STATION 3 ANSWERS

1.    What is the organ shown?

Abdominal aorta with atheroma.

2.    Name 3 major risk factors.

a.    Non-modifiable risk factors: increasing age, male gender, family history, genetic abnormalities.

b.    Modifiable risk factors: hyperlipidaemia, hypertension, cigarette smoking, diabetes.

3.    What are the complications?

a.    Reduction of blood flow through arteries due to decreased size of lumen leading to ischaemic heart disease, peripheral vascular disease and cerebrovascular disease.

b.    Predisposition to thrombosis: if the fibrous cap over an atheromatous plaque breaks down, collagen fibers in the abnormal intima are exposed to the thrombogenic substances, e.g. Hageman factor in circulating blood (triggering off the intrinsic pathway of the coagulation cascade) and this initiates the formation of a thrombus. This thrombus may suddenly complete the occlusion of an already narrowed coronary artery leading to myocardial infarct.

c.    Weakening of vessel wall and aneurysm formation: severe atheroma in the intima eventually leads to thinning of the media, loss of smooth muscle cells and elastic fibers, and progressive replacement by non-contractile inelastic collagen. The media becomes functionally incompetent and this leads to generalized dilatation of the artery over the years to form an aneurysm. 

Copyright � Joseph Ong 2003