Beyond angiographic success: six-month patency and functional gains in above-the-knee versus below-the-knee endovascular interventions

Abstract

Background Endovascular angioplasty is widely used in the management of peripheral arterial disease (PAD); however, comparative data on mid-term patency and functional outcomes between above-the-knee (ATK) and below-the-knee (BTK) interventions remain limited. Lesion level may play a critical role in determining mid-term durability and functional recovery following revascularization.Methods This retrospective cohort study included 240 patients with symptomatic PAD who underwent successful percutaneous transluminal angioplasty between January 2018 and January 2025. Patients were equally stratified according to the anatomical level of intervention into ATK (n = 120) and BTK (n = 120) groups. Six-month primary patency, defined as uninterrupted vessel patency with <= 30% residual stenosis, was evaluated using computed tomography angiography (CTA). Secondary outcomes included six-month ankle-brachial index (ABI) values, absolute ABI improvement (ABI delta), and overall functional recovery. Lesion severity was primarily assessed using the Peripheral Arterial Calcium Scoring System (PACCS), with grades 2, 3, and 4 reported for the study population.Results At the six-month follow-up, the primary patency rate was significantly higher in the ATK group compared with the BTK group (93.3% vs. 77.5%; p = 0.001). Morphological analysis revealed a high burden of calcification in both cohorts, with severe stages (PACCS Grade 3-4) observed in 62.9% of the total study population (60% in the ATK group and 65.8% in the BTK group; p = 0.610). While both groups demonstrated significant initial improvement following intervention, six-month ABI values were significantly higher in the ATK cohort (0.96 +/- 0.13 vs. 0.90 +/- 0.19; p = 0.003). Furthermore, the absolute functional gain (ABI delta) was significantly greater after ATK interventions (0.43 +/- 0.16 vs. 0.37 +/- 0.24; p = 0.028). Within the BTK cohort, patency varied substantially by target vessel, with the peroneal artery exhibiting the lowest primary patency (45.0%). Notably, concomitant coronary artery disease (CAD) emerged as a paradoxical predictor of higher patency (91.2% vs. 80.2%; p = 0.025), reflecting the protective impact of rigorous systemic medical management in these high-risk patients.Conclusions ATK angioplasty is associated with significantly superior six-month primary patency and functional outcomes compared with BTK interventions. Although BTK angioplasty remains indispensable for limb salvage in advanced PAD, lesion-level characteristics and morphological severity-specifically the high burden of calcification (PACCS Grade 3-4) observed in over 60% of cases-profoundly influence mid-term durability. The findings highlight that despite significant morphological complexity and a high calcification burden, ATK interventions offer superior outcomes. These findings underscore the importance of anatomy-driven revascularization strategies, aggressive systemic medical management, and tailored surveillance protocols, particularly following infrapopliteal interventions.