Accuracy and safety of carbon dioxide inferior vena cavography.

PURPOSE: The purpose of this study was to assess the accuracy of carbon dioxide compared to iodinated contrast material for determining inferior vena cava (IVC) diameter prior to filter placement, and to assess the safety of CO2 when used for this purpose. PATIENTS AND METHODS: Consecutive patients undergoing inferior vena cavography prior to filter placement were prospectively evaluated with use of both CO2 and iodinated contrast material. The diameter of the IVC was measured and compared in the same four locations in each patient for both agents. The diameter was corrected for magnification and pin-cushion distortion. The ability of CO2 to correctly classify IVC diameter as < or =28 mm or >28 mm, based on the IVC diameter with iodinated contrast material, was determined. A consensus panel assessed renal vein visualization with CO2 and iodinated contrast material. Blood pressure and arterial oxygen saturation were measured immediately before and after CO2 injection. RESULTS: Among 30 patients, there was no significant difference in the measured diameter of the IVC with CO2 versus iodinated contrast material after correction for magnification and pin-cushion distortion. One of 30 patients (3.3%) in this study was misclassified as having an IVC < or =28 mm with CO2 when, in fact, the IVC diameter was >28 mm based on iodinated contrast material. This could be clinically significant for certain IVC filters. Forty-seven percent of renal veins identified on contrast venography were identified by CO2 vena cavography. There was no significant difference in the blood pressure or oxygen saturation values measured before and after CO2 injection. However, one patient with pulmonary artery hypertension did experience transient, symptomatic hypotension after CO2 injection. CONCLUSIONS: In most patients, CO2 vena cavography accurately evaluated IVC diameter prior to filter placement. In 3.3% of patients, the discrepancy in measurements between CO2 and iodinated contrast material could be clinically significant, depending on the type of filter placed. CO2 was less accurate than iodinated contrast material in identifying renal veins. Although CO2 vena cavography is safe in the majority of patients, it should be used with caution in patients with pulmonary hypertension.     

Vena cavography with CO(2) versus with iodinated contrast material for inferior vena cava filter placement: a prospective evaluation

PURPOSE: To determine whether carbon dioxide (CO(2)) vena cavography can safely guide the placement of inferior vena cava (IVC) filters. MATERIALS AND METHODS: One hundred nineteen patients were prospectively enrolled in this study. CO(2 )cavograms were obtained and evaluated for IVC diameter, location of renal veins, and presence of thrombus and venous anomalies. If CO(2 )cavography was judged to be adequate, an IVC filter was deployed. After filter placement, cavography was performed with iodinated contrast material; these images were compared with the CO(2) cavograms. RESULTS: Two patients experienced mild side effects related to venous CO(2) injection. Comparison of cavograms obtained with CO(2) and iodinated contrast-enhanced material showed the caval size to be within 3 mm in all 119 patients. In 116 patients (97.5%), CO(2) cavography was judged to be adequate, and in 115 patients, filters were placed. In three (2.5%) patients, it was necessary to perform iodinated contrast-enhanced cavography before filter deployment. All six cases of venous anomaly and 11 (78.6%) of 14 cases of thrombosis were clearly identified with CO(2) cavography. One filter was maldeployed owing to misinterpretation of the CO(2) cavogram. CONCLUSION: CO(2) cavography is well tolerated, safe, and adequate for identification of the parameters necessary for filter deployment. It is especially valuable in patients with a history of reaction to iodinated contrast material or renal insufficiency.     

Gadolinium,carbon dioxide,and iodinated contrast material for planning inferior vena cava filter placement: a prospective trial

