Evaluation of a new percutaneous stainless steel Greenfield filter.

PURPOSE: To evaluate a new percutaneous Greenfield filter with an alternating hook design and over-the-wire delivery system. MATERIALS AND METHODS: The alternating hook stainless steel Greenfield filter was evaluated in a prospective clinical trial between March 10, 1994, and January 27, 1995. Filters were placed in 75 patients in nine clinical centers and follow-up with radiographs and ultrasound scans was carried out at 30 days. RESULTS: Clinical trial results revealed successful placement in all patients. There were four cases of filter limb asymmetry (5.3%) without clinical sequelae, with one incidence of failure to span the cava. No significant migration was found. There were no clinically suspected pulmonary emboli, but one instance of probable caval penetration (1.7%) did occur. Caval occlusion was documented in three patients (5%). CONCLUSION: The percutaneous stainless steel Greenfield filter provides ease of insertion and improved deployment while maintaining the high standards of efficacy and safety associated with the standard and titanium Greenfield filters.

Early duplex scan evaluation of four vena caval interruption devices.

PURPOSE: Transvenous inferior vena cava (IVC) filters are used successfully for prevention of pulmonary embolism (PE), but early thrombotic complications such as insertion site thrombosis (IST) and inferior vena cava thrombosis (IVCT) may occur after placement. The frequency of these complications has been uncertain particularly for the wide variety of newer devices. This study was performed to prospectively evaluate IST and IVCT with color-flow venous duplex ultrasound scanning after four IVC filters were placed: the birds' nest filter, the titanium Greenfield filter, the stainless steel Greenfield filter, and the Simon nitinol filter. METHODS: Percutaneous IVC filters were placed in 174 patients over a 21-month period. A birds' nest filter was used in 39 (22%) cases, a titanium Greenfield filter in 67 (39%) cases, a stainless steel Greenfield filter (25%) in 43 patients, and a Simon nitinol filter in 25 (14%) cases. Filters were placed for major deep venous thrombosis in 113 (63%) patients, after PE in 26 (15%) patients, and with prophylaxis in 35 (20%) patients. All patients had color-flow venous duplex ultrasound scanning of the insertion site and the inferior vena cava 7 to 10 days after placement or before discharge to document IST or VCT. RESULTS: Early IST occurred in 43 (24.7%) cases, and early IVCT was observed in 20 (12%) cases in this series. No significant difference was found in the incidence of IST or IVCT among the four filter types used. The incidence of IVCT was significantly higher in patients having filters placed for PE. Men were more likely to receive a prophylactic filter than women in this study, but thrombotic complications were not related to patient sex. Thrombosis was seen with equal frequency at all insertion sites used. No patient died of PE after filter placement during the study period. CONCLUSIONS: The incidence of thrombotic complications for all devices was higher than has generally been reported. No IVC filter used in this study demonstrated superior performance with regard to these thrombotic complications. As vena cava interruption devices are developed or significantly modified, prospective objective analysis of associated thrombotic complications will allow logical selection for clinical use.

Detection of bleeding in patients with major pelvic fractures: value of contrast-enhanced CT.

OBJECTIVE: We performed a retrospective review of trauma patients who had undergone both pelvic angiography and preangiographic i.v. contrast-enhanced CT to determine whether CT can accurately demonstrate the presence or absence of pelvic bleeding in patients with multisystem trauma and major pelvic fractures. SUBJECTS AND METHODS: We reviewed the medical records and imaging studies of all patients, identified through a trauma radiology database, who had undergone pelvic angiography and preangiographic contrast-enhanced CT during a 48-month period. Results of CT scans were recorded by consensus interpretation of three radiologists without knowledge of angiographic findings. Sites of contrast material extravasation seen on CT scans were noted and compared with sites of bleeding or vascular injury identified by selective pelvic angiography. RESULTS: Thirty patients with blunt trauma and pelvic fractures underwent both pelvic angiography and preangiographic CT studies. Findings on pelvic angiograms were positive at 26 sites in 19 patients and included contrast agent extravasation at 23 sites and vessel abnormalities without extravasation at three sites. Preangiographic pelvic CT scans showed contrast agent extravasation at 20 sites in 16 patients. Three patients had no contrast agent extravasation demonstrated by CT but had bleeding demonstrated by angiography. CT detected bleeding in 16 of 19 patients who had extravasation or vascular injury demonstrated by angiography, for a sensitivity of 84%. Results of pelvic angiography were negative in 11 patients, and none had evidence of bleeding on preangiographic CT scans. Two sites of contrast agent extravasation identified in two patients by CT did not show bleeding at angiography, for a specificity of 85% for the detection of bleeding. The overall accuracy of CT for determining the presence or absence of bleeding was 90%. CONCLUSION: Knowledge of sites of ongoing hemorrhage is crucial for optimizing the sequence of diagnostic and therapeutic studies in patients with blunt trauma. Contrast-enhanced CT of the pelvis, which is often performed for hemodynamically stable trauma patients, is a noninvasive technique that is highly accurate in determining the presence or absence of ongoing pelvic hemorrhage. This information can assist in initial management decisions involving patients with multisystem trauma and major pelvic fractures.

Salvage of renal allograft function and lower extremity venous patency with thrombolytic therapy: case report and review of the literature.

Five months after a cadaveric renal transplants a 69-year-old man was admitted with caval, iliac, and renal allograft vein thrombosis that occurred in the setting of a previously placed caval filter. The patient's urine output and renal function deteriorated rapidly. Thrombolytic therapy with urokinase was begun, and lysis of the thrombus occurred in 72 hours. The patient's renal function returned to baseline, and the transplant was salvaged. Moreover lower extremity venous patency and valvular function were maintained. We report the case and review the literature on thrombolytic therapy for renal allograft vein and lower extremity deep venous thrombosis.

