Thoracic aortic dissection. Death may not always be due to rupture with haemorrhage. Unusual complications which can be missed at autopsy

OBJECTIVES: Aortic dissection (AD) can be a challenging diagnosis. At autopsy, the aorta may not be dilated and intimal tears may be missed or found without obvious rupture or haemorrhage. We report our experience of AD at a tertiary referral centre with review of 32 cases and discuss 2 unusual complications.

METHODS/RESULTS: 32 cases of which 12 females and 20 male and 18 out of 32 cases were aged below 40. All of the cases were examined macroscopically and microscopically. 30 out of 32 cases (93%) died due to rupture associated with the AD. Two unusual complications were proximal extension of AD into left coronary artery (CA) with intramural haematoma blocking the vessel and AD involving the ostium of the right CA resulting in avulsion of the right CA from the aorta. Mode of death in both these cases were myocardial ischemia. Sections of the aorta in all cases confirmed extensive cystic medial degeneration with disorganisation, fragmentation and disappearance of the elastin fibres with increased collagen and smooth muscle nuclear degeneration.

CONCLUSION: Pathologists should be thorough when examining the aorta, the aortic valve and root in AD. When a rupture site cannot be found it is important to look for unusual complications involving the CAs. Histology plays an important role to corroborate the cause of death.