Abstract 12340: Vascular Pathology of Critical Limb Ischemia; Comparison of Plaque Characteristics Between Anterior and Posterior Tibial Arteries

Background and aims: The number of patients with peripheral arterial disease (PAD) is increasing, and when it develops into critical limb ischemia (CLI), the 5-year mortality rate is as high as 50%. Nevertheless, there are few histopathological reports of PAD. We analyzed the pathology of anterior tibial artery (ATA) and posterior tibial artery (PTA) obtained from the patients who underwent low extremity amputation due to CLI. Methods: Thirty tibial arteries removed from 15 lower limb amputation specimens were examined. Dissected ATAs and PTAs were subjected to ex-vivo soft X-ray radiography, followed by pathological examination using 860 transverse sections. Results: The distribution of calcified area per vessel area is significantly higher in PTAs than in ATAs by the soft X-ray radiography images (ATAs, 48.3% ± 19.2 versus PTAs, 61.6% ± 23.9; p < 0.05). Morphological and immnunohistological examination revealed eccentric plaque with necrotic core and macrophage infiltration was prominent in ATAs than in PTAs(ATAs, 48.3% ± 19.2 versus PTAs, 61.6% ± 23.9; p < 0.05) (ATAs, 48.3% ± 19.2 versus PTAs, 61.6% ± 23.9; p < 0.05). Moreover, thromboembolic lesions were frequently identified in PTAs than in ATAs (ATAs, 11.1% versus PTAs 15.8%; p < 0.05). The proportion of intimal calcification area and medial calcification area were significantly higher in ATAs and PTAs, respectively (intima; ATAs, 0% [0-16.8] versus PTAs, 0% [0-11.7%]; p <0.05, media; PTAs, 38.2% versus ATAs, 15.7%; p < 0.05). Conclusions: Histological features were strikingly different among these arteries of the patients with CLI. To clarify the pathological features of CLI may contribute to establish the therapeutic strategy for PAD, particularly below the knee arteries.