Background and Aims: The popliteal vein is the mainstream approach currently to perform catheter-directed thrombolysis (CDT) for patients with deep vein thrombosis (DVT) of the lower limbs. However, for some patients with mixed DVT or specific postural requirements in whom the popliteal vein access cannot be established, the lower leg deep venous puncture approach may be an alternative treatment option. Therefore, this study was conducted to investigate the feasibility and safety of using lower leg deep venous puncture approach to perform CDT for the treatment of patients with acute mixed DVT. 
Methods: The clinical data of 172 patients with acute mixed DVT admitted from January 2012 to December 2017 were retrospectively analyzed. Of the patients, 89 cases underwent CDT treatment through the lower leg deep venous puncture approach (puncture group), 54 cases underwent CDT by posterior tibial vein puncture under direct vision after exposure of the posterior tibial vein (incision group) and 29 cases underwent thrombolysis via dorsal superficial vein of foot (superficial vein group). The relevant clinical variables of the three groups of patients were analyzed and compared.
Results: In puncture group, deep venous puncture was successfully performed in 86 patients (96.6%), including 37 cases of the posterior tibial vein, 21 cases of the fibular vein, and 28 cases of the anterior tibial vein. In incision group, the vascular sheath was successfully inserted from the posterior tibial vein in all patients (100%). Gastrointestinal hemorrhage and cerebral hemorrhage in 2 patients each in puncture group, and gastrointestinal hemorrhage occurred in 3 patients in incision group and occurred in one patient in superficial vein group, respectively. The incidence rates of bleeding events among the three group had no statistical difference (P>0.05). The patency rate of CDT was 86.5% (77/89) in puncture group and 59.3% (32/54) in incision group, and the difference was statistically significant (P=0.034). The reduction of the thigh circumference and the dose of urokinase used in puncture group were significantly larger than those in the other two groups (all P<0.05). The difference in reduction of the calf circumference showed no statistical difference among the three groups (F=1.152, P=0.320). The incidence rates of mild to moderate post-thrombotic syndrome (PTS) showed no statistical differences among the three groups at 6, 12, 18 and 24 months after operation (χ2=0.301, P=0.860; χ2=0.875, P=0.646; χ2=3.010, P=0.222; χ2=4.446, P=0.108), and no severe PTS occurred in all the three groups. There was no statistical difference in the Villalta scores among the three groups at 6 months after operation (F=1.177, P=0.302), but the Villalta scores in puncture group were superior to those in the other two groups at 12, 18 and 24 months after operation, and except for no statistical significance reached between puncture group and incision group at 12 months after operation (P=0.108), all other differences had statistical significance (all P<0.05). The CIVID-2 scores in puncture group were all superior to those in the other two group at 6, 12, 18 and 24 months after operation, and all differences reached a statistical significance (all P<0.05).
Conclusion: Using lower leg deep venous puncture approach to perform CDT has a higher thrombolysis rate than those of CDT after deep vein exposure and superficial vein thrombolysis, with no increase in major bleeding events. So, it is a preferred choice for acute mixed DVT.