Interventional approaches to deep vein thrombosis

Successful Intravascular Ultrasound-Guided Thrombus Removal and Angioplasty for Phlegmasia Cerulea Dolens in a Young Male With a History of Multiple Lower Extremity Deep Vein Thrombosis

Phlegmasia cerulea dolens is a rare and severe form of deep venous thrombosis (DVT), characterized by an extensive thrombus burden and compromised venous outflow. We present the case of a 28-year-old male with a history of bilateral lower extremity DVTs and multiple venous stents who presented with acute-onset pain and swelling in the left lower extremity. Diagnostic imaging confirmed an acute DVT extending throughout the left lower extremity, including the external iliac vein. Given the diagnosis of phlegmasia cerulea dolens, a multidisciplinary approach involving interventional cardiology, orthopedic surgery, and vascular surgery was adopted. Intravascular ultrasound (IVUS)-guided thrombus removal and angioplasty were performed to restore venous outflow and improve limb perfusion. The procedure successfully removed a significant amount of thrombus and improved flow throughout the venous system. The patient exhibited an excellent clinical response, with pain resolution and improved perfusion. This case highlights the challenges and effectiveness of a combined intervention in managing complex phlegmasia cerulea dolens cases with previous venous stents.

Real-time device tracking under MRI using an acousto-optic active marker

PURPOSE

This work aims to demonstrate the use of an "active" acousto-optic marker with enhanced visibility and reduced radiofrequency (RF) -induced heating for interventional MRI.

METHODS

The acousto-optic marker was fabricated using bulk piezoelectric crystal and π-phase shifted fiber Bragg grating (FBGs) and coupled to a distal receiver coil on an 8F catheter. The received MR signal is transmitted over an optical fiber to mitigate RF-induced heating. A photodetector converts the optical signal into electrical signal, which is used as the input signal to the MRI receiver plug. Acousto-optic markers were characterized in phantom studies. RF-induced heating risk was evaluated according to ASTM 2182 standard. In vivo real-time tracking capability was tested in an animal model under a 0.55T scanner.

RESULTS

Signal-to-noise ratio (SNR) levels suitable for real-time tracking were obtained by using high sensitivity FBG and piezoelectric transducer with resonance matched to Larmor frequency. Single and multiple marker coils integrated to 8F catheters were readout for position and orientation tracking by a single acousto-optic sensor. RF-induced heating was significantly reduced compared to a coax cable connected reference marker. Real-time distal tip tracking of an active device was demonstrated in an animal model with a standard real-time cardiac MR sequence.

CONCLUSION

Acousto-optic markers provide sufficient SNR with a simple structure for real-time device tracking. RF-induced heating is significantly reduced compared to conventional active markers. Also, multiple RF receiver coils connected on an acousto-optic modulator can be used on a single catheter for determining catheter orientation and shape.

The efficacy of rotational pharmaco-mechanical thrombectomy in patients with acute iliofemoral deep vein thrombosis: Is the standard treatment of deep vein thrombosis changing?

OBJECTIVE

In this study, we aimed to evaluate the efficiency of rotational thrombectomy device in pharmaco-mechanical thrombolysis for symptomatic acute ilio-femoral deep vein thrombosis.

MATERIALS AND METHODS

Between August 2013 and May 2018,82 patients with acute deep vein thrombosis comprising the iliofemoral segment whom underwent Pharmaco-mechanical thrombolysis were evaluated retrospectively. The Cleaner thrombectomy device was used. The resolution of thrombi was examined and graded. Development of post-thrombotic syndrome was assessed with Villalta scores.

RESULTS

75 patients (91.4%) had complete thrombus resolution. Between 50-99% resolution was noted in 6 patients (7.4%) and in one (1.2%) case less than %50 thrombus resolution was obtained. Seventy-five patients (91%) of the cohort could be treated in a single session; 7 patients (8.6%) required reintervention(s). Although improved post-thrombotic syndrome rates were lower at the short term, Villalta scores gradually increased during follow up.

CONCLUSIONS

In conclusion, Pharmaco-mechanical thrombolysis with Cleaner thrombectomy device is a safe and beneficial method for the treatment of acute iliofemoral deep vein thrombosis. Long term follow up data of large volume multicenter studies are warranted.

