Aortic aneurysm
According to a review of global data through 2019, the prevalence of abdominal aortic aneurysm ("AAA") worldwide was about 0.9% in people under age 79 years,[4] whereas a 2014 review reported a range of 2-12%, occurring in about 8% of men more than 65 years of age.[5] The incidence of AAA is four times higher in men than in women at any age.[4] Death occurs in about 55-64% of people having rupture of the AAA.[4]
The etiology remains an area of active research. Known causes include trauma, infection, and inflammatory disorders. Risk factors include cigarette smoking, advanced age, dyslipidemia, hypertension, and coronary artery disease.[4] The pathophysiology of the disease is related to an initial arterial insult causing a cascade of inflammation and extracellular matrix protein breakdown by proteinases leading to arterial wall weakening.[6] They are most commonly located in the abdominal aorta, but can also be located in the thoracic aorta.
Aortic aneurysms result from a weakness in the wall of the aorta and increase the risk of aortic rupture. When rupture occurs, massive internal bleeding results and, unless treated immediately, shock and death can occur. One review stated that up to 81% of people having AAA rupture will die, with 32% dying before reaching a hospital.[7]
Screening with ultrasound is indicated in those at high risk. Prevention is by decreasing risk factors, such as smoking, and treatment is either by open or endovascular surgery. Aortic aneurysms resulted in about 152,000 deaths worldwide in 2013, up from 100,000 in 1990.[8]
Aortic aneurysms are classified by their location on the aorta.
Prevention[edit]
The risk of aneurysm enlargement may be diminished with attention to the patient's blood pressure, smoking and cholesterol levels. There have been proposals to introduce ultrasound scans as a screening tool for those most at risk: men over the age of 65.[19][20]
Anacetrapib is a cholesteryl ester transfer protein inhibitor that raises high-density lipoprotein (HDL) cholesterol and reduces low-density lipoprotein (LDL) cholesterol.
Anacetrapib reduces progression of atherosclerosis, mainly by reducing non-HDL-cholesterol, improves lesion stability and adds to the beneficial effects of atorvastatin[21]
Elevating the amount of HDL cholesterol in the abdominal area of the aortic artery in mice both reduced the size of aneurysms that had already grown and prevented abdominal aortic aneurysms from forming at all. In short, raising HDL cholesterol is beneficial because it induces programmed cell death. The walls of a failing aorta are replaced and strengthened. New lesions should not form at all when using this drug.[22]
Screening[edit]
Screening for an aortic aneurysm so that it may be detected and treated prior to rupture is the best way to reduce the overall mortality of the disease. The most cost-efficient screening test is an abdominal aortic ultrasound study. Noting the results of several large, population-based screening trials, the US Centers for Medicare and Medicaid Services (CMS) now provides payment for one ultrasound study in all smokers aged 65 years or older ("SAAAVE Act").[23]