PROfunda Femoris Vein Thrombosis Evaluation and Clearance to Improve Outcomes of Endovascular Treatment for Acute Iliofemoral Deep Vein Thrombosis

PROfunda Femoris Vein Thrombosis Evaluation and Clearance to Improve Outcomes of Endovascular Treatment for Acute Iliofemoral Deep Vein Thrombosis: a Multicenter Randomized Controlled Study (The PROTECT Study)

Patients with iliofemoral vein thrombosis are prone to developing post-thrombotic syndrome (PTS). The profunda femoris vein (PFV) is an important inflow of the iliofemoral vein. Profunda femoris vein thrombosis clearance (PFV-TC) may improve the patency of iliofemoral vein and reduce the occurrence of PTS.

Study Overview

• Status: Recruiting
• Conditions: Deep Vein Thrombosis
• Intervention / Treatment: Procedure: Percutaneous mechanical thrombectomy with profunda femoris vein thrombosis clearance (PMT with PFV-TC); Procedure: Percutaneous mechanical thrombectomy without profunda femoris vein thrombosis clearance (PMT without PFV-TC)

Detailed Description

Acute lower extremity deep vein thrombosis (DVT) can lead to obstruction of veins, causing sudden lower limb swelling. Patients may also develop post-thrombotic syndrome (PTS) manifesting as recurrent lower limb swelling, skin disorders, and even non-healing ulcers, which severely affects the patient's quality of life. Among lower extremity DVT, thrombosis involving the iliofemoral veins is the most severe, with an incidence of PTS as high as 20%-50%. Percutaneous mechanical thrombectomy (PMT) utilizes mechanical aspiration to rapidly remove thrombus, relieve venous obstruction, and restore luminal patency. According to the results of a prospective clinical study, PMT can effectively improve the primary thrombus clearance rate and shorten hospital stay in patients with DVT. Among 329 patients, 192 (58.5%) achieved complete thrombus removal using the AngioJet catheter. PMT was once considered to be the first-line treatment option for DVT. However, the results of the ATTRACT study, published in 2017 in New England Journal of Medicine, sparked considerable controversy regarding the use of PMT for DVT. The ATTRACT study found that there was no significant difference in the incidence of PTS at two years after PMT compared with anticoagulation alone. Although PMT can rapidly remove thrombus, is it unable to improve the long-term outcomes for patients with DVT? According to previous studies, the primary patency rate at 12 months after PMT for acute iliofemoral venous thrombosis ranges from 77% to 85%, while the incidence of PTS at 24 months postoperatively is as high as 40%. Residual thrombus is an important cause of thrombus recurrence, re-occlusion of the vein, and poor clinical outcomes. Previous studies have primarily focused on thrombus clearance in the popliteal vein, superficial femoral vein, common femoral vein, and iliac vein, while neglecting the assessment and clearance of profunda femoris vein (PFV) thrombosis. As the PFV is an important inflow of the iliofemoral vein, whether PFV-TC can improve the patency rate and clinical outcomes of endovascular treatment for acute iliofemoral DVT remains unclear. In a preliminary study, the investigators analyzed and compared two cohorts: one receiving conventional endovascular treatment for acute iliofemoral venous thrombosis, and the other receiving conventional treatment combined with Profunda femoris vein thrombosis clearance (PFV-TC). The results showed that the 24-month patency rate of the iliofemoral vein was 90% vs. 72%, and the incidence of PTS was 11% vs. 32% (P<0.05). These findings were published in November 2025 in European Journal of Vascular and Endovascular Surgery. This study has garnered widespread attention, and de Wolf MAF published an invited commentary on this study, acknowledging the value of this approach in the endovascular treatment of acute iliofemoral DVT. Therefore, the investigators hypothesize that PFV-TC can improve inflow and reduce the incidence of PTS for iliofemoral DVT. However, high-level evidence is still lacking. The present study is a prospective, multicenter, randomized, open-label, evaluator-blinded, 1:1 parallel-controlled clinical trial investigating PFV-TC, aiming to obtain higher-level evidence to guide endovascular treatment of acute iliofemoral DVT.

• Study Type: Interventional
• Enrollment (Estimated): 140
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Qihong Ni; Phone Number: +8615801900772; Email: niqihong1989@163.com

Study Locations

• China
  • Shanghai, China
    • Recruiting
    • RenJi Hospital
    • Contact: Qihong Ni; Phone Number: +8615801900772; Email: niqihong1989@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age ≥ 18 years and ≤ 85 years;
2. Diagnosed with acute iliofemoral DVT involving iliac vein, common femoral vein, and the proximal segment (orifice) of PFV (confirmed by preoperative ultrasound, CT venography, or pre-procedural venography);
3. Time from symptom onset to endovascular treatment ≤ 14 days;
4. Patient receives endovascular treatment with PMT;
5. Patient provides written informed consent.

