Device and imaging-specific volumetric analysis of clot lysis after percutaneous mechanical thrombectomy for iliofemoral DVT

Purpose: To determine the most accurate method of assessing clot lysis after percutaneous mechanical thrombectomy for iliofemoral deep vein thrombosis (DVT) and to evaluate the effectiveness of two different pharmacomechanical thrombectomy devices. Methods: Between 2004 and 2009, 33 patients (18 women; mean age 47 years) with iliofemoral DVT underwent pharmacomechanical thrombectomy using the AngioJet (n=18) or Trellis (n=15) devices with 10 mg of tenecteplase. Intravascular ultrasound (IVUS) and venography were performed over the iliofemoral segments before and after treatment. Cross-sectional vessel and lumen diameters were measured from the IVUS scans and the post-procedure anteroposterior and lateral venograms at 3 points (proximal, mid-section, and distal) along each iliofemoral vein by 2 independent observers blinded to the treatment method. Volumes of the recanalized segments were calculated and compared to volumes of the original venous segments to assess clot lysis with each PMT device. IVUS scans and venograms were also compared for their ability to identify residual lesions or clot in need of treatment. Repeatability between and among observers was analyzed using the Bland and Altman method. Results: All procedures were successfully completed; there were only 2 minor bleeding complications. The mean volume of the recanalized segment was 2255±66 mm³ by IVUS, representing 80% lysis of the clot compared to what was perceived as >90% lysis with venography (p<0.05). IVUS was able to delineate significant residual thrombus, stenosis, or May-Thurner anatomy requiring ancillary interventions in 100% of patients versus 48% (16/33) on the venograms (p<0.01). Quantitative assessments of the diameters of the involved venous segments from the venograms and IVUS were consistent between and among observers. Comparing the similar patient subgroups, AngioJet resulted in greater clot lysis (88%) versus the Trellis device (72%; p<0.01), corresponding to recanalized venous segment volumes of 2486±74 and 2025±57 mm ³ and total venous segment volumes of 2826±84 and 2813±79 mm³, respectively. Conclusion: IVUS is superior to venography for detection of residual thrombus and underlying venous pathology after pharmacomechanical thrombectomy. While greater clot lysis was seen with the AngioJet system, both the AngioJet and Trellis devices resulted in excellent clinical clot lysis.