Selective thrombolysis in acute deep vein thrombosis: Evaluation of adjuvant therapy in vivo

Purpose: To evaluate in a porcine model of acute deep vein thrombosis (DVT) the efficacy of dalteparin and antithrombin with respect to heparin for local adjuvant therapy during selective thrombolysis, and the utility of nitroglycerin and iloprost as heparin supplements. Methods: DVT was induced in both hind limbs using a previously described technique (n = 20). Thirty minutes later, the animal was heparinized (2500 IU IV), and bilateral sequestrated thrombolysis was performed using 8 mg alteplase: both external iliac veins were endoluminally occluded with Swan-Ganz catheters, and a multi-sideport infusion wire coaxially introduced through each catheter and advanced into the ipsilateral popliteal vein. In the control limbs, tissue plasminogen activator (tPA) 8 mg was injected as 0.8-ml boluses at 3-min intervals for 2 hr as a 0.25-mg/ml solution containing heparin 50 IU/ml (n = 20). On the contralateral side, heparin was substituted with either dalteparin 50 IU/ml (n = 5) or antithrombin 12.5 IU/ml (n = 5), or supplemented with either nitroglycerin 0.075 mg/ml (n = 5) or iloprost (150 ng/ml) (n = 5). Blood samples were taken at predetermined intervals to measure the activated partial thromboplastin time (aPTT), prothrombin time (PT), and fibrinogen concentration. At autopsy, the thrombus mass in the iliofemoral veins was measured, and the extent of residual thrombosis in the venous tributaries graded at four sites. Results: Bilateral thrombolysis was successfully completed in all animals. The median thrombus mass in the iliofemoral veins after thrombolysis was 0.48 g (range 0.06–1.58 g), 0.95 g (0.59–1.29 g), 0.74 g (0.52–0.96 g), and 0.29 g (0.0–0.77 g) for dalteparin, antithrombin, iloprost, and nitroglycerin respectively, as compared with 0.53 g (0.18–0.88 g) (p = 0.69), 0.97 g (0.46–1.15 g) (p = 0.69), 0.53 g (0.48–1.10 g) (p = 0.69), and 0.18 g (0.13–1.04 g) (p = 0.5) for the respective controls. Likewise, the severity of residual thrombosis in the venous tributaries was not affected by the constituents of adjuvant therapy. Nitroglycerin induced a small drop in blood pressure, which was transient. The temporal change in aPTT was similar in all four groups. Invariably PT progressively shortened during thrombolysis (p = 0.0001); this effect was somewhat blunted with antithrombin. Fibrinogen levels demonstrated a time-dependent increase (p = 0.004) that was not influenced by the adjuvant therapy used. Conclusions: Dalteparin or antithrombin demonstrated no appreciable advantage over heparin as local adjuvant therapy for selective venous thrombolysis. Supplementation of heparin with iloprost or nitroglycerin also had virtually no effect on thrombolytic efficacy.     

Simulated flow pattern in massive pulmonary embolism: Significance for selective intrapulmonary thrombolysis

Purpose: The flow pattern in the central pulmonary arteries proximal to large pulmonary emboli was studied experimentally. The currents to which thrombolytic agents are exposed when administered via an intrapulmonary catheter were visualized in order to explain the lack of benefit of local versus systemic administration. Methods: By illumination of suspended microspheres, the flow pattern proximal to an obstructing embolus was visualized in an in vitro pulmonary arterial flow model. In six dogs massive pulmonary embolism was created. A pigtail catheter was positioned in the pulmonary artery immediately proximal to the central edge of the occluding embolus. To allow visualization of the local flow pattern, a small amount of contrast material (4 ml) was injected through the catheter at a high flow rate (25 ml/sec). The course of the radiopaque spot that emerged from the catheter tip within 160 msec was monitored with digital subtraction angiography at a frame rate of 12.5 frames/sec. In two dogs, the study was repeated after embolus fragmentation with the same catheter position. Results: The flow model study revealed formation of a vortex proximal to the occluding embolus. In vivo experiments showed that the radiopaque spot was whirled by the vortex proximal to the embolus and made only evanescent contact with the edge of the embolus. Regardless of the embolus location, the contrast spot was washed into the non-occluded ipsilateral and contralateral pulmonary arteries within 0.40–0.64 sec. After embolus fragmentation, the contrast spot was carried completely into the formerly occluded artery. Conclusion: Flow studies explain why thrombolytic agents administered via a catheter positioned adjacent to the embolus may have no more effect than systemically administered agents. An enhanced local effect is precluded by the rapid washout into the non-occluded pulmonary arteries and subsequent systemic dilution. These results support the practice of direct intrathrombic injection of thrombolytics or local thrombolysis as an adjunct to embolus fragmentation.     

