Rob H.W. Strijkers

Safety and Feasibility of Ultrasound-accelerated Catheter-directed Thrombolysis in Deep Vein Thrombosis

OBJECTIVE One in four patients with primary iliofemoral deep vein thrombosis (DVT) develops post-thrombotic syndrome (PTS) within 1 year despite optimal standard anticoagulant therapy. Removal of thrombus by thrombolytic drugs may prevent PTS. The aim of this study was to assess the short-term safety and efficacy of ultrasound-accelerated catheter-directed thrombolysis (US-accelerated CDT). DESIGN This was a prospective non-randomised interventional study with US-accelerated CDT for DVT. PATIENTS AND METHODS Twelve patients with DVT (seven caval-iliofemoropopliteal, three iliofemoropopliteal, one femoropopliteal and one superior caval vein thrombosis) receiving standard anticoagulant and compression therapy, were treated with additional US-accelerated CDT (13 procedures) using the EKOS Endowave(®) system (EKOS Corporation, Bothell, WA, USA) between October 2008 and January 2010. RESULTS Thrombolysis was successful in 85% (11/13), with complete clot lysis (>90% restored patency) and in one case with partial clot lysis (50-90% restored patency). No pulmonary embolism and one bleeding at the catheter-insertion site were observed. In three patients, underlying lesions were successfully treated with balloon angioplasty and stent insertion. Four patients developed early recurrent thrombosis due to untreated residual venous obstruction. CONCLUSION US-accelerated CDT is a safe and promising treatment in patients with DVT. Residual venous obstruction should be treated by angioplasty and stent insertion to avoid early re-thrombosis.

Management of deep vein thrombosis and prevention of post-thrombotic syndrome.

#### Summary points The annual global incidence of deep vein thrombosis (DVT) of the leg is 1.6 per 1000.1 Classically, venous thrombosis of a lower limb begins in a deep calf vein and propagates more proximally. Symptoms include swelling, pain, and redness of the leg, depending on the vein segment(s) involved (see table 1⇓).2 Patients are at risk of pulmonary embolism.3 Despite optimal conservative treatment with anticoagulation and compression, one in four patients develops a post-thrombotic syndrome within one year,2 and one in three develops a recurrent DVT within five years.4 Patients with post-thrombotic syndrome have poor quality of life.5 A more aggressive approach to treatment, such as removal of early thrombus using catheter directed thrombolysis, might improve outcomes for patients with DVT compared with standard anticoagulation treatment.4 5 6 7 8 9 10 11 12 We review standard and new, more aggressive, management of DVT for the generalist reader, drawing from recent guidelines, cohort studies, small randomised controlled trails, and meta-analyses. All authors are investigators in the CAVA trial, which is one of three randomised controlled trials currently investigating outcomes after treatment with catheter …

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

Purpose To assess the feasibility of identifying deep vein thrombosis characteristics with contrast enhanced magnetic resonance venography. Materials and Methods A total of 53 cases of deep vein thrombosis extending in and/or above the common femoral vein were evaluated by 4 independent observers (2 expert, 2 novice) using pre-determined characteristics to determine the thrombosis present to be acute, sub-acute or old. If present, chronic remnants of a previous deep vein thrombosis were reported. Additionally these image qualifications were compared to the reported duration of complaints. Results In all cases all observers were able to qualify the thrombosis. The interobserver agreement between the experts was excellent (kappa 0.97) and good between expert and novice (kappa 0.82). Thrombosis identified as acute had an average duration of complaints of 6,5 (2–13) days, sub‐acute 13 (8–18) days and old 22 (15–32) days. Conclusion Qualification of thrombosis as acute, sub-acute or old and identification of chronic remnants of DVT with CE-MRV using routinely identifiable characteristics is feasible and reproducible with good to excellent interobserver agreement.

Venous In-stent Thrombosis Treated by Ultrasound Accelerated Catheter Directed Thrombolysis

OBJECTIVE/BACKGROUND Stent placement in the venous system is an increasingly used treatment modality in chronic venous obstruction and as additional treatment after thrombolytic therapy in ilio-femoral deep vein thrombosis (DVT). Experience in treating in-stent thrombosis with ultrasound accelerated catheter directed thrombolysis (UACDT) is reported. METHODS A retrospective analysis of patients treated for venous stent occlusion, after percutaneous transluminal angioplasty (PTA) and stent placement for either chronic venous occlusive disease or persistent vein compression in patients with acute DVT was performed. Duration of occlusion and suspected clot age were assessed using patient complaints and typical findings on duplex ultrasonography (DUS). DUS and venography were used to assess patency and to determine the cause of re-occlusion. Acute treatment of occlusion was by UACDT. Additional procedures included PTA, stent placement, and creation of an arteriovenous (AV) fistula. RESULTS Eighteen patients (median age 43 years; 67% male), treated for occluded stent tracts with UACDT between January 2009 and July 2014, were identified. Indications for initial stenting were treatment of chronic venous obstructive disease (12 patients) and treatment of underlying obstruction after initial thrombolysis in acute DVT (six patients). Technical success was achieved in 11/18 (61%) patients. Primary patency in 8/11 patients was 73% at last follow up (median follow up 14 months [range 0-41 months]). Additional treatments after successful lysis were re-stenting (seven patients) and creation of an AV fistula (six patients). CONCLUSION Treatment with UACDT of recently occluded stent tracts is feasible and effective. Recanalization of the stent tract can be achieved in most cases. Additional interventions were frequently used after successful UACDT treatment. Suboptimal stent positioning caused the majority of the stent occlusions.

Risk factors of postthrombotic syndrome before and after deep venous thrombosis treatment.

Postthrombotic syndrome is the most common complication after deep venous thrombosis. Postthrombotic syndrome is a debilitating disease and associated with decreased quality of life and high healthcare costs. Postthrombotic syndrome is a chronic disease, and causative treatment options are limited. Prevention of postthrombotic syndrome is therefore very important. Not all patients develop postthrombotic syndrome. Risk factors have been identified to try to predict the risk of developing postthrombotic syndrome. Age, gender, and recurrent deep venous thrombosis are factors that cannot be changed. Deep venous thrombosis location and extent seem to predict severity of postthrombotic syndrome and are potentially suitable as patient selection criteria. Residual thrombosis and reflux are known to increase the incidence of postthrombotic syndrome, but are of limited use. More recently developed treatment options for deep venous thrombosis, such as new oral factor X inhibitors and catheter-directed thrombolysis, are available at the moment. Catheter-directed thrombolysis shows promising results in reducing the incidence of postthrombotic syndrome after deep venous thrombosis. The role of new oral factor X inhibitors in preventing postthrombotic syndrome is still to be determined.

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.