Impact of Circumferential Calcification and Acquired Minimum Lumen Area on 1-Year Primary Patency After Drug-Coated Balloon Angioplasty for Femoropopliteal Lesions.

BACKGROUND: Severe calcification predicts restenosis after drug-coated balloon (DCB) angioplasty for femoropopliteal lesions, but whether an adequate post-procedural minimum lumen area (MLA) can attenuate this effect, and how intravascular ultrasound (IVUS) circumferential calcification compares with angiographic Peripheral Arterial Calcium Scoring System (PACSS), remain unclear. METHODS: In this exploratory sub-analysis of the multicenter REAL-LEAD registry, we studied 224 femoropopliteal lesions (222 analyzable) treated with a DCB-only strategy under IVUS guidance across 14 Japanese institutions, classified by IVUS calcification angle (≥ 180° vs. < 180°) and PACSS grade (3-4 vs. 0-2). Cox models assessed 1-year loss of patency; post-procedural MLA was modeled continuously. RESULTS: Restenosis occurred in 37 lesions (16.7%) over 1 year. An IVUS calcification angle ≥ 180° independently predicted loss of patency (HR 2.17, 95% CI 1.10-4.26, p = 0.025); PACSS grade 3-4 did not retain significance after identical adjustment (HR 1.79, 95% CI 0.91-3.54, p = 0.092). Each 1.0 mm2 decrease in MLA increased restenosis hazard by 32% (HR 1.32, 95% CI 1.19-1.47, p < 0.001). Despite comparable external elastic membrane area at the MLA site (p = 0.67), severely calcified lesions acquired a smaller MLA. Severely calcified lesions with an adequate MLA achieved 1-year patency (90.6%) approaching that of low-calcification lesions with an adequate MLA (94.7%), while low-calcification lesions with an inadequate MLA fared worse (73.4%). CONCLUSIONS: IVUS-defined circumferential calcification, but not angiographic PACSS, independently predicted restenosis after DCB-only angioplasty. An adequate post-procedural MLA appeared to attenuate the adverse impact of severe calcification, supporting IVUS-guided optimization of acute luminal gain as an actionable procedural target.