Safety and Efficacy of Aspiration Thrombectomy or Pharmacomechanical Thrombectomy after Catheter-Directed Thrombolysis for the Treatment of Acute Iliofemoral Deep Vein Thrombosis

PURPOSE

To evaluate the safety and efficacy of additional aspiration thrombectomy (AT) or pharmacomechanical thrombectomy (PMT) after catheter-directed thrombolysis (CDT) for the treatment of acute iliofemoral deep vein thrombosis (AIFDVT).

MATERIALS AND METHODS

Between May 2017 and December 2018, 40 patients with AIFDVT were enrolled. Twenty underwent AT after CDT (CDTAT), while the remaining 20 underwent PMT using an AngioJetTM device after CDT (CDTPMT). Thrombus clearance was assessed using computed tomography venography at 1 week after the procedure, as follows: grade I, ≤50%; grade II, 51% to 75%; grade III, >75%. Grade III was considered a successful outcome. Treatment outcomes (thrombus clearance, thrombolytic therapy duration, urokinase dose, major complications, residual filter thrombosis, and Villalta score) were compared between the groups.

RESULTS

Successful thrombus clearance was achieved in 95% of the patients in both groups. Significant decreases in the thrombolytic therapy duration (P=0.018) and urokinase dose (P=0.014) were noted in the CDTPMT group. Major complications were not noted in both groups. Residual filter thrombi >10 mm were found in 6 filters in the CDTAT group and in 1 filter in the CDTPMT group (P=0.038). The Villalta scores at 6 months were 1.47±1.24 and 1.12±0.92 in the CDTAT and CDTPMT groups, respectively (P=0.372).

CONCLUSION

Both methods may be safe and effective management options for patients with AIFDVT. CDTPMT can reduce urokinase dosage, time and remained filter thrombus compared to CDTAT. Studies conducted in the future should compare the effects of overnight CDT followed by PMT with those of single-session PMT on patients with AIFDVT.

Radiation- and contrast medium-free catheter-directed thrombolysis for early pregnancy-related massive iliocaval deep venous thrombosis

Catheter-directed thrombolysis for iliofemoral deep venous thrombosis (DVT) aims to reduce acute leg symptoms and to prevent the post-thrombotic syndrome. There are no data from controlled trials in pregnant patients. Reports of thrombolysis for treatment of DVT during pregnancy are scarce. Pregnancy is considered a relative contraindication to thrombolytic therapy because of the risk of bleeding and concerns about the effects of radiation exposure on the fetus. We report on a catheter-directed thrombolysis procedure without radiation and contrast medium exposure in a first-trimester pregnant patient with massive iliofemoral DVT and free-floating thrombus extending to the suprarenal inferior vena cava.

Safety and efficacy of pharmacomechanical thrombolysis for acute and subacute deep vein thrombosis patients with relative contraindications

To evaluate the safety and efficacy of pharmacomechanical thrombolysis (PMT) performed for patients with relative contraindications.From June 2014 to December 2016, 112 patients with acute or subacute proximal deep vein thrombosis (DVT) were enrolled in this study. 60 patients (including 27 acute DVT patients and 33 subacute DVT patients) were treated with catheter-directed thrombolysis (CDT), and 52 patients with relative contraindications (including 25 acute DVT patients and 27 subacute DVT patients) with PMT. Assessment of venous recanalization was conducted using venography the time Inferior vena cava filter is removed, and complications were used to compare safety and efficacy between the groups.The outcomes of acute DVT patients no matter which kind of therapy performed, CDT or PMT, were significant better than subacute DVT patients (PCDT = .04 and PPMT = .01). However, there was no significant difference between CDT acute group and PMT acute group or between CDT subacute group and PMT subacute group (Pacute = .80 and Psubacute = .84). For complications of all patients, there was no mortality and major bleeding occurred.PMT could be a safe and effective management for DVT patients with relative contraindications, and the acute DVT may achieve better outcomes when they receive CDT or PMT.

Clinical implications of the anatomical variation of deep venous thrombosis

Introduction

Little is known about the anatomic variation and its implication in patients with lower limb deep venous thrombosis (DVT). We studied the clinical presentation, site of thrombosis and risk factors based on the anatomic distribution of lower limb DVT.

Methods

A retrospective analysis of clinically suspected DVT cases was conducted between 2008 and 2012. DVT was categorized by the location of the thrombosed segment and limb involved. The DVT anatomic segments were assessed according to left-to-right ratio, predisposing factors and clinical presentations.

