Cigarette smoking is associated with endothelial dysfunction and increased arterial stiffness, key determinants of cardiovascular risk. This systematic review published in the European Journal of Preventive Cardiology assessed whether smoking cessation or switching to exclusive electronic cigarette (EC) use was associated with changes in vascular function in adult smokers, based on prospective clinical studies.

A comprehensive search of PubMed, Scopus, Web of Science, and Embase was conducted on October 13, 2025. Eligible studies included randomized controlled trials (RCTs), quasi-experimental studies, and prospective cohort studies reporting vascular outcomes, i.e., pulse wave velocity (PWV), augmentation index (AIx), and flow-mediated dilation (FMD) after smoking cessation or switching to ECs. Risk of bias was evaluated using Joanna Briggs Institute tools, and certainty of evidence was graded using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Results were synthesized qualitatively.

Twenty-three studies comprising 11,702 participants were included (14 cohort, 5 quasi-experimental, and 4 RCTs). Smoking cessation was consistently associated with improvements in PWV, AIx, and FMD, with some effects observed within one month and sustained up to 24 months. Certainty of evidence was very low overall, except for moderate certainty from RCTs assessing FMD. RCTs evaluating ECs reported significant improvements in FMD irrespective of nicotine content. Sensitivity analyses excluding lower-quality RCTs supported primary findings.

Smoking cessation was associated with early favorable changes in vascular markers. Certainty of evidence ranged from moderate to very low across outcomes.