Evaluation of aortic wall strength in HIV associated thoracic ascending aortic aneurysm

Abstract

Objectives: To determine whether there are differences in collagen quantity of aneurysmal and non-aneurysmal aortic walls as a surrogate marker for aortic wall strength in patients with confirmed human immunodeficiency virus (HIV) associated thoracic ascending aortic aneurysm (TAAA).

Methods: The patients with HIV associated TAAA were enrolled in the study and underwent surgery as part of their routine management. We compared collagen quantity in aneurysmal and non-aneurysmal aortic tissue in TAAA with regards to hydroxyproline concentration as a surrogate measure for collagen content and sent aneurysmal aorta for routine clinical histological assessment. This data was analysed to identify potential relations between aortic aneurysm formation and the collagen content of the aortic wall.

Results: The study included 12 patients with HIV aortopathy (9 females, mean age 47 ±10 years). In total 33 tissue samples were investigated (14 aneurysmal,13 nonaneurysmal aortic tissue and 6 aortic leaflets). There was no difference in hydroxyproline concentration of aneurysmal aortic tissue and seemingly normal tissue (20.21 ± 6.14µg/mg vs 21.20 ± 8.55 µg/mg; P=0.87). No difference was noted in hydroxyproline concentration between aneurysmal vs seemingly normal aortic tissue vs aortic valve leaflets (20.21 ± 6.14µg/mg vs 21.20 ± 8.55 µg/mg vs 17.79± 8.15µg/mg; P=0.65). Histology showed fragmentation of elastin fibres in 50% of the cases.

Conclusion: No difference in collagen concentration in the aneurysmal and nonaneurysmal aortic tissue was noted. However, most of the aneurysmal tissue had fragmentation of elastin fibres.