Tracheobronchial metal stents: effects of covering a bronchial ostium in pigs.

RATIONALE AND OBJECTIVES: The purpose of this study was to examine the effects of placing a metal stent across a bronchial orifice. MATERIALS AND METHODS: Nine pigs were used as test subjects, because the right upper lobe bronchus comes directly off the trachea in these animals. One of three types of metal stents was placed into the trachea of each pig and covered the orifice of the right upper lobe bronchus. Follow-up studies were performed at 1 and 3 months to evaluate the right upper lobe for signs of bronchial obstruction, infection, and atelectasis. The animals were sacrificed at 3 months to study the histopathologic changes of the trachea and lungs. RESULTS: Two upper lobe bronchi remained patent; seven were obstructed by granulation tissue or plugs of mucus and inflammatory cells. Right upper lobe infiltration and atelectasis were seen in eight animals. Interestingly, radiographic opacities were also common in other lung segments. There was a tendency toward fewer and less extensive lung opacities at 3 months compared with that at 1 month. At histopathologic examination, areas of both acute and chronic pneumonia were found in the right upper lobe of all animals. The segment of trachea covered by the stent was lined with a thin layer of granulation tissue containing neutrophils, monocytes, and lymphocytes. The stent luminal surface was covered with columnar, cuboidal, and stratified squamous epithelium. Tracheal stenosis was seen in three animals because of excessive granulation tissue in two and a collapsed stent in one. CONCLUSION: Placement of metal stents in pig trachea covering the orifice of the right upper lobe bronchus resulted in retention of secretions and secondary infection in the right upper lobe and other distant lung segments.

Refractory ascites: midterm results of treatment with a transjugular intrahepatic portosystemic shunt.

PURPOSE: To assess midterm results and examine factors associated with successful treatment of refractory ascites with creation of a transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: In 50 patients with refractory ascites, TIPS creation was performed. Clinical and ultrasound follow-up were performed. Success was defined as survival with no further therapeutic paracentesis and decreased ascites. RESULTS: Mean follow-up was 11.6 months after the TIPS procedure. Major complications occurred in 16% of patients including intraperitoneal hemorrhage, refractory encephalopathy, and progression of liver and renal failure. Overall mortality was 60% (30 patients). In 23 (62%) of 37 patients not lost to follow-up, ascites was controlled successfully at 1-3 months. A bilirubin level greater than 3.0 mg/dL (52 mumol/L) and creatinine level greater than 1.9 mg/dL (170 mumol/L) were associated with treatment failure (86% treatment failure at 3 months) and early mortality (P = .03). In all 14 patients alive at 1-year follow-up, ascites was controlled successfully. CONCLUSION: TIPS creation is often useful in treatment of severe ascites not controlled with medical therapy. In patients with advanced liver and renal failure, TIPS creation is not associated with a definite benefit and may hasten death.

Iliofemoral deep venous thrombosis: safety and efficacy outcome during 5 years of catheter-directed thrombolytic therapy.

PURPOSE: To prospectively evaluate the angiographic and clinical results of using catheter-directed thrombolytic therapy for the treatment of acute iliofemoral deep venous thrombosis (IFDVT). MATERIALS AND METHODS: All consecutive patients with acute IFDVT referred for thrombolytic treatment from July 1990 to December 1995 were included in this clinical data analysis. Infusions of urokinase were administered via a multisidehole infusion catheter. Angioplasty, stent placement, mechanical thrombectomy, and other procedures were often performed in conjunction with the thrombolytic procedure. RESULTS: Seventy-seven patients and 87 limbs were treated. The overall technical success rate was 79%, and was 86% for iliac veins and 63% for femoral veins. The primary and secondary patency rates at 1 year were 63% and 78%, respectively, for the iliac veins, and 40% and 51%, respectively, for the femoral veins. Patients with malignant disease fared worse. Patients requiring stent placement appeared to have inferior outcomes. A previous history of DVT did not appear to affect the results. Bleeding requiring transfusion and hematomas were the major complications encountered. Pulmonary embolus was not a significant problem. Technical success rates were lower in patients who had had symptoms for more than 4 weeks compared to those who had a more recent onset of symptoms. CONCLUSION: Current data suggest that catheter-directed thrombolytic therapy is safe and effective in achieving intermediate-term venous Patency. The long-term clinical benefits of this procedure remain, however, to be established.

