Intracranial Aneurysms: Relevance of Superposed Blood Pulse Waves and Tobacco Smoke?

Background: Intracranial aneurysms (IAs) are found in around 3–4% of elderly people. The authors attempt to answer why IAs develop exclusively in the circle of Willis (CW) and why IAs in the frontal cerebral arteries are unusually frequent in men. Methods: The location and frequency of IAs were analyzed using relevant publications (MEDLINE and PubMed). Results: It is suggested that superposed blood pulse waves may have an influence on the development of IAs. The superposition of blood pulse waves is caused by the meeting of the bilateral cerebral arteries in the CW. The predominance of IAs in women is striking (about 1.7:1). However, IAs in the anterior cerebral arteries and anterior communicating artery are significantly more common in men than in women (approximately 1.8:1). The authors hypothesize that greater nicotine abuse in men may explain this phenomenon. Cigarette smoke apparently reaches the anterior cerebral arteries via the olfactory pathway. Conclusion: It seems possible that superposed pulse waves are a substantial factor in the occurrence of IAs. The toxic effects of tobacco smoke appear to have greater impact on IA development than the sex-specific influences that are responsible for the predominance of IAs in women.