M. J. Gimeno

The Günther Tulip Retrievable Filter: Prolonged Temporary Filtration by Repositioning within the Inferior Vena Cava

PURPOSE To report experience with the retrievable Günther Tulip filter (GTF) as a means of temporary caval filtration for the prevention of pulmonary embolism (PE) with use of a technique that prolongs filter dwell time beyond 14 days. MATERIALS AND METHODS Eighty-eight GTFs were implanted in 87 patients. The GTFs were placed with the intention of retrieval in all patients within 14 days after initial implantation. In 23 of the 87 patients (26%), there was a need to prolong temporary caval filtration beyond the recommended period of 14 days. This was successfully achieved with use of percutaneous techniques from the right internal jugular vein whereby the filter was repositioned to a different location within the inferior vena cava (IVC) before definitive device removal. RESULTS Of 88 GTFs implanted in 87 patients, 70 were successfully retrieved and 18 were left in place permanently. Forty-seven filters in 46 patients were removed after initial implantation with no need for percutaneous repositioning within the IVC to prolong dwell time (mean dwell time, 13 days). In the 23 patients who required repositioning of 23 GTFs within the IVC to prolong temporary caval filtration, the mean dwell time was 34.8 days; the mean number of repositioning procedures was 1.5, the mean time between repositioning procedures was 13.8 days, and the mean fluoroscopy time was 4.4 minutes in patients in whom filter retrieval was attempted. One patient underwent placement and subsequent removal of the GTF twice for perioperative prophylaxis against PE on two separate occasions. No filters were misplaced in an unintended location or tilted (>15 degrees ) in relation to the main caval axis after deployment. In one patient, a GTF became permanently fixed in the IVC 16 days after initial implantation and could not be removed percutaneously. Nine patients had mild or moderate-sized cervical hematomas. One patient had recurrent asymptomatic PE 2 months after filter insertion. CONCLUSION Dwell times of 14 days can be achieved in most patients before device removal. Prolongation of the dwell time beyond 14 days can be safely and easily achieved by performing percutaneous repositioning of the device within the IVC via a jugular approach.

Mechanical and Enzymatic Thrombolysis for Massive Pulmonary Embolism

PURPOSE To assess the efficacy and safety of mechanical fragmentation combined with intrapulmonary thrombolysis in massive pulmonary thromboembolism (PTE) with hemodynamic impairment. MATERIALS AND METHODS Fifty-nine patients diagnosed with massive PTE with hemodynamic impact were treated. The initial clinical symptoms were shock in 23 patients (38.9%), syncope in eight (13.5%), and dyspnea at rest in 28 (47.4%). Mean O2 saturation was 67.8%. Mean pulmonary artery pressure (PAP) was 42.1 mm Hg. During fragmentation, thrombolysis was administered in the form of a urokinase bolus of 200,000-500,000 U in 57 patients and 20 mg of recombinant tissue plasminogen activator (rt-PA) in two patients. The mean urokinase dose used was 2,500,000 IU, whereas the total dose of rt-PA was 100 mg. Heparin sodium infusion was performed to reach activated partial thromboplastin time ratios of 2. The follow-up consisted of clinical assessment, pulmonary scintigraphy, and echocardiography. The patients received treatment with dicoumarin for 6 months after the procedure. RESULTS Clinical improvement was seen in 56 patients (94%). Three patients died. The mean PAP after the treatment was 21.8 mm Hg. The mean posttreatment Miller index was 0.35. Technical success was achieved in all cases and clinical symptoms improved in all cases except those in which the patients died. Pulmonary scintigraphy showed improved perfusion in all cases. Echocardiography was performed after 3-6 months, showing a mean pressure of 22.8 mm Hg (corrected values). There were no signs of recurrent PTE or arterial hypertension in the follow-up. CONCLUSION The data provided confirm the efficacy and safety of mechanical fragmentation and pharmacologic thrombolysis in the treatment of massive PTE with hemodynamic impairment, showing improvement of symptoms and a decrease in PAP.

Animal experience in the Günther Tulip retrievable inferior vena cava filter.

