A strategy of aggressive regional therapy for acute iliofemoral venous thrombosis with contemporary venous thrombectomy or catheter-directed thrombolysis

Innovative use of contegra valved conduit in left iliocaval stent thrombosis

Thrombosis of an iliofemoral vein accounts for 25% of all lower extremity deep vein thrombosis (DVT) and is associated with an increased risk of pulmonary embolism (PE), limb malperfusion, and post-thrombotic syndrome (PTS). Endothelial injury, hypercoagulability and stasis constitute Virchow's triad of thrombogenesis. Common predisposing conditions include the postoperative state, prolonged immobility (e.g., travel, hospitalization), malignancy, pregnancy, and inherited hypercoagulable conditions. Long-term complications of DVT include persistent lower extremity edema, venous claudication, hyperpigmentation, and ulceration-collectively called as PTS and are associated with a reduced quality of life with increased health care expenses. The indications for open surgical revascularization are rare and usually reserved for patients whose symptoms are refractory to anticoagulation and endovascular treatment. Here, we report a successful decompression of severe venous edema of left lower limb post left iliocaval stent thrombosis in a 50-year-old female patient. We used two contegra valved conduits which were sutured end to end with each other in the same direction as a bypass graft. Proximal end of the conduit was anastomosed to left common femoral vein and the distal end to the distal inferior vena cava (IVC). It provided prompt and effective venous outflow with complete resolution of the venous edema of left lower limb. computed tomography (CT) venogram done after 3 months of surgery showed patent contegra valved conduit with thrombosed iliocaval stent.

Advances in Operative Thrombectomy for Lower Extremity Venous Thrombosis

Lower extremity deep venous thrombosis is a leading cause of morbidity and mortality. The mainstay of therapy is medical. However, anticoagulation does not remove the thrombus and restore venous patency. In select patients, early thrombus removal and anticoagulation can restore venous patency, preserve venous valve function, and may reduce the incidence of postthrombotic syndrome. Catheter-directed therapies are minimally invasive with low complication rates. However, in patients with a contraindication to thrombolytic agents who can receive anticoagulation, open thrombectomy should be considered if indications for thrombus removal are met and patients are good operative risks.

May-Thurner Syndrome: Three Patients Treated with Catheter-Directed Thrombolysis and Stent Placement

Compression of the proximal left iliac vein by the right common iliac artery (May-Thurner syndrome) is an unusual cause of iliofemoral thrombosis. Several different surgical approaches have been advocated to alleviate or bypass the compression, but few reports exist of successful treatment using interventional techniques. The authors report three cases of left common iliac vein thrombosis caused by May-Thurner syndrome in two women aged 51 and 36 years, and one man aged 56 years. The two women had long histories of left leg swelling, with recurrent episodes of left iliac venous thrombosis; the man had acute symptoms and no previous history of venous thrombosis or leg swelling. Venography in all patients demonstrated left iliac vein thrombosis associated with large pelvic venous collaterals. Catheter-directed thrombolysis was performed successfully, allowing visualization of the lesions treated with balloon venoplasty and stenting. All three patients were treated with warfarin following stent placement, and all have had improvement or resolution of their symptoms and patent left iliac and femoral veins by duplex scan at 8 to 12 months of follow-up. The authors conclude that (1) Catheter-directed thrombolysis of left iliac vein thrombosis may identify patients with May-Thurner syndrome, which may occur more commonly than previously reported; (2) May-Thurner syndrome may be effectively treated nonoperatively by balloon venoplasty and stenting of the stenotic segment; and (3) the role of warfarin and the long-term results of this treatment are currently unknown.

Contemporary management of acute and chronic deep venous thrombosis

INTRODUCTION

This review aims to provide an update on the management of deep vein thrombosis (DVT).

SOURCES OF DATA

A systematic search of PubMed, Google Scholar and Cochrane databases was carried out.

AREAS OF AGREEMENT

Direct oral anticoagulants (DOACs) are as effective and easier to use than vitamin K antagonists for the treatment of DVT. Catheter-directed thrombolysis can reduce post thrombotic syndrome in patients with iliofemoral DVT. Compression bandaging can help heal a venous ulcer.

AREAS OF CONTROVERSY

Compression hosiery to prevent post thrombotic syndrome. Long-term evidence to show clinical benefit of using endovenous therapies to restore deep vein patency.

GROWING POINTS

Developing imaging methods to identify patients who would benefit from venous thrombolysis. The evolution of dedicated venous stents.

AREAS TIMELY FOR DEVELOPING RESEARCH

Understanding the mechanisms that lead to stent occlusion and investigation into the appropriate treatments that could prevent in-stent thrombosis is required.

Original approach for thrombolytic therapy in patients with Ilio-femoral deep vein thrombosis : 2 years follow-up

Objective

The aim of the study was to discuss the results of catheter-directed thrombolysis and complementary procedures to treat acute iliofemoral deep vein thrombosis (DVT) evaluating the safety and effectivness of an easy access such as the Great Saphenous Vein.

Methods and materials

A total of 22 consecutive patients with iliofemoral thrombosis and two patients with femoro-popliteal thrombosis on recent onset diagnosed with Ultrasound Doppler and contrast venography underwent intrathrombus drip infusion of urokinase while intravenous heparin was continued using saphenical access. Residual venous stenosis were treated in six patients by percutaneous balloon Angioplasty and stenting. All patients underwent routine venous duplex imaging at 30 days, 3 months, 6 months and every 6 months thereafter.