Results

A total of 637 patients with DVT were included with a mean age of 50 ± 17 years (51%; females). The most frequently thrombosed segments were popliteal, posterior tibial and profunda femoris veins. DVT was more common at the left side, with a left-to-right ratio of 1.5:1. Bilateral DVT cases (38.5%) had more prior history of DVT as compared to left- (20.3%) and right-sided DVTs (22.6%); p = 0.01. Bilateral DVT was complicated more with post-thrombotic syndrome (leg ulcer) ( p = 0.02). The rates of pulmonary embolism (25%) and mortality (23.1%) were significantly higher for bilateral DVT in comparison to left- and right-sided DVT. Abnormal coagulation profile was significantly associated with posterior tibial DVT (81% vs. 71.4%; p = 0.01) as compared to patients with normal coagulation profile.

Conclusion

Lower limb DVTs are more common at the left side; however, patients with bilateral DVT have higher frequency of recurrence, post-thrombotic syndrome, pulmonary embolism and mortality. The anatomic segments of DVT show specific distribution depending on the predisposing factors. These findings could improve our understanding of the pathophysiology and management of DVT patients.

Pathogenesis of Thromboembolism and Endovascular Management

Venous thromboembolism (VTE), a disease that includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is associated with high mortality, morbidity, and costs. It can result in long-term complications that include postthrombotic syndrome (PTS) adding to its morbidity. VTE affects 1/1000 patients, costs $13.5 billion annually to treat, and claims 100,000 lives annually in the US. The current standard of care for VTE is anticoagulation, though thrombolysis may be performed in patients with PE and threatened limb. This review discusses pathogenesis and medical treatment of VTE and then focuses on endovascular treatment modalities. Mechanical- and catheter-directed thrombolysis (CDT) is discussed, as well as patient selection criteria, and complications. The first prospective study (CaVenT) comparing CDT with anticoagulation alone in acute DVT, despite study shortcomings, corroborates the existing literature indicating improved outcomes with CDT. The potential of the ongoing prospective, multicenter, randomized ATTRACT trial is also highlighted.

Bioprinted thrombosis-on-a-chip

Pathologic thrombosis kills more people than cancer and trauma combined; it is associated with significant disability and morbidity, and represents a major healthcare burden. Despite advancements in medical therapies and imaging, there is often incomplete resolution of the thrombus. The residual thrombus can undergo fibrotic changes over time through infiltration of fibroblasts from the surrounding tissues and eventually transform into a permanent clot often associated with post-thrombotic syndrome. In order to understand the importance of cellular interactions and the impact of potential therapeutics to treat thrombosis, an in vitro platform using human cells and blood components would be beneficial. Towards achieving this aim, there have been studies utilizing the capabilities of microdevices to study the hemodynamics associated with thrombosis. In this work, we further exploited the utilization of 3D bioprinting technology, for the construction of a highly biomimetic thrombosis-on-a-chip model. The model consisted of microchannels coated with a layer of confluent human endothelium embedded in a gelatin methacryloyl (GelMA) hydrogel, where human whole blood was infused and induced to form thrombi. Continuous perfusion with tissue plasmin activator led to dissolution of non-fibrotic clots, revealing clinical relevance of the model. Further encapsulating fibroblasts in the GelMA matrix demonstrated the potential migration of these cells into the clot and subsequent deposition of collagen type I over time, facilitating fibrosis remodeling that resembled the in vivo scenario. Our study suggests that in vitro 3D bioprinted blood coagulation models can be used to study the pathology of fibrosis, and particularly, in thrombosis. This versatile platform may be conveniently extended to other vascularized fibrotic disease models.

Ultrasound Assisted Endovascular Thrombolysis in Adolescents: 2 Case Reports

Descending iliofemoral thrombosis in children is a rare event. Anticoagulation therapy with low-molecular-weight-heparin is standard of care. However, patency cannot be achieved in all cases, increasing the risk for rethrombosis and postthrombotic syndrome. To reduce the risk of venous valve failure in adults, local catheter-directed thrombolysis is used to reopen vessels. Two adolescent girls (17 and 15 years old) presented with acute descending iliofemoral thrombosis of the left common iliac, external, and common femoral veins. Anticoagulation with enoxaparin was started until insertion of an EkoSonic Mach 4e catheter for ultrasound-assisted local thrombolysis with recombinant tissue plasminogen activator and administration of unfractionated heparin. Success was monitored by increases in D-dimer levels and ultrasound findings. After 24 hours respectively 48 hours, complete recanalization was obtained. No complication occurred except minimal local bleeding. Screening for hereditary thrombophilia revealed a heterozygous antithrombin mutation in 1 girl (ie, the 15-year-old). May-Thurner syndrome was identified in both girls, necessitating stenting of the left common iliac veins and continuation of anticoagulation therapy with enoxaparin and acetylsalicylic acid. No rethrombosis or complications occurred during the follow-up period. Ultrasound-assisted catheter-directed local thrombolysis with the EkoSonic Mach 4e system was effective in achieving immediate recanalization of the occluded veins and should be considered in children experiencing descending iliofemoral thrombosis. The fast recanalization might reduce the incidence of postthrombotic syndrome. May-Thurner syndrome is regularly found in these patients, and if present, requires stenting of the common iliac vein to avoid early reocclusion. However, long-term patency of iliac vein stenting in children remains to be examined.

