Epidemiology of aortic disease - aneurysm, dissection, occlusion

The physiological infrarenal aortic diameter varies between 12.4 mm in women an 27.6 mm in men. As defined, an aneurysmatic dilatation begins with 29 mm. According to that, 9% of all people above the age of 65 are affected by an abdominal aortic aneurysm (AAA). Compared with the female sex, the male sex predominates at a rate of about 5:1. The disease is predominant in men of the white race. In black men, black and white women the incidence of AAA is identical. 38 to 50 percent of the AAA patients (patients) suffer from hypertension, 33 to 60% from coronary, 28% from cerebrovascular and 25% from peripheral occlusive disease. The AAA expansion rate varies between 0.2 and 0.8 cm per year and is exponential from a diameter of 5 cm on. In autopsy studies, the rupture rates with AAA diameters of <5 cm, between 5.1 and 6.9 cm, and of >7 cm were below 5%, 39% and 65%, respecitvely. 70% of the AAA patients do not die of a rupture, but of a cardiac disease. Serum markers, such as metalloproteinases and procollagen peptides are significantly increased in AAA patients. Thoraco-abdominal aneurysms (TAA) make up only 2 to 5% of all degenerative aneurysms. 20 to 30% of the TAA patients are also affected by an AAA. 80% of the TAA are degenerative, 15 to 20% are a consequence of the chronic dissection - including 5% of Marfan patients -, 2% occur in case of infections and 1 to 2% in case of aortitis. The TAA incidence in 100,000 person-years is 5.9% during a monitoring period of 30 years. In case of TAA, an operation is indicated with a maximum diameter of 5.5 to 6 cm and more and, in case of a Marfan's syndrome (incidence of 1:10,000), with a maximum diameter of 5.5 cm and more. With regard to aorto-iliac occlusive diseases, there are defined 3 types of distribution. Type I refers to the region of the bifurcation itself. Type II defines the diffuse aortoiliac spread of the disease. Type III designates multiple-level occlusions also beyond the inguinal ligament. Type I patients in most cases are female and more frequently suffer from hyperlipidaemia, while Type II patients are affected by hypertension and diabetes. Compared to Type II patients, Type I patients have a life expectancy that is 10 years higher. Type I and Type II patients often suffer from a pelvic claudication and, unlike Type III patients, are more frequently affected by arterio-arterial embolisms. (orig.)