Results

Complete patency of thrombosed veins was restored in 22 patients (91 %) with prompt symptomatic relief. There were no major complications in the immediate outcomes. At follow-up, two patients reported a persistant slim iliac vein stenosis, two patients had post-thrombotic syndrome, and two patients showed Deep Vein Reflux.

Conclusion

Local thrombolysis using saphenical access was a safe and effective approach for the treatment of acute iliofemoral deep vein thrombosis. It seems to be a valid, easy and safe alternative, reducing the risks of haematoma and venous lesions, which can be observed when using femoral, popliteal, and trans-jugular access.

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.

Interventional treatment of venous thromboembolism: a review

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most common cardiovascular disease after coronary artery disease and cerebrovascular disease and is responsible for significant morbidity and mortality in the general population. Full dose anticoagulation is the standard therapy for VTE, both for the acute and the long-term phase. The latest guidelines of the American College of Chest Physicians recommend treatment with a full-dose of unfractioned heparin (UFH), low-molecular-weight-heparin (LMWH), fondaparinux, vitamin K antagonist (VKA) or thrombolysis for most patients with objectively confirmed VTE. Catheter-guided thrombolysis and trombosuction are interventional approaches that should be used only in selected populations; interruption of the inferior vena cava (IVC) with a filter can be performed to prevent life-threatening PE in patients with VTE and contraindications to anticoagulant treatment, bleeding complications during antithrombotic treatment, or VTE recurrences despite optimal anticoagulation. In this review we summarize the currently available literature regarding interventional approaches for VTE treatment (vena cava filters, catheter-guided thrombolysis, thrombosuction) and we discuss current evidences on their efficacy and safety. Moreover, the appropriate indications for their use in daily clinical practice are reviewed.

Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about treatment for venous thromboembolic disease is part of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do or do not outweigh risks, burden, and costs. Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see "Grades of Recommendation" chapter). Among the key recommendations in this chapter are the following: for patients with objectively confirmed deep vein thrombosis (DVT) or pulmonary embolism (PE), we recommend anticoagulant therapy with subcutaneous (SC) low-molecular-weight heparin (LMWH), monitored IV, or SC unfractionated heparin (UFH), unmonitored weight-based SC UFH, or SC fondaparinux (all Grade 1A). For patients with a high clinical suspicion of DVT or PE, we recommend treatment with anticoagulants while awaiting the outcome of diagnostic tests (Grade 1C). For patients with confirmed PE, we recommend early evaluation of the risks to benefits of thrombolytic therapy (Grade 1C); for those with hemodynamic compromise, we recommend short-course thrombolytic therapy (Grade 1B); and for those with nonmassive PE, we recommend against the use of thrombolytic therapy (Grade 1B). In acute DVT or PE, we recommend initial treatment with LMWH, UFH or fondaparinux for at least 5 days rather than a shorter period (Grade 1C); and initiation of vitamin K antagonists (VKAs) together with LMWH, UFH, or fondaparinux on the first treatment day, and discontinuation of these heparin preparations when the international normalized ratio (INR) is > or = 2.0 for at least 24 h (Grade 1A). For patients with DVT or PE secondary to a transient (reversible) risk factor, we recommend treatment with a VKA for 3 months over treatment for shorter periods (Grade 1A). For patients with unprovoked DVT or PE, we recommend treatment with a VKA for at least 3 months (Grade 1A), and that all patients are then evaluated for the risks to benefits of indefinite therapy (Grade 1C). We recommend indefinite anticoagulant therapy for patients with a first unprovoked proximal DVT or PE and a low risk of bleeding when this is consistent with the patient's preference (Grade 1A), and for most patients with a second unprovoked DVT (Grade 1A). We recommend that the dose of VKA be adjusted to maintain a target INR of 2.5 (INR range, 2.0 to 3.0) for all treatment durations (Grade 1A). We recommend at least 3 months of treatment with LMWH for patients with VTE and cancer (Grade 1A), followed by treatment with LMWH or VKA as long as the cancer is active (Grade 1C). For prevention of postthrombotic syndrome (PTS) after proximal DVT, we recommend use of an elastic compression stocking (Grade 1A). For DVT of the upper extremity, we recommend similar treatment as for DVT of the leg (Grade 1C). Selected patients with lower-extremity (Grade 2B) and upper-extremity (Grade 2C). DVT may be considered for thrombus removal, generally using catheter-based thrombolytic techniques. For extensive superficial vein thrombosis, we recommend treatment with prophylactic or intermediate doses of LMWH or intermediate doses of UFH for 4 weeks (Grade 1B).

