Thrombotic luminal occlusion associated with insignificant atherosclerosis is commonly observed in critical limb ischemia (CLI) and suggests the possibility of thromboembolic disease, based on a study aimed at characterizing the pathology of peripheral artery disease (PAD) in below- and above-knee amputation specimens from CLI patients. The findings were presented August 27 at ESC Congress 2018 and simultaneously published in the Journal of the American College of Cardiology.

Researchers examined 299 peripheral arteries in 121 amputations specimens from 95 patients, 75 of whom presented with CLI and 20 who had amputations for other reasons. The pathological characteristics were separately recorded for femoral and popliteal arteries (FEM-POP), and infrapopliteal arteries (INFRA-POP).

Results found atherosclerotic plaques were more frequent in FEM-POP (23 of 34, 67.6%) compared with INFRA-POP (79 of 205, 38.5%) arteries from CLI patients. Additionally, 69% of the arteries from CLI patients showed ≥70% stenosis, which researchers said was due to significant pathological intimal thickening, fibroatheroma, fibrocalcific lesions, or restenosis; luminal thrombi; or without significant atherosclerotic lesions.

Researchers also noted the presence of chronic luminal thrombi was more frequently observed in arteries with insignificant atherosclerosis, especially INFRA-POP. Acute thrombotic occlusion was less frequently encountered in INFRA-POP than FEM-POP arteries. Medial calcification was also present in 71.1% of large arteries.

"The pathological findings in lower-extremity arteries suggest possible mechanisms of progression of PAD to CLI, and may support the preventive role of antithrombotic agents," researchers said.