Evaluation of venous anatomy after treatment with an intraluminal tissue debulking system in a porcine model.
Abstract
Background
Residual venous obstruction and in-stent restenosis (ISR) are common and challenging complications that may occur after interventional procedures performed for acute deep vein thrombosis (DVT) or chronic ilio-femoral venous obstruction. A novel fully integrated thrombectomy system (Recana Thrombectomy Device, RTD) was designed to treat (ISR) and native vessel obstructions. The system includes a debulking catheter, collection baskets, and a family of sheaths (Figure 1). This report describes its use in animal models of native and stented veins to assess safety compared to currently available thrombectomy devices.
Methods
The RTD was studied in comparison to 2 currently marketed thrombectomy devices, the Argon CLEANER 15™ (CLEANER) and the Inari ClotTriever® (ClotTriever). Devices were studied in a porcine iliac vein model used in a manner consistent with Good Laboratory Practice for Nonclinical Laboratory Studies. 26 iliac veins in 13 animals were studied to evaluate performance in normal veins (9 animals, 18 iliac veins) and in 4 animals with 8 iliac veins pre-treated with iliac stents implanted 21 days prior to device treatment. Twelve normal iliac veins were treated with the RTD, 4 normal veins were treated with CLEANER and 2 with the ClotTriever. Five pre-stented iliac veins were treated with the RTD, and 3 pre-stented veins were treated with the CLEANER. Procedures were completed under fluoroscopic and IVUS guidance. For each model, both iliac veins were treated with 10 passes of the test or control thrombectomy device through the length of the common and external iliac veins. Survival and sacrifice periods were completed at varied timepoints to evaluate peak histological injury potential, vein wall healing and vein patency. Necropsy was performed at 5 ± 2 days or 30 ± 2 days after catheter intervention for gross evaluation of the iliac veins and other related tissues. Histology was performed on representative sections of treated iliac veins to evaluate wall damage, thrombosis, or other effects of intervention.
Results
All animals survived to their designated endpoints with no unexpected mortality. One common femoral vein access complication led to unilateral perivenous hematoma and thrombosis. Another animal showed post-intervention venous constriction with eventual vessel occlusion. All other iliac veins (n=24) remained patent without significant stenosis at necropsy. No clinically relevant lacerations, perforations, or hemorrhagic events were observed with either the Test or Control devices. Histology revealed intimal disruption and inflammation with all devices, more pronounced with the RTD compared to CLEANER but similar to those seen after use of the ClotTriever. Mild perivenous bruising occurred in some Test device cases, without evidence of transmural bleeding.
Conclusions
In an in-vivo model of stented and native iliac veins, a novel venous tissue debulking system was able to engage intraluminal material without serious injury. Vein wall trauma was comparable to a commonly used mechanical thrombectomy device, with no transmural lacerations or device-related hemorrhage. These findings support continued development toward initial clinical trials in patients with venous obstruction.