intercostal veins from T 10 to T 6. This vessel finally curved towards the right to reach the superior vena cava after having drained the right superior intercostal veins. The left superior intercostal vein ended in a short vessel draining into the left brachiocephalic vein. This condition may be represented in a standard chest radiograph by the so-called "aortic nipple". Agenesis of the azygos vein, suspected because of the presence of this radiological sign, should be confirmed in the living by means of computerized tomography. This can clarify the anatomy of the mediastinal vessels precisely. Embryological pattern of the azygos system accounting for its possible defects is discussed.     

Clinical features, image analysis, and laparoscopic and histological liver findings in Budd-Chiari syndrome

BACKGROUND/AIMS: Clinical manifestations and histological features of the liver in Budd-Chiari syndrome (BCS), with or without idiopathic membranous obstruction of the inferior vena cava (MOVC), vary according to whether BCS is acute, subacute or chronic. We clarified the diagnostic features in 6 patients with MOVC and in 1 without MOVC. METHODOLOGY: Five patients with subacute or chronic type BCS with MOVC complaining of epigastric pain, hematemesis and encephalopathy, and signs of portal hypertension or collateral circulation were seen. There was 1 asymptomatic patient with MOVC. One patient with acute type BCS without MOVC revealed hepatic and multi-organ failure. Liver function tests in BCS with MOVC were similar to those in liver cirrhosis, and laboratory data in acute type without MOVC were quite the same as those seen in fulminant hepatitis. Non-invasive image analysis by US, CT and MRI showed thrombi and obstruction of the IVC, and extrahepatic vasculature or communication between hepatic veins and IVC. Vena cavography showed the length of obstruction in IVC and collateral circulation in the extrahepatic or intrahepatic veins. Liver biopsy demonstrated massive hemorrhagic necrosis in acute type without MOVC, and laparoscopy with liver biopsy in asymptomatic, subacute and chronic type with MOVC showed subcapsular hemorrhage, congestion, fibrosis, and cirrhotic features. CONCLUSIONS: The non-invasive image analysis was complementary to vena cavography, and liver biopsy with or without laparoscopy was essential not only for diagnosis of acute, subacute, and chronic BCS, but also for therapeutic decision-making.     

Intermittent complete vascular exclusion of the liver during hepatectomy: technique and indications

BACKGROUND/AIMS: Complete intermittent vascular exclusion of the liver (IVEL) combines clamping of the hepatic pedicle with clamping of the hepatic veins without interruption of the caval flow. The major advantages of this technique are that patient preclamping fluid overload is avoided, major haemodynamic changes due to caval clamping are escaped, and it allows a very long clamping time. Disadvantage of this technique is the necessity of looping the terminal part of the hepatic veins. METHODOLOGY: In this prospective study, 41 cases of IVEL (Representing 19% of the hepatectomies carried out for cancer during the same period) used for difficult hepatectomies were analyzed, and the operative technique is presented. RESULTS: IVEL was feasible in 90% of the 46 attempted cases, and completely controlled the bleeding in 90% of the cases. The mean duration of IVEL was 69.2 minutes (Range: 37 to 140), and was greater than 130 minutes in three patients. No liver failure occurred during the postoperative course. CONCLUSION: We conclude that IVEL without caval clamping is a new, and valuable, technique of vascular exclusion of the liver. Its application is indicated in the following conditions: 1. For patients who should have classical vascular exclusion but cannot tolerate vena cava clamping (18% of the cases), 2. for patients with pathological liver parenchyma when intrahepatic venous pressure is high, 3. for patients with impaired liver parenchyma, requiring conservative surgery that leads to anatomic or non-anatomic resection close to a vein (Example: A tumor located in the dihedral angle of the terminal part of two hepatic veins), 4. for patients with tumors closely located to a hepatic vein that must be preserved and sharply dissected (Example: A left trisegmentectomy that requires pelting of the right hepatic vein), and 5. for the scarce patient with tumors infiltrating the major hepatic veins, constraining a hepatic vein reconstruction to preserve liver function.     