Inferior Vena Cava Thrombosis

Thrombosis of the inferior vena cava (IVC) is an under-recognized entity that is associated with significant short- and long-term morbidity and mortality. In absence of a congenital anomaly, the most common cause of IVC thrombosis is the presence of an unretrieved IVC filter. Due to the substantial increase in the number of IVC filters placed in the United States and the very low filter retrieval rates, clinicians are faced with a very large population of patients at risk for developing IVC thrombosis. Nevertheless, there is a paucity of data and societal guidelines with regards to the diagnosis and management of IVC thrombosis. This paper aims to enhance the awareness of this uncommon, but morbid, condition by providing a concise, yet comprehensive, review of the etiology, diagnostic approaches, and treatment strategies in patients with IVC thrombosis.

Clinical Outcome of a Portosplenomesenteric Venous Thrombosis in Necrotizing Acute Pancreatitis with Protein C and S Deficiency Treated by Anticoagulation Therapy Alone

Cases of splanchnic venous thrombosis have not been described in Cameroon. Their prevalence in acute pancreatitis is variable. With the emergence of acute intra-abdominal infections including typhoid fever and peritoneal tuberculosis in situations of acquired immunodeficiency syndrome, these cases will become frequent. We report the case of a portosplenomesenteric venous thrombosis related to necrotizing acute pancreatitis associated with proteins C and S deficiency, in a 46-year-old Cameroonian man, without particular past medical history. He was admitted for abdominal pain which had been evolving for 3 weeks and accompanied by vomiting. In the absence of hemorrhagic risk factor, the patient received low molecular weight heparin followed by oral warfarin. The abdominal ultrasound check on the 12th day showed a partial recanalization of venous thrombosis. The abdominal contrast-enhanced CT scanner at day 30 on oral anticoagulation therapy showed collateral vessels and small bowel edema. At the same time the upper gastrointestinal endoscopy showed grade II esophageal varices. We have maintained oral anticoagulation therapy. This case highlights that an early effective anticoagulation heparin therapy is needed for a clear benefit in case of suspected PSMVT. It is certain that the sooner the treatment is given, the better outcome will be.

Endovascular Interventions for Acute and Chronic Lower Extremity Deep Venous Disease: State of the Art

The societal and individual burden caused by acute and chronic lower extremity venous disease is considerable. In the past several decades, minimally invasive endovascular interventions have been developed to reduce thrombus burden in the setting of acute deep venous thrombosis to prevent both short- and long-term morbidity and to recanalize chronically occluded or stenosed postthrombotic or nonthrombotic veins in symptomatic patients. This state-of-the-art review provides an overview of the techniques and challenges, rationale, patient selection criteria, complications, postinterventional care, and outcomes data for endovascular intervention in the setting of acute and chronic lower extremity deep venous disease. Online supplemental material is available for this article.

Successful treatment of phlegmasia cerulea dolens in a nonagenarian patient with chronic iliac vein occlusion using a Cleaner thrombectomy device

A 91-year-old man was admitted to the emergency room with a 3-day history of severe pain, swelling and cyanosis in his left leg. Duplex ultrasound findings were suggestive of acute left popliteal and iliofemoral venous thrombosis. Heparin was initiated and pharmacomechanical thrombolysis (PMT) was performed with the use of a Cleaner thrombectomy device. At the completion of PMT, repeat venography revealed chronic proximal iliac vein occlusion. After the procedure, alteplase was infused via the intra-arterial catheter at a rate of 0.5 mg/h over 24 h to clear the thrombus distal to the popliteal vein and residual thrombus. The patient's signs and symptoms improved markedly after the intervention. There were no minor or systemic bleeding problems. He was discharged home 10 days after the procedure without any complications.

