Clinical and Economic Evaluation of the Trellis-8 Infusion Catheter for Deep Vein Thrombosis

Histotripsy and Catheter-Directed Lytic: Efficacy in Highly Retracted Porcine Clots In Vitro

OBJECTIVE

Standard treatment for deep vein thrombosis (DVT) involves catheter-directed anticoagulants or thrombolytics, but the chronic thrombi present in many DVT cases are often resistant to this therapy. Histotripsy has been found to be a promising adjuvant treatment, using the mechanical action of cavitating bubble clouds to enhance thrombolytic activity. The objective of this study was to determine if histotripsy enhanced recombinant tissue plasminogen activator (rt-PA) thrombolysis in highly retracted porcine clots in vitro in a flow model of occlusive DVT.

METHODS

Highly retracted porcine whole blood clots were treated for 1 h with either catheter-directed saline (negative control), rt-PA (lytic control), histotripsy, DEFINITY and histotripsy or the combination of rt-PA and histotripsy with or without DEFINITY. Five-cycle, 1.5 MHz histotripsy pulses with a peak negative pressure of 33.2 MPa and pulse repetition frequency of 40 Hz were applied along the clot. B-Mode and passive cavitation images were acquired during histotripsy insonation to monitor bubble activity.

RESULTS

Clots subjected to histotripsy with and without rt-PA exhibited greater thrombolytic efficacy than controls (7.0% flow recovery or lower), and histotripsy with rt-PA was more efficacious than histotripsy with saline (86.1 ± 10.2% compared with 61.7 ± 19.8% flow recovery). The addition of DEFINITY to histotripsy with or without rt-PA did not enhance either thrombolytic efficacy or cavitation dose. Cavitation dose generally did not correlate with thrombolytic efficacy.

CONCLUSION

Enhancement of thrombolytic efficacy was achieved using histotripsy, with and without catheter-directed rt-PA, in the presence of physiologic flow. This suggests these treatments may be effective as therapy for DVT.

Assessment of bubble activity generated by histotripsy combined with echogenic liposomes

Objective.Histotripsy is a form of focused ultrasound therapy that uses the mechanical activity of bubbles to ablate tissue. While histotripsy alone degrades the cellular content of tissue, recent studies have demonstrated it effectively disrupts the extracellular structure of pathologic conditions such as venous thrombosis when combined with a thrombolytic drug. Rather than relying on standard administration methods, associating thrombolytic drugs with an ultrasound-triggered echogenic liposome vesicle will enable targeted, systemic drug delivery. To date, histotripsy has primarily relied on nano-nuclei inherent to the medium for bubble cloud generation, and microbubbles associated with echogenic liposomes may alter the histotripsy bubble dynamics. The objective of this work was to investigate the interaction of histotripsy pulse with echogenic liposomes.Approach.Bubble clouds were generated using a focused source in anin vitromodel of venous flow. Acoustic emissions generated during the insonation were passively acquired to assess the mechanical activity of the bubble cloud. High frame rate, pulse inversion imaging was used to track the change in echogenicity of the liposomes following histotripsy exposure.Main results.For peak negative pressures less than 20 MPa, acoustic emissions indicative of stable and inertial bubble activity were observed. As the peak negative pressure of the histotripsy excitation increased, harmonics of the excitation were observed in OFP t-ELIP solutions and plasma alone. Additional observations with high frame rate imaging indicated a transition of bubble behavior as the pulse pressure transitioned to shock wave formation.Significance.These observations suggest that a complex interaction between histotripsy pulses and echogenic liposomes that may be exploited for combination treatment approaches.

Imaging to intervention: Thoracic outlet syndrome

Thoracic outlet syndrome (TOS) is a clinical disorder resulting from compression of the neurovascular bundle of the lower neck and upper chest. TOS can be categorized into neurogenic, venous, and arterial subtypes which result from anatomical compression of the brachial plexus, subclavian vein, and subclavian artery, respectively. This can lead to neurogenic pain as well as vascular injury with thrombosis and thromboembolism. Interventional and diagnostic radiologists play a critical role in the imaging diagnosis and treatment of vascular TOS. Prompt imaging and endovascular management with surgical collaboration has been shown to provide the most successful and long-lasting clinical outcomes, from vessel patency to symptom relief. In this article, we review the anatomy and clinical presentations of TOS as well as the initial imaging modalities used for diagnosis. Furthermore, we detail the role of the diagnostic and interventional radiologist in the management of TOS, including pre-procedure and endovascular interventions, along with medical and surgical treatments. PRECIS: Diagnostic and Interventional Radiologists play a key role in diagnosis and management of vascular thoracic outlet syndromes and are critical for timely and successful outcomes.

