Type A aortic dissection
Acute aortic dissection (AAD) is one of the acute aortic syndromes, along with intramural hematoma, penetrating ulcer, and aortic rupture. AAD is a relatively uncommon condition (the incidence is approximately 2.6 to 3.5 per 100,000 population per year), but often fatal if not timely treated with reconstructive surgery.
Etiologically, AADs can result from congenital causes (structural defect present at birth), genetically determined with onset during childhood or even later, or acquired (inflammatory, degenerative, neoplastic, traumatic).
From a morphological point of view, the AAD consists of a breach in the thickness of the aorta wall, between the tunica media and the intima, leading to the creation of a 'false lumen' between these two layers, into which blood infiltrates. It rarely remains localized and often progresses by slimming the aortic wall and, in some cases, extending outside the vessel. AAD involving the aorta from its ascending intrapericardial portion (as in our case) and/or the arch of the aorta is termed acute type A aortic dissection (ATAAD) according to the Stanford classification.
ATAAD is associated with a high mortality rate, near 50% at 48 hours without surgical intervention;
Furthermore, it is noted that the lesion described radiologically in the right lung corresponded histologically to a chondroid hamartoma. At the same time, no significant macro/microscopic changes were detected in the central nervous system.
The fever observed on the admission was not associated with an infectious focus as the suspected endocarditis. The microscopic examination of the heart valves and endocardium lacked inflammatory infiltrate. Notwithstanding, fever is a sign often related to AAD, which could be caused by thrombi formation, necrotic tissue, cytokines, free radicals and oxygen radicals that are associated with aortic dissection.
Also, no microscopic findings associated with hypertension in either the lungs or the kidneys, and no signs of atherosclerosis or arteritis were found.
In conclusion, the most consistent etiological hypothesis is therefore that of an abnormality of the connective tissue, not further specified.
The final autopsy diagnosis was, therefore, death due to dissection of the intrapericardial aorta (aortic dissection type A), associated with intrapericardial aortic rupture, massive hemopericardium, and cardiac tamponade.
1 Mészáros I, Mórocz J, Szlávi J, et al. Epidemiology and clinicopathology of aortic dissection. Chest. 2000;117(5):1271-8.
2 Melvinsdottir IH, Lund SH, Agnarsson BA, Sigvaldason K, Gudbjartsson T, Geirsson A. The incidence and mortality of acute thoracic aortic dissection: results from a whole nation study. Eur J Cardiothorac Surg. 2016;50(6):1111-7.
3 Thiene G, Basso C, Della Barbera M. Pathology of the Aorta and Aorta as Homograft. J Cardiovasc Dev Dis. 2021;8(7):76.
4 Wortmann M, Peters AS, Erhart P, Körfer D, Böckler D, Dihlmann S. Inflammasomes in the pathophysiology of aortic disease. Cells. 2021;10(9):2433.
5 Daily PO, Trueblood HW, Stinson EB, Wuerflein RD, Shumway NE. Management of acute aortic dissections. Ann Thorac Surg. 1970;10(3):237-47.
6 Anagnostopoulos CE, Prabhakar MJ, Kittle CF. Aortic dissections and dissecting aneurysms. Am J Cardiol. 1972;30(3):263-73.
7 Shimada S, Nakamura H, Kurooka A, et al. Fever associated with acute aortic dissection. Circ J. 2007;71(5):766-71.