Veins of Retzius at CT during arterial portography: anatomy and clinical importance

PURPOSE: To classify the veins of Retzius demonstrated at computed tomography (CT) during arterial portography (CTAP) on the basis of anatomic location and to evaluate the relationship between the frequency of CT visualization and associated disease. MATERIALS AND METHODS: The authors reviewed axial CTAP scans from 130 patients. Patients were classified into one of two groups: patients with liver cirrhosis (group 1 [n = 81]) and patients without liver cirrhosis (group 2 [n = 49]). RESULTS: The pathways of the veins of Retzius were classified as follows: (a) The ileocolic vein drained into the inferior vena cava (IVC) or the right renal vein through the right gonadal vein (n = 61); (b) the pancreaticoduodenal vein drained into the IVC (n = 8); (c) the proximal branches of the superior mesenteric vein drained into the left gonadal vein (n = 6); and (d) the ileocolic vein drained directly into the IVC (n = 5). The veins of Retzius were demonstrated in 41 (51%) of the 81 patients in group 1 and 26 (53%) of the 49 patients in group 2. There was no statistically significant difference between the two groups. CONCLUSION: The veins of Retzius were demonstrated at CTAP in approximately 50% of patients with and 50% of patients without liver cirrhosis.     

Clinical experience with temporary vena caval filters

PURPOSE: To look at the benefits and complications of different vena caval filters inserted prophylactically. Three temporarily implantable caval filter systems were used in 67 patients. MATERIALS AND METHODS: Twelve Cook filters (six transjugular, six transfemoral), 11 Angiocor filters (one transjugular, 10 transbrachial), and 44 Antheor filters (three transjugular, four transfemoral, 37 transbrachial) were successfully implanted. In known iliac vein or caval thrombosis, the prophylactic filters were placed during thrombolytic therapy in 46 cases, surgery in 17 cases, thrombosis in pregnancy in three cases, and high-dose heparinization without lysis in one case. RESULTS: One patient had a fatal pulmonary embolism during treatment; seven thrombi were detected in the filter. Other complications were caused either by the underlying therapy alone (one fatal outcome of abdominal aorta aneurysmal surgery, two cases of cerebral hemorrhage, two cases of retroperitoneal hematomas, two cases of streptokinase fever reactions, one compartment syndrome, two cases of macrohematuria), by the combination of therapy and caval filter implantation (three cases of groin hematomas, three cases of arm hematomas), or by filter implantation alone (two cases of subclavian vein thrombosis, one catheter infection, one dislocation, one air embolism, one basket rupture). The bleeding complications were related to the aggressive thrombolytic therapy and would have occurred without filter implantation. CONCLUSION: Because temporary caval filters have no long-term complications per se, their use seems sensible as long as there are stringent indications, including the presence of iliac vein or caval thrombosis and risk of thrombus mobilization. The Antheor filter system was the most convenient system for implantation.     

Portal decompression using the inferior mesenteric vein

We report five patients with variceal hemorrhage, in three cases secondary to diffuse thrombosis of the portal, superior mesenteric and splenic veins. Mesenteric angiography demonstrated patency of the inferior mesenteric vein (IMV) in each, and successful portal decompression by anastomosis of the IMV to the left renal vein (n = 4) or the inferior vena cava (n = 1) was accomplished. Bleeding was permanently controlled: four patients have survived from one to eight years post-operatively. Because shunt procedures utilizing the IMV are technically straightforward, subtotally decompress the portal system and avoid the right upper quadrant, they may be advantageous in certain clinical settings.     