Paget-Schroetter Syndrome (PSS) and Adjunctive Treatment With Mechanical Aspiration Thrombectomy and Catheter Directed Thrombolysis: A Case Report and Review of Literature

Paget-Schroetter syndrome, also known as venous thoracic outlet syndrome, is primarily an effort-induced thrombosis of the subclavian and axillary veins. Treatment modalities involve systemic anticoagulation, catheter-directed thrombolysis (CDT), and surgical decompression. Early endovascular intervention is noted to improve outcomes and result in symptomatic relief. Here we implore the usage of the novel mechanical aspiration thrombectomy device as an adjunct to CDT for the management of peripheral venous thrombosis and highlight it as a treatment option resulting in substantial radiological and symptomatic improvement.

(More than) doubling down: Effective fibrinolysis at a reduced rt-PA dose for catheter-directed thrombolysis combined with histotripsy

Deep vein thrombosis is a major source of morbidity and mortality worldwide. For acute proximal deep vein thrombosis, catheter-directed thrombolytic therapy is an accepted method for vessel recanalization. Thrombolytic therapy is not without risk, including the potential for hemorrhagic bleeding that increases with lytic dose. Histotripsy is a focused ultrasound therapy that generates bubble clouds spontaneously in tissue at depth. The mechanical activity of histotripsy increases the efficacy of thrombolytic therapy at doses consistent with current pharmacomechanical treatments for venous thrombosis. The objective of this study was to determine the influence of lytic dose on histotripsy-enhanced fibrinolysis. Human whole blood clots formed in vitro were exposed to histotripsy and a thrombolytic agent (recombinant tissue plasminogen activator, rt-PA) in a venous flow model perfused with plasma. Lytic was administered into the clot via an infusion catheter at concentrations ranging from 0 (control) to 4.54 μg/mL (a common clinical dose for catheter-directed thrombolysis). Following treatment, perfusate samples were assayed for markers of fibrinolysis, hemolysis, and intact red blood cells and platelets. Fibrinolysis was equivalent between the common clinical dose of rt-PA (4.54 μg/mL) and rt-PA at a reduction to one-twentieth of the common clinical dose (0.23 μg/mL) when combined with histotripsy. Minimal changes were observed in hemolysis for treatment arms with or without histotripsy, potentially due to clot damage from insertion of the infusion catheter. Likewise, histotripsy did not increase the concentration of red blood cells or platelets in the perfusate following treatment compared to rt-PA alone. At the highest lytic dose, a refined histotripsy exposure scheme was implemented to cover larger areas of the clot. The updated exposure scheme improved clot mass loss and fibrinolysis relative to administration of lytic alone. Overall, the data collected in this study indicate the rt-PA dose can be reduced by more than a factor of ten and still promote fibrinolysis when combined with histotripsy.

Assessment of histological characteristics, imaging markers, and rt-PA susceptibility of ex vivo venous thrombi

Venous thromboembolism is a significant source of morbidity and mortality worldwide. Catheter-directed thrombolytics is the primary treatment used to relieve critical obstructions, though its efficacy varies based on the thrombus composition. Non-responsive portions of the specimen often remain in situ, which prohibits mechanistic investigation of lytic resistance or the development of diagnostic indicators for treatment outcomes. In this study, thrombus samples extracted from venous thromboembolism patients were analyzed ex vivo to determine their histological properties, susceptibility to lytic therapy, and imaging characteristics. A wide range of thrombus morphologies were observed, with a dependence on age and etymology of the specimen. Fibrinolytic inhibitors including PAI-1, alpha 2-antiplasmin, and TAFI were present in samples, which may contribute to the response venous thrombi to catheter-directed thrombolytics. Finally, a weak but significant correlation was observed between the response of the sample to lytic drug and its magnetic microstructure assessed with a quantitative MRI sequence. These findings highlight the myriad of changes in venous thrombi that may promote lytic resistance, and imaging metrics that correlate with treatment outcomes.

Single-Session Treatment of Patients with Symptomatic Iliocaval and Iliofemoral Deep Vein Thrombosis: Technical Results of a Prospective Pilot Study

PURPOSE

To investigate the short-term results of single-session treatment of iliocaval and iliofemoral DVT using a single thrombectomy device.

MATERIALS AND METHODS

This prospective pilot study analyzed patients with acute iliocaval or iliofemoral DVT treated in a single session using the JETi thrombectomy system. All analyses were performed on an intention-to-treat basis. The cohort consisted of 53 limbs in 47 patients (27 women), with a mean age of 57 years (range, 16-88 years). The primary safety and efficacy endpoints were freedom from major adverse events (MAEs) and reestablishment of unobstructed flow in a single session, respectively.