Effects of acute global venous obstruction and unfractionated heparin on muscle cytokine synthesis

Phlegmasia cerulea dolens is a devastating complication of massive deep venous thrombosis, which is clinically characterized by massive lower extremity tissue edema and subsequent arterial insufficiency. These experiments evaluated the local tissue effects of acute global venous obstruction combined with partial arterial ischemia. Experiments were performed to assess the effects of heparin on the cytokine response to simultaneous venous and partial arterial obstruction. Murine hind limbs were subjected to conditions of unilateral venous occlusion and partial tourniquet limb ischemia, which was confirmed by laser Doppler imaging (LDI). Mice underwent either hind limb venous obstruction with intravenous unfractionated heparin (200IU/kg) or intravenous saline 5min before venous occlusion. Sham-treated mice were subjected to anesthesia alone without venous occlusion. After 3hr, the mice were killed and tissue was harvested for measurement of edema (wet to dry weight ratio, W/D), muscle viability, indices of local thrombosis (thrombin-antithrombin complex [TAT]), and cytokine analysis for growth-related oncogene-1 (GRO-1) and interleukin-6 (IL-6, protein via enzyme-linked immunoassay and mRNA via reverse transcriptase polymerase chain reaction). Bleeding time and volume were documented in saline- and heparin-treated mice to confirm systemic anticoagulation. Administration of intravenous heparin resulted in a marked increase in bleeding time and volume. LDI confirmed venous obstruction and ongoing arterial inflow. Venous obstruction resulted in severe visible edema that correlated with a significantly higher W/D ratio but was not associated with a significant decrease in muscle viability. GRO-1 and IL-6 protein and mRNA levels were significantly elevated in the venous occlusion group compared to sham. Heparin therapy significantly decreased TAT3 levels but did not alter the profile of GRO-1 or IL-6 protein levels seen with venous occlusion. Venous occlusion with partial ischemia induces a unique and potent local cytokine expression. Heparin therapy did not ameliorate the cytokine response. These data indicate that heparin therapy does not modulate the cytokine response to venous obstruction.

Phlegmasia cerulea dolens

Phlegmasia dolens is a rare form of massive venous thrombosis of the lower extremities that is associated with a high degree of morbidity, including venous gangrene, compartment type syndrome, and arterial compromise. We report the sonographic findings in a patient who presented with phlegmasia dolens.

Treatment of Acute Iliofemoral Deep Venous Thrombosis: A Strategy of Thrombus Removal

Patients with acute iliofemoral deep vein thrombosis (DVT) suffer the most severe postthrombotic sequelae. The majority of physicians treat all patients with acute DVT with anticoagulation alone, despite evidence that postthrombotic chronic venous insufficiency, leg ulceration, and venous claudication are common in patients treated only with anticoagulation. The body of evidence to date in patients with iliofemoral DVT suggests that a strategy of thrombus removal offers these patients the best long-term outcome. Unfortunately, currently published guidelines use outdated experiences to recommend against the use of techniques designed to remove thrombus, ignoring recent clinical studies showing significant benefit in patients who have thrombus eliminated. Contemporary venous thrombectomy, intrathrombus catheter-directed thrombolysis, and pharmacomechanical thrombolysis are all options that can be offered to successfully remove venous thrombus with increasing safety. The authors review evidence supporting the rationale for thrombus removal and discuss the most effective approaches for treating patients with acute iliofemoral DVT.

Pulse-spray Pharmacomechanical Thrombolysis for Proximal Deep Vein Thrombosis

OBJECTIVE

The aim of this study was to evaluate the efficacy, safety, and feasibility of pulse-spray pharmacomechanical thrombolysis to treat proximal deep vein thrombosis (DVT) in conjunction with the placement of a non-permanent IVC filter.

METHODS

We studied 31 consecutive patients with acute proximal DVT defined as the inferior vena cava (IVC), iliac vein and/or femoral vein, who were diagnosed using duplex ultrasonography and/or contrast venography. All were treated with pulse-spray urokinase. Early success was assessed by comparing the pre- and post-treatment venographic severity score. Non-permanent IVC filters were used to reduce the risk of pulmonary thromboembolism.

RESULTS

The average total urokinase dose was 1.71 million IU (range: 0.72-3.6 million IU) and the average duration of therapy was 2.4 days. The average percentage of thrombus lysed was 85% (range: 22-100%). A large thrombus trapped by the filter was detected using cavography before extraction of the filter in one patient. There was no major treatment-related adverse event.

CONCLUSION

The combination of pulse-spray pharmacomechanical thrombolysis and the prophylactic use of a non-permanent IVC filter was a safe and effective approach for treating acute proximal DVT.

Intermittent pneumatic compression of the foot and calf improves the outcome of catheter-directed thrombolysis using low-dose urokinase in patients with acute proximal venous thrombosis of the leg

OBJECTIVE

Catheter-directed thrombolysis (CDT) is a promising treatment of acute proximal deep vein thrombosis (DVT) to prevent the postthrombotic syndrome by early removal of thrombus. During CDT for DVT patients, the calf muscle pump is compromised because of immobility. Intermittent pneumatic compression (IPC) can be used to increase venous flow during bed rest. The CDT with IPC may lyse venous thrombus better than CDT alone. The purpose of this study was to evaluate the efficiency and safety of IPC during CDT for DVT using low-dose urokinase.

METHODS

Twenty-four patients with proximal DVT confirmed by duplex ultrasonography underwent CDT alone (10 cases) and CDT with IPC and a temporary inferior vena cava filter (14 cases) for 3 to 6 days. Pulmonary emboli (PEs) were assessed by pretreatment and posttreatment pulmonary angiogram or spiral computed tomography of the chest, and in the CDT/IPC patients, a posttreatment inferior vena cavogram was performed. The initial results were evaluated by venogram immediately after CDT, and the late results were evaluated by venous disability score and duplex ultrasonography 6 to 36 months after treatment.

