Pathological Analysis of Medial and Intimal Calcification in Lower Extremity Artery Disease

Abstract

The prevalence and degree of lower extremity artery disease in hemodialysis (HD) patients is higher than in the general population. However, the pathological features have not yet been evaluated. The aim of the study was: 1) to compare lesion characteristics of lower extremity artery disease in HD vs non-HD patients; and 2) to determine factors associated with severe medial calcification. Seventy-seven lower limb arteries were assessed from 36 patients (median age 77 years; 23 men; 21 HD and 15 non-HD) who underwent autopsy or lower limb amputation. Arteries were serially cut at 3- to 4-mm intervals creating 2,319 histological sections. Morphometric analysis and calcification measurements were performed using ZEN software. Calcification with a circumferential angle (arc) ≥180° was defined as severe calcification. Multivariable logistic regression was used to identify risk factors for severe medial calcification. The degree of the medial calcification arc was significantly higher in the HD group compared to the non-HD group (P < 0.0001). In the multivariable analysis, HD was associated with severe medial calcification in below-the-knee lesions (OR: 17.1; P = 0.02). The degree of intimal calcification in above-the-knee lesions was also significantly higher in HD patients with a higher prevalence of advanced atherosclerotic plaque (P = 0.02). The prevalence of severe bone formation was more common in the HD patients (P = 0.01). Hemodialysis patients demonstrated a higher degree of medial and intimal calcification compared with non-HD patients. The difference was more prominent in the medial calcification of below-the-knee lesions.