Changes in tunneled catheter tip position when a patient is upright.

PURPOSE: To determine the relative changes in position of tunneled catheters from supine to upright patient position and factors affecting catheter tip migration. MATERIALS AND METHODS: One hundred forty-six different tunneled catheters were placed through the subclavian or jugular veins radiologically, and catheter positions were documented with use of cine radiography at the time of placement. Follow-up chest radiographs were obtained with the patient in the upright position within 48 hours after placement. Catheter tip positions were numbered from 1 to 8, with 1 representing the innominate/superior vena cava junction and 8, the lower right atrium. Patient sex and weight, the site of catheter entry, and the size and type of catheter were correlated with the relative change in position on the follow-up chest radiogrpahs. RESULTS: There was a statistically significant (P < .0001) change in catheter position on the follow-up chest radiographs, with a mean difference of 1.5 catheter positions (usually mid-right atrium initially to low superior vena cava on follow-up). Catheter tip migration was greater for catheters in the subclavian veins, in females, and in obese patients. CONCLUSIONS: The catheter tip migrates significantly from the initial position at the time of placement as compared to when the patient assumes the upright position. This knowledge is important in achieving the desired final catheter position.

Iliofemoral venous stenoses: effectiveness of treatment with metallic endovascular stents.

PURPOSE: To assess effectiveness of metallic endovascular stents in treatment of venous stenoses and occlusions. MATERIALS AND METHODS: Stents were placed intravenously in 56 patients (59 stenoses or occlusions) over a 6-year period. Stent sites included the inferior vena cava (n = 10) and common iliac (n = 31), external iliac (n = 46), common femoral (n = 27), and superficial femoral veins (n = 4). Indications for stent placement included stenoses from pelvic malignancy and its treatment; trauma, surgery, or pregnancy; and idiopathic stenoses. Patients underwent anticoagulation therapy for 3-6 months after stent placement. Follow-up was performed with duplex ultrasound. RESULTS: With use of life-table analysis, overall primary and secondary 1-year patency rates were 50% and 81%, respectively. Primary and secondary 4-year patency rates were and 50% and 75%, respectively. Five patients died of primary disease progression within 6 months after stent placement. Major complications occurred in 6.8% of cases. One-year secondary patency rates were statistically significantly lower (P = .05) for patients with malignant disease, although primary patency rates were comparable. Overall sustained decrease in symptoms (P < .0001) was observed 1 year later. CONCLUSION: Endovascular stent placement is a nonsurgical alternative for reestablishment of venous flow and sustained relief of symptoms in patients with malignant or benign pelvic venous disease.

Applications of the Amplatz snare device during interventional radiologic procedures.

The Amplatz gooseneck snare (Microvena, St. Paul, MN) is a recently developed device for the percutaneous removal of intravascular foreign bodies [1-5] (Fig. 1). In the past several years, various other applications of this snare system have been devised for placing, replacing, repositioning, or removing guidewires, catheters, and other devices during interventional procedures. The Amplatz gooseneck snare, which has been described [1], comes in a variety of loop sizes and is provided with either 4- or 6-French guiding catheters, although substitution with any of several soft, blunt-tipped guiding catheters is possible [5]. The principal advantage of the Amplatz snare over past systems is that the loop is at a right angle to the catheter, easing the capture of foreign bodies, devices, or catheters.

Mechanical thrombectomy: results of early experience.

PURPOSE: To evaluate the clinical application of a mechanical thrombectomy device in occluded lower extremity arteries and bypass grafts. MATERIALS AND METHODS: A mechanical thrombectomy device was used in five patients with acutely occluded lower extremity bypass grafts (n = 2) or superficial femoral arteries (n = 3). RESULTS: The thrombus was completely removed in three cases (two bypass grafts and one native superficial femoral artery). In two of the patients with occlusions in the native superficial femoral artery, the thrombus was partially removed. In these two patients, the aspirate demonstrated a more fibrous thrombus that was not easily fragmented. In one of these two patients, the coagulum was thought to be embolic from the heart. CONCLUSION: The thrombectomy device works well in recent thromboses, particularly in polytetrafluoroethylene grafts in which organization does not occur. Its efficacy in chronically occluded vessels is not certain.