RESULTS

There was no symptomatic PE in either group. In CDT with IPC, one new asymptomatic PE was found, but there was no large thrombus in the inferior vena cava. The initial thrombolytic results of CDT with IPC were better than those of CDT alone (five cases of complete lysis in the CDT/IPC group and none in the CDT alone group). In the follow-up, the deep veins were patent and competent in 43% (6/14) in the CDT/IPC group, compared with 17% (1/6) in the CDT-alone group. The venous disability score showed that the CDT/IPC group had less disability than the CDT-alone group.

CONCLUSIONS

This pilot study showed that adding IPC to CDT using low-dose urokinase for DVT treatment of the leg resulted in better early and late outcomes compared with CDT alone and was not associated with an increased risk of symptomatic PEs.

Stents in Common Iliac Vein Obstruction with Acute Ipsilateral Deep Venous Thrombosis: Early and Late Results

PURPOSE

To evaluate, by imaging and clinical follow-up, the effectiveness and long-term results of stent placement in cases of common iliac vein obstruction associated with ipsilateral deep vein thrombosis (DVT).

MATERIALS AND METHODS

Retrospective analysis of 22 patients (13 women, nine men; median age, 58 years) with common iliac vein obstruction with ipsilateral DVT was performed for this study. All patients presented with leg edema or pain and were treated with catheter-directed thrombolysis (1,000-2,000 U urokinase per kg body weight per hour; n = 19), aspiration thrombectomy (n = 21), or angioplasty (n = 14) followed by stent placement (n = 22) via an ipsilateral popliteal vein approach (right, n = 2; left, n = 20) under ultrasonographic (US) guidance. Patients were then followed by duplex US, and patency rates were determined by Kaplan-Meier survival analysis.

RESULTS

The mean procedure time was 15 hours (range, 1-23 hours) and the mean urokinase dose was 1,980,000 U (range, 600,000-3,600,000 U) before the implantation of 27 stents. Three patients did not receive urokinase. The technical success rate was 96% (26 of 27 stents) and the clinical success rate was 95% (21 of 22 patients). The causes of common iliac vein obstruction were May-Thurner syndrome (n = 16), pelvic mass (n = 2), and unknown (n = 4). The early complications included upward stent migration in one patient and a spinal epidural hematoma in another. The late complication was partial stent obstruction, which was successfully treated by thrombolysis and angioplasty in one patient. Follow-up lasted 1-41 months (mean, 21.4 months). Overall, the 1-year and 2-year primary patency rates were both 95% and the 1-year and 2-year secondary patency rates were both 100%.

CONCLUSION

Directed catheter thrombolysis and aspiration of DVT are relatively safe, and the use of stents improves patency results in cases of common iliac vein obstruction.

Thrombolytic Therapy: Current Clinical Practice

Thrombolytic therapy is an essential tool in the array of therapies designed to reopen arteries and veins occluded with thrombus. As the use of thrombolytic agents has entered mainstream practice, their application has expanded to include a wide variety of indications and settings. Thrombolytic agents are used in patients who have thrombosis of coronary arteries, precerebral and cerebral arteries, the aorta, iliac and mesenteric arteries, and peripheral arteries. The use of thrombolysis in venous thrombosis has included deep venous thrombosis of the upper and lower extremities and vena cava, mesenteric veins, cerebral veins, and central access catheters. Guidelines are available from the American College of Cardiology/American Heart Association regarding thrombolysis in myocardial infarction and from the American Stroke Association regarding thrombolysis in acute ischemic stroke.

Endovascular management of iliofemoral venous occlusive disease

New developments in the management of both acute and chronic iliac vein occlusive disease offer exciting options for the treatment of this often debilitating condition. Percutaneous clot removal using thrombolysis, mechanical thrombectomy, or a combination of the two is fast becoming the treatment of choice for patients presenting with acute iliofemoral deep vein thrombosis. Recanalization of chronic iliac vein occlusions with balloon angioplasty and stenting relieves symptoms of extremity swelling and pain in the majority of treated patients. Existing data provide convincing proof of the efficacy of endovascular recanalization procedures, and upcoming prospective, controlled trials will further clarify the role of these techniques in the therapeutic armamentarium.

Catheter-directed thrombolysis for deep venous thrombosis

Venous thromboembolism (VTE) represents a significant clinical problem, affecting patients of all age groups, nationalities, and socioeconomic strata. Despite its prevalence, the paradigms for care are largely centered around primary or secondary prophylaxis, with less emphasis on actual treatment of the thrombus. With the recent rapid development of advanced endovascular techniques, it is now feasible to dissolve many thrombi using catheter-directed thrombolysis (CDT), and favorable clinical experience has been reported in over 600 patients. If performed safely, the purported benefits of CDT for DVT include a decreased incidence of persistent phlebitic symptoms, improved quality of life and, possibly, a decreased incidence of recurrent thrombotic events.

L-arginine improves endothelial vasoreactivity and reduces thrombogenicity after thrombolysis in experimental deep venous thrombosis

PURPOSE

Nitric oxide (NO) is important in regulation of platelet aggregation, endothelial function, and intravascular thrombosis. The purposes of this study were to assess the effect of thrombolysis on endothelial function in a porcine model of deep venous thrombosis (DVT) and to evaluate the effect of NO precursor l-arginine on endothelial function after thrombolytic therapy.