PURPOSE: To prospectively compare the diagnostic accuracy of CO(2) and gadolinium to iodinated contrast material for inferior vena cavography before inferior vena cava (IVC) filter placement. MATERIALS AND METHODS: Forty patients underwent injection of iodinated contrast material, CO(2), and gadolinium. Iodinated contrast material was used as the standard. Caval diameter was determined with calibrated software. Three readers blinded to contrast agent used measured the distance from the superior image border to the inferior margin of the renal veins and from the inferior image border to the iliac bifurcation. The measurements with CO(2) and gadolinium were compared to those with iodinated contrast material to obtain the interobserver and intraobserver variability. The presence or absence of caval thrombus and variant anatomy was noted. The same readers reexamined 12 studies in a separate session to determine intraobserver variability and correlation. RESULTS: Caval diameter differed by 0.4 mm or less for all three agents. Measurements with all agents were within 2 mm of each other for all patients. Gadolinium and CO(2) were not significantly different from one another in measuring caval diameter. At the initial reading, compared with iodinated contrast material, gadolinium had greater mean interobserver error in measuring the distance to the iliac bifurcation and both renal veins (range, 1.6-1.8 mm) than CO(2) (range, 0.2-1.4 mm). This finding, although statistically significant for gadolinium (P <.05), was of doubtful clinical relevance. Interobserver correlation was significantly worse for CO(2) at the levels of the iliac bifurcation (P =.02) and right renal vein (P =.008). Interobserver correlation for gadolinium was similar to that for iodinated contrast material at all levels. At repeat reading, there was significantly inferior intraobserver correlation with use of CO(2) for both renal veins (P <.05) compared to iodinated contrast material and for the left renal vein (P <.05) compared to gadolinium. Gadolinium identified three of three renal vein anomalies identified with iodinated contrast material whereas CO(2) localized one of three. CONCLUSION: CO(2) and gadolinium had limitations when compared with iodinated contrast material. Gadolinium provided superior consistency in identifying relevant landmarks for filter placement. CO(2) demonstrated significantly greater mean correlative error than gadolinium at initial and repeat readings.     

Ultrasonically guided inferior vena cava stent placement: experience in 83 cases

PURPOSE: Traditionally, inferior vena cava (IVC) stent placement is performed with fluoroscopic guidance. The object of this study was to evaluate use of ultrasound (US) as guidance for IVC stent placement for the management of Budd-Chiari syndrome. MATERIALS AND METHODS: Eighty-three patients with IVC membranous stenosis (n = 30), membranous occlusion (n = 19), segmental stenosis (n = 21), or segmental occlusion (n = 13) underwent IVC recanalization, balloon dilation, and stent placement under US guidance. Among the 83 patients, 67 had at least one patent hepatic vein, while 16 patients had three occluded hepatic veins. RESULTS: IVC stents were successfully placed in 79 of 83 patients, with a success rate of 95%. After the procedure, the symptoms and signs of IVC obstruction disappeared or markedly improved in all patients, and the blockage of hepatic outflow was alleviated in 67 patients. Pericardial effusion, complete atrial ventricular block, and stent migration into the right atrium occurred, respectively, in one patient. During 1-46-month follow-up, stent restenosis occurred in one patient; the other stents remained open and functioned effectively. CONCLUSION: Because of the absence of nonionizing radiation and iodinated contrast material, and its low cost, US is well suited and often preferred for guidance of IVC stent placement.     

Intravascular ultrasound in interventional radiology

Intravascular ultrasound (IVUS) imaging provides useful additional information to X-ray angiography in selected cases of balloon angioplasty and stent placement with complex vascular anatomy and unclear findings at angiography. It facilitates accurate measurements of the vessel dimensions and reveals the extent of the disease for the selection of proper angioplasty balloon size, as well as confirms full expansion and attachment of the stent or stent graft to the arterial wall. Intravascular US imaging contributes useful information for the basis of planning surgical or endovascular therapy of aortic dissection and is valuable for guiding percutaneous fenestration of the dissection flap. This imaging modality facilitates placement of vena cava filter without cavography and/or fluoroscopy in patients with contraindication for iodine contrast media and/or X-ray fluoroscopy. Technical development may further increase utility of IVUS imaging in interventional radiology. Received: 22 May 2000; Accepted: 7 June 2000     

