Safety and efficacy of e-cigarettes in those with atherosclerotic disease: a review.

Smoking cessation is the most effective intervention to reduce mortality in patients with established atherosclerotic cardiovascular disease (ASCVD), with 'e-cigarettes' becoming an increasingly used intervention to achieve smoking cessation. The current review aims to summarise the current evidence base for their efficacy and safety in the ASCVD cohort. A search of the PUBMED and MEDLINE databases using the terms 'e-cigarette', 'cessation', 'safety' and 'efficacy' since 2012 yielded 706 results. Both observational and experimental studies were included, while those with an unavailable full text, non-English or duplicates were excluded, yielding 78 relevant articles, with 13 subsequent additional articles included from a search of reference lists, for a total of 91 included papers. E-cigarette vapour contains many known pro-atherosclerotic substances and has been demonstrated to potentiate traditional atherosclerotic mechanisms. While e-cigarettes may be more effective in promoting smoking cessation in the general population over a medium term (>6 months), when compared with nicotine replacement therapy (NRT), few studies specifically examined those with ASCVD, despite the latter having a higher baseline quit rate (52% vs 2%). Most studies compare e-cigarettes with NRT alone and do not include pharmacotherapy, which may be more effective in the ASCVD cohort. The single randomised controlled trial addressing the research question favoured traditional methods. Those that successfully quit smoking using e-cigarettes are more likely to continue to use the intervention at 1 year (90% vs 9%). Conflicting advice exists regarding the utilisation of e-cigarettes for smoking cessation. E-cigarettes may be inferior to standard care for smoking cessation in those with ASCVD, and their use is likely to promote the key drivers of the atherosclerotic process already active in this cohort.