Ultrasound thrombolysis in hemodialysis access: In vitro investigation

Purpose: To evaluate the effectiveness of ultrasound thrombolysis in occluded hemodialysis access shunts using an in vitro model. Methods: Thrombosed hemodialysis accesses were simulated by clotted bovine blood in a flow model (silicone tubing; inner diameters 4, 6, and 9 mm). After retrograde and antegrade sheath placement (7 Fr), mechanical thrombolysis was performed using an ultrasound probe (Acolysis, Angiosonics, Morrisville, NC, USA). The tip of the device measured 2.2 mm in diameter. During sonication, the catheter was moved slowly back and forth using an over-the-wire system. Thirty complete occlusions [tubing diameters 4 mm (n = 12), 6 mm (n = 12), 9 mm (n = 6)] were treated. Initial thrombus weights were 3.5 (± 0.76) g, 7.7 (± 1.74) g, and 19.4 (± 2.27) g for the three diameters. Maximum sonication time was 15 min for each probe. Results: With this device, we were able to restore a continuous lumen in all 12 occluded 4∼mm silicone tubes. No wall-adherent thrombi remained after sonication for 3.5–9.6 min. In hemodialysis access models with diameters of 6 mm, thrombus fragments persisted in 25% (3/12 accesses). These were located in the medial portion of the access loop and near to the puncture sites. However, flow was re-established after 5.0–13.0 min of treatment in all settings. Mechanical dissolution of thrombus material failed in five of six access models with diameters of 9 mm, even though ultrasound energy was applied for the maximum of 15 min. Conclusion: In a clotted hemodialysis shunt model, successful ultrasound thrombolysis was limited to small access diameters and small amounts of thrombus.     

Percutaneous Radiologic, Surgical Endoscopic, and Percutaneous Endoscopic Gastrostomy/Gastrojejunostomy: Comparative Study and Cost Analysis

Purpose: To compare the results and costs of three different means of achieving direct percutaneous gastroenteric access. Methods: Three groups of patients received the following procedures: fluoroscopically guided percutaneous gastrostomy/gastrojejunostomy (FPG, n= 42); percutaneous endoscopic gastrostomy/gastrojejunostomy (PEG, n= 45); and surgical endoscopic gastrostomy/gastrojejunostomy (SEG, n= 34). Retrospective review of the medical records was performed to evaluate indications for the procedure, procedure technical success, and outcome. Estimated costs were compared for each of the three procedures, using a combination of charges and materials costs. Results: Technical success was greater for FPG and SEG (100% each) than for PEG (84%, p= 0.008 vs FPG and p= 0.02 vs SEG). All patients (n= 7) who failed PEG subsequently underwent successful FPG. Success in placing a gastrojejunostomy was 91% for FPG, and estimated at 43% for PEG and 0 for SEG. Complications did not differ in frequency among groups. For gastrostomy, the average cost per successful tube was lowest in the PEG group ($1862, p= 0.02); FPG averaged $1985, and SEG $3694. SEG costs significantly more than FPG or PEG (p= 0.0001). For gastrojejunostomy, FPG averaged $2201, PEG $3158, and SEG $3045. Conclusion: Technical success for gastrostomy is higher for FPG and SEG than PEG. Though PEG is the least costly procedure, the difference is modest compared with FPG. For gastrojejunostomy, FPG offers the highest technical success rate and lowest cost. Due to high costs associated with the operating room, SEG should be reserved for those patients undergoing a concurrent surgical procedure.     

