The abdominal aorta is the favourite site of a teaching specimen: here the plaques are thicker, the calcification coarser, and here the aneurysm forms. An abdominal aortic aneurysm (AAA) is a local dilatation of the infrarenal aorta. The Kazakhstan Ministry of Health protocol No. 196 includes an aneurysm ≥3.0 cm (or a history of aortic surgery) among the categories for dyslipidaemia screening: it is a marker of atherosclerotic disease, not "an incidental ultrasound finding".
The teaching morphological diagnosis required by the curriculum: atherosclerotic saccular aneurysm of the abdominal aorta with rupture. The saccular form is a sac-like outpouching of one wall; the fusiform form is a diffuse dilatation of the circumference. At autopsy: the aneurysm cavity is filled with laminated thrombus, the wall shows atheromatosis and calcification, the rupture is more often retroperitoneal (a haematoma in the retroperitoneal tissue) or into the free abdominal cavity (instantaneous massive blood loss). The clinical teaching portrait of rupture: sudden pain in the abdomen and/or lower back, collapse, a pulsatile mass — a generalised construct, not someone's actual case.
Thresholds for elective treatment — ESVS 2024 (Wanhainen A. et al., Eur J Vasc Endovasc Surg. 2024;67:192–331). In men with an asymptomatic AAA <55 mm, elective repair is not recommended. Elective repair should be considered at a diameter ≥55 mm in men and ≥50 mm in women; the recommendation was downgraded (IIa, level C) because of a lack of high-quality evidence. The explicitly negative recommendation is against treating a fusiform degenerative AAA <55 mm in men and <50 mm in women. The diameter for the decision is preferably measured by ultrasound. Surveillance of small aneurysms (ESVS 2024, IIa): in men, ultrasound every 5 years at 25–29 mm (subaneurysmal dilatation), every 3 years at 30–39 mm, annually at 40–49 mm, every 6 months at ≥50 mm — taking into account life expectancy and fitness for future repair.
ESVS 2024 does not recommend restricting physical and sexual activity in a small AAA. This is unexpected for a student accustomed to "sparing the aneurysm", and therefore it must be said out loud: the society's 2024 recommendation is exactly this.
Other aortic complications of atherosclerosis that you need to be able to name: atheromatous ulcers of the arch and thoracic aorta as a source of emboli to the brain and the periphery; occlusion of branches (mesenteric — chronic mesenteric ischaemia, "abdominal angina"; renal — renovascular syndrome); mural thrombosis.
The boundary of the lesson. Not every aortic aneurysm is atherosclerotic: there are hereditary aortopathies, inflammatory and infectious (mycotic) aneurysms. ESVS 2024 separately discusses complex, inflammatory, mycotic and saccular aneurysms. The teaching diagnosis "atherosclerotic saccular aneurysm with rupture" presupposes the morphology of atherosclerosis in the wall, not any sac. The 55/50 mm thresholds refer to fusiform degenerative AAA, not automatically to all saccular ones.