Gwen K. Nazarian

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.

Mechanical Thrombectomy with the Amplatz Device: Human Experience

PURPOSE The authors present their early experience of mechanical arterial and graft thrombectomy with the Amplatz thrombectomy device. PATIENTS AND METHODS Preliminary data are presented for 14 patients treated with the Amplatz thrombectomy catheter. The procedure was carried out in 10 arterial polytetrafluorethylene grafts, in two native arteries, and in two patients with venous thrombosis. RESULTS The thrombectomy catheter completely removed the clot in 11 patients and partially removed clot in three patients. Mean thrombectomy time was 2 minutes 45 seconds. Despite distal blood pressure cuff occlusion, two instances of insignificant distal embolization occurred. Mechanical clot dissolution has consistently produced hemolysis without adverse clinical effects. The underlying causative factors such as stenoses were treated by means of angioplasty, atherectomy, or surgical endarterectomy. CONCLUSION Mechanical thrombectomy with this device is a new, effective technique and can rapidly remove the thrombus. From preliminary results, the device seems most promising in clearing out thrombi in occluded synthetic femoral-to-popliteal bypass grafts. The device could have wider application if it were steerable and if it could be introduced from the contralateral approach.

Recirculation-type Amplatz Clot Macerator: Determination of Particle Size and Distribution☆

PURPOSE A high-speed mechanical clot macerator was tested in vitro, and the distributions and sizes of residual particles produced by this device were determined. MATERIALS AND METHODS Human thrombi aged for 4 days and 10 days were macerated using a recirculation-type Amplatz thrombectomy device with an 8-F, high-speed screw propeller. The device was activated for 15, 30, and 60 seconds. Two different methods of particle measurement were used to determine overall particle distribution and to determine the size and number of large particles. RESULTS The recirculation device liquefied 99.2% of 4-day-old and 98.8% of 10-day-old thrombi, producing particles ranging in size from 13 to 1,000 microns; all particles were smaller than 1,000 microns. Particle size and distribution results were identical for the 30-second and 60-second activation times. CONCLUSION The recirculation-type thrombectomy device appears to perform well as a method of macerating human thrombi. Clinical trials need to be conducted to test the device further and to determine if it can be used safely on venous as well as arterial occlusions.

Venous Recanalization by Metallic Stents After Failure of Balloon Angioplasty or Surgery: Four-Year Experience

PurposeThis retrospective study describes our updated experience in treating venous stenoses and occlusions with metallic endovascular stents.MethodsGianturco, Palmaz, and Wallstent stents were placed in 55 patients over a 4-year period. Stent sites included the subclavian veins (9), innominate veins (3), superior vena cava (4), inferior vena cava (3), iliac veins (29), femoral veins (5), and portal veins (6). The most common indications for stent placement were malignant stenoses and chronic pelvic venous occlusions. Venoplasty and/or urokinase were used as ancillary therapy. Patients were anticoagulated for 3–6 months. Follow-up included clinical assessment and duplex ultrasound.ResultsLifetable analysis shows 59%, 63%, and 72% primary, primary assisted, and secondary 1-year patency rates, respectively. The 4-year primary patency rates were the same. Duration of patency depended on the venous site. Death was a complication of stent placement in 2 patients and 12 patients died within 6 months after stent placement from primary disease progression. Although early failures were more common in stents placed across occlusions than stenoses, 1-year secondary patency rates were comparable. Primary patency rates were only slightly lower in patients with malignant obstruction than in patients with benign disease.ConclusionEndovascular stent placement provides a nonsurgical alternative for reestablishment of venous flow and symptomatic relief in patients with benign as well as malignant venous obstruction.

Hemolytic Effect of the Amplatz Thrombectomy Device

PURPOSE The hemolytic effect of the Amplatz thrombectomy device (ATD) was evaluated in nine dogs and in nine patients. MATERIALS AND METHODS The device was activated for 1-2 minutes in the abdominal aorta, inferior vena cava, or femoral artery of nine dogs. The device was activated for 1-4 minutes in the nine patients in occluded lower extremity bypass grafts (n = 5), native superficial femoral artery (n = 1), a pulmonary artery embolus (n = 1), a portocaval shunt (n = 1), and an iliac vein stent (n = 1). Patients were examined for laboratory evidence of hemolysis following mechanical thrombectomy. RESULTS In all dogs haptoglobin level decreased, free hemoglobin level in the plasma increased, and hemoglobinuria was present. There was no change in renal function. The level of haptoglobin decreased and the level of plasma free hemoglobin increased in eight patients, with hemoglobinuria detected in one. More hemolysis was observed in the animals than in the patients. CONCLUSION The ATD has a definite transient hemolytic effect. Until further studied, it should not be used in children and should be used with caution in patients who are anemic, hypoxemic, or have potentially reversible renal insufficiency. Activation time should be monitored closely because hemolysis probably increases with increasing activation time.

In vitro and in vivo experimental evaluation of a new vena caval filter.

PURPOSE A new stainless steel (MP35N alloy) vena cava filter without a central stasis point was evaluated in vitro and in vivo. MATERIALS AND METHODS The clot-trapping efficiency and hemodynamic flow pattern of the filter were assessed in a flow model and were compared with those of currently available commercial filters including the Vena Tech-LGM, Simon nitinol, Greenfield, and Birds Nest filters. The new filter was placed in the inferior vena cava (IVC) of 31 dogs; 21 of the 31 dogs were followed up with cavography for up to 3 months. At the termination of the study, the filters and IVCs were examined grossly and histologically. An in vivo clot-trapping test was carried out in five dogs. RESULTS The least turbulence was noted with the new filter and the titanium Greenfield filter. The stainless steel Greenfield and Simon nitinol filters caused major flow disturbances. Migration within 5 cm of initial placement occurred in two animals (9.5%). There were no IVC thromboses, perforations, or filter embolizations. An in vivo clot-trapping study showed an 80% efficiency for small thrombi (3 x 20 mm) and 100% efficiency for large thrombi (6 x 20 mm) with the new filter. The Simon and the new filter had the best clot-trapping capabilities. The Vena Tech-LGM and Birds Nest filters were slightly inferior and the Greenfield filter demonstrated by far the lowest trapping capacity. CONCLUSION The new vena cava filter is easily introduced percutaneously through a 12-F sheath and appears to be very promising due to its high filtering capability, low turbulence, nonmagnetic properties, good mechanical stability, and hypothrombogenicity. Clinical trials are warranted.