RESULTS

The mean duration of symptoms was 8.5 days ± SD 9.2, with 10 patients (11 limbs, 21.3%) presenting with a symptom duration of >14 days. Twelve (25.5%) patients had thrombosis of the inferior vena cava and the iliofemoral segments. During the index procedure, unobstructed flow was reestablished in 47 of 53 (88.6%) limbs in 41 of 47 (87.2%) patients (primary endpoint) with no MAEs through 30 days. Overall, unobstructed flow was restored in 50 of 53 (94.3%) limbs and in 44 of 47 (93.6%) patients.

CONCLUSIONS

Successful single-session treatment of patients with acute iliocaval and iliofemoral DVT is feasible with a high rate of efficacy and a low rate of adverse events. Such patients may be treated on an outpatient basis.

Clot Degradation Under the Action of Histotripsy Bubble Activity and a Lytic Drug

Deep vein thrombosis is a major source of morbidity worldwide. For critical obstructions, catheter-directed thrombolytics are the frontline therapy to achieve vessel recanalization. Techniques that aid lytic therapy are under development to improve treatment efficacy and reduce procedure-related complications. Histotripsy is one such adjuvant under development that relies on focused ultrasound for in situ nucleation of bubble clouds. Prior studies have demonstrated synergistic effects for clot dissolution when histotripsy is combined with lytic therapy. The success of this combination approach is hypothesized to promote thrombolytic efficacy via two mechanisms: erythrocyte fractionation (hemolysis) and increased lytic activity (fibrinolysis). In this study, the contributions of hemolysis and fibrinolysis to clot degradation under histotripsy and a lytic were quantified with measurements of hemoglobin and D-dimer, respectively. A linear regression analysis was used to determine the relationship between hemoglobin, D-dimer, and the overall treatment efficacy (clot mass loss). A similar analysis was conducted to gauge the role of bubble activity, which was assessed with passive cavitation imaging, on hemolysis and fibrinolysis. Tabulation of these data demonstrated hemolysis and fibrinolysis contributed equally to clot mass loss. Furthermore, bubble cloud activity promoted the generation of hemoglobin and D-dimer in equal proportion. These studies indicate a multifactorial process for clot degradation under the action of histotripsy and a lytic therapy.

The Cleaner XT™ Device as an Endovascular Adjunct for Pharmacomechanical Thrombolysis of Thrombosed Arteriovenous Fistulas and Grafts

Objective: This paper documents our experience using the Cleaner XT™ device (Argon Medical Devices, Plano, TX, USA) for pharmacomechanical thrombolysis (PMT) of thrombosed haemodialysis arteriovenous grafts (AVG) and fistulas (AVF). Materials and Methods: This was a retrospective case series (n=17) over six months at Singapore General Hospital. We evaluated demographics, procedural data, technical and procedural success, patency rates and complications. Results: There were 8 (47%) males and the patients' mean age was 66 (± 5.7) years. The mean age of AVF/AVG was 1605 (± 1099) days. All procedures were performed under local anaesthetic. PMT was performed within a mean time of 40 (±34.3) hours from the presentation. Technical, clinical and procedural success was 15/17 (88%). The thrombolysis agents used were tissue plasminogen activator (52.9%) and urokinase (41.2%). Mean primary patency time was 114 (± 116) days, with a 65% 1-month and 47% 3-month primary patency rates. The mean secondary patency time was 155 (±132) days, with 76% one-month and 65% three-month secondary patency rates, respectively. AVF rupture occurred in 3/17 (18%) cases but did not involve loss of the access circuit. Conclusion: The Cleaner XT™ device is a safe, minimally invasive endovascular tool for PMT in thrombosed AVF/AVG, with relatively high success and low complication rates.

In Vitro Thrombolytic Efficacy of Single- and Five-Cycle Histotripsy Pulses and rt-PA

Although primarily known as an ablative modality, histotripsy can increase the efficacy of lytic therapy in a retracted venous clot model. Bubble cloud oscillations are the primary mechanism of action for histotripsy, and the type of bubble activity is dependent on the pulse duration. A retracted human venous clot model was perfused with and without the thrombolytic recombinant tissue plasminogen activator (rt-PA). The clot was exposed to histotripsy pulses of single- or five-cycle duration and peak negative pressures of 0-30 MPa. Bubble activity within the clot was monitored via passive cavitation imaging. The combination of histotripsy and rt-PA was more efficacious than rt-PA alone for single- and five-cycle pulses with peak negative pressures of 25 and 20 MPa, respectively. For both excitation schemes, the detected acoustic emissions correlated with the degree of thrombolytic efficacy. These results indicate that rt-PA and single- or multicycle histotripsy pulses enhance thrombolytic therapy.