[Recanalisation therapy of deep leg and pelvic vein thrombosis]

The conservative treatment of deep leg and pelvic vein thrombosis leads to permanent damage of recanalised veins, which in cases of long distance clots as well as involvement of the pelvic level, increase the risk of developing a postthrombotic syndrome. Such subsequent damage of the deep veins can only be avoided if occluded veins are rapidly recanalised and the function of the valves is successfully reestablished. Recanalisation may consist of surgical, fibrolytic and interventional methods and aims to minimize any subsequent damage; however no potential benefit of recanalisation versus standard treatment has yet been proven by means of methodologically adequate comparative studies. Thus, the indications for recanalisation must remain strict and be founded on a thorough risk-benefit assessment.

Acute pancreatitis complicated by massive inferior vena cava and right atrial thrombosis: a case report

Venous thrombosis is a relatively common complication of acute pancreatitis. A 58-year-old man came to our emergency department with abdominal pain. Pancreatitis complicated with a huge thrombosis through inferior vena cava (IVC) to right atrium and left renal vein was diagnosed. Gabexate and enoxaparin were administered for pancreatitis and thrombosis. Surgical removal of thrombosis was considered but was not possible because of poor general condition. Despite conservative management, the patient expired. We believe this is the first case of pancreatitis complicated by right atrial thrombosis.

In vitro demonstration of focused ultrasound thrombolysis using bifrequency excitation

Focused ultrasound involving inertial cavitation has been shown to be an efficient method to induce thrombolysis without any pharmacological agent. However, further investigation of the mechanisms involved and further optimization of the process are still required. The present work aims at studying the relevance of a bifrequency excitation compared to a classical monofrequency excitation to achieve thrombolysis without any pharmacological agent. In vitro human blood clots were placed at the focus of a piezoelectric transducer. Efficiency of the thrombolysis was assessed by weighing each clot before and after sonication. The efficiencies of mono- (550 kHz) and bifrequency (535 and 565 kHz) excitations were compared for peak power ranging from 70 W to 220 W. The thrombolysis efficiency appears to be correlated to the inertial cavitation activity quantified by passive acoustic listening. In the conditions of the experiment, the power needed to achieve 80% of thrombolysis with a monofrequency excitation is reduced by the half with a bifrequency excitation. The thermal effects of bifrequency and monofrequency excitations, studied using MR thermometry measurements in turkey muscle samples where no cavitation occurred, did not show any difference between both types of excitations when using the same power level.

Feasibility of identifying deep vein thrombosis characteristics with contrast enhanced MR-Venography

Purpose

To assess the feasibility of identifying deep vein thrombosis characteristics with contrast enhanced magnetic resonance venography.

Materials and Methods

A total of 53 cases of deep vein thrombosis extending in and/or above the common femoral vein were evaluated by 4 independent observers (2 expert, 2 novice) using pre-determined characteristics to determine the thrombosis present to be acute, sub-acute or old. If present, chronic remnants of a previous deep vein thrombosis were reported. Additionally these image qualifications were compared to the reported duration of complaints.

Results

In all cases all observers were able to qualify the thrombosis. The interobserver agreement between the experts was excellent (kappa 0.97) and good between expert and novice (kappa 0.82). Thrombosis identified as acute had an average duration of complaints of 6,5 (2–13) days, sub‐acute 13 (8–18) days and old 22 (15–32) days.

Conclusion

Qualification of thrombosis as acute, sub-acute or old and identification of chronic remnants of DVT with CE-MRV using routinely identifiable characteristics is feasible and reproducible with good to excellent interobserver agreement.

Basic data related to thrombolytic therapy for acute venous thrombosis

BACKGROUND

Treatment guidelines for thrombolysis in iliofemoral deep venous thrombosis (DVT) are based on a limited number of observational and prospective studies. The acute venous thrombosis: thrombus removal with adjunctive catheter-directed thrombolysis (ATTRACT) trial will be the first large, multicenter randomized control trial to evaluate the relative advantages of several current treatment strategies. The objective of this study was to summarize the existing data that inform the use of catheter-directed thrombolysis (CDT) or pharmacomechanical thrombectomy in the management of acute iliofemoral DVT.

METHODS

A search of the current literature was done using PubMed, Ovid, and Cochrane databases for all available articles published up to December 2013.

