Pathology of Critical Limb Ischemia; Comparison of Plaque Characteristics Between Anterior and Posterior Tibial Arteries.

Aims: Though the number of patients with peripheral arterial disease (PAD) and critical limb ischemia (CLI) is increasing, few histopathological studies of PAD, particularly that involving below-the-knee arteries, has been reported. We analyzed the pathology of anterior tibial artery (ATA) and posterior tibial artery (PTA) specimens obtained from patients who underwent lower extremity amputation due to CLIMethods: Dissected ATAs and PTAs were subjected to ex-vivo soft X-ray radiography, followed by pathological examination using 860 histological sections. This protocol was approved by the Ethics Review Board of Nihon University Itabashi Hospital (RK-190910-01) and Kyorin University Hospital (R02-179).

Results: The calcified area distribution was significantly larger in PTAs than in ATAs on soft X-ray radiographic images (ATAs, 48.3% ±19.2 versus PTAs, 61.6% ±23.9; p＜0.001). Eccentric plaque with necrotic core and macrophage infiltration were more prominent in ATAs than in PTAs (eccentric plaque: ATAs, 63.7% versus PTAs, 49.1%; p＜0.0001, macrophage: ATAs, 0.29% [0.095 - 1.1%] versus PTAs, 0.12% [0.029 - 0.36%]; p＜0.001), histopathologically. Thromboembolic lesions were more frequently identified in PTAs than in ATAs (ATAs, 11.1% versus PTAs 15.8%; p＜0.05). Moreover, post-balloon injury pathology differed between ATAs and PTAs.

Conclusions: Histological features differed strikingly between ATAs and PTAs obtained from CLI patients. Clarifying the pathological features of CLI would contribute to establishing therapeutic strategies for PAD, particularly disease involving below-the knee-arteries.