Abstract No. 390 Mechanical Thrombectomy of Deep Vein Thrombosis Patients Treated with the ClotTriever System: Interim 2-Year Outcomes from the CLOUT Registry

Mechanical thrombectomy is increasingly utilized for deep vein thrombosis (DVT) treatment with strong acute safety and effectiveness outcomes; however, long-term outcomes are needed. Interim results up to 2-year follow-up are presented from the CLOUT registry. The prospective, multisite CLOUT registry (NCT03575364) enrolled 499 DVT patients across 43 US sites irrespective of symptom duration, failed prior treatment, or bilateral disease. All patients were treated with the ClotTriever System (Inari Medical, Irvine, CA). Duplex ultrasound (DUS) for flow and compressibility, Villalta scores to assess post-thrombotic syndrome (PTS), revised venous clinical severity (rVCSS), edema, pain (NPRS), and EuroQoL group 5-D (EQ-5D) scores were assessed to 2 years. Most (99.4%) patients were treated in a single session, estimated blood loss was 40 mL, and adjunctive thrombolytics was used in 0.4% patients. Complete or near-complete thrombus removal was reported in 91.2% of patients, while 30-day serious adverse event rate was 8.6%. Two-year follow-up for 168 patients was completed to date. At 2 years, DUS demonstrated flow in 94.6% of treated limbs (123/130), while normal or partial vein compressibility was seen in 96.2% (125/130), both P< 0.0001 vs baseline. Baseline median Villalta score was 9.0 [IQR: 5.0–14.0], which decreased to 1.0 [IQR: 0.0–3.0] at 2 years (P< 0.0001). Furthermore, only 18.2% (28/154) of limbs had any PTS and 4.5% (7/154) had moderate or severe PTS. Median rVCSS was 6.0 [IQR: 3.0–9.0] at baseline and reduced to 2.0 [IQR: 1.0–4.0] at 2 years (P< 0.0001). Median EQ-5D quality of life score at baseline was 0.687 [IQR: 0.458–0.823] and 1.0 [IQR: 0.861–1.0] at 2 years (P< 0.0001). Additional outcomes up to 2-year follow-up are listed in Table 390.1. Interim 2-year results of the CLOUT registry demonstrate that thrombus removal by the ClotTriever System resulted in sustained benefits throughout the 2-year follow-up.390.1Outcomes to 2 YearsBaseline30-Day6-Month1-Year2-YearP Value1DUS, by limb Flow present (%)27.285.392.795.594.6< 0.0001 Compressible (%)28.087.691.996.796.2< 0.0001Villalta score, by limb (median)9.03.01.01.01.0< 0.0001By limb (%) Any PTS (Villalta >4)81.228.423.219.318.2< 0.0001 Moderate to severe PTS (Villalta >9)46.99.18.98.84.5< 0.0001rVCSS, median6.03.03.03.02.0< 0.0001Edema, mid-calf circum. (cm, median)39.038.038.038.037.00.0023NPRS, median5.02.00.00.00.0< 0.0001EQ-5D, median0.6870.8611.0001.0001.000< 0.00011Wilcoxon signed-rank or McNemar's tests between baseline and 2 years. Open table in a new tab