RESULTS

Of those studies, which included at least 25 patients, 19 case series were identified from 1996 to 2012. Treatment groups included anticoagulation, surgical thrombectomy, pharmacomechanical thrombectomy, and CDT. Cases observed in each ranged from 26 to 101. Three studies were identified which derived data from national multicenter registries. Only 2 randomized control trials were identified from 2002 to 2012. Both support the use of CDT over anticoagulation alone for treatment of iliofemoral DVT.

CONCLUSIONS

Present treatment guidelines for acute iliofemoral DVT have been in flux and are derived from a relatively small amount of clinical data. They are summarized here in anticipation of results from the ongoing ATTRACT trial.

A prospective randomized trial of catheter-directed thrombolysis with additional balloon dilatation for iliofemoral deep venous thrombosis: a single-center experience

PURPOSE

Catheter-directed thrombolysis (CDT) is effective for acute iliofemoral deep venous thrombosis (DVT), but CDT remains partially effective for subacute DVT. The aim of this study was to conduct a prospective randomized controlled single-centre clinical trial to compare CDT alone with CDT with additional balloon dilatation for the treatment of iliofemoral DVT.

METHODS

The trial was performed between February 2007 and January 2011. Iliofemoral DVT patients lacking effective therapy before enrollment were randomly assigned either to CDT (control group) or to CDT with additional balloon dilatation (intervention group). Insufficiency Epidemiological and Economic Study-Quality of Life (VEINES-QOL), Severity of Venous Lower Limb Symptoms (VEINES-Sym), 36-Item Short-Form Health Survey (SF-36), and Villalta scores were obtained at scheduled follow-up.

RESULTS

Seven hundred twenty-two patients were screened, and 386 eligible patients were randomized. No significant difference for mean total Villalta score was observed between the intervention group (4.20 ± 3.05) and the control group (4.89 ± 3.45). However, post hoc analysis of the scores in subacute patients showed significant differences between the intervention group and the control group from 1 month (6.79 ± 4.23, 8.28 ± 5.03, P = 0.02) to 24 months (4.21 ± 3.08, 5.67 ± 3.71, P = 0.006). A significant difference was also observed in subacute patients at the end of follow-up for VEINES-QOL/Sym (52.87 ± 6.52, 50.31 ± 6.07, P = 0.009; 51.87 ± 6.37, 49.72 ± 5.96, P = 0.02) and SF-36 PCS/MCS (45.02 ± 12.07, 41.13 ± 11.68, P = 0.03; 53.26 ± 11.43, 49.50 ± 11.06, P = 0.03).

CONCLUSION

Subacute iliofemoral DVT patients lacking effective therapy during acute phase, might receive more benefits from CDT with additional balloon dilatation. However, CDT alone is highly effective for acute patients.

Mechanical thrombectomy of iliac vein thrombosis in a pig model using the Rotarex and Aspirex catheters

PURPOSE

To investigate the efficacy and safety of mechanical thrombectomy for iliac vein thrombosis using Rotarex and Aspirex catheters in a pig model.

MATERIALS AND METHODS

Iliac vein thrombosis was induced in six pigs by means of an occlusion-balloon catheter and thrombin injection. The presence of thrombi was verified by digital subtraction angiography (DSA) and computed tomography (CT). Thrombectomy was performed using 6F and 8F Rotarex and 6F, 8F, and 10F Aspirex catheters (Straub Medical AG, Wangs, Switzerland). After intervention, DSA and CT were repeated to evaluate the efficacy of mechanical thrombectomy and to exclude local complications. In addition, pulmonary CT was performed to rule out pulmonary embolism. Finally, all pigs were killed, and iliac veins were dissected to perform macroscopic and histological examination.

RESULTS

Thrombus induction was successfully achieved in all animals as verified by DSA and CT. Subsequent thrombectomy lead to incomplete recanalization of the iliac veins with residual thrombi in all cases. However, the use of the 6F and 8F Rotarex catheters caused vessel perforation and retroperitoneal hemorrhage in all cases. Application of the Aspirex device caused one small transmural perforation in a vessel treated with a 10F Aspirex catheter, and this was only seen microscopically. Pulmonary embolism was detected in one animal treated with the Rotarex catheters, whereas no pulmonary emboli were seen in animals treated with the Aspirex catheters.

CONCLUSION

The Aspirex catheter allowed subtotal and safe recanalization of iliac vein thrombosis. In contrast, the use of the Rotarex catheter caused macroscopically obvious vessel perforations in all cases.