Aspects on arterial dimensions with special reference to aneurysmal disease

The incidence of abdominal aortic aneurysms (AAA) is increasing. The risk of rupture is related to diameter. However, rupture may occur also in small AAA. To evaluate the size of an aneurysm when related to the predicted normal aortic diameter might be a better predictor of risk. AAA:s, range 40-55 mm were studied in relation to gender. No difference in AAA diameter was found. However, body surface area was lower in females than in males, accordingly the predicted normal aortic size was lower in females. Thus, the diameter increase from the predicted aortic diameter, was larger in females. This indicates a more diseased aneurysm wall in females than males despite similar AAA diameter, and a need for individualisation in the evaluation of an aneurysmal size.

The possibility that an AAA is not only a local vascular disease in the abdominal aorta, but rather a generalised process in the vascular system has recently been emphasised. The diameters of the common femoral (CFA) and popliteal artery (PA), prone to aneurysmal dilatation in AAA-patients, were studied in healthy subjects. The diameters increased with age not only during, but also after termination of growth. Between 25 and 70 years, CFA increased 12 and 21 %, PA 26 and 22 %, in males and females respectively. Not only age, but also body surface area, and gender affected the diameter, with larger arteries in males. Nomograms were constructed which were used in the study of AAA patients. After excluding the few found peripheral aneurysms, as well as peripheral vascular occlusive disease, no dilating diathesis was found. This supports the hypothesis that specific genetic, or other factors, not present in the majority of the AAA:s are responsible for the occurrence of concomitant peripheral aneurysms. Further, the generalised vascular dilating diathesis seen in some patients seems to be a specific entity not necessarily affiliated with AAA disease.