A particular phenotype of ascending aorta aneurysms as precursor of type A aortic dissection.
OBJECTIVE
We aimed to identify a phenotype of ascending thoracic aortic aneurysm (TAA), which, more than others, evolves into type A dissection (TAD).


METHODS
Aortic specimens were obtained from patients undergoing surgical repair of TAA and TAD (108 and 26, respectively). Histopathological and immunohistochemical analyses were performed by using adequate tissue specimens, appropriate techniques and criteria.


RESULTS
We identified the three following TAA phenotypes: phenotype I (cystic medial degeneration balanced by a substitutive fibrosis, in absence of medial apoptosis and with a faint collagenase concentration), phenotype II (cystic medial degeneration of higher grade, respectively, than substitutive fibrosis, with focal medial apoptosis and moderate collagenase concentration), and phenotype III (elevated cystic medial degeneration without substitutive fibrosis, with plurifocal medial apoptosis and severe collagenase concentration). The same medial degenerative lesions of TAA phenotype III were observed in TAD tissue samples.


CONCLUSIONS
The morphological identity of medial lesions observed in both the TAA phenotype III and in TAD aortas might be assumed to be the precursor-and consequently the optimal biomarker- of dissection, independently of aneurysm diameter or valvular disorder. Identification of genetic risk factors, useful both in diagnostics and in developing more targeted treatment for individual patients, might also be needed.
Unit of Cardiac Surgery, Department of Surgery and Oncology, University of Palermo, Palermo, Italy. bacalipi@libero.it
Calogera
C
Pisano
Emiliano
E
Maresi
Daniele
D
Merlo
Carmela Rita
CR
Balistreri
Giuseppina
G
Candore
Marco
M
Caruso
Massimiliano
M
Codispoti
Giovanni
G
Ruvolo
D000368:Aged; D000784:Aortic Dissection / Q000201:enzymology / Q000209:etiology* / Q000473:pathology; D001013:Aorta, Thoracic / Q000201:enzymology / Q000473:pathology*; D017545:Aortic Aneurysm, Thoracic / Q000150:complications* / Q000201:enzymology / Q000473:pathology; D017209:Apoptosis; D015415:Biomarkers / Q000032:analysis; D018450:Disease Progression; D005260:Female; D005355:Fibrosis; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D008875:Middle Aged; D010641:Phenotype; D011379:Prognosis
D015415:Biomarkers; D020780:Matrix Metalloproteinase 9