SHORT-TERM HIGH WATTAGE E-CIGARETTE CESSATION IMPROVES CARDIORESPIRATORY OUTCOMES IN REGULAR USERS

Abstract

Objective: Tobacco smoking enhances cardiovascular (CV) risk in hypertensive patients. Whether smoking cessation by means of electronic-cigarette (e-cigarette) is advisable in such patients is unsettled. Propylene glycol (PG) and glycerol (GLY) are e-cigarette vehicles allowing liquid vaporization and nicotine transport. As PG/GLY are small hydrophilic-molecules that quickly cross the lung-epithelium, we emitted the hypothesis that e-cigarette vaping cessation for a short-time in regular-users allows a complete clearance of aerosol deposit from the lungs, with subsequent reversibility of vaping-induced cardiorespiratory toxicity we previously demonstrated. In order to verify our new hypothesis, we tested effects of short-time vaping cessation in regular e-cigarettes-users by means of clinical/biological cardiorespiratory-parameters evaluation. Furthermore, acute effects of e-cigarette with and without nicotine were assessed. Design and method: Thirty regular e-cigarettes-users were enrolled in this randomized investigator-blinded crossover three-periods study. The periods consisted of: 1-nicotine e-cigarettes vaping for 5-days before the experimental-session (nicotine-session); 2-nicotine free vaping for 5-days before the experimental-session (nicotine-free-session); and 3-complete cessation of e-cigarette vaping for 5-days before the experimental-session (stop-session). Baseline clinical/biological cardiorespiratory-parameters were assessed at the beginning of each of the 3 experimental-sessions. The participants were then invited to vape acutely: 1) ten nicotine-puffs (acute-nicotine-vaping in the nicotine-session); 2) ten nicotine-free-puffs (acute-nicotine-free-vaping in the nicotine-free-session); and 3) ten sham-puffs (acute-sham-vaping in the stop-session). Results: Serum measurements of PG and nicotine indicated that our participants respected the study-protocol. In comparison to the nicotine-session and the nicotine-free-session, baseline heart rate was lower (p < 0.001; Figure 1.A) and baseline serum club-cell-protein-16 concentration, an anti-inflammatory-lung-protein, was higher (p < 0.05; Figure 1.B) in the stop-session. Compared to acute-sham-vaping, acute-nicotine-vaping decreased skin oxygen tension (Figure 1.C), increased heart-rate (Figure 1.D) as well as systolic and diastolic blood pressure (Figure 1.E and F).Conclusions: In regular e-cigarette-users, short-time e-cigarette cessation improved lung outcomes. In addition, acute vaping with and without nicotine seemed to disturb transiently lung-gas-exchanges. Finally, as observed previously in naïve e-cigarette users, only vaping with nicotine altered hemodynamic-parameters. High-wattage e-cigarettes should be considered with caution in patient at CV risk until further data on their long-term lung toxicity become available.