Histological evaluation of age-related variations in saphenous vein grafts used for coronary artery bypass grafting

INTRODUCTION Venous coronary artery bypass grafts (CABG) might undergo a process of arterialization resulting in neointimal formation and medial hypertrophy. It is often followed by critical occlusion of the graft lumen. The aim of the study was to assess histological representative features of saphenous vein reconstruction in aging as well as to establish optimal patients' age limits applicable for optimal selection of grafts. MATERIAL AND METHODS One hundred and ten patients undergoing venous CABG were divided into 4 age subgroups: (A) 50 years and less, (B) 51-60 years, (C) 61-70 years and (D) > 70 year-old subjects. Distal venous graft segments were saved for an adequate morphometric assay which was followed by suitable statistical analysis. RESULTS The entire venous wall thickness as well as its tunica media were found to become significantly thinner between subgroups A and D. The number of smooth muscle cell (SMC) nuclei within the tunica media did not differ between study subgroups. The majority of these nuclei in subgroup D were found, however, to be more elongated than in subgroup A (SMC length/width index in subgroup D was found to be significantly higher than in subgroup A). CONCLUSIONS Progressive, age-related thinning of the venous wall and tunica media as well as SMC nucleus elongation might suggest impairment of SMCs' migration and proliferation rate. Consequently, individuals aged 70 years and over may benefit clinically more from venous CABG than younger patients due to the lower risk of arterialization and occlusion of the graft lumen in the future.