METHODS

DVT was created in bilateral iliac veins by deploying a self-expanding stent-graft that incorporated an intraluminal stenosis, from a groin approach. Five pigs underwent sham operation. After 7 days of DVT, animals were randomized to three groups: saline pulse-spray (saline group, n = 5), thrombolytic pulse-spray with tissue plasminogen activator (alteplase, 8 mg; t-PA group, n = 5), and thrombolytic pulse-spray plus intravenous l-arginine (20 mmol/L; arginine group, n = 5). At 2 weeks iliac vein patency was evaluated at venography and intravascular ultrasound scanning. NO level was determined with a chemiluminescent assay of the nitrite and nitrate metabolites (NO(x)). Thrombogenicity was evaluated with radiolabeled platelet and fibrin deposition. Veins were harvested and evaluated with light microscopy and scanning electron microscopy. Endothelial function was evaluated with organ chamber analysis.

RESULTS

All iliac veins remained patent at 2 weeks. The luminal areas in the sham, saline, t-PA, and arginine groups were 53 +/- 23 mm(2), 14 +/- 11 mm(2), 34 +/- 19 mm(2), and 42 +/- 21 mm(2), respectively. No difference in endothelial cell structure was observed between the three treatment groups at light microscopy or scanning electron microscopy. Although no difference in fibrin deposition was noted among the three treatment groups, decreased platelet deposition occurred in the arginine group compared with the saline or t-PA groups (P <.05). The arginine group showed greater endothelial-dependent relaxation compared with the t-PA or saline groups (73% +/- 23% vs 49% +/- 18% and 32% +/- 21%; P <.05). Local NO(x) level in the arginine group was correspondingly higher compared with the saline or t-PA groups (1.8 +/- 0.3 micromol/L vs 0.3 +/- 0.05 micromol/L and 0.2 +/- 0.04 micromol/L; P <.05).

CONCLUSIONS

NO precursor l-arginine supplementation enhances NO production at sites of venous thrombosis. Moreover, l-arginine preserves endothelial vasoreactivity and reduces platelet deposition after thrombolysis in iliac DVT. These data suggest that l-arginine may preserve endothelial function after thrombolysis and may reduce the likelihood of postthrombotic syndrome.

Safety of plasmin in the setting of concomitant aspirin and heparin administration in an animal model of bleeding

Plasmin is a direct thrombolytic which has been shown to have a strikingly favorable benefit to risk profile in comparison with plasminogen activators, notably tissue plasminogen activator (t-PA). As heparin is known to increase the risk of hemorrhage when co-administered with a plasminogen activator, we asked whether adjunct antithrombotic agents such as aspirin and heparin would affect the safety of plasmin. Three groups of rabbits were administered plasmin at a dose (4 mg kg-1) designed to induce significant decreases in antiplasmin, fibrinogen and factor (F)VIII, to about 25, 40 and 40%, respectively, of baseline values, but not cause prolongation of the ear puncture bleeding time. In a blinded and randomized trial, the results show that an intravenous aspirin bolus plus heparin administered as a bolus followed by a maintenance continuous infusion did not significantly prolong the bleeding time during plasmin infusion. These data indicate that in the rabbit, concomitant use of aspirin plus heparin does not affect the safety of a therapeutic dose of plasmin.

Thrombolytic therapy: clinical applications

The therapeutic use of thrombolytic agents is the result of the increasing understanding of the pathophysiologic mechanisms underlying normal and deranged thrombosis and fibrinolysis. Plasminogen activators capable of increasing the production of plasmin exhibit considerable efficacy in the treatment of a variety of arterial and venous thrombotic disorders. The ideal thrombolytic agent has not been developed, but the desired clinical result of rapid opening of the thrombosed vessel without reocclusion, without activation of systemic fibrinogenolysis, and without a risk of hemorrhage are defined. Clinical studies clearly demonstrate that the addition of a variety of adjunctive agents to available thrombolytics enhances benefit without inordinate risk. The addition of intravascular angioplasty and stenting to thrombolysis increases the potential long-term benefit. Newer thrombolytic agents and new protocols for the use of existing therapies offer the promise of saving many who would otherwise succumb to coronary or cerebral arterial thrombosis or to venous thromboembolism.

Thrombolytic therapy

The therapeutic use of thrombolytic agents is the natural result of the increasing understanding of the pathophysiologic mechanisms underlying normal and deranged thrombosis and fibrinolysis. Plasminogen activators capable of increasing the production of plasmin exhibit considerable efficacy in the treatment of a variety of arterial and venous thrombotic disorders. The ideal thrombolytic agent has yet to be developed but the desired clinical result of rapid opening of the thrombosed vessel without reocclusion, without activation of systemic fibrinogenolysis, and without a risk of hemorrhage is well defined. Clinical studies clearly demonstrate that the addition of a variety of adjunctive agents to the available thrombolytics enhances benefit without inordinate risk. The addition of intravascular angioplasty and stenting to thrombolysis increases the potential long-term benefit. Newer thrombolytic agents and new protocols for the use of existing therapies offer the promise of saving many who would otherwise succumb to coronary or cerebral arterial thrombosis or to venous thromboembolism.

Iliofemoral deep vein thrombosis: conventional therapy versus lysis and percutaneous transluminal angioplasty and stenting

OBJECTIVE

To compare conventional treatment (heparin and warfarin) of iliofemoral venous thrombosis with multimodality treatment (lysis and stenting).