Endovascular management of inferior vena cava filter thrombotic occlusion

Objective Inferior vena cava occlusion is a potentially life-threatening complication related to caval filters. We present our experience with filter-induced inferior vena cava occlusion in order to assess the feasibility, safety, and effectiveness of endovascular management. Methods A retrospective review of all patients undergoing inferior vena cava filter placement over a 60-month study period was performed. From this cohort, a total of 10 cases of inferior vena cava occlusion after filter placement were identified. Demographics, clinical data, procedures, and outcomes were extracted. Patients were followed to the last clinic visit or until they died. Results One-hundred eighty filters were placed by our group practice during the study period. Of those, a total of 10 patients were identified. Overall, there were 7 males; the mean age was 57.1 years (25-78 years). The median time between inferior vena cava filter placement and filter occlusion was 105 days (range 5-4745 days). All patients were clinically symptomatic at the time of their presentation. Nine out of 10 patients were successfully managed endovascularly. Trellis™-8 thrombectomy was the most common endovascular strategy performed ( n = 9). Four patients had balloon angioplasty, two of those with stent placement for chronically occluded inferior vena cava/iliac veins. No thromboembolic complications developed during a median follow-up period of 233 days (range 4-1083 days). Conclusions Endovascular management of inferior vena cava occlusion is feasible, safe, and effective in decreasing thrombus burden in the presence of an inferior vena cava filter. Further studies evaluating long-term inferior vena cava patency and optimal surveillance regimen after endovascular management of filter-related inferior vena cava occlusion are warranted.

Pharmacomechanical Catheter-Directed Thrombolysis for Deep-Vein Thrombosis

BACKGROUND

The post-thrombotic syndrome frequently develops in patients with proximal deep-vein thrombosis despite treatment with anticoagulant therapy. Pharmacomechanical catheter-directed thrombolysis (hereafter "pharmacomechanical thrombolysis") rapidly removes thrombus and is hypothesized to reduce the risk of the post-thrombotic syndrome.

METHODS

We randomly assigned 692 patients with acute proximal deep-vein thrombosis to receive either anticoagulation alone (control group) or anticoagulation plus pharmacomechanical thrombolysis (catheter-mediated or device-mediated intrathrombus delivery of recombinant tissue plasminogen activator and thrombus aspiration or maceration, with or without stenting). The primary outcome was development of the post-thrombotic syndrome between 6 and 24 months of follow-up.

RESULTS

Between 6 and 24 months, there was no significant between-group difference in the percentage of patients with the post-thrombotic syndrome (47% in the pharmacomechanical-thrombolysis group and 48% in the control group; risk ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.11; P=0.56). Pharmacomechanical thrombolysis led to more major bleeding events within 10 days (1.7% vs. 0.3% of patients, P=0.049), but no significant difference in recurrent venous thromboembolism was seen over the 24-month follow-up period (12% in the pharmacomechanical-thrombolysis group and 8% in the control group, P=0.09). Moderate-to-severe post-thrombotic syndrome occurred in 18% of patients in the pharmacomechanical-thrombolysis group versus 24% of those in the control group (risk ratio, 0.73; 95% CI, 0.54 to 0.98; P=0.04). Severity scores for the post-thrombotic syndrome were lower in the pharmacomechanical-thrombolysis group than in the control group at 6, 12, 18, and 24 months of follow-up (P<0.01 for the comparison of the Villalta scores at each time point), but the improvement in quality of life from baseline to 24 months did not differ significantly between the treatment groups.

CONCLUSIONS

Among patients with acute proximal deep-vein thrombosis, the addition of pharmacomechanical catheter-directed thrombolysis to anticoagulation did not result in a lower risk of the post-thrombotic syndrome but did result in a higher risk of major bleeding. (Funded by the National Heart, Lung, and Blood Institute and others; ATTRACT ClinicalTrials.gov number, NCT00790335 .).

Pharmacomechanical Thrombolysis for Deep Vein Thrombosis in May-Thurner Syndrome

Objective

Patients with May-Thurner syndrome presenting with acute deep vein thrombosis benefit from early lysis of clot and endovascular treatment. We evaluated the outcome of patients with May-Thurner syndrome who presented with deep vein thrombosis, managed with pharmacomechanical thrombolysis as the primary mode of intervention, in combination with angioplasty and stent placement.

Methods

We reviewed all patients with May-Thurner syndrome managed in our institution between January 2009 to December 2015. Patency rate and postthrombotic syndrome were evaluated as primary end points.

