A Prospective, Multicenter, Single-Arm Trial of Peripheral Vein Thrombectomy Stent System in Deep Venous Thrombosis

Tendfast™ Peripheral Vein Thrombectomy Stent System

Tendfast™ Peripheral Vein Thrombectomy Stent System (Tendfast™) is a mechanical thrombectomy system consisting of a peripheral vein thrombectomy stent and a thrombus aspiration catheter. Guided by a guidewire, the stent is delivered to the thrombus, deployed against the vessel wall to engage, scrape, and collect the thrombus into its mesh for removal, after which manual negative-pressure aspiration through the catheter clears residual thrombus and restores blood flow.

Thrombus clearance (immediately post-procedure): The thrombus clearance rate is divided into 3 grades: Grade I is <50%; Grade II is 50%-95%; Grade III is >95%. The lower extremity veins are divided into 7 segments: inferior vena cava, common iliac vein, external iliac vein, common femoral vein, proximal superficial femoral vein, distal superficial femoral vein, and popliteal vein. Pre- and post-procedure luminal patency is visually assessed by venography: a patent lumen is scored as 0 points, partial occlusion (<50%) as 1 point, severe occlusion (50%-95%) as 2 points, and complete occlusion (95%-100%) as 3 points. The formula for the thrombus clearance rate is: (preoperative venous patency score - postoperative venous patency score) / preoperative venous patency score × 100%. A thrombus clearance rate of Grade II or above is considered effective.

Compared with before discharge, worsening of symptoms with imaging confirmation that the target lesion thrombus occludes the vessel or interrupts blood flow, requiring repeat intervention.

Occurrence and severity grading assessed by the Villalta score. PTS is defined as a Villalta score >4. The Villalta score includes 5 symptoms (pain, muscle cramps, heaviness, paresthesia, itching) and 6 signs (pretibial edema, pigmentation, lipodermatosclerosis, redness of the skin, superficial venous dilatation, calf muscle tenderness). Severity is classified as mild (5-9), moderate (10-14), and severe (>14 and/or presence of skin ulcer).

Successful delivery of the thrombectomy device to the target lesion, successful deployment, and successful withdrawal of the delivery system.

Immediate post-procedure thrombus clearance rate of Grade II or above and no major adverse event before discharge

Evaluation of clinical symptoms by comparing improvement from baseline to post-treatment. VCSS includes 10 clinical elements (pain, varicose veins, edema, skin pigmentation, inflammation, induration, number of active ulcers, ulcer size, and use of compression therapy), each scored 0-3 by severity, with a total score of 30.

Improvement/change compared with pre-operation based on the CIVIQ-20 score. CIVIQ is a specific, self-administered quality-of-life questionnaire for patients with chronic venous disease of the lower extremities. It includes 20 items across 4 domains-social, psychological, physical, and pain-and mainly reflects the impact of chronic venous insufficiency on patients' quality of life.

all-cause death, major bleeding, new-onset symptomatic pulmonary embolism, and target lesion thrombus recurrence. Major bleeding is defined as intracranial hemorrhage or severe bleeding that leads to death, surgery, discontinuation of treatment, or transfusion. Transfusion [15] is defined as two or more units of whole blood (400 mL) or red blood cells (240 mL). Symptomatic pulmonary embolism is defined as pulmonary embolism with clinical symptoms such as dyspnea, chest pain, hemoptysis, panic, cough, or syncope. Target lesion thrombus recurrence is defined as worsening symptoms compared with before discharge, with imaging confirmation that the target lesion thrombus occludes the vessel or interrupts blood flow and requires repeat intervention.

Adverse event rate within 12 months after surgery

Serious adverse event rate within 12 months after surgery