Suprarenal inferior vena cava filters: a 20-year single-center experience

PURPOSE: To assess the clinical safety and efficacy of suprarenal inferior vena cava (IVC) filters during long-term follow-up. MATERIALS AND METHODS: In this retrospective study, the authors collected the following data about patients who underwent suprarenal IVC filter placement at their institution between 1988 and 2007: demographics, clinical presentation, indications for filter placement, reasons for placing the filter in the suprarenal IVC, type of filter, frequency of pulmonary embolism (PE) after filter placement, and filter-related problems during follow-up. RESULTS: Seventy patients (32 male and 38 female patients; mean age, 60 years) had suprarenal IVC filters. Sixty-two patients presented with symptoms of venous thromboembolism (VTE) and eight had incidental asymptomatic VTE at imaging. Indications for filter placement were as follows: contraindication to anticoagulation (n = 48), complications and/or failure of anticoagulation (n = 12), added protection (n = 8), and prophylaxis (n = 2). Suprarenal placement was chosen due to IVC thrombus (n = 41), intrinsic and/or extrinsic narrowing of the infrarenal IVC (n = 9), renal and/or gonadal vein thrombus (n = 3), congenital IVC anomalies (n = 6), pelvic mass (n = 5), pregnancy (n = 3), and other reasons (n = 3). The following filters were used: Greenfield (n = 29), Simon Nitinol (n = 5), Vena-Tech (n = 3), TrapEase (n = 22), OptEase (n = 3), Tulip (n = 6), Bird's Nest (n = 1), and Recovery (n = 1). During follow-up (mean, 573 days +/- 953), postfilter PE was suspected in 10 patients; eight patients underwent computed tomography (CT), one of whom had PE at CT. None developed new symptoms of caval thrombosis. Abdominal CT (performed in 30 patients at a mean of 543 days +/- 768) showed thrombus in the filter in three patients, fracture in one patient, and penetration of the IVC wall in two patients. CONCLUSIONS: Suprarenal filters are safe and effective in preventing PE. The placement of IVC filters above the renal veins does not carry an added risk of complications.     

Venography with carbon dioxide as a contrast agent

Purpose The purpose of this study was to evaluate the feasibility, safety, and potential role of carbon dioxide (CO₂) as a contrast agent for venography.Methods Consecutive patients with contraindications to iodinated contrast agents or with unsatisfactory iodinated contrast studies underwent CO₂ digital subtraction venography. The images were rated by three experienced angiographers. Image quality and complications were assessed.Results Over a 14-month period, 66 vein segments were studied in 21 patients. There was good correlation between experienced angiographers on CO₂ image quality (R_i = 0.80) and good agreement on diagnosis (k = 0.62). In 91% of the vein segments evaluated with CO₂ there was interobserver agreement on the diagnosis. Upper extremity veins were adequately imaged with CO₂ alone in all (6/6) patients with contraindications to iodinated contrast. Following suboptimal iodinated contrast studies in six patients, CO₂ produced significantly better quality upper extremity central vein images (p < 0.05). Pain following injection into peripheral veins was the only CO₂-related complication. Inferior vena cava (IVC) filters were successfully deployed with CO₂ alone in 78% (7/9) of patients; two required iodinated contrast.Conclusion Based upon initial experience, CO₂ venography can be recommended in patients with contraindications to iodinated contrast or unsatisfactory iodinated contrast studies.Presented before the Annual Meeting and Postgraduate Course, Cardiovascular and Interventional Radiological Society of Europe, June 7, 1994, Aghia Pelaghia, Crete, Greece.     

An unopened titanium greenfield IVC filter: Intravascular ultrasound to reveal associated thrombus and aid in filter opening

A titanium Greenfield filter did not open following placement in the infrarenal inferior vena cava (IVC). Abdominal radiograph and cavogram showed no definite reason for filter malfunction. Intravascular ultrasound (IVUS) demonstrated the unopened filter in the IVC with thrombus binding the legs. The thrombus was disrupted with a catheter, and the filter completely expanded with a balloon. IVUS documented full-filter opening in addition to residual thrombus in the filter following manipulation.     

Experience with the Amplatz retrievable vena cava filter

The Amplatz retrievable inferior vena cava filter was designed to be used as either a permanent indwelling filter or a short-term, percutaneously removable filter. The authors placed 52 filters in 52 patients. No deaths occurred as a result of filter placement or usage. Follow-up in 42 (81%) patients included inferior vena cavography (n = 31), computed tomography (n = 4), duplex ultrasound (n = 4), and autopsy (n = 3). Inferior vena cava thrombosis was found in seven (17.5%) of the 40 previously nonobstructed venae cavae studied. Two patients with caval thrombosis required a second filter to prevent embolization of thrombus that had extended to the lung side of the first filter. No clinically evident pulmonary emboli after filter placement have been noted. Six filters were successfully retrieved or repositioned percutaneously. The relatively high rate of caval thrombosis with extension above the filter may be due to a higher trapping efficiency or to filter geometry. The role of this filter in the treatment of deep venous thrombosis and pulmonary emboli is unclear.     

