David Dexter (Sentara Vascular Specialists, Norfolk, USA) shared one-year data from the CLOUT registry this week at The VEINS 2023 (28–30 October, Las Vegas, USA).
Long-term, prospective outcome data after mechanical thrombectomy for deep vein thrombosis (DVT) are lacking. The CLOUT (ClotTriever Outcomes) registry is a prospective, multicentre study evaluating patient outcomes for proximal lower extremity DVT treated with the ClotTriever system (Inari Medical).
CLOUT is the largest mechanical thrombectomy study in the field of DVT, said Dexter, and although positive results have been previously published, this is the first report of one-year outcomes for all available patients. Patients in CLOUT were aged ≥18 years and enrolled regardless of bilateral disease, duration of symptoms, prior treatment failure for the current DVT event, or contraindications to thrombolytic therapy. A total of 310 patients completed the one-year follow-up visit.
One year after mechanical thrombectomy, moderate-to-severe post-thrombotic syndrome (PTS; Villalta score ≥10) was observed in 8.8% of treated limbs. The overall PTS rate (Villalta score ≥5) was 19.3%. Venous patency, as measured by the presence of flow with normal or partial compressibility on duplex ultrasound, was observed in 94.2% of cases. Additionally, significant improvements from baseline in revised Venous Clinical Severity Score, Numeric Pain Rating Scale score, and EQ-5D questionnaire score were demonstrated.
In the real-world, all-comer CLOUT registry, one-year outcomes demonstrate a low rate of PTS following treatment with the ClotTriever system, which was complemented by patient-centric improvements in symptom relief and quality of life. Study follow-up through two years is ongoing.
Dexter stated that these favourable clinical outcomes highlight the need for randomised controlled trial data comparing mechanical thrombectomy with standard of care anticoagulation treatment. The recently initiated randomised controlled DEFIANCE trial will compare the ClotTriever system to anticoagulation for the treatment of symptomatic iliofemoral DVT.