SUMMARY BACKGROUND DATA

Several studies have reported on conventional therapy for iliofemoral venous thrombosis with disappointing results. However, more recent studies have reported better results with multimodality treatment.

METHODS

Fifty-one consecutive patients with extensive iliofemoral venous thrombosis were treated during a 10-year period. If there were no contraindications, patients were given the option to choose between conventional therapy (group 1) and multimodality therapy (group 2). The multimodality treatment strategy included catheter-directed lysis followed by percutaneous transluminal balloon angioplasty (PTA) and stenting for residual iliac stenoses. All patients underwent routine venous duplex imaging at 30 days, 3 months, 6 months, and every 6 months thereafter.

RESULTS

There were 33 patients in group 1 and 18 patients in group 2. Demographic and clinical characteristics were comparable for both groups. Initial lysis was achieved in 16 of 18 patients (89%) in group 2. Ten of 18 patients in group 2 had residual stenosis after lysis (8 primary and 2 secondary to malignancy), and they were treated with PTA/stenting with an initial success rate of 90%. Two patients in group 1 (6%) had a symptomatic pulmonary embolism (none in group 2). At 30 days, venous patency and symptom resolution were achieved in 1 of 33 patients (3%) in group 1 versus 15 of 18 (83%) in group 2. Kaplan-Meier analysis showed primary iliofemoral venous patency rates at 1, 3, and 5 years of 24%, 18%, and 18% and 83%, 69%, and 69% for groups 1 and 2, respectively. Long-term symptom resolution was achieved in 10 of 33 patients (30%) in group 1 versus 14 of 18 (78%) in group 2. Kaplan-Meier life table analysis showed similar survival rates at 1, 3, and 5 years of 100%, 93%, and 85% for group 1 and 100%, 93%, and 81% for group 2.

CONCLUSIONS

Lysis/stenting treatment was more effective than conventional treatment in patients with iliofemoral vein thrombosis.

Tissue plasminogen activator for the treatment of deep venous thrombosis of the lower extremity: a systematic review

OBJECTIVE

To assess, by systematic review, the efficacy and safety of recombinant tissue plasminogen activator (rt-PA) in the treatment of lower extremity deep venous thrombosis (DVT). A secondary objective is to assess the optimal dose and route of administration of rt-PA.

METHODS

Included studies were randomized, controlled trials comparing rt-PA plus unfractionated heparin (UFH) to UFH alone, rt-PA at different doses, or rt-PA by different routes of administration in the treatment of DVT. Outcomes had to be described in terms of percent change in venographic patency for efficacy (>50% lysis) and in sufficient detail for complications (major and minor hemorrhages and other). The search strategy included searching electronic databases and contacting pharmaceutical agencies and content experts. Study quality was assessed using the Jadad scale. A threshold quality score was used to exclude trials.

RESULTS

Five studies met the following inclusion criteria: three comparing rt-PA plus UFH vs UFH alone (180 patients); one comparing high-dose vs low-dose rt-PA (32 patients); and one comparing systemic vs local administration of rt-PA (151 patients). In studies comparing rt-PA vs placebo, patients assigned to rt-PA were more likely to have > 50% lysis and complications (summary odds ratios [OR], 11.7; 95% confidence interval [CI], 2.61 to 52.5; and OR, 9.95; 95% CI, 2.21 to 44.7, respectively). Major and intracerebral hemorrhages were not significantly increased. One study comparing different doses demonstrated that high-dose and low-dose rt-PA were equally efficacious (OR, 0.88; 95% CI, 0.05 to 14.78). Local rt-PA was neither more efficacious nor riskier than systemic rt-PA.

CONCLUSION

This systematic review does not support routine use of rt-PA for DVT.

Mechanical thrombectomy in patients with deep venous thrombosis

PURPOSE

To report our experience with mechanical thrombectomy in proximal deep vein thrombosis (DVT).

METHODS

Eighteen patients with a mean (+/- SD) age of 37.6 +/- 16.1 years who presented with DVT in the iliac and femoral vein (n = 3), inferior vena cava (n = 5), or inferior vena cava and iliac vein (n = 10), were treated with the Amplatz Thrombectomy Device after insertion of a temporary caval filter.

RESULTS

Successful recanalization was achieved in 15 of 18 patients (83%). Overall, the percentage of thrombus removed was 66 +/- 29%: 73 +/- 30% at caval level and 55 +/- 36% at iliofemoral level. Complementary interventions (seven patients) were balloon angioplasty (n = 2), angioplasty and stenting (n = 2), thrombo-aspiration alone (n = 1), thrombo-aspiration, balloon angioplasty, and permanent filter (n = 1), and permanent filter alone (n = 1). There was one in-hospital death. Follow-up was obtained at a mean of 29.6 months; three patients had died (two cancers, one myocardial infarction); 10 had no or minimal sequelae; one had post-phlebitic limb.

CONCLUSION

Mechanical thrombectomy is a potential therapeutic option in patients presenting with proximal DVT.

Catheter-Directed Thrombolysis for the Treatment of Acute Iliofemoral Deep Venous Thombosis

Objective:

Acute iliofemoral deep venous thrombosis (DVT) is a serious venous thrombotic disorder with potentially morbid post-thrombotic sequelae. The purpose of this report is to present our single-centre evolution of technique and the results of catheter-directed thrombolysis for the treatment of acute iliofemoral DVT, and put it into perspective with current literature.

