Risk factors are age, gender, genetics; hyperlipidaemia, hypertension, diabetes, smoking; inactivity, obesity, stress. Mechanism is tissue injury, adhesion of platelets and monocytes, migration of monocytes from lumen and media with monocytes becoming macrophages and accumulating lipid, smooth muscle proliferation and finally well developed plaque. There can be haemorrhage into one of these plaques.
Complications can be aneurysms, usually occur in the aorta due to tunica media weakening, causes massive haemorrhage and dissection. Plaques are a major source of thromboemboli, leading to stroke. There is also often peripheral vascular disease leading to ulceration/infection, loss of mobility, ongoing pain and amputation as well as ischaemic damage to other organs. Kidney and brain are common sites of ischaemia due to thrombi.