Evaluation of the inferior vena cava with intravascular US after Greenfield filter placement.

An animal model was used to evaluate the utility of intravascular ultrasound (US) imaging of the inferior vena cava (IVC) following Greenfield filter placement. Ten Greenfield filters were placed in the IVCs of five sheep and three dogs. Experimentally induced thrombi were injected into four filters at the time of placement. Intravascular US and cavography were performed 4 weeks after filter implant. The imaging studies were evaluated for demonstration of filter position, orientation, and leg distribution, as well as prediction of caval wall penetration by filter hooks. Experimentally induced and spontaneous intrafilter thrombi were also imaged. Findings were compared with those of postmortem examination. Exact filter position and orientation were most simply and accurately demonstrated on radiographs. Filter leg distribution and extent of intrafilter thrombus were best evaluated on intravascular US images. The prevalence of caval wall penetration was underestimated with both studies. The results of this animal study suggest that the information about the IVC provided at cavography and intravascular US following Greenfield filter placement may be complementary.     

CT fluoroscopic guided insertion of inferior vena cava filters

The value and use of inferior vena cava (IVC) filters is well documented and has been growing since the first reported filter placement in 1973 and the first percutaneous insertion in 1982. Access routes now include both jugular veins, both ante-cubital veins and both femoral veins. However, all insertions require some form of imaging, usually fluoroscopy, to identify the location of the filter with respect to the IVC and the renal veins. We describe two cases where the patients' weight was significantly greater than the weight limit of the angiography table, necessitating insertion under CT fluoroscopic guidance.     

Clinical comparison of two optional vena cava filters

PURPOSE: To compare the clinical safety and efficiency of two optional inferior vena cava (IVC) filters. MATERIAL AND METHODS: Ninety-three consecutive Günther Tulip filters (92 patients) were compared with 83 consecutive OptEase filters (80 patients). Filters were placed at the same institution in patients with high-risk multiple trauma or those undergoing neurosurgery with contraindications to primary prophylaxis (70 patients in the Günther Tulip group and 44 in the OptEase group) and in patients with venous thromboembolism and contraindications to anticoagulation (22 patients in the Günther Tulip group and 36 in the OptEase group). The filters were placed in an angiography suite. Catheter vena cavography was performed before filter placement and intended retrieval. Permanent filters were followed-up with duplex ultrasonography and conventional radiography. RESULTS: All filters were inserted infrarenally without any complications. Fluoroscopy times for placement and retrieval were longer for the Günther Tulip group than the OptEase group. The mean dwelling time was 11 days (range, 3-27 days) for the Günther Tulip filters and 13.8 days (range, 1-34 days) for the OptEase filters. No symptomatic pulmonary emboli (PE) occurred in patients with intended temporary filtration while the devices were in place. Forty-six of the 93 Günther Tulip filters (49%) and 58 of the 83 OptEase filters (70%) were removed. Two Günther Tulip filters could not be retrieved for technical reasons. The mean follow-up for the permanent Günther Tulip (n = 19) and OptEase (n = 8) filters was 41 and 7 months, respectively. One patient from each group had late caval thrombosis. There were no cases of filter migration or disintegration. CONCLUSION: Both optional IVC filters are safe and seem to prevent symptomatic PE. On the basis of the fluoroscopy times, the OptEase filters appear to be more operator-friendly. Late filter-associated complications are rare with these filter designs.     

Recurrent pulmonary embolism after Greenfield filter placement

Three patients with documented recurrent pulmonary embolism with an inferior vena cava (IVC) Greenfield filter in place were examined with contrast-material-enhanced cavography. Mechanisms for recurrent pulmonary embolism were found to be propagation of thrombus through the filter struts, occlusion of the IVC at the level of the filter, and loss of contact of the filter hooks with a portion of the caval wall.     

