Impact of the below-knee lower extremity arterial calcification score on clinical outcomes in patients with intermittent claudication due to iliofemoral artery disease

Abstract Background The coronary arterial calcification score—also known as the Agatston score—is a well-recognized marker for cardiovascular prognosis. However, established indicators for the quantitative assessment of the lower-extremity arterial calcification are lacking, and its clinical impact on subsequent outcomes remains ill-defined. Purpose We aimed to investigate the impact of the below-knee lower extremity arterial calcification score (BK-LEACS), calculated using non-contrast lower limb computed tomography (CT), on clinical outcomes after endovascular treatment (EVT) for de novo iliofemoral artery disease. Methods We retrospectively analyzed 161 consecutive patients with intermittent claudication treated for de novo iliofemoral artery disease between April 2018 and December 2023, excluding those without pre-EVT lower limb CT. The BK-LEACS was calculated using the Agatston scoring method. Each patient’s score was calculated as the sum of the calcification scores of the anterior-tibial, posterior-tibial, and peroneal arteries of both legs. The primary outcome was major cardiovascular and limb events (MACLE), which included all-cause death, nonfatal myocardial infarction and stroke, major amputation of the target limb, and target vessel revascularization at 1 year after EVT. Cox proportional hazards analysis was used to explore the independent predictors of clinical outcomes. Results The cohort had a mean age of 76.0 ± 9.4 years, with 75.3% being male. Receiver operating characteristic curve analysis showed that BK-LEACS was a univariate factor that predicted MACLE within 1 year after EVT, showing moderate accuracy (area under the curve = 0.703) with the optimal BK-ACS cutoff (121). The study population was divided into higher and lower BK-LEACS groups (BK-LEACS 121 and ≤ 121, respectively) based on the optimal cutoff value, and their outcomes were compared. The mean age was significantly higher in the higher BK-LEACS group than in the lower BK-LEACS group. However, no significant differences were observed between groups regarding diabetes, hemodialysis, prior coronary artery disease, or stroke prevalence. The higher BK-LEACS group had significantly lower rate of 1-year freedom from MACLE than the lower BK-LEACS group (80.2% vs. 96.9%, log-rank, p = 0.016). Additionally, the 1-year patency rate was significantly lower in the higher BK-LEACS group than in the lower BK-LEACS group (74.8% vs. 96.7%, p 0.001). Cox proportional hazards analysis revealed that a higher BK-LEACS ( 121) was an independent predictor of MACLE (odds ratio: 3.65, 95% CI: 1.20-11.09, p = 0.022) after adjusting for age, sex, risk factors, and lesion characteristics. Conclusion A higher BK-LEACS was independently linked to a higher risk of MACLE in patients with intermittent claudication due to iliofemoral artery disease who underwent EVT. Performing a non-contrast lower-limb CT before EVT may help identifying high-risk patients who require careful attention.