Surgical pathology of chronic ascending aortic dissections

A majority of aortic dissections affect the ascending aorta and are acute in nature. Chronic dissections in this region are uncommon. This report characterises the clinicopathological features of 15 non-iatrogenic chronic ascending aortic dissections.

Among 65 patients who had surgery for ascending aortic dissection over a period of 6 years, 15 showed morphological evidence of chronic dissection. Clinical data and morphological features of these were analysed.

Twelve patients (80%) were over the age of 50 years, with a male predominance (11 patients, 73.33%). Exertional dyspnoea was the most common presenting symptom, while chest pain was noted in three cases. An echocardiographic diagnosis of dissection was made in six patients. The disease was restricted to the ascending aorta in nine (60%) and all had aortic regurgitation of varying severity. Areas of recent dissection were also noted in three specimens. The risk factors or pathogenetic mechanisms noted were hypertension in four and Marfan's syndrome, penetrating atherosclerotic ulcer, patent ductus arteriosus, and vehicular accident, in one patient each. The aortic segment of the latter patient had shown intimal flaps to be associated with multiple saucer-shaped depressions with thin walls. These features were also noted in two of the seven patients without risk factors and in two hypertensives. This raises the possibility of subclinical intimal injury sustained during sudden deceleration with blunt chest trauma. Significant aortopathy was seen in 10 cases.

Chronic dissections as a cause of aortic regurgitation and aneurysmal dilatation, especially in the elderly, should be kept in mind. This may follow sudden deceleration intimal injuries, superimposed on aged-related medial degeneration.