Cardiovascular effects of electronic cigarettes and heated tobacco products: Clinical evidence from a narrative review

This review critically examines the cardiovascular (CV) implications of switching from combustible cigarettes (CCs) to combustion-free nicotine products, namely heated tobacco products (HTPs) and electronic cigarettes (e-cigarettes). Noncommunicable diseases, particularly cardiovascular disease (CVD), remain the leading global cause of mortality, with smoking as a major modifiable risk factor. While complete smoking cessation provides the greatest health benefit, many smokers transition to alternative nicotine delivery systems. Evidence from randomized trials, observational studies, and cohort analyses indicates that switching to HTPs or e-cigarettes significantly reduces exposure to harmful and potentially harmful constituents (HPHCs), including carbon monoxide (CO) and carcinogens, with biomarker improvements comparable to those observed after smoking cessation. Short-term studies suggest favorable changes in endothelial function, arterial stiffness, and oxidative stress, although nicotine-containing products may still exert acute CV effects. Long-term data, although limited, indicate a reduced incidence of major adverse cardiovascular events (MACEs) among exclusive users compared with continued smokers. However, heterogeneity in product design, usage patterns, and study methodologies limits the ability to draw definitive conclusions. Overall, current evidence suggests that non-combustible nicotine products may represent a harm reduction strategy for smokers who are unable or unwilling to quit, although they are not risk-free. Further large-scale, long-term studies with clinically relevant endpoints are required to clarify their CV safety profile and to inform evidence-based public health policies.