Patients and methods:

Between May 1988 and April 2000, 54 patients were treated with catheter-directed thrombolysis for occlusive iliofemoral and vena caval thrombosis. Average age was 45 years (range 17-68 years) and the duration of leg symptoms was 5.2 days (range 2-30 days). Routine vena caval filters were not used, although caval filters were inserted in patients with irregular and non-occlusive vena caval thrombus. Initially, urokinase infusion via a right jugular vein and/or contralateral femoral vein approach was used, delivering a 250000-500000 U bolus followed by continuous infusion of 250000-300000 LVh. Catheter delivery has evolved to an ultrasound-guided popliteal or posterior tibial vein puncture and the use of recombinant tissue plasminogen activator at a bolus dose of 4–8 mg followed by 2–4 mg/h. All patients received heparin infusion at 500-1000 U/h.

Results:

Fifty-one of the 54 patients had successful catheter positioning. Forty-five (83%) had a successful outcome. Of those that failed, 2 were treated with a known chronic occlusion and in 2 patients plasminogen deficiency was suspected. Two patients had persistent iliac vein lesions which led to early re-thrombosis. Overall, 14 (26%) were asymptomatic, 28 (52%) demonstrated moderate improvement, 6 (11%) showed mild improvement and 6 (11%) had no clinical improvement. Serious complications occurred in 5 patients (9%). Four (7%) required blood transfusion and 1 (2%) required operative evacuation of an inguinal haematoma with repair of the common femoral vein. Eight patients (15%) developed a puncture site haematoma and 1 patient (2%) had a guidewire perforation of the common femoral vein.

Conclusions:

Catheter-directed thrombolysis is the preferred treatment for symptomatic iliofemoral DVT. Following successful lysis, residual iliac vein lesions should be corrected with balloon angioplasty and stenting if necessary. Considering the current results and those of contemporary series, a successful outcome can be anticipated in 80-85% of patients, with a significant improvement in quality of life when compared with standard anticoagulation.

Endovascular management of acute extensive iliofemoral deep venous thrombosis caused by May-Thurner syndrome

PURPOSE

The authors report their experience on the treatment of acute extensive iliofemoral deep venous thrombosis (DVT) due to May-Thurner syndrome using endovascular techniques.

MATERIALS AND METHODS

During a 1-year period, 10 symptomatic women (age range, 22-52 years; mean, 35.5 years) were referred for treatment. After ascending venography, an infusion catheter system was placed and urokinase was infused locally into the thrombus burden. After near complete clot dissolution (> or = 95%) or lytic stagnation, the residual left common iliac vein narrowing was treated by means of angioplasty and/or placement of Wallstent endoprosthesis. All patients continued to receive oral warfarin. Patients were followed-up by means of clinic visits, and stent patency was assessed by means of duplex Doppler sonography performed at 1, 3, 6, and 12 months, and then yearly thereafter.

RESULTS

The total dose of urokinase used and the duration of infusion were 5.87 +/- 2.57 million units (range, 3.18-10.7) and 51.95 +/- 21.57 hours (range, 26.5-89), respectively. After completion of thrombolytic therapy, the iliac vein narrowing was successfully treated by deployment of a Wallstent endoprosthesis in all 10 patients because of failure of angioplasty. No major bleeding complications occurred. Initial clinical success was 100%, with complete resolution of symptoms in all patients. One patient, who was hypercoagulable and was receiving chemotherapy for metastatic adenocarcinoma, had recurrent symptomatic acute DVT 1 month after therapy. She underwent successful repeated lysis. The remaining nine patients were asymptomatic, with a mean follow-up of 15.2 months (range, 6-36 months). One asymptomatic patient, at 36-month follow-up ultrasound, had iliac vein occlusion and well-developed venous collaterals. Serial ultrasonography in all 10 patients showed no evidence of valvular insufficiency in the femoral and popliteal veins.

CONCLUSION

Catheter-directed thrombolytic therapy for the treatment of acute extensive iliofemoral DVT due to May-Thurner syndrome is an effective method for restoring venous patency and provides relief of the acute symptoms. The underlying left common iliac vein lesion invariably needs to undergo stent placement.

Left iliac vein occlusion: its clinical spectrum

The cases reported here demonstrate the variability of the clinical manifestations of left common iliac venous occlusive disease. In each instance, therapy must be adjusted to meet the symptomatic needs of the individual patient. The experience reported here should reinforce the fact that occlusions even 25 months or longer in duration may be reopened. Continuing patency can be enhanced by stent placement.

Endovascular management of iliac vein compression (May-Thurner) syndrome

PURPOSE

To evaluate the feasibility of endovascular techniques in treating venous outflow obstruction resulting from compression of the iliac vein by the iliac artery of the left lower extremity (May-Thurner syndrome).

MATERIALS AND METHODS

A retrospective analysis of 39 patients (29 women, 10 men; median age, 46 years) with iliac vein compression syndrome (IVCS) was performed. Nineteen patients presented with acute deep vein thrombosis (DVT) and 20 patients presented with chronic symptoms. All patients presented with leg edema or pain. In the acute group, patients were treated with catheter-directed thrombolysis (120,000-180,000 IU urokinase/h) and angioplasty followed by stent placement. In the chronic group, patients were treated with use of angioplasty and stent placement alone (n = 8), or in combination with thrombolysis (n = 12). Patients were then followed-up with duplex ultrasound and a quality-of-life assessment.

