Smoking and mortality after acute coronary syndrome

This study investigated the effect of smoking on acute coronary syndrome (ACS). They found that smoking was associated with lower mortality.

Smoking is a known cause of heart disease. Smoking leads to an increase in atherosclerotic plaques (fatty deposits) in the arteries. Acute coronary syndrome (ACS) is a term used to describe events such as a heart attack. Major adverse cardiac events (MACE) such as heart attacks or strokes can lead to mortality (death). Although smoking leads to heart disease, some smokers may have lower mortality risk. It is not clear why this is. This phenomenon is called ‘Smoker’s paradox’. Some studies suggest that smokers are less likely to die after a MACE than non-smokers. Other studies did not find any ‘protective’ effects from smoking. 

Patients with ACS may undergo percutaneous coronary intervention (PCI). This restores blood flow. It is unclear if smoking affects mortality risk after PCI. 

This study performed a strict analysis of 17 ACS studies. 55,491 patient records were included in the analysis. 21,981 patients were smokers. Patients in these studies underwent PCI for ACS. The authors analysed the rates of MACE including heart attacks. They also analyzed mortality rates. 

Smokers had a 46% lower mortality risk after PCI for ACS, compared to non-smokers. The risk was similar at 30-days and 1 year after ACS. Smokers were more likely to be younger, male and with lower rates of diabetes. The risk of MACE was similar in both smokers and non-smokers. 

The authors concluded that smoking was associated with a lower risk of mortality, but not of MACE after ACS.

Patients that smoked were more likely to be younger and healthier. This would have an impact on mortality risk. This study only presented the outcomes for 1 year. Further studies for longer periods of time are needed. Smoking is not good for overall health and should always be avoided.