Exclusion Criteria:

1. Presence of pre-existing PTS in the limb scheduled for treatment, or a history of symptomatic DVT in the same limb;
2. Concurrent symptomatic acute DVT involving the iliac vein and/or common femoral vein in the contralateral limb;
3. Known allergy to heparin, low-molecular-weight heparin, contrast media, or other relevant agents;
4. Concomitant severe pulmonary embolism with hemodynamic compromise, such as hypoxia or hypotension;
5. Intolerance to endovascular intervention due to concurrent acute systemic illness, severe dyspnea, or other contraindications;
6. Concomitant severe renal insufficiency with creatinine clearance < 30 ml/min;
7. Presence of active bleeding, severe hepatic insufficiency, bleeding diathesis, or other coagulation disorders;
8. Concomitant severe anemia (hemoglobin < 8.0 mg/dL) or thrombocytopenia (platelet count < 80,000/mL);
9. History of subarachnoid hemorrhage, intracranial hemorrhage, intracranial vascular malformation, or intracranial aneurysm;
10. Pregnancy;
11. Presence of other diseases (e.g., advanced malignancy, cardiac insufficiency) with an estimated life expectancy < 24 months;
12. Participation in another clinical trial of a drug or medical device within the past 1 month that may interfere with the present study;
13. Unwillingness to participate in this trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PMT with PFV-TC group; PMT with PFV-TC group (experimental group)	Procedure: Percutaneous mechanical thrombectomy with profunda femoris vein thrombosis clearance (PMT with PFV-TC); PMT with PFV-TC group (experimental group): Based on the control group, access is obtained via the contralateral common femoral vein using a crossover technique, or via a popliteal-profunda communicating vessel approach to PFV. The thrombus status of the PFV is assessed, and PMT is performed on the PFV thrombosis. After thrombectomy, venography is performed to evaluate the patency of the PFV. Successful PFV-TC is defined as the presence of continuous flow from the distal PFV to the CFV, including complete clearance (no residual thrombus) and partial clearance (continuous flow with residual thrombus). Conversely, the absence of continuous flow is defined as failed PFV-TC.
Active Comparator: PMT without PFV-TC group; PMT without PFV-TC group (control group)	Procedure: Percutaneous mechanical thrombectomy without profunda femoris vein thrombosis clearance (PMT without PFV-TC); An appropriate puncture approach is selected, including the ipsilateral calf vein, ipsilateral popliteal vein, or ipsilateral femoral vein. Under ultrasound guidance, a vascular sheath is inserted after puncture, and systemic heparinization is performed. Using a guidewire and catheter, the guidewire is advanced antegradely into the inferior vena cava to establish a pathway. After the pathway is established, PMT is performed using a mechanical thrombectomy device. Acceptable thrombectomy devices include commercially available mechanical aspiration thrombectomy devices such as the AngioJet catheter (Boston Scientific, USA) and the Indigo catheter (Penumbra Inc, USA). After thrombectomy, the outcome is evaluated by venography. If iliac vein stenosis greater than 50% is detected, balloon dilation is performed using a balloon matched to the normal vessel diameter. If residual stenosis remains greater than 50% after balloon dilation, stent implantation is performed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Post-Thrombotic Syndrome (PTS)	Assessed by the Villalta score. The Villalta scale is the recommended tool for diagnosing and grading the severity of PTS. It is a composite score based on 11 items (5 patient-reported symptoms and 6 clinician-assessed signs), each rated from 0 (absent) to 3 (severe), yielding a total score ranging from 0 to 33. A score of 0-4 indicates no PTS, whereas a score of ≥5 or venous ulcer confirms the diagnosis of PTS. Specifically, scores of 5-9 indicate mild PTS, 10-14 indicate moderate PTS, and a score of ≥15 or venous ulcer indicates severe PTS. Higher scores reflect greater disease severity.	at 24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of moderate-to-severe PTS	Assessed by the Villalta score	at 6, 12, and 24 months
Patency rate of the ipsilateral iliofemoral vein	Assessed by color Doppler ultrasound	at 12 months and 24 months
Recurrence rate of symptomatic Deep Vein Thrombosis (DVT)	Assessed by symptoms combined with ultrasound examination in the ipsilateral limb	at 24 months
Rate of re-intervention	Assessed by documentation of clinical reintervention	at 24 months
Incidence of PTS	Assessed by the Villalta score	at 6 and 12 months
Quality of life score	Assessed by Venous Insufficiency Epidemiological and Economic Study Quality of Life questionnaire (VEINES-QOL). The minimum value is 0 and the maximum value is 100. Higher score means a better outcome.	at 6, 12, and 24 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of major bleeding	Defined by International Society on Thrombosis and Haemostasis (ISTH) criteria	at 24 months
Incidence of symptomatic Pulmonary Embolism (PE)	Assessed by symptoms combined with contrast-enhanced computed tomography examination	at 24 months
Incidence of symptomatic Venous Thromboembolism (VTE)	Assessed by symptoms combined with ultrasound and contrast-enhanced computed tomography examination	at 24 months
All-cause mortality	All-cause death	at 24 months

Collaborators and Investigators

• Sponsor: RenJi Hospital
• Collaborators: Changhai Hospital; First People's Hospital of Hangzhou; West China Hospital; Chengdu University of Traditional Chinese Medicine; Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University; Wenzhou Central Hospital

Study record dates

Study Major Dates

• Study Start (Actual): June 24, 2026
• Primary Completion (Estimated): June 30, 2029
• Study Completion (Estimated): December 31, 2029

Study Registration Dates

• First Submitted: May 26, 2026
• First Submitted That Met QC Criteria: May 26, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): September 2, 2026
• Last Update Submitted That Met QC Criteria: August 31, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Deep venous thrombosis; Post-thrombotic syndrome; Percutaneous mechanical thrombectomy; Profunda femoris vein
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Embolism and Thrombosis; Venous Insufficiency; Thrombosis; Venous Thrombosis; Postthrombotic Syndrome
• Other Study ID Numbers: The PROTECT Study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No