Diagnosis of vascular compression at the thoracic outlet using gadolinium-enhanced high-resolution ultrafast MR angiography in abduction and adduction

Gadolinium-enhanced magnetic resonance angiography allows rapid evaluation of the vascular structures of the thoracic outlet both in the neutral position and in abduction during one examination within FDA-approved dose limitations for contrast agents. The technique appears to be a good screening one for patients suspected of having vascular thoracic outlet syndrome.     

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

Purpose: 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. Methods: 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. Results: 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.     

Retrievable IVC square stent filter: Experimental study

Purpose: In vitro and in vivo evaluation of a new retrievable, home-made, inferior vena cava (IVC) Square stent filter (SSF) with two trapping levels. Methods: In vitro, the SSF was compared in a flow model with the stainless steel Greenfield filter (SGF) for emboli- trapping efficiency by serially passing 300 emboli of 3 and 6 mm in diameter and 15–30 mm in length in each type of filter. Nine swine were used for the in vivo testing of the SSF for deployment and retrievability, emboli-trapping efficiency, stability, and self-centering ability and two were used (total of 11 swine) for testing repositioning and retrievability of the SSF at 2 weeks and for gross and histologic IVC changes at 2 months. Results: In vitro, the SSF and SGF had similar efficiency in trapping large emboli but the SSF had significantly better efficiency than the SGF for trapping all sizes of emboli (91.7% vs 81%), medium size emboli (93% vs 80%), and small emboli (86% vs 69%). Efficiency decreased in both filters from the first to the fifth embolus in each series but was still significantly better for the SSF. With the SSF, 89% of emboli were caught at the primary and 11% at the secondary filtration level. In the nine animals used for acute studies, the SSF was easily placed in all 27 attempts, assumed a central position 26 times, and was easily retrieved in 21 of 22 attempts. One tilted filter needed additional manipulation for retrieval. During emboli injection in five swine, the SSF had 97.2% emboli-trapping efficiency and demonstrated good stability. In the two animals used for longer-term evaluation, the filters were easily retrieved 2 weeks after implantation. Histologic evaluation at 2 months showed neointimal proliferation around the SSF wires in contact with the IVC wall, which was otherwise normal. Conclusion: The SSF is a promising filter. It is easy to place and retrieve, is stable after placement, and has high efficiency for trapping emboli. Promising results justify further experimental and eventual clinical studies with a commercially manufactured SSF.     

Comparative Efficacy of Pulse-Spray Thrombolysis and Angioplasty Versus Surgical Salvage Procedures for Treatment of Recurrent Occlusion of PTFE Dialysis Access Grafts

Purpose: To compare the efficacy of surgery versus pulse-spray thrombolysis and angioplasty in patients with recurrent thrombosis of polytetrafluoroethylene (PTFE) dialysis access grafts. Methods: We analyzed 96 consecutive interventions for thrombosed PTFE dialysis access grafts in 18 patients. Primary patency after thrombolysis and angioplasty (n= 25) was compared with primary patency following thrombectomy alone (n= 50) or thrombectomy followed by graft revision (n= 21) using life-table analysis. A Cox proportional hazards model that accounted for graft age and number of previous interventions was used to generate the relative risk for recurrent occlusion following therapy. Results: Life-table analysis showed that patency after thrombolysis and angioplasty was greater than that following thrombectomy alone (p= 0.02). After accounting for the age of the graft and the number of previous interventions (average six per patient), the relative risk for recurrent occlusion [3.0; 95% confidence intervals (CI): 1.5, 6.4] was greater for thrombectomy alone than for thrombolysis/angioplasty [0.6; CI = 0.3, 1.3]. The relative risks of repeat occlusion following thrombolysis/angioplasty [0.6; CI = 0.3, 1.3] and thrombectomy/surgical revision [1.0; CI = 0.5, 1.7] were similar. Conclusion: Outcome data from our retrospective study on recurrent thrombosis of PTFE dialysis access grafts suggest that thrombolysis/angioplasty is superior to thrombectomy alone, and equivalent to thrombectomy/surgical revision.     

