Abstract 724: Effect of Arterial Calcification on Lower Extremity Ischemia Score is Independent of Occlusive Disease

Abstract

Objective: Calcification in lower extremity arteries is associated with a higher risk of amputation and may reflect the amount of atherosclerotic plaque in lower extremity vessels. The association between calcification, occlusive disease, and severity of ischemia, however, has not been explored. We tested the hypothesis that the association between calcification and worsening limb status was mediated by concomitant occlusive disease. Methods: Rutherford ischemia categories, tibial artery calcification (TAC) scores, and the extent of occlusive disease were measured in 276 patients with or without symptomatic peripheral artery disease. Other factors included age, sex, race, and history of diabetes, tobacco use, hypertension, or hyperlipidemia. Patients with severe renal insufficiency (eGFR <30) and patients with aortoiliac disease or acute ischemia were excluded. Multivariable ordinal logistic regression models were constructed using Rutherford ischemia categories (0 - 6) as the dependent variable. Results: When both asymptomatic and symptomatic patients were included in our model, tobacco use, hypertension, occlusion index, and TAC scores were independently associated with increasing Rutherford categories. In multivariate analyses involving only those patients with symptomatic PAD, only the tibial calcification score (OR 2.06 (1.39-3.06), p<0.01) and tobacco use (OR 2.69 (1.03-6.99), p=0.04) maintained an independent association with worsening ischemia categories. Conclusions: Calcification is associated with worsening lower extremity ischemia categories in a way that is independent of the extent of arterial occlusive disease. Further research aimed at understanding the contribution of arterial calcification to ischemia in PAD is warranted, as are efforts to develop treatments to control it.