M. Zwaan

Current practice of temporary vena cava filter insertion: a multicenter registry.

PURPOSEnTo evaluate the current practice of temporary vena cava filter placement and its complications.nnnMATERIALS AND METHODSnA multicenter registry was conducted from May 1995 until May 1997 using a standardized questionnaire. One hundred eighty-eight patients were evaluated. Patient characteristics, filter indications, filter characteristics, and complications were registered.nnnRESULTSnDeep vein thrombosis was proven in 95.2% of the patients. Main filter indication was thrombolysis therapy (53.1%). Average filter time was 5.4 days. An Antheor filter was inserted in 56.4%, a Guenther filter in 26.6%, and a Prolyser filter in 17.%. Transfemoral filter implantation was slightly preferred (54.8%). Four patients died of pulmonary embolism (PE) during filter protection. Major filter problems were filter thrombosis (16%) and filter dislocation (4.8%). When thrombus was found in or at the filter before explantation, additional thrombolysis was performed in 16.7%, additional filter implantation in 10%, and thrombus aspiration in 6.7%; 4.8% of filters were replaced with permanent filters.nnnDISCUSSIONnTemporary vena cava filters are placed to prevent PE in a defined patient population. Despite their presence, PEs still occur in a small percentage. Problems of filter thrombosis and dislocation have to be solved.nnnCONCLUSIONnThe results of this multicenter registry support the need for innovative filter design, as well as a randomized, prospective study.

Central Venous Access Ports Placed by Interventional Radiologists: Experience with 125 Consecutive Patients

AbstractPurpose: To assess safety and function of central venous port systems implanted percutaneously in the interventional radiology suite.n Methods: One hundred and twenty-five consecutive ports in 123 patients were evaluated retrospectively. One hundred and twenty ports were implanted via the subclavian vein.n Results: Technical success was 100%. Fourteen patients (11.2%) experienced immediate procedural complications, all minor (pneumothorax 1.6%). During follow-up (4–343 days, mean service period 97.8 days), nine complications occurred, six of which were major. These were three port infections which led to hospitalization and port removal, one chamber penetration through the skin, and two port occlusions. Port removal as a result of complications was performed in six patients. Altogether, 20 complications occurred within a total of 11,056 days of service, which means 1.8 events per 1000 days of service.n Conclusion: Percutaneous implantation of central venous port systems is safe and easy to perform. Complication rates of this study compare favorably with those of other radiological and surgical series.

Clinical experience with temporary vena caval filters.

PURPOSEnTo look at the benefits and complications of different vena caval filters inserted prophylactically. Three temporarily implantable caval filter systems were used in 67 patients.nnnMATERIALS AND METHODSnTwelve 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.nnnRESULTSnOne 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.nnnCONCLUSIONnBecause 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.

Efficacy of permanent and retrievable vena cava filters: experimental studies and evaluation of a new device.

nPurpose: To evaluate the efficacy ofnvena cava filters and to compare them with the new TrapEase filter.nMethods: Thrombus capture rates of 10 permanent andnretrievable vena cava filters were tested in vitro in vertical andnhorizontal positions with thrombus diameters of 3 and 5 mm (length 30nmm) and tube diameters of 21 and 28 mm. Testing included the newnTrapEase filter. Results were compared statistically using Fisher’snexact test (capture rates) and the Kruskal–Wallis testn(construction).nResults: Best-ranked filters were thenBird’s Nest, the TrapEase and the Simon Nitinol filters. ThenTempofilter, the Greenfield and the Keeper filter performed worst.nThrombus capture rates were significantly higher in the verticalnposition and also higher for large thrombi and in the small cavandiameter. Conical filters performed worse than filters with two or morenfiltration levels.nConclusion: Filters with two or morenfiltration levels show the highest filtration efficiency in vitro andncan be recommended, especially for the critically ill who will probablynnot tolerate even small emboli. The TrapEase filter is a promisingndevice and should be evaluated clinically.nn

In Vitro Studies of Temporary Vena Cava Filters

AbstractPurpose: To evaluate the clot trapping capacity of different temporary vena cava filters in a vena cava model.n Methods: A vena cava flow model was built using PVC tubing, a hemodialysis membrane and a pulsatile pump. Blood was imitated by a Dextran 40 solution. Five different temporary vena cava filters and two prototypes were tested using human thrombi. The mechanism of clot capture was observed.n Results: Decreasing rank order according to decreasing percentage of clots captured for the 21-mm diameter vena cava model was Cook (C) > Angiocor (A) > Cordis (CD) > Antheor (TF-6) > DIL for thrombi with a diameter of 3 mm and A > C > CD > TF-6 > DIL for 5-mm thrombi. In a cava with diameter of 28 mm, decreasing rank order was C > CD = A > TF-6 > DIL and C > CD = A > DIL > TF-6 for 3- and 5-mm thrombi, respectively. Two new prototypes, the TF-8 and TF-10 filters, achieved better results than the TF-6 filter and were in most conditions comparable to the A and CD filters. In most cases, thrombi were trapped between filter and cava wall.n Conclusion: The vena cava flow model demonstrates significant differences in rates of clot capture (range 22%–98%) depending on cava diameter, thrombus size, and filter type.