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

Purpose: To assess safety and function of central venous port systems implanted percutaneously in the interventional radiology suite. 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. 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. 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.     

The Diagnosis and Treatment of Intratesticular Varicocele

A case of varicocele is reported. The dilated veins were situated in the left testis. The diagnosis required color Doppler sonography. Successful treatment was performed by transcatheter embolization of the left spermatic vein. The control sonogram revealed complete regression. A literature search yielded only three previous cases of intratesticular varicocele. No data were found on the treatment of this entity. Received: 0/00/00/Accepted: 0/00/00     

Oscillating probe aspiration thrombectomy: ComparativeIn vitro evaluation of two concepts

Aspiration thrombectomy supported by an oscillating metal probe within the catheter allows continuous aspiration of large thrombi without catheter obstruction. Thrombus aspiration assisted by an ultrasound-driven probe (frequency 26 kHz) and by an electric motor-driven probe (frequency 40 Hz) was compared in two differentin vitro models: aspiration of large clots from a Petri dish and recanalization of thrombotic occlusions in a flow model. Comparable results were found for a 1 mm ultrasound-driven probe and a 0.5 mm motor-driven probe. The motor-driven device, however, seems to be more appealing forin vivo application because of its simplicity, probe flexibility, absence of thermal effects, and low cost.     

Percutaneous Introducibility of the Expandable Vascular Sheath System and Injury Potential of Balloon-Assisted Thrombectomy: Preliminary In Vivo Results

Purpose: To test the percutaneous introducibility of the expandable vascular sheath (EVS) system and the safety of percutaneous balloon-assisted thrombectomy. Methods: The EVS was inserted directly (n= 9) or through a 9.5 Fr regular vascular introducer sheath (n= 9) into the femoral arteries and veins and carotid arteries in four dogs (18–21 kg). Balloon-assisted thrombectomies were simulated in iliac arteries. Histologic examinations were done at sites of funnel deployment immediately (n= 4) and 25 days (n= 8) after the intervention. Results: The EVS was successfully introduced into six of nine vessels by a direct percutaneous approach. Balloon-assisted thrombectomy using the EVS device caused localized intimal denudation, disruption of the internal elastic lamina, and mild hemorrhages into the media; one arterial dissection at the site of funnel deployment was seen. All indirect insertions and funnel deployments were successful. Twenty-five days after the experiments, intimal hyperplasia was noted in all cases. Conclusion: Percutaneous balloon-assisted thrombectomy may cause mild vascular injuries. Direct percutaneous introduction of the EVS device cannot be recommended yet.     

Successful Intraarterial Thrombolysis of an Ischemic Limb Four Days After Laparoscopic Cholecystectomy

Intraarterial thrombolysis is usually contraindicated after abdominal surgery because of the risk of bleeding. However, it is a highly effective treatment for embolic acute limb ischemia, particularly for clearing the distal vessels. We report a case in which intraarterial thrombolysis was safely used 4 days after laparoscopic cholecystectomy in a patient with an acutely ischemic leg due to embolus.     