可回收支架治疗下腔静脉阻塞合并血栓形成的中期疗效

目的 观察可回收支架治疗下腔静脉阻塞(BCS)合并血栓形成的中期疗效.方法 8例下腔静脉合并血栓BCS,采用术中抗凝溶栓治疗后,行钝性破膜小球囊预扩张后植入可回收支架,最后使用大球囊充分扩张闭塞膜.术后给予抗凝溶栓治疗,待血栓消失后经颈内静脉将可回收支架取出.其中下腔静脉节段性闭塞合并血栓患者同时置入"Z"型支架.术后用彩色多普勒随访疗效.结果 8例患者均成功实施了介入治疗,血栓均在短期内消失,可回收支架顺利取出,术中未发生肺动脉栓塞和其他并发症.彩色多普勒超声随访3～12个月,2例下腔静脉狭窄,余6例可回收支架置入部位未见血栓形成、局部再狭窄及管壁增厚等情况发生.结论 使用可同收支架治疗下腔静脉阻塞合并血栓形成疗效满意.     

The Kimray-Greenfield filter: evaluation by duplex real-time/pulsed Doppler ultrasound

The Kimray-Greenfield filter is a wire cage which is inserted into the inferior vena cava (IVC) to prevent thrombi originating in pelvic and leg veins from embolizing to the lungs. Duplex real-time/pulsed Doppler ultrasound was used to evaluate placement and function in 38 patients (46 examinations). Real-time examination successfully identified the IVC and filter in 89% of cases. Pulsed Doppler studies demonstrated flow above and below the filter in 76%, accurately predicting normal flow in most cases. In 4 patients, Doppler scans revealed little or no flow distal to the filter; contrast cavograms confirmed obstruction secondary to thrombosis. This appears to be an accurate, noninvasive method of assessing postoperative reliability of the Kimray-Greenfield filter.     

Membranous obstruction of the inferior vena cava with Budd-Chiari syndrome: MR imaging findings.

Membranous obstruction of the inferior vena cava (IVC) is a curable cause of a primary type of Budd-Chiari syndrome. Magnetic resonance (MR) imaging and vena cavography were performed on nine patients with membranous obstruction of the IVC. The MR findings were retrospectively analyzed and compared with computed tomographic findings in seven patients. The morphologic features of membranous obstruction of the IVC on spin-echo MR images were a curvilinear soft-tissue membrane (five cases) or an obliterated lumen of a hepatic segment of the IVC (four cases) in transverse or sagittal views. The lumen below the obstruction revealed flow-related signal (seven cases), intraluminal thrombus (one case), and thrombotic occlusion (one case). The hepatic veins were narrow and disoriented without connection to the hepatic segment of the IVC just below the diaphragm. On T2-weighted images, inhomogeneity with high signal intensity was shown more prominently in the hepatic parenchyma in Simson type II or III membranous obstruction. Other findings were hepatosplenomegaly, enlarged caudate lobe, cirrhotic liver, associated hepatoma, and presence of various collaterals.     

下腔静脉滤器预防肺栓塞及其并发症

目的 探讨下腔静脉滤器置入术(IVCF)预防肺动脉栓塞(PE)的疗效、相关并发症及处理.方法70例下肢深静脉血栓患者,溶(取)栓术前均行下腔静脉滤器置入术:永久性Trap Ease滤器(TEF)20枚,永久性Vena Tech滤器(VTF)31枚,可回收性OptEase~(TM)滤器(OEF)13枚,临时性TempoⅡ滤器8枚;71枚位置在肾静脉开口下方,1枚位置在肾静脉开口上方.结果 术后随访8～72个月.70例中,无一例出现PE,6例出现相关的并发症.结论 下腔静脉滤器置入可以有效预防肺梗死,但应严格掌握适应证.     

