Advanced atherosclerosis is associated with increased medial degeneration in sporadic ascending aortic aneurysms.
OBJECTIVE
The pathogenesis of non-familial, sporadic ascending aortic aneurysms (SAAA) is poorly understood, and the relationship between ascending aortic atherosclerosis and medial degeneration is unclear. We evaluated the prevalence and severity of aortic atherosclerosis and its association with medial degeneration in SAAA.


RESULTS
Atherosclerosis was characterized in ascending aortic tissues collected from 68 SAAA patients (mean age, 62.9 ± 12.0 years) and 15 controls (mean age, 56.6 ± 11.4 years [P = 0.07]) by using a modified American Heart Association classification system. Upon histologic examination, 97% of SAAA patients and 73% of controls showed atherosclerotic changes. Most SAAA samples had intermediate (types 2 and 3, 35%) or advanced atherosclerosis (types ≥ 4; 40%), whereas most control samples showed minimal atherosclerosis (none or type 1, 80%; P < 0.001 after adjusting for age). In a separate analysis, we examined the total incidence and grade distribution of medial degenerative changes among SAAA samples according to atherosclerosis grade. Advanced atherosclerosis was associated with higher grades of smooth muscle cell depletion (P < 0.001), elastic fiber depletion (P = 0.02), elastic fiber fragmentation (P < 0.001), and mucopolysaccharide accumulation (P = 0.04). Aortic diameter was larger in SAAA patients with advanced atherosclerosis than in patients with minimal (P = 0.04) or intermediate atherosclerosis (P = 0.04). Immunostaining showed marked CD3+ T-cell and CD68+ macrophage infiltration, MMP-2 and MMP-9 production, and cryopyrin expression in the medial layer adjacent to atherosclerotic plaque.


CONCLUSIONS
SAAA tissues exhibited advanced atherosclerosis that was associated with severe medial degeneration and increased aortic diameter. Our findings suggest a role for atherosclerosis in the progression of sporadic ascending aortic aneurysms.
Michael E. DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Adult Cardiothoracic Surgery, Texas Heart Institute, PO Box 20345, Houston, TX 77225, USA.
Paul T
PT
Albini
Department of Cardiovascular Pathology, Texas Heart Institute, PO Box 20345, Houston, TX 77225, USA.
Ana Maria
AM
Segura
Michael E. DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Adult Cardiothoracic Surgery, Texas Heart Institute, PO Box 20345, Houston, TX 77225, USA.
Guanghui
G
Liu
Dan L. Duncan Institute for Clinical and Translational Research, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Charles G
CG
Minard
Michael E. DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Adult Cardiothoracic Surgery, Texas Heart Institute, PO Box 20345, Houston, TX 77225, USA.
Joseph S
JS
Coselli
Division of Medical Genetics, Department of Internal Medicine, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Suite 1200, Houston, TX 77030, USA.
Dianna M
DM
Milewicz
Michael E. DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Adult Cardiothoracic Surgery, Texas Heart Institute, PO Box 20345, Houston, TX 77225, USA. Electronic address: hyshen@bcm.edu.
Ying H
YH
Shen
Michael E. DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Adult Cardiothoracic Surgery, Texas Heart Institute, PO Box 20345, Houston, TX 77225, USA. Electronic address: slemaire@bcm.edu.
Scott A
SA
LeMaire
D000368:Aged; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D001011:Aorta / Q000473:pathology*; D001014:Aortic Aneurysm / Q000150:complications* / Q000473:pathology*; D050197:Atherosclerosis / Q000150:complications / Q000473:pathology*; D017252:CD3 Complex / Q000378:metabolism; D016022:Case-Control Studies; D018450:Disease Progression; D004547:Elastic Tissue / Q000473:pathology; D004549:Elastin / Q000378:metabolism; D005260:Female; D006025:Glycosaminoglycans / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000473:pathology; D000097382:CD68 Molecule
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D017252:CD3 Complex; D004549:Elastin; D006025:Glycosaminoglycans; C067980:CD68 antigen, human; D000097382:CD68 Molecule
Aorta; Atherosclerosis; Elastin; Muscle; Smooth; Thoracic aneurysm