Stent Placement on Fresh Venous Thrombosis

Purpose: To report on the efficacy of fixing fresh venous thrombus to the venous wall by stent placement. Methods: Seven patients underwent stenting to treat acute venous thrombosis. In two patients, the hemodialysis fistula was thrombosed with the thrombus extending into the brachial veins. In three patients, the hemodialysis fistula was patent but massive swelling of the ipsilateral arm was caused by proximal venous thrombosis. Two patients presented with iliac venous thrombosis within stented pelvic veins. Stent placement was preceded by other mechanical thrombectomy methods in all cases. Results: Attachment of thrombus to the venous wall was successful in all cases treated. Acute rethrombosis did not occur. Follow-up patency in dialysis patients was 7.2 ± 2.1 months. One patient had rethrombosis of the dialysis graft 3 months after primary treatment. Three patients developed restenosis within a mean period of 7.7 months. One shunt remained patent for 10 months with no event of reobstruction during follow-up. In both patients with iliac stent placement, the vein remained patent over a follow-up period of 8 and 12 months respectively. Conclusion: Stenting fresh venous thrombus can achieve immediate venous patency. It may be used as an alternative approach when all other percutaneous methods fail. Frequent restenosis within stented veins limits its use to very selected cases. Received: 0/00/00/Accepted: 0/00/00     

Evaluation and complications of direct graft puncture in thrombolysis and other interventional techniques

Purpose: To evaluate the value and complications of direct graft puncture in conducting interventional procedures in synthetic vascular bypass grafts. Methods: We retrospectively reviewed 65 direct graft punctures in 50 patients undergoing a variety of interventional vascular procedures. In two patients the grafts were found to be infected and the procedures abandoned. Results: Complications encountered included hematomas that did not require treatment in three patients, and four hematomas requiring surgical drainage. One graft became infected (despite prophylactic cefuroxime), after three consecutive punctures over a 10-day period for a variety of interventions. All the patients who developed hematomas had undergone pharmacological thrombolysis. Conclusion: Direct graft puncture is a relatively safe technique, with a minimal risk of infection and hemostatic complications attributable to thrombolysis. In 31 of the 41 patients undergoing successful thrombolysis, additional percutaneous procedures were undertaken, and these were facilitated by the direct graft puncture route.     

Recurrent TIPS failure associated with biliary fistulae: Treatment with PTFE-covered stents

Purpose: To evaluate the efficacy of covered stents for the treatment of transjugular intrahepatic portosystemic shunt (TIPS) obstruction in human subjects with identified or suspected biliary fistulae. Methods: Five patients were treated for early failure of TIPS revisions. All had mid-shunt thrombus, and four of these had demonstrable biliary fistulae. Three patients also propagated thrombus into the native portal venous system and required thrombolysis. TIPS were revised in four patients using a custom-made polytetrafluoroethylene (PTFE)-covered Wallstent, and in one patient using a custom-made PTFE-covered Gianturco Z-stent. Results: All identified biliary fistulae were successfully sealed. All five patients maintained patency and function of the TIPS during follow-up ranging from 2 days to 21 months (mean 8.4 months). No patient has required additional revision. Thrombosis of the native portal venous system was treated with partial success by mechanical thrombolysis. Conclusion: Early and recurrent failure of TIPS with mid-shunt thrombosis, which may be associated with biliary fistulae, can be successfully treated using covered stents. Stent-graft revision appears to be safe, effective, and potentially durable.     

Superselective Urokinase Infusion Therapy for Dorsalis Pedis Artery Occlusion in Buerger's Disease

Occlusion of the proximal left dorsalis pedis artery (DPA) in a patient with Buerger's disease was treated by continuous urokinase intraarterial infusion using a microcatheter. Recanalization of the DPA and healing of a toe ulcer were achieved. The patient remains asymptomatic during a 4-year follow-up. Received: 0/00/00/Accepted: 0/00/00     

In Vitro Evaluation of a Rheolytic Thrombectomy System for Clot Removal from Five Different Temporary Vena Cava Filters