Temporary Vena Cava Filters and Ultrahigh Streptokinase Thrombolysis Therapy: A Clinical Study

AbstractPurpose: To assess the efficacy of temporary vena cava filters in patients undergoing ultrahigh-dose streptokinase thrombolysis for iliocaval thrombosis and to determine therapy success and filter and therapy complications.nMethods: Forty-five patients were studied regarding extension and characteristics of thrombosis, duration, success, and complications of thrombolysis therapy, filter type, access route, pulmonary embolisms, and filter complications.nResults: Complete recanalization was achieved in 57% of cases. Filters were inserted predominantly via a transbrachial route. One fatal pulmonary embolism (2%) occurred 1 day after starting thrombolysis. No other pulmonary embolism was noted. Other complications were induced by thrombolysis alone (n = 12), thrombolysis and filter (n = 9), and filter alone (n = 11).Conclusion: Fatal pulmonary embolisms as a complication of ultrahigh-dose treatment of pelvic or caval thrombosis can not safely be prevented by the temporary vena cava filters currently available. Filter design needs to be improved.

Non-absorbable fat-dense oral contrast agent for abdominal computed tomography

Opacification of the gastrointestinal tract for CT scanning is usually achieved by oral administration of a diluted iodine solution or barium suspension. As high-density contrast agents often cause image degrading artifacts, we investigated the value of a paraffin-methylcellulose emulsion as an oral CT scanning agent. Diseases of the intestinum were clearly outlined with paraffin emulsion, and image degrading artifacts were virtually not encountered.

Initial clinical experience with a new pulsed dye laser device in angioplasty of limb ischemia and shunt fistula obstructions

Selective plaque ablation with laser radiation at 405-530 nm in vitro has been reported. We investigated the possibilities of a new pulsed dye laser device for in vivo recanalization of arteries in ischemic lower limbs and stenoses/occlusions of arterio-venous hemodialysis shunt fistulae. A specially designed 9F or 7F multifiber catheter was used for treatment of 10 patients with lower limb artery obliterations and 11 patients with malfunctioning hemodialysis access fistulae (HAF). The recanalization technical success was 5/5 in the iliac arteries (IA), 4/5 in the superficial femoral arteries (SFA), and 11/11 in the HAF. Early re-occlusions occurred in one SFA and one IA, respectively, caused by very bad run-off. There was one clinically insignificant SFA perforation. Additional balloon angioplasty was considered necessary in 10/16 lesions. Mean ankle-arm index increased from 0.68 to 0.97. With two exceptions all HAF patients were re-integrated in the dialysis program. Pulsed dye laser angioplasty promises to be an effective and fast method for plaque ablation/debulking. The first clinical experience confirms previous in vitro results. In particular laser recanalization may become the method of choice for treatment of rigid HAF obstructions and it seems to be superior to vascular surgery or balloon angioplasty alone.

Angiography and angioscopy with injector-applied carbon dioxide

In 10 laboratory swines we investigated an automatic gas injector for angiography and angioscopy that allows the reproducible injection of variable quantities of gas, with variable pressure and injection times. With small volumes of carbon dioxide (CO2; 10–50 cc; 850–1250 mbar application pressure) a column of gas can be created, which facilitates digital subtraction angiography comparable to conventional contrast media (CM) or an angioscopy within a sufficiently bloodless visual field. A total of 93 of 127 angiographies of the abdominal aorta and 49 of 57 angiographies using CO2 were successful. A lack of success was obtained in selective angiographies. The use of injector-controlled CO2 application is an alternative for angiography in patients who are at increased risk using conventional CM. This technique was an unexpectedly excellent method of performing a renal venogram as well as a fast splenoportogram. Petcutaneous transluminal CO2 angioscopy affords a bloodless inspection of the aorta and side branches for a period of several minutes.

The value of computed tomography and ultrasound in cases of inflammatory aneurysms of the abdominal aorta

In a retrospective study 344 CT examinations of patients with suspected aneurysms of the abdominal aorta were evaluated with respect to the inflammatory character of the aneurysm. In 207 cases surgical therapy was conducted. In 144 of those 207 cases preoperative ultrasound examination results were also available. Frequency of inflammatory aneurysms, as classified by CT, was 10.2% (35/344) and in the subgroup of surgically treated aneurysms, 14.0% (29/207). Sensitivity and specifity of CT to realise the inflammatory type of aneurysm was 86.2% and 97.2%. The respective figures for ultrasound examinations on the basis of 144 surgically treated aneurysms were 26.1% and 100%. We conclude that even in cases of sonographically unequivocal abdominal aneurysms CT should be performed because ultrasound is not sufficiently sensitive to realise an inflammatory character of the aneurysm, which can have great impact on surgical strategy.