Cranial vena caval thrombosis secondary to invasive mediastinal lymphosarcoma in a cat

A 12-year-old female cat was diagnosed with a cranial vena caval thrombosis in association with a mediastinal lymphosarcoma. The cause of the cranial vena caval thrombosis was thought to be invasion of the venous wall by neoplastic lymphoid cells. Clinical signs of cranial vena caval thrombosis, such as swelling and oedema of the submandibular area, the ventral part of the neck and the forelimbs, were related to a space-occupying mediastinal lymphosarcoma, which also induced respiratory distress and cyanosis. Non-selective angiocardiography demonstrated the occlusion of the cranial vena cava and abnormal venous collateral vessels feeding the heart which are accepted as the venographic hallmark of clinically overt cranial vena caval syndrome. At postmortem examination, an intracaval thrombus, 5 cm in length, was seen extending from the costocervical vein to the sulcus terminalis of the right atrium.     

Predominant mutations induced by the Thermococcus litoralis, vent DNA polymerase during DNA amplification in vitro

Severe stenosis or occlusion of either the superior or the inferior vena cava requires surgical bypass grafting in a selected group of patients. When the obstruction extends into the major tributaries, a bifurcated graft becomes necessary. We present the cases of 2 surgically treated patients, each of whom received a stented polytetrafluoroethylene bifurcated graft constructed at the time of the operation. Symptoms disappeared post-operatively in 1 patient and abated in the other. Both grafts became occluded within 1 year; however, that was sufficient time for collateral venous circulation to develop, enabling both patients to respond well to conservative therapy. We conclude that stented polytetrafluoroethylene bifurcated grafts may be suitable for selected patients as a bridge until collateral veins can form. The development of more compliant venous grafts may provide even more favorable results.     

Mechanical thrombectomy in acute and subacute thrombosis with use of the Amplatz device: arterial and venous applications

PURPOSE: To perform a feasibility study of the Amplatz Thrombectomy Device (ATD) in a variety of vascular territories with acute or subacute thrombosis. MATERIALS AND METHODS: Thirteen patients (mean age, 44.6 years) with multiple risk factors who had acute/subacute thrombosis of the inferior vena cava (IVC) and iliac veins (n = 3), superior vena cava (SVC) and/or subclavian veins (n = 3), lower extremity polytetrafluoroethylene (PTFE) graft (n = 2), iliac artery (n = 2), portal vein and transjugular intrahepatic portosystemic shunt (TIPS) (n = 2), and an IVC to pulmonary artery Fontan conduit (n = 1), were treated by means of mechanical thrombectomy with use of the ATD. Thrombolysis failed to recanalize the vessels when used before thrombectomy for 12-34 hours in three patients, and was contraindicated in three other patients. Thrombolysis was used as a complement to the ATD procedure in five patients. RESULTS: Technical success was achieved in 11 patients, and procedure success was achieved in 10 patients. Failure was observed in the remaining three patients. One patient with a PTFE graft was successfully declotted but thrombosis occurred 2 weeks later, requiring surgery. The other patient with a PTFE graft did not improve and needed surgery to declot and treat the distal anastomosis and distal circulation. The two patients with an occluded iliac artery underwent successful declotting but rethrombosis occurred in one shortly after the procedure requiring thrombolytic therapy. One patient with TIPS thrombosis improved and another patient with a thrombosed portal vein did not improve after thrombectomy. CONCLUSION: The ATD is useful for recanalization of acute/subacute clotted native vessels and grafts. The application of the device is broad, and although declotting can be achieved in most cases, long-term success may be limited by anatomical and technical problems of the grafts and multifactorial clinical problems of severely sick patients, as was the case in the series. The use of additional thrombolytic therapy may be necessary in a number of patients.     