Results

A total of seven patients (6 females, 1 male) with a mean ± SD age of 48 ± 17 years and mean ± SD body mass index of 29.64 ± 7.25 kg/m2 were identified. Six patients presented with acute deep vein thrombosis and one presented with chronic venous insufficiency. Five patients underwent pharmacomechanical thrombolysis (TRELLIS and altepase) with concomitant stenting of the common iliac vein, one had only angioplasty with stent placement, and one had only pharmacomechanical thrombolysis. Median time from presentation to pharmacomechanical thrombolysis was 4 days (range = 1–9). Patency rate and postthrombotic syndrome at 12 months were 100% and 0%, respectively. No patient experienced major bleeding or pulmonary embolism. The median length of stay was 3 days (range = 0–4). There was no mortality associated with the procedure. The mean ± SD follow-up was 26 ± 15 months.

Conclusions

In patients with May-Thurner syndrome, pharmacomechanical thrombolysis is an effective approach for the management of acute deep vein thrombosis, decreasing thrombus burden, and long-term postthrombotic syndrome when used in conjunction with stenting.

Etiology and treatment of acute inferior vena cava thrombosis

Inferior vena cava thrombosis (IVCT) is a rare but severe disease that is associated with a high rate of mortality. IVCT can be categorized into primary versus secondary thrombosis dependent upon the underlying pathophysiology. The diagnosis includes both clinical probability assessment as well as the imaging evaluation. The optimal therapeutic strategy remains the target of continued research. Although anticoagulation therapy remains fundamental in treating IVCT, its inherent limitations have led to the use of minimally invasive, endovascular treatment options, including transcatheter thrombolysis, mechanical thrombectomy or a combination of these techniques. This review focuses on the etiology, diagnostic assessment, and endovascular treatment options for IVCT.

Pharmacomechanical Thrombectomy in Paget-Schroetter Syndrome

PURPOSE

The purpose of the study was to evaluate feasibility of pharmacomechanical thrombectomy (PMT) in the treatment of Paget-Schroetter syndrome (PSS) followed by thoracoscopic or open surgical decompression of the subclavian vein.

METHODS

Twenty-two out of 27 consecutive patients with PSS received PMT using the Trellis-8 peripheral infusion system (Covidien) between 2010 and 2014. Subsequent surgery was performed in 18 of those patients, 9 patients were treated with thoracoscopic, 7 patients with subclavicular, and 2 patients with transaxillary first rib resection, 4 patients were treated with PMT and anticoagulation alone. Technical success, complications, and patency were registered.

RESULTS

PMT was successful in 21 (95 %) patients; 1 patient with unsatisfactory lysis received further catheter-directed thrombolysis, which, however, did not improve the result. The mean endovascular procedure time was 105 ± 33 min (range 70-200 min), and the required median amount of thrombolytic agent was 500,000 international unit (IU; range 250,000-1,000,000 IU). Adjunctive balloon venoplasty and aspiration were used in 18 (82 %) and 7 (32 %) cases, respectively. One patient had an intimal tear of the subclavian vein that was discovered and repaired during surgery. There were no other complications related to the endovascular procedure. At follow-up, 18 of 21 patients (86 %) with follow-up imaging available had patent subclavian vein, and all except 1 of the 22 patients were asymptomatic. The mean follow-up time was 25 ± 17 months.

CONCLUSIONS

In experienced hands, PMT is effective for early thrombus removal in PSS. Surgical decompression must be considered after PMT.

A phantom model study to identify the most effective manual aspiration thrombectomy for acute deep-vein thrombosis of the lower extremity

AIM

To identify the most effective manual aspiration thrombectomy (MAT) method for the initial endovascular management of acute deep-vein thrombosis (DVT) in the lower extremity using a phantom model.

MATERIALS AND METHODS

An acute DVT phantom model was created by infusing a bovine acute thrombus in a 20-mm diameter, 120-cm long plastic tube with banding of the distal portion. A total of 32 types of aspiration methods using combinations of two aspiration catheters (8 and 10 Fr), four syringes (10, 20, 40, and 50 ml), and four different aspiration methods (I, II, III, and IV) were performed. Each method was performed 10 times. The total weight of the aspirated thrombus was measured and compared among the 32 aspiration methods. The aspiration methods were classified based on the length of the dynamic catheter withdrawal (0 cm [method I], 15 cm [II], 30 cm [III], or >45 cm [IV]) while maintaining continuous negative pressure using a syringe. Analysis of variance and Student's t-test were used for statistical analysis.

RESULTS

There were no statistically significant differences in the total amount of aspirated thrombus among the various types of aspiration catheters and syringes; however, different aspiration methods showed significantly different results. Acute thrombus was most effectively aspirated by method IV irrespective of the catheter and syringe used. The longer the length of dynamic catheter withdrawal, the greater the amount of total thrombi that could be aspirated, irrespective of the type of aspiration catheter and syringe used (IV > III > II > I; p<0.05).