RESULTS

Initial technical success was achieved in 34 of 39 patients (87%). The overall patency rate at 1 year was 79%. Symptomatically, 85% of patients were completely or partially improved compared with findings before treatment. Thirty-five of 39 patients received stents. The 1-year patency rate for patients with acute symptoms who received stents was 91.6%; for patients with chronic symptoms who received stents, the 1-year patency rate was 93.9%. Five technical failures occurred. Major complications included acute iliac vein rethrombosis (< 24 hours) requiring reintervention (n = 2). Minor complications included perisheath hematomas (n = 4) and minor bleeding (n = 1). There were no deaths, pulmonary embolus, cerebral hemorrhage, or major bleeding complications.

CONCLUSION

Endovascular reconstruction of occluded iliac veins secondary to IVCS (May-Thurner) appears to be safe and effective.

Advances in Therapy and the Management of Antithrombotic Drugs for Venous Thromboembolism

This review focuses on antithrombotic therapy for venous thromboembolism and covers a diverse range of topics including a discussion of emerging anticoagulant drugs, a renewed focus on thrombolytic agents for selected patients, and an analysis of the factors leading to adverse events in patients on warfarin, and how to optimize therapy. In Section I Dr. Weitz discusses new anticoagulant drugs focusing on those that are in the advanced stages of development. These will include drugs that (a) target factor VIIa/tissue factor, including tissue factor pathway inhibitor and NAPc2; (b) block factor Xa, including the synthetic pentasaccharide and DX9065a; (c) inhibit factors Va and VIIIa, i.e., activated protein C; and (d) block thrombin, including hirudin, argatroban, bivalirudin and H376/95. Oral formulations of heparin will also be reviewed.

In Section II, Dr. Comerota will discuss the use of thrombolysis for selected patients with venous thromboembolism. Fibrinolytic therapy, which has suffered from a high risk/benefit ratio for routine deep venous thrombosis, may have an important role to play in patients with iliofemoral venous thrombosis. Dr. Comerota presents his own results with catheter-directed thrombolytic therapy and the results from a large national registry showing long-term outcomes and the impact on quality of life.

In Section III, Dr. Ansell presents a critical analysis of the factors responsible for adverse events with oral anticoagulants and the optimum means of improving outcomes. The poor status of present day anticoagulant management is reviewed and the importance of achieving a high rate of “time in therapeutic range,” is emphasized. Models of care to optimize outcomes are described, with an emphasis on models that utilize patient self-testing and patient self-management of oral anticoagulation which are considered to be the ultimate in anticoagulation care. The treatment of venous and arterial thromboembolism is undergoing rapid change with respect to the development of new antithrombotic agents, an expanding list of new indications, and new methods of drug delivery and management. In spite of these changes, many of the traditional therapeutics are still with us and continue to play a vital role in the treatment of thromboembolic disease. The following discussion touches on a wide range of therapeutic interventions, from old to new, exploring the status of anticoagulant drug development, describing a new intervention for iliofemoral venous thrombosis, and analyzing the critical factors for safe and effective therapy with oral anticoagulants.

Advances in Therapy and the Management of Antithrombotic Drugs for Venous Thromboembolism

This review focuses on antithrombotic therapy for venous thromboembolism and covers a diverse range of topics including a discussion of emerging anticoagulant drugs, a renewed focus on thrombolytic agents for selected patients, and an analysis of the factors leading to adverse events in patients on warfarin, and how to optimize therapy. In Section I Dr. Weitz discusses new anticoagulant drugs focusing on those that are in the advanced stages of development. These will include drugs that (a) target factor VIIa/tissue factor, including tissue factor pathway inhibitor and NAPc2; (b) block factor Xa, including the synthetic pentasaccharide and DX9065a; (c) inhibit factors Va and VIIIa, i.e., activated protein C; and (d) block thrombin, including hirudin, argatroban, bivalirudin and H376/95. Oral formulations of heparin will also be reviewed.

In Section II, Dr. Comerota will discuss the use of thrombolysis for selected patients with venous thromboembolism. Fibrinolytic therapy, which has suffered from a high risk/benefit ratio for routine deep venous thrombosis, may have an important role to play in patients with iliofemoral venous thrombosis. Dr. Comerota presents his own results with catheter-directed thrombolytic therapy and the results from a large national registry showing long-term outcomes and the impact on quality of life.

In Section III, Dr. Ansell presents a critical analysis of the factors responsible for adverse events with oral anticoagulants and the optimum means of improving outcomes. The poor status of present day anticoagulant management is reviewed and the importance of achieving a high rate of “time in therapeutic range,” is emphasized. Models of care to optimize outcomes are described, with an emphasis on models that utilize patient self-testing and patient self-management of oral anticoagulation which are considered to be the ultimate in anticoagulation care. The treatment of venous and arterial thromboembolism is undergoing rapid change with respect to the development of new antithrombotic agents, an expanding list of new indications, and new methods of drug delivery and management. In spite of these changes, many of the traditional therapeutics are still with us and continue to play a vital role in the treatment of thromboembolic disease. The following discussion touches on a wide range of therapeutic interventions, from old to new, exploring the status of anticoagulant drug development, describing a new intervention for iliofemoral venous thrombosis, and analyzing the critical factors for safe and effective therapy with oral anticoagulants.