Evaluation of aortic wall strength in human immunodeficiency virus associated thoracic ascending aortic aneurysm: a pilot study.

Background: Human immunodeficiency virus (HIV) associated aortopathy is associated with considerable morbidity and mortality. The pathophysiology of aortic wall strength in HIV thoracic aortic aneurysm has not been studied.

Methods: The patients with HIV associated thoracic ascending aortic aneurysm (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, median age 49 years). In total 33 tissue samples were investigated (14 aneurysmal, 13 non-aneurysmal aortic tissue and 6 aortic leaflets). There was no difference in hydroxyproline concentration of aneurysmal aortic tissue and seemingly normal tissue [19.40 (15.19-22.98) 20.85 (15.55-25.83) µg/mg; P=0.82]. No difference was noted in hydroxyproline concentration among aneurysmal, seemingly normal aortic tissue and aortic valve leaflets [19.40 (15.19-22.98) 20.85 (15.55-25.83) 19.09 (13.94-22.00) µg/mg; P=0.86]. Histology showed fragmentation of elastin fibres in 50% of the cases.

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