“…Andreasen TH et al 29 Synergistic mechanisms (i.e., hypertensions, alcohol consumption, stimulant drugs, and hypercolestemia) can increase the risk of rupture as they can amplify the hemodynamic stress against the walls of the aneurysms risk of aneurysm recurrence as it was analyzed in the study conducted by Futchko et al 32 , in which the odds ratios (ORs) for aneurysm recurrence for current and former smokers were 2.739 and 2.698, respectively, compared with never smokers. In the same way, Aguiar et al 33 also investigated this relationship based on the results obtained from 167 IAs treated by microsurgical clipping, from which 38 patients developed residual lesions, as 27 of them were current smokers compared with only 11 nonsmokers. Thus, it revealed an increased risk of residual aneurysms for current smokers (OR 3.38, 95%CI), possibly due to the effects of cigarette substances on the vessel well and on the blood flow of the brain as already described on the above mechanisms.…”