CONCLUSION

MAT can be performed most effectively using method IV. Effective MAT relies on the length of the dynamic catheter withdrawal while maintaining continuous negative pressure using a syringe in the initial endovascular management of acute DVT in the lower extremity.

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.

A Multicenter, Retrospective Study of the Effectiveness of the Trellis-8 System in the Treatment of Proximal Lower-Extremity Deep Vein Thrombosis

BACKGROUND

Deep vein thrombosis (DVT) occurs in up to 600,000 patients in the United States annually and can lead to long-term morbidity because of the post-thrombotic syndrome. The multicenter isolated-pharmacomechanical thrombolysis device (ISOL-8) study was designed to determine the safety and efficacy of the Trellis™-8 peripheral infusion system when used as the primary intervention to achieve DVT thrombolysis in patients with proximal lower-extremity occlusive DVT, and track the incidence and severity of the post-thrombotic syndrome (PTS) symptoms in patients 2 years after treatment.

METHODS

Data were collected retrospectively from 6 centers on patients treated with the Trellis-8 system, an isolated-pharmacomechanical thrombolysis device (IPMTD). Patients with occlusive lower-extremity DVT involving at least the iliac and/or common femoral vein were included. Patient demographics, medical history, procedure outcomes, complications, and follow-up venous duplex and Venous Clinical Severity Score (VCSS) were collected through 24 months. Data analysis of outcomes were performed at 1 and 12 months. A 24-month analysis was not performed because of the small number of patients for whom 24-month data could be collected.

RESULTS

A total of 151 limbs in 139 patients were treated with IPMTD. The mean ± standard deviation (SD) procedure time was 122.6 ± 63.4 min. Single session treatment was delivered in 69.9% (93 of 133) of cases. Occlusive DVT extended from the femoral into the external and/or common iliac vessel segments in most of the cases (113 of 151 limbs; 74.8%). Before treatment, 23.2% (35 of 151) of the treated limbs, based on a history of prior ipsilateral DVT or preoperative imaging revealing chronic venous scar, were expected to have some chronic venous disease despite presenting with acute symptoms. After treatment, 43.7% (66 of 151) of the limbs showed evidence of chronic thrombus. The average amount (mean ± SD) of thrombolysis, as determined by venogram, was highest in patients who had acute thrombus (81 ± 19.7%), compared with subacute thrombus (61 ± 22.5%) and complex cases involving acute and/or subacute thrombus on chronic scar (56 ± 26.5%). VCSS scoring showed the number of patients with none and/or mild pain, varicose veins, and skin changes at 1-month remained stable at 12 months whereas the percent of patients with none and/or mild venous edema improved from 71.7% at 1 month (38 of 53) to 86.8% (46 of 53) at 12 months. Twenty-four-month follow-up data were available for only 15% (23 of 151) of patients. No clinically significant pulmonary emboli or major periprocedural bleeding events were reported.

CONCLUSIONS

Patients with acute lower-extremity DVT involving the proximal veins can be safely and successfully treated with IPMTD. Major procedural bleeding was absent. The occurrence of severe PTS after primary treatment with Trellis-8 system IPMTD is low. Further long-term follow-up data are needed to confirm the benefit of intervention for thrombus removal compared with standard medical management.

Iliofemoral deep vein thrombosis: Percutaneous endovascular treatment options

Venous thromboembolism is defined as an acute venous thrombotic event that targets two disease entities: deep vein thrombosis (DVT), pulmonary embolism, or both. The most common site of DVT origin is in the lower extremities, with 50% of patients exhibiting no symptoms. Although anticoagulation is the gold standard for DVT, early clot removal, especially of proximal iliofemoral DVT, is felt to reduce the incidence of postthrombotic syndrome (PTS) by preserving valve function. Up to one-half of all patients with an iliofemoral DVT treated only with anticoagulation subsequently develop long-term complications, including PTS. Beside anticoagulation, DVT treatment options may include pharmaceutical and/or mechanical therapies. Mechanical therapies consist of either endovascular percutaneous catheter-directed (PCD) interventions or open operative thrombectomy. There are several different PCD procedures available, consisting of catheter-directed thrombolysis, mechanical thrombectomy, combination pharmacomechanical devices, and postthrombus extraction (angioplasty and/or stenting). Endovascular therapies in the management of acute iliofemoral DVT are evolving with a variety of devices available to treat this disease entity. The purpose of this article is to provide an overview of the PCD therapies used when treating patients experiencing an acute iliofemoral DVT along with associated nursing considerations. Off-label device use is not included.

