Predictors of Clinical Outcomes of Pharmacomechanical Catheter-Directed Thrombolysis for Acute Iliofemoral Deep Vein Thrombosis: Analysis of a Multicenter Randomized Trial

Rationale and Design of the DEFIANCE Study: A Randomized Controlled Trial of Mechanical Thrombectomy Versus Anticoagulation Alone for Iliofemoral Deep Vein Thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a common medical condition that is associated with clinically significant sequelae, including postthrombotic syndrome (PTS). Anticoagulation alone remains the guideline-recommended treatment for many patients with iliofemoral DVT. Recent technological advances have led to an increase in the use of mechanical thrombectomy for DVT, but mechanical thrombectomy-based procedures have not yet been compared with standard-of-care anticoagulation therapy in randomized studies.

METHODS

The DEFIANCE study (ClinicalTrials.gov: NCT05701917) is an international and actively enrolling randomized controlled trial (RCT) in lower extremity DVT assessing an interventional strategy that includes mechanical thrombectomy with the ClotTriever System (Inari Medical, Irvine, CA) versus anticoagulation alone. Approximately 300 patients with unilateral iliofemoral DVT and symptom duration ≤12 weeks will be randomized 1:1. Study conduct includes an independent core laboratory for duplex ultrasound assessment, an independent medical monitor for safety adjudication, and evaluation of PTS severity on the Villalta scale using best clinical practices. The primary endpoint is a composite outcome structured as a hierarchal win ratio of 1) the occurrence of treatment failure or therapy escalation as adjudicated by the medical monitor, with failure defined as amputation or gangrene of the target leg or venous thromboembolism-related mortality, and 2) the assessment of PTS severity at the 6-month follow-up visit. In addition to being a component of the primary endpoint, the severity of PTS at 6 months is also evaluated as a stand-alone secondary endpoint. An additional secondary endpoint is a composite of outcomes at the 10-day visit and is structured as a hierarchal win ratio of 1) vessel compressibility on duplex ultrasound, 2) patient-reported pain, and 3) improvement of edema. The safety endpoints are access site complications requiring endovascular or surgical repair and the occurrence through the 30-day visit of mortality, major bleeding, or new symptomatic pulmonary embolism.

CONCLUSIONS

DEFIANCE will be the first RCT to evaluate a mechanical thrombectomy-based interventional approach versus anticoagulation therapy alone for DVT. The results will inform the treatment of patients with iliofemoral DVT and the prevention of PTS-associated morbidity.

TRIAL REGISTRATION

DEFIANCE: RCT of ClotTriever System Versus Anticoagulation In Deep Vein Thrombosis (DEFIANCE), ClinicalTrials.gov: NCT05701917, URL: https://clinicaltrials.gov/study/NCT05701917?cond=Deep%20Vein%20Thrombosis&term=defiance&rank=1.

Comparing anticoagulant therapy alone, anticoagulant therapy in combination with catheter-directed thrombolysis, and anticoagulant therapy in combination with pharmacomechanical catheter-directed thrombolysis in the patients with optional inferior vena cava filter-related thrombosis: A single-center retrospective study

OBJECTIVE

To analyze the treatment methods and efficacy of inferior vena cava filter thrombosis (IVCFT).

MATERIALS AND METHODS

In this retrospective study, the clinical data for 47 patients with IVCFT who underwent sequential treatment at the Department of Vascular Surgery, Tianjin Medical University Second Hospital, from January 2020 to January 2023 were analyzed. Patients were divided into three groups according to the treatment method: anticoagulant therapy (AC group), anticoagulation plus catheter-directed thrombolysis (CDT group), and anticoagulation plus AngioJet thrombectomy plus catheter-directed thrombolysis (PCDT group). The evaluation criteria for efficacy mainly included preoperative and postoperative clinical symptoms (Villalta score), thrombus diameter, thrombus clearance rate, filter retrieval rate, filter retention time, and urokinase dosage.

