Cardiovascular effects of electronic cigarettes

Introduction:
This text provides an analysis of the potential adverse effects of electronic cigarettes (ECs) on cardiovascular health. The authors review the constituents, level of exposure to toxicants, and potential mechanisms of cardiovascular toxicity of ECs compared with tobacco cigarettes. They also summarize available human data on cardiovascular effects of ECs to assess likely cardiovascular harm and provide relevant advice for clinicians treating patients with cardiovascular disease (CVD) who are seeking to use ECs to aid in smoking cessation.

Key Points:

* EC devices generate a vapor or aerosol that delivers nicotine without combusting tobacco.
* ECs typically contain propylene glycol, vegetable glycerin, nicotine, and flavorings.
* ECs cannot be considered as a single device, and the exposure to nicotine and toxicants from one EC cannot be generalized across devices.
* The main constituents of e-liquid include propylene glycol and vegetable glycerin as the carrier solvents, nicotine, and flavorings. Low levels of contaminants might be present, either co-extracted with nicotine from tobacco or derived from the EC device.
* ECs generate both highly reactive, short-lived free radicals, and stable, long-lived free radicals, which are 100-fold to 1,000-fold lower than those generated by cigarette smoke.
* Particles generated by ECs are reported to have a bimodal size distribution, including both nanoparticles and submicron particles.
* Most e-liquids are flavored, and thousands of different flavors are currently available. Flavorings might contain alcohol, mixtures of terpenes and aldehydes, and known toxic chemicals such as diacetyl and benzaldehyde.
* Nicotine is unlikely to be a major contributor to cigarette-induced atherosclerosis, but it can contribute to acute cardiovascular events and mortality in the presence of ischaemic heart disease.

Main Message:
The text highlights the potential cardiovascular toxicity of ECs and emphasizes the need for further research to fully understand the health effects of EC use. While the risk of EC use is likely to be much less than that of cigarette smoking, the variability in EC devices, e-liquids, and use patterns makes it challenging to quantify the exposure to potentially toxic chemical emissions. Clinicians should be aware of the potential cardiovascular risks associated with EC use and provide appropriate advice to patients with CVD who are seeking to use ECs to aid in smoking cessation.

Benowitz, Neal L., and Joseph B. Fraiman. “Cardiovascular Effects of Electronic Cigarettes.” Nature Reviews Cardiology 14, no. 8 (august 2017): 447–56. https://doi.org/10.1038/nrcardio.2017.36.