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[Pathology of aortic dissection]
1Department of Pathology, Keio University School of Medicine, Tokyo, Japan.
Insights
Aortic dissection, a serious condition, presents with varied symptoms and is often linked to hypertension and genetic disorders like Marfan syndrome. Understanding its features and classification is crucial for diagnosis.
Area of Science:
- Cardiovascular Medicine
- Pathology
- Genetics
Background:
- Aortic dissection, though uncommon, has severe and diverse clinical manifestations requiring prompt exclusion in emergent cases.
- The Stanford classification is now preferred over the DeBakey classification due to its clinical utility.
Purpose of the Study:
- To outline the key features and underlying pathogenesis of aortic dissection.
- To discuss the association between aortic dissection, systemic hypertension, and heritable connective tissue disorders.
Main Methods:
- Review of clinical and pathological features of aortic dissection.
- Discussion of current classification systems and etiological factors.
Main Results:
- Aortic dissection typically involves an intimal tear, often in the ascending aorta or distal to the left subclavian artery, with dissection occurring in the outer media.
- Systemic hypertension is a common comorbidity, suggesting a hemodynamic contribution to pathogenesis alongside aortic wall fragility.
- Mutations in the fibrillin gene are confirmed in Marfan syndrome, reclassifying 'cystic medial necrosis' as a secondary change.
Conclusions:
- Aortic dissection is characterized by specific anatomical and pathological features, influenced by hemodynamic stress and inherent aortic wall weaknesses.
- Heritable connective tissue disorders, particularly Marfan syndrome, are significant risk factors, with genetic mutations impacting aortic integrity.
Abstract:
Aortic dissection is not a popular disease but it should be listed in the disease to be excluded especially in acute emergent cases, because of its serious and protean clinical manifestations. While DeBakey classification was used over 30 years. Stanford classification is now widely accepted for its clinical availabilities. The features of the aortic dissection are 1) presence of the intimal tear at the proximal end in almost all cases, 2) its frequent location in the ascending aorta and aortic segment just distal to the left subclavian artery, and 3) the dissected plane at the outer media or medial-adventitial border. Systemic hypertension is frequently noticed in cases with aortic dissection. These features suggest hemodynamic effect as a pathogenic factor in addition to mural fragility of the aorta. Aortic dissection is frequently encountered in Marfan syndrome and other heritable diseases of connective tissue. Concerning Marfan syndrome, mutation of fibrillin gene was confirmed. Fibrillin is a microfibril consisting of glycoprotein closely bound to elastin. Therefore, traditional "cystic medial necrosis" which was referred as a principal morphological change corresponding to aortic dissection is now thought to be a secondary change to the aortic injuries occurred in the aortic wall.