AbstractPurpose: To assess the retrievability of the Gunther Tulip temporary inferior vena cava filter from a technical viewpoint, and consider the histopathologic changes that occur at the anchoring site of the filter prongs to the vein endothelium in Landrace pigs. Methods: Twenty-two Gunther Tulip retrievable filters were inserted in 22 experimental Landrace pigs via the jugular vein. Device implantation time was 0, 3, 7, 12, 14, 15, 16, 20, 30, 35 and 56 days. Study subjects were divided into two groups. In one group the filter was retrieved percutaneously via the jugular vein whereas in the other group it was removed surgically. The specimens obtained (vena cava and filter) were histopathologically examined. Prior to filter retrieval, a venacavography was obtained in all cases. Degree of retrieval difficulty was rated as follows: no difficulty (N), slight (S), mild (M), high (H) and unretrievable (U). Results: Of the 22 implanted filters, 11 should have been removed percutaneously but this was impossible in three cases (U). In four cases the device was retrieved with no difficulty (N); in two cases the degree of difficulty was mild (M) and in other two it was high (H) and slight (S) respectively. Retrieval difficulties were observed after 16 days. Starting from day 20, there was evidence of fibrosis with thick intimal proliferation and total filter prong involvement, which accounts for the difficulty in retrieving the device. Conclusions: It is advisable not to exceed a filter retrieval time of 16 days in view of the fibrotic changes reported. It might be necessary to perform a larger study with more animals and with retrieval times between 14 and 20 days.

Radiation myelopathy in over-irradiated patients: MR imaging findings

Abstract. The objective of this work is to report the MRI findings in patients with radiation myelopathy due to accidental local over-irradiation syndrome. Eight patients (seven males and one female) were suffering from over-irradiation syndrome as a result of treatments from a malfunctioning linear electron accelerator. The mean accidental estimated dose was 136 Gy delivered to the “open-neck” (seven cases) and to the thoracic wall (one case), during a mean of 5.4 sessions (range 1–9 sessions). Paresthesia and weakness in the upper extremities were the earliest symptoms (87.5 %), with evolution to paralysis in all patients. No patient is alive (mean survival time 64 days). In all cases MRI was negative for neurologic lesions in the acute phase ( < 90 days from irradiation; Radiation Therapy Oncology Group scoring system). Late signs of radiation myelitis manifested as high-intensity signals on T2-weighted images in three patients, and as Gd-DTPA enhancement of T1-weighted images in one case. Autopsies performed on four patients who died in acute phase showed morphologic alterations in white matter: edema in 75 %, and necrosis and glial reaction as well as obliterative vasculitis in all cases. In cases of over-irradiation, MRI may be normal in acute phase even if the patients have severe neurologic deficit, as positive MRI findings appear only in delayed radiation myelitis.

Retrievability of Uncoated Versus Paclitaxel-coated Günther-Tulip IVC Filters in an Animal Model

PURPOSE To compare in a pilot study, the retrievability and inferior vena cava (IVC) wall reaction elicited by uncoated and paclitaxel-coated Günther-Tulip filters in the animal model. MATERIALS AND METHODS Three groups with five pigs each underwent infrarenal IVC implantation of Günther-Tulip filters. Paclitaxel-coated filters were used in Groups A and B and uncoated filters were used in Group C. Filters were removed at 14, 19, 22, 26, and 30 days after implantation. A laparotomy was performed to remove filters from animals in group A and filters from animals in groups B and C that could not be retrieved via the right transjugular approach. Filter-induced venous wall changes were evaluated by examination of IVC venography, feasibility of filter removal at different implantation times, and laparotomy and microscopic findings. Feasibility of filter retrieval and venous wall changes were correlated. RESULTS IVC cavography showed no abnormality. Filters in animals in group B were uneventfully removed by a right jugular approach. Uncoated filter removal was not feasible in three of five animals in group C (19, 22, and 26 days). Microscopically, animals in group A had absent filter-induced IVC wall changes at 14, 19, 22, and 26 days and minimal changes at 30 days post implantation; animals in group B had absent filter-induced IVC wall changes at 14, 19, and 22 days and minimal changes at 26 and 30 days; animals in group C had moderate filter-induced IVC wall changes at 14 days and severe changes at 19, 22, 26, and 30 days. CONCLUSIONS This pilot study suggests that endothelial reaction to the presence of IVC filters in the porcine model is diminished by addition of paclitaxel coating to these filters. Further studies are necessary to substantiate these results.

Fragmentación mecánica y fibrinólisis intrapulmonar en el tratamiento del tromboembolismo pulmonar masivo con repercusión hemodinámica