The Günther temporary inferior vena cava filter for short-term protection against pulmonary embolism

Purpose To evaluate clinically the Günther temporary inferior vena cava (IVC) filter. Methods Eleven IVC filters were placed in 10 patients. Indications for filter placement were surgical pulmonary embolectomy in seven patients, pulmonary embolism in two patients, and free-floating iliofemoral thrombus in one patient. Eight filters were inserted from the right femoral approach, three filters from the left. Follow-up was by plain abdominal radiographs, cavography, and duplex ultrasound (US). Eight patients received systemic heparinization. Follow-up, during 4–60 months after filter removal was by clinical assessment, and imaging of the lungs was performed when pulmonary embolism (PE) was suspected. Patients received anticoagulation therapy for at least 6 months. Results Ten filters were removed without complications 7–14 days (mean 10 days) after placement. One restless patient pulled the filter back into the common femoral vein, and a permanent filter was placed. In two patients a permanent filter was placed prior to removal. One patient developed sepsis, and one an infection at the insertion site. Clinically no recurrent PE developed with the filter in place or during removal. One patient had recurrent PE 7 months after filter removal. Conclusion The Günther temporary IVC filter can be safely placed for short-term protection against PE. The use of this filter is not appropriate in agitated or immunocompromised patients.     

Intravascular ultrasound-guided direct intrahepatic portacaval shunt: description of technique and technical refinements

PURPOSE: This is a prospective study designed to demonstrate the safety and feasibility of creating a direct inferior vena cava (IVC)-to-portal vein shunt with use of a new type of intravascular ultrasound (IVUS) to guide the puncture and completing the shunt with the use of a polytetrafluoroethylene (PTFE)-covered stent graft. MATERIALS AND METHODS: IVC-to-portal vein shunts were created in 31 sequential patients for ascites (n = 31) or bleeding (n = 8). Transfemorally placed IVUS transducers were positioned in the IVC to guide the puncture from the IVC to the portal vein, which was performed from a transjugular approach with a modified Rosch-Uchida liver access set. A 9-MHz axial imaging IVUS system was used for the first 11 patients, and a variable 5-10-MHz sagittal IVUS imaging system was used for the next 20 patients. The shunts were completed with the use of single (n = 11) or overlapping (n = 20) PTFE-covered Palmaz stent-grafts, deployed primarily at a diameter of 8 mm. Patients were followed clinically and with US, venography, and inspection at liver transplantation to establish 30-day patency rates. RESULTS: All direct intrahepatic portacaval shunts (DIPSs) were created successfully. Both IVUS systems were able to adequately guide the portal vein puncture. Resolution and operator confidence were subjectively superior with the sagittal IVUS imaging system compared to the axial IVUS system. Two extrahepatic portal vein punctures occurred during the procedures. Both were controlled by the placement of sheaths and subsequent placement of stent-grafts. Both patients remained asymptomatic, although one required transfusion of blood products. The mean portosystemic gradient was reduced from 24 mm Hg before DIPS creation to 10 mm after DIPS creation. Embolization of varices was also performed in eight patients with history of recent gastrointestinal bleeding. Two patients died in the first week of acute liver failure. Two patients with hepatocellular carcinoma refused further follow-up. Of the 27 remaining patients, patency was demonstrated in all DIPS at 30 days by US, venography, or direct inspection at liver transplantation. CONCLUSIONS: IVUS-guided direct IVC-to-portal vein shunts may be created successfully with minimal complications. The use of a stent-graft is recommended for this procedure. Modifications of current technique and IVUS systems are described.     

Percutaneous insertion of the Kimray-Greenfield filter: technical considerations and problems

Kimray-Greenfield filters were inserted percutaneously into the inferior vena cava (IVC) in 57 patients. Thirty-six were placed from the right femoral vein, 14 from the left femoral vein, and seven from the right internal jugular vein. There were no deaths or major complications and only six minor complications. Inferior vena cavography was done before filter insertion in all cases. Cavography is vital to determine feasibility of filter insertion, route of insertion, and filter location; pertinent findings include caval size, presence or absence of clot in the IVC or iliac veins, and position of the renal veins. The guide wire provided with the standard filter introduction set has a tendency to catch on the filter as the wire is withdrawn. A stiff wire with a straight, tapered, floppy tip was substituted. The femoral approach is preferred when it is feasible. Though there was only one known occurrence of femoral vein thrombosis at the filter insertion site, other cases may have occurred and may not have been detected. If the frequency of this complication proves to be significant, the preferred route for filter insertion may have to be reconsidered.