RESULTS

This study included 47 patients, of whom 31 were males (65.9%) and 16 females (34.1%), with a mean age of 72.05 ± 8.32 years. An Aegisy filter was used in seven patients, whereas an Illicium filter was used in forty patients. There were a total of nineteen patients in the anticoagulation-only group, with complete dissolution of the intraluminal thrombus in five patients, a residual thrombus with a maximum diameter ≤1 cm in three patients, and a residual thrombus with a maximum diameter >1 cm in eleven patients. The Villalta score was 7.16 ± 0.6 before treatment and decreased to 3.79 ± 0.59 after treatment. The thrombus diameter decreased from an average of 1.46 ± 0.2 cm before treatment to an average of 0.85 ± 0.14 cm after treatment. The retrieval rate for the filters was 42.11% (8/19), with an average dwell time of 27.4 ± 1.3 days for the filters. The CDT group consisted of 17 patients. Among whom we observed, complete dissolution of the intraluminal thrombus was observed in six patients, residual thrombus with a maximum diameter ≤1 cm in nine patients, and residual thrombus with a maximum diameter >1 cm in two patients. The Villalta score decreased from 7.53 ± 0.83 before treatment to 2.06 ± 0.39 after treatment. The thrombus diameter also decreased from 1.46 ± 0.16 cm before treatment to 0.35 ± 0.11 cm after treatment. The retrieval rate of the filters was 88.24% (15/17), and the average filter indwelling time was 19.25 ± 4.5 days. The PCDT group consisted of 11 patients. We observed complete dissolution of the intraluminal thrombus in four patients, residual thrombus with a maximum diameter ≤1 cm in six patients, and residual thrombus with a maximum diameter >1 cm in one patient. The Villalta score decreased from 7.45 ± 0.76 before treatment to 2.09 ± 0.55 after treatment. The thrombus diameter decreased from 1.50 ± 0.21 cm before treatment to 0.33 ± 0.35 cm after treatment, and the rate of filter retrieval was 90.91% (10/11).

CONCLUSION

The three treatments of anticoagulation therapy, CDT, and PCDT were meaningful for preoperative and postoperative thrombolysis and symptom improvement in patients with IVCFT. The application of CDT and PCDT was superior to anticoagulation therapy, while there was no significant difference between the CDT and PCDT group. The retrieval rate of filters in the anticoagulation therapy group was the lowest, with no significant difference between the CDT and PCDT group.

The role and principles of stenting in acute iliofemoral venous thrombosis

Catheter-directed interventions for acute iliofemoral deep venous thrombosis (DVT) have been increasingly used over the past 15 years to target severe symptomatology and prevention of post-thrombotic syndrome incidence or reduce its severity if it were to develop. Aside from successful thrombus removal, adjunctive stents are frequently required to treat an uncovered lesion or significant residual thrombus to ensure quality of life improvement besides retarding DVT recurrence and post-thrombotic syndrome. As the evidence is mounting, the need and role for stenting, as well as the principles of an optimal technique, in the acute DVT setting are now better understood. Accumulating experience appears to favor stenting in the acute setting. The diameter of the stent, the length, the extent of overlapping, and the landing zones are crucial determinants of a successful durable outcome. This article endeavors to guide the interventionalist on stenting when encountering a patient with acute symptomatic iliofemoral DVT with concerns of quality of life impairment.

Pharmacomechanical Thrombectomy and Catheter-Directed Thrombolysis, with or without Iliac Vein Stenting, in the Treatment of Acute Iliofemoral Deep Vein Thrombosis

BACKGROUND

This study aims to evaluate and compare the outcomes and clinical efficacy of pharmacomechanical thrombectomy (PMCT) plus catheter-directed thrombolysis (CDT) and PMCT combined with CDT and venous stenting in managing acute iliofemoral deep vein thrombosis (DVT), while also assessing the long-term safety and efficacy of these interventions.

METHODS

A retrospective case-control study spanning 3 years involved 112 patients presenting with acute symptomatic iliofemoral deep vein thrombosis (DVT), each with a symptom duration of less than 14 days. Patients were consecutively categorized into two groups based on individual clinical indications: PMCT + CDT vs. PMCT + CDT + venous stent. Statistical analyses were conducted to compare clinical features and outcomes between the two groups. Additionally, patients were followed up for 24 months post-treatment, during which quality of life (QoL) and severity of post-thrombotic syndrome (PTS) were analyzed.