Objetivos Evaluar la eficacia y seguridad de la fragmen-tacion mecanica asociada a trombolisis intrapulmonar en el tromboembolismo pulmonar (TEP) masivo con alteracion hemodinamica. Material y metodo Un total de 51 pacientes diagnosti-cados de TEP masivo con repercusion hemodinamica. Se in-cluyeron bajo este epigrafe pacientes con TEP agudo con un indice de Miller superior a 0,50 y una presion medida en la arteria pulmonar principal superior 30 mmHg. Cuadro cli-nico de inicio: 19 shock, 6 sincope y 26 disnea intensa de reposo. La saturacion de O 2 medida por pulsioximetria: 71,4%. Presion media en arteria pulmonar: 46,1 mmHg. Se realizo fragmentacion de los tromboembolos mas importan-tes. Durante la fragmentacion se administro un bolo de fi-brinolitico. A traves del cateter se administro infusion de fibrinolitico. El seguimiento se realizo con valoracion clini-ca, gammagrafica pulmonar y ecocardiografica. Resultados Tras la fragmentacion y administracion del bolo de trombolitico se observo mejoria clinica en 49 pacien-tes (97,2%). La presion media postratamiento mecanico y farmacologico fue de 24,1 mmHg. Exito tecnico del 100%. Conclusiones Los datos aportados avalan la eficacia y se-guridad de la fragmentacion mecanica y trombolisis farma-cologica en el tratamiento del TEP masivo con afectacion hemodinamica, mejorando la sintomatologia y disminuyen-do la presion arterial pulmonar.

Geochemical processes controlling water salinization in an irrigated basin in Spain: Identification of natural and anthropogenic influence

Salinization of water bodies represents a significant risk in water systems. The salinization of waters in a small irrigated hydrological basin is studied herein through an integrated hydrogeochemical study including multivariate statistical analyses and geochemical modeling. The study zone has two well differentiated geologic materials: (i) Quaternary sediments of low salinity and high permeability and (ii) Tertiary sediments of high salinity and very low permeability. In this work, soil samples were collected and leaching experiments conducted on them in the laboratory. In addition, water samples were collected from precipitation, irrigation, groundwater, spring and surface waters. The waters show an increase in salinity from precipitation and irrigation water to ground- and, finally, surface water. The enrichment in salinity is related to the dissolution of soluble mineral present mainly in the Tertiary materials. Cation exchange, precipitation of calcite and, probably, incongruent dissolution of dolomite, have been inferred from the hydrochemical data set. Multivariate statistical analysis provided information about the structure of the data, differentiating the group of surface waters from the groundwaters and the salinization from the nitrate pollution processes. The available information was included in geochemical models in which hypothesis of consistency and thermodynamic feasibility were checked. The assessment of the collected information pointed to a natural control on salinization processes in the Lerma Basin with minimal influence of anthropogenic factors.

Use of an introducer sheath for colonic stent placement

Abstract. We describe a technical modification of Wallstent implantation for the treatment of malignant rectosigmoid and descending colonic obstructions. The modification is the routine placement of an introducer sheath via the rectum before stent implantation in order to straighten the rectosigmoid region. This device facilitates catheter and guide wire manipulations and obtaining specimen biopsies for histopathological studies. The introducer sheath has been used without complications in 21 consecutive patients.

Characterisation and modelling of mixing processes in groundwaters of a potential geological repository for nuclear wastes in crystalline rocks of Sweden

This paper presents the mixing modelling results for the hydrogeochemical characterisation of groundwaters in the Laxemar area (Sweden). This area is one of the two sites that have been investigated, under the financial patronage of the Swedish Nuclear Waste and Management Co. (SKB), as possible candidates for hosting the proposed repository for the long-term storage of spent nuclear fuel. The classical geochemical modelling, interpreted in the light of the palaeohydrogeological history of the system, has shown that the driving process in the geochemical evolution of this groundwater system is the mixing between four end-member waters: a deep and old saline water, a glacial meltwater, an old marine water, and a meteoric water. In this paper we put the focus on mixing and its effects on the final chemical composition of the groundwaters using a comprehensive methodology that combines principal component analysis with mass balance calculations. This methodology allows us to test several combinations of end member waters and several combinations of compositional variables in order to find optimal solutions in terms of mixing proportions. We have applied this methodology to a dataset of 287 groundwater samples from the Laxemar area collected and analysed by SKB. The best model found uses four conservative elements (Cl, Br, oxygen-18 and deuterium), and computes mixing proportions with respect to three end member waters (saline, glacial and meteoric). Once the first order effect of mixing has been taken into account, water-rock interaction can be used to explain the remaining variability. In this way, the chemistry of each water sample can be obtained by using the mixing proportions for the conservative elements, only affected by mixing, or combining the mixing proportions and the chemical reactions for the non-conservative elements in the system, establishing the basis for predictive calculations.

Ileocolic Arteriovenous Fistula with Superior Mesenteric Vein Aneurism: Endovascular Treatment

We report a case of a venous aneurysm secondary to an acquired ileocolic arteriovenous fistula in a 64-year-old woman with recurrent abdominal pain and history of appendectomy. The aneurysm was diagnosed by ultrasound and computed tomography. Angiography showed an arteriovenous fistula between ileocolic branches of the superior mesenteric artery and vein. This vascular abnormality was successfully treated with coil embolization.