Previous studies showed that although PTA could be used for most of chronic ischemic diseases in lower extremity, up to 40% of cases developed restenosis 6 to 12 months after operation. Currently, it has been widely accepted that vascular endothelial hyperplasia is the main mechanism of restenosis. Sufficient inhibition of endothelial cell proliferation will be helpful to reduce the demand for TLR. Lipophilic paclitaxel is one of the most promising agents for serving this goal. In vivo experiments confirmed that intraoperative application of paclitaxel, either added in the contrast medium or coated onto angioplasty balloons, could effectively inhibit vascular endothelial hyperplasia. Paclitaxel is hydrophobic, making it easy to gathering upon the arterial intima and exerting a long-time influence. After releasing, paclitaxel may produce direct inhibition on arterial intima, thereby reducing the occurrence of restenosis and improving the long-term patency[12–14].
Recently, several randomized clinical trials applying DCB for the treatment of chronic ischemic diseases in lower extremity have been reported. THUNDER trial was a multicenter, randomized controlled study. A total of 154 patients were randomly divided into three groups. One group was treated with paclitaxel-coated balloons (n = 48), a second group was treated with uncoated balloons with paclitaxel dissolved in the contrast medium (n = 52), and the control group was treated with uncoated balloons and standard nonionic contrast medium (n = 54). The mean lesion length was 7.4 cm. At 6 months, the mean LLL was 1.7 mm in the control group, as compared with 0.4 mm (P < 0.001) in the DCB group and 2.2 mm (P = 0.11) in the group treated with paclitaxel in the contrast medium. The mean TLR at 6 months was 37% in the control group, 4% in the DCB group (P < 0.001), and 29% in the group treated with paclitaxel in the contrast medium (P = 0.41). DCBELLUM trial was a prospective, randomized controlled study, consisting of 50 patients and 122 lesions (including femoropopliteal and infrapopliteal lesions). At 12 months, LLL was 0.64 mm in DCB group vs. 1.81 mm in the conventional PTA group (P = 0.01). The TLR was 12.2% for DCB and 35.3% for PTA (P < 0.05). Amputation rate was 4% for DCB vs. 12% for PTA (P = 0.36). The IN.PACT SFA trial was a prospective, multicenter, single-blinded, randomized trial in which 331 patients with intermittent claudication or ischemic rest pain attributable to superficial femoral and popliteal artery disease were randomly assigned in a 2:1 ratio to treatment with DCB or conventional PTA. Mean lesion length and the percentage of total occlusions for the DCB and PTA arms were 8.94 and 8.81 cm (P = 0.82) and 25.8% and 19.5% (P = 0.22), respectively. One year follow-up results showed that DCB resulted in a higher primary patency versus PTA (82.2% vs. 52.4%; P < 0.001), After 36 months of follow-up, the results were still statistically different (69.5% versus 45.1%; log rank P < 0.001). The rates of clinically driven TLR(12 mouths) were 2.4% and 20.6% for the DCB and PTA groups, (P < 0.001), and the results of 36 mounths were 15.2% and 31.1% (P = 0.002) [2, 8]. Similar results were also observed in Lutonix Global SFA Registry  ,DEBATE SFA trial and ISAR-PEBIS.
In this study, the rate of target lesion restenosis at one year follow-up was 17.3%, similar to IN.PACT SFA trial (17.8%). Considering the longer length of treated segment (179.6 vs. 89.4 mm) and higher percentage of total occlusions (78.5% vs. 25.8%) in our trial, it seems possible to speculate that Acotec DCB is superior to Medtronic DCB used in IN.PACT SFA. The proportion of stent implantation was 13.1%, higher than that in the IN.PACT SFA trial (7.3%). The reason is likely to be the worse situation of patients at baseline, such as long length of target lesions, in our study. Rutherford stage improvement was observed in 80.8%, 74.7% and 67.9% of limbs, respectively, 1, 2 and 3 years following treatment. Clinically driven TLR was 8.2% at the first year, relatively higher than DCB arm reported in the IN.PACT SFA trial (2.4%) and the BIOLUX P-III study(6.9%), whereas significantly lower than PTA arm (20.6%). In this study ,freedom from clinically driven TLR was 88.4% at 2 years which was higher than IN.PACT Global Study(83.3%).
Statistical analysis revealed that patients with femoropopliteal artery lesions were likely to obtain better outcomes in comparison with those with infrapopliteal lesions. The restenosis rate at 1, 2 and 3 year was 15.5% vs. 23.3% (P < 0.001), 17.5% vs. 31.1% (P < 0.001), and 25.3% vs. 41.9% (P = 0.001), respectively, in femoropopliteal and BTK arm, and the TLR rate was 5.9% vs. 15.8% (P < 0.001), 9.3% vs. 18.9% (P = 0.002), and 15.8% vs. 25.8% (P = 0.008), respectively. In the IN.PACT DEEP trail ,Freedom from clinically driven target lesion revascularization through 5 years was 70.9%. The results of the IN.PACT DEEP randomized controlled trial showed comparable effectiveness and safety outcomes for the DCB and PTA arms. The paclitaxel-coated IN.PACT Amphirion DCB was not efficient in terms of reducing restenosis and TLR rates compared with PTA.
There were some shortcomings in this study. First, it was a single-center and retrospective study. Second, some participants were lost to follow-up. For instance, 133 patients underwent DCB treatment before April 2017. Except for 6 death and 11 amputation, 20 cases were lost to follow-up, leaving 96 cases whose data could be collected for 3-year analysis. Third, based on clinical data published recently that conventional PTA was evidently inferior to DCB, we did not used it in treatment as control.