Paget-Schroetter syndrome: A review and Algorithm (WASPS-IR)

Venous compression syndromes are rare and occur due to the entrapment of vein(s) in confined anatomical spaces bounded by osseous and non-osseous structures. Here we present a review of Paget-Schroetter Syndrome, an important cause of upper extremity of deep vein thrombosis, its associated clinical and radiological findings as well as treatment options.

Diagnosis and management of iliac vein thrombosis in pregnancy resulting from May-Thurner Syndrome

One of the least recognized risks for the development of deep venous thrombosis (DVT) is iliac vein compression or the May-Thurner Syndrome (MTS), in which most often, the right common iliac artery compresses the subjacent left common iliac vein. We present three patients with MTS complicated by massive left lower extremity DVT managed with percutaneous pharmacomechanical thrombectomy during pregnancy. Although often not considered in obstetrics, percutaneous therapies to resolve extensive thrombosis should be considered in pregnant women, as they have the potential to improve symptoms and mitigate the risk of developing post-thrombotic syndrome.

Thrombectomy without lysis: the future?

The results of the CaVent-study and the expected results of the ATTRACT and CAVA trials will form the base of evidence to support that rapid cloth removal is beneficial for patients with iliofemoral DVT. Although beneficial, there are still significant risks associated with this therapy. Therefore alternative methods for rapid cloth removal without lysis are a potential valid alternative. In this article we describe the techniques currently available for thrombolysis and discuss the potential improvements to be made to clot removal techniques in the future.

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.

Pharmacomechanical thrombolysis in the management of paget-schroetter syndrome

Paget-Schroetter syndrome (PSS) is a rare form of thoracic outlet syndrome caused by axillosubclavian vein thrombosis which typically presents in healthy young adults. Prompt therapy, traditionally by means of catheter-directed thrombolysis (CDT) prior to definitive surgery, can prevent the subsequent onset of postthrombotic syndrome (PTS) and considerable disability. As CDT is associated with major haemorrhage and high overall treatment cost, pharmacomechanical thrombectomy (PMT) seems to be an attractive alternative which combines pharmacological thrombolysis with mechanical clot disruption. The Trellis-8 peripheral infusion catheter is an example of such a treatment which provides topical thrombolysis in an isolated zone. We describe the use of the Trellis-8 PMT system in the successful management of three patients with PSS.

Use of a Trellis device for endovascular treatment of venous thrombosis involving a duplicated inferior vena cava

Congenital anomalies of the inferior vena cava (IVC) are increasingly recognized with CT and venography techniques. Although many patients with IVC anomalies are asymptomatic, recent studies have suggested an association with venous thromboembolism. We report the case of a 62-year-old woman with extensive venous clot involving the infrarenal segment of a duplicated left IVC who underwent pharmacomechanical thrombectomy and tissue plasminogen activator catheter-directed thrombolysis with complete deep venous thrombosis resolution. To our knowledge this is the first reported case in the English literature of the use of a Trellis thrombectomy catheter in the setting of duplicated IVC.

Biochemical dynamics relevant to the safety of low-dose, intraclot alteplase for deep vein thrombosis

Intraclot tissue plasminogen activator (tPA) has been shown to be an effective treatment for deep vein thrombosis (DVT) (Radiology 2008;246:619 and J Vasc Interv Radiol 2011;22:1107). We sought to correlate pharmacokinetics of tPA, fibrinogen, fibrinolytic inhibitors, and D-dimers with the safety and efficacy of intraclot tPA. Thirty subjects received intraclot tPA for lower extremity DVT by infiltrating the thrombus with ≤10 mg doses tPA in an open-label study, using a pulse-spray catheter. We measured various parameters over 8 h following a first dose of tPA. Mean tPA levels of 75 units per mL (95% confidence interval 19-131 units/mL) were seen immediately after administration of a mean tPA dose of 8.0 mg (SD 1.5 mg). tPA levels returned to baseline within 2 h of completion of treatment. Plasminogen activator inhibitor-1 (PAI-1) was consumed following tPA treatment, but rose to levels significantly greater than baseline (P < 0.001). Fibrinogen decreased slightly, but remained >125 mg/dL for all subjects. α2-antiplasmin decreased from a mean of 115 units/mL to 56 units/mL after tPA administration (P < 0.001) and remained decreased for 8 h. Plasminogen at baseline (112 units/mL) decreased to 89 units/mL immediately after tPA administration (P < 0.001) and was unchanged thereafter. D-dimer levels were >20 μg/mL in all but 4 subjects, one of whom was the only one to fail to achieve clot lysis. The safety of low-dose, intraclot tPA is due to its short persistence in the circulation, lack of hypofibrinogenemia, and a reflexive rise of PAI-1. Subjects whose D-dimers remain <20 μg/mL are at risk of not achieving thrombolysis.

