The short-term outcome of residual thrombus of the lower extremity after pharmacomechanical catheter-directed thrombolysis for deep vein thrombosis

BACKGROUND: This study aimed to assess the short-term effect of residual thrombus of the lower extremity after pharmacomechanical catheter-directed thrombolysis (PCDT) on the incidence of post-thrombotic syndrome (PTS) and iliofemoral vein patency rate in patients who underwent PCDT. METHODS: There were 94 continuous patients with severe deep vein thrombosis (DVT) of the lower extremities admitted to our hospital between March 2016 and June 2018; 73 cases receiving PCDT and verified with iliac vein compression syndrome (IVCS) were assigned into two groups. Thirty-nine patients without thrombus of the popliteal and infrapopliteal veins were assigned to the proximal DVT group. The remaining 34 cases were placed in the extensive DVT group. The thrombus scores, including venous registry index (VRI) score, Marder score, and Society for Vascular Surgery (SVS) score before and after PCDT, the primary two years’ cumulative rate of iliofemoral patency, and the rate of PTS, and complications were analyzed retrospectively. RESULTS: Ultimately, 27 patients in the proximal DVT group and 26 cases in the extensive DVT group completed the study. The two groups had no significant differences in terms of basic characteristics, complication and the rate of PTS (P>0.05). However, there were significant differences in terms of postoperative mean thrombus score and the mean degree of thrombosis removal score by Marder and SVS scores, residual thrombus by lower thrombosis classification (LET) and the two years’ cumulative iliofemoral vein patency rate (P<0.05). And the logistic regression analysis demonstrated the residual thrombus of LET class II [odds ratio (OR), 4.619, 95% confidence interval (CI), 1.090–19.567, P=0.038] was an independent risk factor for iliofemoral vein occlusion. CONCLUSIONS: The residual thrombus of LET class II is an independent risk factor for iliofemoral vein occlusion. It is very important to keep the patency of the popliteal vein when deciding to use a stent to maintain iliofemoral vein patency. Furthermore, the anterior tibial vein approach and crisscross technique may be two important alternative methods that can be used to address the thrombus of popliteal vein for patients with extensive DVT.