Budd-Chiari syndrome: a common complication of Beh?et's disease

OBJECTIVE: The Budd-Chiari syndrome is characterized by venous outflow obstruction of the liver, usually occurring as a consequence of thrombosis of the hepatic veins. Vasculitis is a major component of Beh?et's syndrome. The aim of this study was to determine the incidence of hepatic vein thrombosis in patients with Beh?et's disease and to estimate the effect of this entity upon the clinical features and course of Beh?et's syndrome. METHODS: During an 8-yr period from 1985 to 1994, from a total of 493 patients with Beh?et's disease seen at Hacettepe University Hospital, the incidence and effect of hepatic vein thrombosis on the clinical course of Beh?et's syndrome was investigated. The hepatic vein thrombosis in each case was documented by hepatic venography and confirmed by digital subtraction angiography, computed tomography, ultrasonography, and liver biopsy. Coagulation parameters including protein C, protein S, and anti-thrombin III levels were easured in each case. The survival of cases with Beh?et's syndrome complicated by Budd-Chiari syndrome and the effect of the Budd-Chiari syndrome on the survival of individuals with Beh?et's syndrome were determined using the Kaplan-Meier technique. RESULTS: Of the 493 cases of Beh?et's syndrome, 53 (10.8%) were found to have one or more large vessel thrombosis. Of these 53 patients, 14 (26.4%) had hepatic vein thrombosis. Of these 14 patients, 8 had an additional inferior vena cava thrombosis and 4 had portal vein as well as total inferior vena cava thrombosis. Only two patients with isolated hepatic vein thrombosis were identified. These two patients and two additional patients with hepatic vein thrombosis plus thrombosis of the hepatic portion of the inferior vena cava are currently alive. Of the 10 patients with total inferior vena cava and hepatic vein thrombosis (4 also had portal vein thrombosis), all 10 died with a mean survival of 10.3 months. During the same time period, 37 patients obtained from a total of 1494 patients with clinical evidence of either portal hypertension, hepatic venous outflow obstruction or inferior vena caval obstruction without Beh?et's syndrome were found to have a Budd-Chiari syndrome. Of these 37 patients, 19 (51%) had an identifiable underlying disorder responsible for their hepatic vein thrombosis. CONCLUSION: Based upon this experience, it appears as if Budd-Chiari syndrome is a relatively frequent complication of Beh?et's disease. When individuals with Beh?et's syndrome have BCS, concurrent thrombosis of the portal vein and inferior vena cava are often found, if the patency of these vessels is assessed. The clinical course of patients with Beh?et's syndrome complicated by Budd-Chiari syndrome is poor. The extent of the vascular thrombosis within the inferior vena cava rather than the presence of the hepatic vein thrombosis per se is the major determinant of survival.     

Extraction and replacement of permanent pacemaker leads through occluded vessels: use of extraction sheaths as conduits--balloon venoplasty as an adjunct

Patients (pts) may present for lead extraction with symptomatic or asymptomatic subclavian vein or superior vena cava thrombosis. Replacement of permanent pacemaker leads (PPLs) in these pts may be difficult and may require accessing a new site. We examined the utility of replacing PPLs through completely occluded vessels using extraction sheaths as conduits through the total occlusion. Over six years, a total of 210 atrial and/or ventricular PPLs were extracted from 137 pts. Two pts presented with angiographically documented thrombotic occlusion of the subclavian vein. One additional pt. who had presented with a superior vena cava (SVC) syndrome, had a totally occluded innominate vein and SVC occlusion. Balloon venoplasty was used as an adjunct to dilate the SVC. In all pts, after PPLs were removed via a subclavian extraction sheath through the occluded vessel, the retained sheath was used to place a guide wire, then a peel away dilating sheath, to insert new PPLs, in each case on the side of total venous occlusion. Seven PPLs and two lead fragments were extracted, and five new PPLs replaced, ipsilateral to the venous occlusion. These data show that extraction of PPLs through thrombosed veins may be performed successfully and may not require replacing the leads through a new site. This technique spares the pt the need to access the opposite subclavian vein, and it avoids an excessive number of PPLs in the subclavian vein and SVC. The procedure illustrates an efficient means to reintroduce new PPLs with the potential to reduce associated morbidity, since repeat puncture of the subclavian vein is not required. Safety of the procedure as a whole must be considered with regard to the known risks of lead extraction, some complications of which may be substantial using current techniques.