Purpose: To evaluate the feasibility of thrombus removal from temporary vena cava filters using a rheolytic thrombectomy device and to assess the embolization rate of this procedure. Methods: Five temporary vena cava filters together with porcine thrombi were placed in a vena cava flow model (semitranslucent silicone tube of 23 mm diameter, pulsatile flow at a mean flow rate of 4 L/min). A rheolytic thrombectomy system (Hydrolyser) was used with a 9 Fr guiding catheter to remove the clots. The effluent was passed through filters of different size and the amount of embolized particles as well as the remaining thrombus were measured. Results: Thrombus removal rates ranged from 85% to 100%. Embolization rates between 47% and 60% were calculated for the different filters. Conclusion: The Hydrolyser is able to remove sufficiently high amounts of thrombus from temporary vena cava filters. However, the amount of embolized particles makes it impossible to utilize this method without special precautions against embolization. Received: 0/00/00/Accepted: 0/00/00     

Catheter direct thrombolysis: Role of actilyse in treatment of acute deep venous thrombosis

Purpose

To evaluate the short and long term efficiency of catheter directed thrombolysis using recombinant tissue type plasminogin activator (r-TPA; Actilyse), in treating acute deep venous thrombosis of the lower limb.

Material and methods

Twenty-eight patients with acute lower limb deep venous thrombosis underwent treatment by direct intra clot injection of thrombolytic therapy; Actilyse.

Result

Thrombus lysis was completed in 23 (82.2%) of 28 patients, partial in 4 (14.3%) patients and not achieved in one (3.5%) patient. There was no major complication. There was no rethrombosis or post thrombotic syndrome in any of the treated 23 patients over the follow up period of one year.

Conclusion

The treatment of acute lower limb deep venous thrombosis using recombinant tissue type plasminogin activator (r-TPA; Actilyse), is safe, effective and achieves significantly better short and long term clinical outcome for patients.     

Peripheral venous access ports: Outcomes analysis in 109 patients

Purpose: To perform a retrospective outcomes analysis of central venous catheters with peripheral venous access ports, with comparison to published data. Methods: One hundred and twelve central venous catheters with peripherally placed access ports were placed under sonographic guidance in 109 patients over a 4-year period. Ports were placed for the administration of chemotherapy, hyperalimentation, long-term antibiotic therapy, gamma-globulin therapy, and frequent blood sampling. A vein in the upper arm was accessed in each case and the catheter was passed to the superior vena cava or right atrium. Povidone iodine skin preparation was used in the first 65 port insertions. A combination of Iodophor solution and povidone iodine solution was used in the last 47 port insertions. Forty patients received low-dose (1 mg) warfarin sodium beginning the day after port insertion. Three patients received higher doses of warfarin sodium for preexistent venous thrombosis. Catheter performance and complications were assessed and compared with published data. Results: Access into the basilic or brachial veins was obtained in all cases. Ports remained functional for a total of 28,936 patient days. The port functioned in 50% of patients until completion of therapy, or the patient's expiration. Ports were removed prior to completion of therapy in 18% of patients. Eleven patients (9.9% of ports placed) suffered an infectious complication (0.38 per thousand catheter-days)—in nine, at the port implantation site, in two along the catheter. In all 11 instances the port was removed. Port pocket infection in the early postoperative period occurred in three patients (4.7%) receiving a Betadine prep vs two patients (4.2%) receiving a standard O.R. prep. This difference was not statistically significant (p = 0.9). Venous thrombosis occurred in three patients (6.8%) receiving warfarin sodium and in two patients (3%) not receiving warfarin sodium. This difference was not statistically significant (p = 0.6). Aspiration occlusion occurred in 13 patients (11.7%). Intracatheter urokinase was infused in eight of these patients and successfully restored catheter function in all but two instances. These complication rates are comparable to or better than those reported with chest ports. Conclusion: Peripheral ports for long-term central venous access placed by interventional radiologists in the interventional radiology suite are as safe and as effective as chest ports.