RESULTS

In this retrospective study, we analyzed a total of 112 consecutive patients, with 63 patients undergoing PMCT + CDT and 49 patients undergoing PMCT + CDT + venous stent. Between the two groups, regarding primary outcomes at 6 months, there was no difference in the observed cumulative patency rates, standing at 82.5% for PMCT + CDT and 81.6% for PMCT + CDT + stent. Survival analyses for primary, primary-assisted, and secondary patency yielded comparable results for PMCT + CDT, with p-values of 0.74, 0.58, and 0.72, respectively. The two-year patency rate was high in both groups (85.7% for PMCT + CDT vs. 83.7% for PMCT + CDT + stent). Additionally, during the follow-up period, there were no statistically significant differences observed in the incidence of PTS or the average Villalta score between the two groups. At 24 months post-intervention, the incidence of post-thrombotic syndrome (PTS) was 11.1% in the PMCT + CDT group and 22% in the PMCT + CDT + stent group (p = 0.381). Both treatment arms of the study groups experienced bleeding complications during the thrombolysis therapy; in the PMCT + CDT group, there were three cases of gastrointestinal bleeding, compared to two cases in the PMCT + CDT + stent group (p = 0.900). Additionally, there was one intracranial hemorrhage in the PMCT + CDT group and two in the PMCT + CDT + stent group.

CONCLUSIONS

Pharmacomechanical thrombectomy (PMCT) combined with catheter-directed thrombolysis (CDT) therapy has shown significant efficacy in alleviating leg symptoms and reducing the occurrence of post-thrombotic syndrome (PTS), including the incidence of moderate-to-severe PTS. On the other hand, the utilization of PMCT + CDT + stent therapy, tailored to individual patients' clinical and venous conditions, may enhance long-term venous patency and lead to superior outcomes, including improved quality of life parameters.

Current Evidence for Endovascular Therapies in the Management of Acute Deep Vein Thrombosis

Acute lower extremity deep vein thrombosis (DVT), specifically proximal iliofemoral DVT, is a relatively common disorder that can result in a chronic debilitating post-thrombotic syndrome (PTS), with a significant effect on a patient's quality of life. Anticoagulation is first-line therapy; however, percutaneous interventions have emerged as treatment options for patients where there is concern that anticoagulation alone will not resolve the DVT as well as prevent PTS. This paper will discuss the existing data on these interventions and review current endovascular techniques, including catheter-directed thrombolysis, pharmacomechanical thrombectomy, and large-bore mechanical thrombectomy in the management of DVT.

Single-procedure 8Fr rheolytic pharmacomechanical thrombectomy for treatment of acute iliofemoral deep venous thrombosis

PURPOSE

We hypothesize that single-procedure venous-specific rheolytic thrombectomy for treatment of acute iliofemoral deep venous thrombosis (DVT) will result in improved clinical symptoms as measured by the venous clinical severity score (VCSS), as well as durable venous patency, with decreased hemorrhagic risks and costs associated with conventional catheter-directed therapy and prolonged lytic exposure.

MATERIALS AND METHODS

Thirty-three consecutive patients with symptomatic, unilateral, iliofemoral DVT who were treated with single-procedure therapy using the 8Fr rheolytic thrombectomy catheter were retrospectively analyzed from 2012-2021. Abstracted data included technical success (> 95% clearance of acute thrombus), adverse events (AEs), and clinical and imaging outcomes at 1-month and 1-year.

RESULTS

Technical success was achieved in all 33 patients. Mean pre-procedure VCSS was 7.5 with mean edema and pain sub-scores of 2.6 and 1.8, respectively. Post-procedural total mean VCSS at one month was significantly improved (mean post-procedure VCSS = 0.3, mean reduction of 7.2, P < 0.01). Clinical improvement was sustained at 1-year (mean total VCSS = 0.2, P < 0.01). Primary patency was achieved in all patients at 1-month and 30 (91%) patients at 1-year. Among the 3 patients in which primary patency was not achieved at 1-year, primary-assisted patency was achieved in 2 patients. Secondary patency was achieved in the remaining patient at 1-year. No hemorrhagic AEs occurred in this study.

CONCLUSION

This study suggests that single-procedure venous-specific rheolytic thrombectomy for treatment of acute iliofemoral DVT is safe and effective, resulting in durable clinical and radiographic results at one year, while also limiting hemorrhagic risks, mitigating costs of admission, and expediting patient discharge.

Impact of thrombosis location on walking capacity: a cohort study of patients with acute deep vein thrombosis

Background

Data on walking impairment during the acute phase of deep vein thrombosis (DVT) are limited.

