Outcomes from the ClotTriever Outcomes Registry show symptom duration may underestimate deep vein thrombus chronicity

The all-comer ClotTriever Outcomes registry assessed indicators of thrombus chronicity in patients with acute, subacute, and chronic lower extremity deep vein thrombosis (DVT). The effectiveness of the ClotTriever System (Inari Medical, Irvine, CA) by chronicity subgroup was also assessed and reported here in this subanalysis.

All-comer patients with lower extremity DVT were enrolled, with no limitation based on the patients' symptom duration. Chronicity was assessed three times and compared: before the procedure based on symptom duration, during the procedure based on available pre-thrombectomy imaging, and visual inspection of the extracted thrombus morphology after thrombectomy. Patients were grouped into acute, subacute, and chronic subgroups according to their post-thrombectomy thrombus chronicity based on thrombus morphology. Analyses on baseline and procedural characteristics along with thrombus removal were performed across subgroups. The effectiveness of thrombus removal was determined by Marder scores adjudicated by an independent core laboratory, with a prespecified primary effectiveness end point of complete or near-complete (≥75%) thrombus removal.

Of the 260 treated limbs from 250 patients, using symptom duration alone, 70.7% were considered acute, 20.9% subacute, and 8.4% chronic. Upon visual inspection, the extracted thrombus chronicity was approximately one-third in each subgroup: 32.7% had acute thrombus, 35.4% subacute thrombus, and 31.9% chronic thrombus. Chronicity assessed using symptom duration alone mismatched the post-thrombectomy chronicity in 55.1% of limbs (P < .0001) with 49.0% being more chronic than suggested by the patients' duration of symptoms. Chronicity assessed using pre-thrombectomy imaging mismatched the post-thrombectomy chronicity in 17.5% of limbs (P < .0001). No patients received thrombolytics and 99.6% were treated in a single session. Complete or near-complete thrombus removal was achieved in a high percentage of limbs regardless of thrombus chronicity: 90.8%, 81.9%, and 83.8% in limbs with acute, subacute, and chronic thrombus, respectively.

This subanalysis from the all-comer ClotTriever Outcomes registry demonstrates that extracted thrombus in DVT may be more chronic than suggested by the patients' duration of symptoms. The addition of imaging is helpful to determine the ability of thrombus to respond to therapy. Irrespective of thrombus chronicity, the ClotTriever system can be effective at removing acute, subacute, and chronic thrombus in a single-session procedure without the need for thrombolytics.