Smoking out the cause of thrombosis.

Cigarette smoke exposure (CSE) is known to increase the risk of arterial thrombosis; almost 40% of smokingrelated deaths are associated with cardiovascular disease.1 Most research has focused on the direct cellular effects of CSE, demonstrating that increased risk of thrombosis is linked to oxidative damage to cardiomyocyte mitochondria,2 increased smooth muscle cell proliferation,3 and increased platelet aggregation.4 Studies examining the effects of CSE on hemostasis have documented decreased expression of tissue factor pathway inhibitor on endothelial cells exposed to serum from chronic smokers5 and increased plasma fibrinogen levels in smokers compared to nonsmokers.6 Few studies have examined the effects of acute CSE on clotting, but increased levels of circulating tissue factor activity7 have been demonstrated after short-term exposure to cigarette smoke. Thus, CSE appears to increase prothrombotic biomarkers and may directly promote thrombosis.