Objectives

This study aimed to assess the degree of walking impairment in patients with acute DVT, with a particular focus on the relation to the DVT's anatomical location.

Methods

Patients with sonographically confirmed DVT were eligible for inclusion in this cohort study. Pain-free walking distance (PWD) and maximum walking distance (MWD) were determined using standardized treadmill ergometer tests and analyzed in relation to DVT location. The impact of previous DVT on walking capacity was evaluated in an exploratory analysis.

Results

The study included 64 patients (31% women; median age, 55 years). The median (IQR) time from diagnosis to exercise test was 3 (1-5) days. Patients with suprainguinal DVT demonstrated significantly shorter median (IQR) MWD than those with infrainguinal DVT (130 (61-202) m vs 565 (128-750) m; P < .01), while PWD did not significantly differ (PWD: 20 (0-30) m vs 40 (0-222) m; P = .14). The proportion of patients who had to terminate treadmill tests prematurely was higher in patients with suprainguinal DVT (91.7% vs 57.7%; P = .04). PWD and MWD seemed to be similar in patients with and without a history of DVT. Premature test termination and suprainguinal DVT location were associated with reduced quality of life, as measured by the EuroQoL Group 5-Dimension 5-Level questionnaire and visual analog scale.

Conclusion

Suprainguinal DVT was linked to a more pronounced walking impairment compared with infrainguinal DVT. Limited walking capacity was associated with a reduced quality of life.

Delphi Consensus on Reporting Standards in Clinical Studies for Endovascular Treatment of Acute Iliofemoral Venous Thrombosis and Chronic Iliofemoral Venous Obstruction

Acute iliofemoral deep vein thrombosis and chronic iliofemoral venous obstruction cause substantial patient harm and are increasingly managed with endovascular venous interventions, including percutaneous mechanical thrombectomy and stent placement. However, studies of these treatment elements have not been designed and reported with sufficient rigor to support confident conclusions about their clinical utility. In this project, the Trustworthy consensus-based statement approach was utilized to develop, via a structured process, consensus-based statements to guide future investigators of venous interventions. Thirty statements were drafted to encompass major topics relevant to venous study description and design, safety outcome assessment, efficacy outcome assessment, and topics specific to evaluating percutaneous venous thrombectomy and stent placement. Using modified Delphi techniques for consensus achievement, a panel of physician experts in vascular disease voted on the statements and succeeded in reaching the predefined threshold of >80% consensus (agreement or strong agreement) on all 30 statements. It is hoped that the guidance from these statements will improve standardization, objectivity, and patient-centered relevance in the reporting of clinical outcomes of endovascular interventions for acute iliofemoral deep venous thrombosis and chronic iliofemoral venous obstruction in clinical studies and thereby enhance venous patient care.

Performance and Head-to-Head Comparison of Three Clinical Models to Predict Occurrence of Postthrombotic Syndrome: A Validation Study

OBJECTIVE

 The SOX-PTS, Amin, and Méan models are three different clinical prediction scores stratifying the risk for postthrombotic syndrome (PTS) development in patients with acute deep vein thrombosis (DVT) of the lower limbs. Herein, we aimed to assess and compare these scores in the same cohort of patients.

METHODS

 We retrospectively applied the three scores in a cohort of 181 patients (196 limbs) who participated in the SAVER pilot trial for an acute DVT. Patients were stratified into PTS risk groups using positivity thresholds for high-risk patients as proposed in the derivation studies. All patients were assessed for PTS 6 months after index DVT using the Villalta scale. We calculated the predictive accuracy for PTS and area under receiver operating characteristic (AUROC) curve for each model.

RESULTS

 The Méan model was the most sensitive (sensitivity 87.7%; 95% confidence interval [CI]: 77.2-94.5) with the highest negative predictive value (87.5%; 95% CI: 76.8-94.4) for PTS. The SOX-PTS was the most specific score (specificity 97.5%; 95% CI: 92.7-99.5) with the highest positive predictive value (72.7%; 95% CI: 39.0-94.0). The SOX-PTS and Méan models performed well for PTS prediction (AUROC: 0.72; 95% CI: 0.65-0.80 and 0.74; 95% CI: 0.67-0.82), whereas the Amin model did not (AUROC: 0.58; 95% CI: 0.49-0.67).

CONCLUSION

 Our data support that the SOX-PTS and Méan models have good accuracy to stratify the risk for PTS.