Frequency, predictors, and effect of the slow-flow phenomenon after drug-coated balloon angioplasty for femoropopliteal lesions.

Drug-coated balloon (DCB) angioplasty for femoropopliteal (FP) lesions has been available in Japan since 2018. In daily practice, we encountered cases of the slow-flow phenomenon after DCB angioplasty. However, no data regarding the slow-flow phenomenon after DCB angioplasty for FP lesions are available. This study aimed to investigate the frequency, predictors, and effect of the slow-flow phenomenon following DCB angioplasty for FP lesions. This single-center, retrospective, observational study analyzed 88 FP lesions treated by DCB angioplasty between April 2018 and July 2019. Patients were divided into the slow-flow group (n = 7) and non-slow-flow group (n = 81) and were analyzed. The primary endpoint was primary patency at 6 months. The slow-flow phenomenon was observed in seven cases (8.0%). The slow-flow group had higher incidence rates of critical limb ischemia (CLI) (71% vs. 25%, p < 0.01), chronic total occlusion (CTO) lesions (86% vs. 26%, p < 0.01), and poor tibial vessel runoff (86% vs. 33%, p < 0.01) and had a longer DCB length (237 ± 56 mm vs. 159 ± 97 mm, p = 0.03) than the non-slow-flow group. The primary patency rate at 6 months was 71% in the slow-flow group and 91% in the non-slow-flow group (p = 0.09). The rate of freedom from target lesion revascularization at 6 months was 71% in the slow-flow group and 97% in the non-slow-flow group (p < 0.01). The amputation-free survival rate at 6 months was 71% and 95% (p = 0.02), whereas the survival rate at 6 months was 71% and 95% (p = 0.02). The incidence rate of the slow-flow phenomenon after DCB angioplasty for FP lesions was 8.0%. CLI, a CTO lesion, poor tibial vessel runoff, and total DCB length were associated with the slow-flow phenomenon. Our results indicate that the slow-flow phenomenon is associated with poor short-term clinical outcomes.