Trauma radiology: part III. Diagnostic and therapeutic angiography in trauma.

Angiography has a central role in both diagnosis and therapy of traumatic vascular injuries from blunt and penetrating mechanisms. Angiography is considered the "gold standard" for establishing the presence of vascular injury, but precise indications and appropriate timing of angiography in certain clinical situations, such as proximity injury to the extremities or penetrating neck injuries, remain controversial. We consider the role of angiography in the diagnosis of major arterial injury in the thorax, selective use of diagnostic and therapeutic angiography for intraabdominal trauma, identification and control of pelvic hemorrhage, and detection of vascular injury of the head, neck, and extremities.

MR angiographic diagnosis of recanalization in a thrombosed pulmonary arteriovenous malformation.

Pulmonary arteriovenous malformation (PAVM) results from an anomalous communication between a pulmonary artery and vein and may lead to life-threatening hemoptysis. Pulmonary angiography is the standard diagnostic technique but may be falsely negative in the unusual instance of a thrombosed PAVM. We report a patient with a thrombosed PAVM in which the initial pulmonary angiogram incorrectly suggested pulmonary embolism. A subsequent magnetic resonance (MR) angiogram demonstrated recanalization of the PAVM, thus establishing the true nature of the lesion and leading to appropriate intervention.

Resolution of inferior vena cava syndrome after embolization of a hepatic adenoma.

A 77-year-old man presented with severe pruritus and massive lower body edema. Computerized axial tomography of the abdomen showed a large hepatic mass compressing the inferior vena cava, and a liver biopsy specimen showed hepatic adenoma. Embolization of vessels feeding the hepatic tumor resulted in complete resolution of pruritus and ascites, and clinical remission has persisted for 1 year following partial obliteration of tumor vasculature. Angiographic ablation of tumor blood supply represents a nonoperative means for inducing clinical remission in patients with symptomatic hepatic adenoma who are at high surgical risk.

Femoral vein thrombosis following percutaneous placement of the Greenfield filter.

Following percutaneous insertion of the Greenfield inferior vena cava filter via the femoral route, patients were evaluated for femoral vein thrombosis by real-time ultrasound or Duplex sonography. In 23 patients (24 veins) the femoral vein was dilated with an 8-mm (24 F) angioplasty balloon catheter. Eight of 24 common femoral veins were thrombosed (33%). These findings indicate that thrombosis is a significant complication of percutaneous filter insertion. Dilation was performed in 20 patients (22 veins) with a 9-mm (27 F) balloon catheter; only three veins were thrombosed (14%). Over-dilation of the femoral vein to 27 F to accommodate the 24 F sheath/dilator set may decrease the incidence of thrombosis.

Preliminary clinical experience with the titanium Greenfield vena caval filter.

Preliminary clinical experience in 40 patients from three institutions is reported for a new titanium model of the Greenfield vena caval filter. The titanium filter is slightly larger than the standard stainless steel filter and can be loaded into a 12 F diameter carrier system as opposed to the 24 F stainless steel filter. In patients ranging from 17 to 94 years of age, percutaneous insertions were made from the right femoral vein in 24 patients, the left femoral vein in 11 patients, and the right internal jugular in 2 patients. Operative access was obtained in 1 patient each from the right femoral, right jugular, and a lumbar vein at laparotomy. Insertion was completed in all cases but 1 and only 1 patient (3%) showed postoperative femoral vein thrombosis. Distal filter migration was seen in 3 cases (7.5%) without sequelae, and there was no proximal migration. The titanium Greenfield vena caval filter provides improved ease of insertion, and the sheath technique should prevent misplacement. Distal migration should be preventable by techniques to promote hook engagement at the time of insertion.

Reevaluation of indications for percutaneous placement of the Greenfield filter.

In our institution twice as many Greenfield filters were inserted in the year after percutaneous placement was begun as in the previous year when all filters were surgically inserted. Review of the indications for surgical and percutaneous filter placement in our hospital reveals that more filters were inserted percutaneously for all indications except recurrent emboli. The rates of percutaneous and surgical filter insertion for prophylaxis with acute deep venous thrombosis were similar (40% and 42%, respectively) and were higher than the majority of reported filter series because of the large number of high risk patients in our hospital population. In evaluating each patient for risk factors concerning the development of venous thromboembolism, the contraindications to anticoagulation, and the effectiveness and possible complications of anticoagulant therapy, we have defined a much broader range of patients as candidates for Greenfield filter insertion than had been considered in our institution in the past.

Percutaneous insertion of the Greenfield inferior vena cava filter: experience with ninety-six patients.

This article evaluates the ease, safety, and convenience of percutaneous Greenfield filter placement and compares percutaneous with surgical placement. Greenfield filters were inserted percutaneously into the inferior vena cava in 96 patients. Ninety filters were placed via the femoral route and 12 were placed from the right internal jugular vein. Six patients had two filters inserted. An inferior venacavogram was performed before filter insertion in all patients. Cavography provided vital information concerning diameter of the inferior vena cava, the level of the renal veins, and the presence and location of thrombus. Filter placement was accomplished in all patients in whom it was attempted. There were four minor complications and one periprocedural death. The incidence of documented femoral vein thrombosis that could be related to percutaneous placement via the femoral veins was 33%; however, none of these patients had permanent venous stasis sequelae. Percutaneous insertion of the Greenfield filter is a safe and convenient procedure and is superior to surgical placement in terms of time, logistics, and the accuracy of filter positioning.

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.