Understanding the effects of tobacco smoke on the pathogenesis of aortic aneurysm

Abstract

Aneurysmal arterial disease is a vascular degenerative condition that is distinct from atherosclerotic and other occlusive arterial diseases. There is regionalization of the predisposition to aneurysm formation within the vascular tree, and the pathological process varies with location. Infrarenal abdominal aortic aneurysm (AAA) is the most common manifestation of aneurysmal disease, and smoking is the dominant risk factor. Smoking is a much greater risk factor for AAA than for atherosclerosis. In addition to playing a role in the pathogenesis of AAA, smoking also increases the rate of expansion and risk of rupture of established AAA. The mechanistic relationship between AAA and smoking is being established by the use of enhanced animal models that are dependent on smoke or smoke components. The mechanisms seem to involve durable alterations in vascular smooth muscle cell and inflammatory cell function. This review examines the clinical, epidemiological, and mechanistic evidence implicating smoking as a cause of aneurysms, focusing on AAA.

Keywords: aneurysm; pathogenesis; risk factor; smoking.

Figure 1

Age-adjusted effects of smoking on the risk of abdominal aortic aneurysm (AAA). Reference groups are nonsmokers for all smoking variables. The vertical error bars show 95% CIs. Adapted with permission from Kent et al.

Figure 2

Both nicotine infusion and experimental smoke exposure can lead to enhanced aneurysm development in murine models. Nicotine seems to directly enhance abdominal