Endovascular management of acute upper extremity deep venous thrombosis and the use of superior vena cava filters

Upper extremity deep venous thrombosis (UEDVT), though less common than lower extremity DVT, is a significant problem with several possible etiologies. The incidence of UEDVT is on the rise, primarily from the increasing use of central venous access devices. However, there are other causes of UEDVT, including primary venous thrombosis (Paget-Schroetter syndrome) and hypercoagulable states associated with underlying malignancy. The morbidity and mortality associated with UEDVT is largely from pulmonary embolism and the postphlebitic syndrome. Nevertheless, many UEDVTs are asymptomatic or patients may present with nonspecific clinical symptoms; therefore, a high index of suspicion is often necessary to make a correct diagnosis. Currently, there is no standard treatment algorithm for UEDVT. Treatment options may range from systemic anticoagulation to surgical correction depending on the etiology of the thrombus, as well as the patient's associated comorbidities, life expectancy and expected quality of life following treatment.

Fatal reperfusion injury after thrombolysis for phlegmasia cerulea dolens

Reperfusion injury after venous thrombolysis for phlegmasia cerulea dolens (PCD), despite its potentially rapid, fatal course, has not been well described in the literature. Two cases of fatal reperfusion injury after venous thrombolysis are reported, and the clinical manifestations and treatment strategies of PCD and the aspects of reperfusion injury relevant to the interventionalist are reviewed.

Pharmacomechanical Thrombolysis of Acute and Chronic Symptomatic Deep Vein Thrombosis: A Systematic Review of Literature

Pharmacomechanical thrombolysis (PMT) is an emerging treatment option for symptomatic deep vein thrombosis (DVT). This may obviate the need for systemic or catheter-directed thrombolysis. PubMed, EMBASE, and Cochrane database search of PMT in acute and chronic symptomatic DVT was undertaken. Baseline demographic and clinical characteristics, procedural details, DVT characteristics, and procedural and clinical outcomes are presented. A total of 8 case series (n = 2528; 1998-2009) qualified for inclusion. Lower extremity symptomatic DVTs constituted the majority of the cases (>80%). Both acute (<14 days) and chronic (>14 days) DVTs were included. Procedural success was 59% to 100% and catheter-directed thrombolysis was used as an adjunct in 16% to 53%. No deaths or major bleeding complications were reported. Pharmacomechanical thrombolysis leads to the immediate resolution of clinical symptoms of DVT in the majority of patients. Pharmacomechanical thrombolysis may be a safe and novel method, when appropriate expertise and resources are available, for the treatment of symptomatic acute and chronic DVT.

The role of thrombolysis in the clinical management of deep vein thrombosis

The cornerstones of current management of deep vein thrombosis (DVT) are the routine use of anticoagulant therapy, graduated elastic compression stockings, and early ambulation. Thrombolytic therapy was previously reserved only for patients with life-, limb-, or organ-threatening complications. However, the postthrombotic syndrome has been increasingly recognized as a frequent and serious long-term complication of DVT. In parallel, endovascular thrombolytic methods have evolved considerably in recent years, prompting discussion and controversy as to whether they should be more liberally used. In some centers, pharmacomechanical catheter-directed thrombolysis is now routinely used in the treatment of acute iliofemoral DVT. Randomized trials are currently under way to determine when the use of pharmacomechanical catheter-directed thrombolysis is appropriate in patients presenting with acute proximal DVT.

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.

Catheter-directed thrombolysis of lower limb thrombosis

Late complications of thrombosis of the deep veins in the region between the popliteal vein termination and the confluence of the common iliac veins and inferior vena cava (suprapopliteal deep-vein thrombosis) are common and often unrecognized by those responsible for the initial management. Pharmacomechanical-assisted clearance of the thrombus at the time of first presentation provides the best opportunity for complete recovery with preservation of normal venous valve function and avoidance of recurrent deep-vein thrombosis and postthrombotic syndrome. Recent interventional radiology methods provide for rapid and complete thrombolysis even in some patients in whom thrombolysis was previously considered contraindicated. This review describes the methods, safety, and efficacy of acute interventional treatment of suprapopliteal deep-vein thrombosis.

Deep venous thrombosis: the opportunity at hand

OBJECTIVE

The use of imaging-guided treatments for deep venous thrombosis (DVT) is accelerating. Increased appreciation of the impact of postthrombotic syndrome on DVT patients' quality of life and advances in thrombolytic methods have together sparked an unprecedented degree of interdisciplinary collaboration in developing contemporary DVT treatment guidelines and a pivotal clinical trial to establish the risk-benefit ratio of interventional DVT therapy.

CONCLUSION

Radiologists should improve their DVT education, support ongoing clinical trials, and collaborate with DVT-focused nonradiologists in their institutions.